WO2002055123A2

WO2002055123A2 - Implantable integral device and corresponding method for deflecting embolic material in blood flowing at an arterial bifurcation

Info

Publication number: WO2002055123A2
Application number: PCT/IL2002/000022
Authority: WO
Inventors: Ygael Grad; Nitzan Zafrir-Pachter; Abraham Rapaport; Boaz Nishri
Original assignee: Mindguard Ltd; Ygael Grad; Nitzan Zafrir-Pachter; Abraham Rapaport; Boaz Nishri
Priority date: 2001-01-11
Filing date: 2002-01-11
Publication date: 2002-07-18
Also published as: IL140869A0; WO2002055123A3; AU2002219493A1; EP1363573A2

Abstract

Implantable integral device (20) and corresponding method for deflecting embolic material in blood flowing (60) at an arterial bifurcation (52), featuring an expandable dual diameter coil element (21) having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of the coil element, and an expanded state having a second diameter greater than the first diameter, wherein a portion (27), of and integral with the coil element deflects the embolic material in the blood flowing toward a first branch (40) of the arterial bifurcation into a second branch (42) of the arterial bifurcation, while filtering the blood flowing toward the first branch of the arterial bifurcation. The portion (27) of the coil element (21) is a finely meshed zone functioning as a deflecting and filtering element, for deflecting the embolic material in the flowing blood while filtering the flowing blood.

Description

IMPLANTABLE INTEGRAL DEVICE AND CORRESPONDING METHOD FOR
DEFLECTING EMBOLIC MATERIAL IN BLOOD FLOWING AT AN ARTERIAL
BIFURCATION
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to implantable medical devices for deflecting embolic material in blood flowing through arteries, and, more particularly, to an implantable integral device and corresponding method for deflecting embolic material in blood flowing at an arterial bifurcation.

The implantable integral device, herein, also referred to as the deflecting device, featuring a unique expandable dual diameter coil element having a portion, herein, also referred to as a deflecting and filtering element, integral with the coil element, for deflecting the embolic material while filtering the blood flowing at the arterial bifurcation, reduces the risk of embolic material entering the internal carotid artery of a subject, and, reduces the risk of blood clots occurring in the subject. Herein, embolic material and blood clots are collectively and interchangeably referred to as'embolic material'.

A major portion of blood supplied to the brain hemispheres is by two major arteries in the neck, referred to as common carotid arteries (CCA), each of which branches off, or bifurcates, into an internal carotid artery (ICA), and, into an external carotid artery (ECA).

Blood to the brain stem is supplied by two vertebral arteries.

Stroke is a leading cause of disability, death, and health care expenditure. It is the second most common cause of death worldwide, exceeded only by heart disease, and is the third most common cause of death in the U. S., as described in Heart And Stroke Statistical
Update, Dallas, Tex., USA, American Heart Association, 2000.

Stroke is caused either by ischemia-infarction or intracranial hemorrhage.

Infarction constitutes 85 to 90 percent of the total group in western countries, as described by Sacco, R. L., Toni, D., and, Mohr, J. P., in Classification Of Ischemic Stroke, Stroke:
Pathophysiology, Diagnosis And Management, editors: Barnett, H. J. M., Mohr, J. P., Stein,
B. M., and, Yatsu, F. M., third edition, Churchill Livingstone, N. Y., USA, 1998,271-83.

The pathogenesis of ischemic stroke is complex with multiple potential mechanisms. The carotid plaque is only one source of stroke, accounting for no more than 15-20 % of cases, as described by Petty, G. W., Brown, Jr., R. D., Whisnant, J. P., Sicks, J. D., O'Fallon, W. M., and, Wiebers, D. O., in Ischemic Stroke Subrypes, A Population-based Study Of Incidence And Risk Factors, Stroke, 1999,30,2513-16. More frequently, infarcts are caused by more proximal sources of emboli, that is, the heart and the aortic arch. The commonest causes of cardioembolic stroke are nonrheumatic (often called nonvalvular) atrial fibrillation, prosthetic valves, rheumatic heart disease (RHD), congestive heart failure, and ischemic cardiomyopathy.

A recent population based study from Rochester, Minn., USA, found that the main identifiable subtype of ischemic stroke was cardioembolic with nearly 30 % of cases, while all large vessel cervical and intracranial atherosclerosis with stenosis altogether constituted about 16 %, as described by Petty et al., ibid. Further, often multiple mechanisms coexist, as described by Caplan, L. R., in Multiple Potential Risks For Stroke, JAMA 2000,283, 1479-80. Wilson, R. G. and Jamieson, D. G., in Coexistence Of Cardiac And Aortic Sources
Of Embolization And High-grade Stenosis And Occlusion Of The Internal Carotid Artery,
J. Stroke Cerebrovasc Dis., 2000,9,27-30, reviewed the experience of Petty et al. with patients who had high grade internal carotid artery stenosis or occlusion, and also had cardiac and aortic evaluation.

Potential cardiac or aortic sources of emboli were present in 54 % of patients; aortic arch plaques greater than 4 mm in diameter were found in 26 % of patients with severe internal carotid artery occlusive disease.'
Prevention is clearly the most cost-effective approach to decreasing the burden of stroke. Available strategies to prevent stroke include medical treatment, surgery (carotid endarterectomy), and carotid stenting.

Current medical treatments include antiplatelet drugs, such as aspirin, ticlopidine, clopidogrel, and dipyridamol, for presumed athreothrombotic origin. These treatments reduce the risk for recurrent ischemic event by no more than 15-20 %. Anticoagulants, such as Warfarin for non valvular atrial fibrillation, reduce the risk by 60 %, however, even in carefully conducted and monitored clinical trials, a substantial number of patients stopped anticoagulation, as described by Hart, R. G., Benavente, O., McBride, R., and,
Pearce, L. A., in Antit11lrombofic Therapy To Prevent Stroke In Patients With Atrial
Fibrillation : A Meta-analysis, Ann Intern Med., 1999,131,492-501.

Carotid endarterectomy was shown to be beneficial in selected cases of medium grade symptomatic, and also in asymptomatic carotid stenosis, by greater than 60 %, whenever complication rates are kept low, as described by Chassin, M. R., in Appropriate Use Of Carotid Endarterecto7-ny (editorial), N. Engl. J. Med., 12998,339,1468-71.

Nevertheless, a high proportion of recurrent stroke was not related to the large artery atherothrombotic disease, but to other causes including cardioembolism, as recently reported by the NASCET (North American Symptomatic Endarterectomy Trial) investigators, Barnett, H. J. M., Gunton, R. W., Eliasziw, M., et al., in Causes And Severity Of Ischemic Stroke In Patients With Internal Carotid Arfery Stenosis, JAMA, 2000,283, 1429-36. In fact, strokes related to cardioembolism tended to be more severe. The population of patients with carotid stenosis in'real life'often includes patients with severe cardiac disease, concomitant protruding aortic arch atheroma, atrial fibrillation, or congestive heart failure.

The proportion of patients with such concomitant disease increases substantially in an elderly population. Thus, the risk of recurrent cardioembolic stroke, even in patients operated for carotid stenosis, is estimated to be substantially higher, as described by Barnett, H. J. M., et al., ibid.

Carotid artery stenting has potential advantages of offering treatment to high risk patients with carotid stenosis, lowering peri-procedural risk, decreasing costs, and reducing patient inconvenience and discomfort. Preliminary results from clinical trials comparing carotid stenting to carotid endarterectomy have shown similar results, as described in
Major Ongoing Stroke Trials, Stroke, 2000,31,557-2.

The approach to prevention of such a multi factorial complex syndrome as stroke is necessarily multifaceted. Carotid angioplasty, with stenting by itself, does not address additional sources of emboli, even after successful reduction of local stenosis. More efficient endovascular approaches to stroke prevention needs to take into account this complexity in cerebrovascular disease. In this context, an intravascular implant that also addresses prevention of emboli from proximal sources can be a valuable addition in the arsenal of the practicing physician.

Introducing filtering means into blood vessels, particularly into veins, has been known for some time. However, filtering devices known in the art are designed for filtering blood flowing in the vena cava, and for stopping embolic material having a diameter of the order of centimeters, but, are unsuitable to deal with arterial embolic material, with which the present invention is concerned, especially in cases where the diameter of such material is typically of the order of down to microns. Furthermore, the flow of blood in the veins does not resemble arterial flow by its hemodynamic properties.

However, when considering the possible cerebral effects of even fine embolic material occluding an artery supplying blood to the brain, the consequences may cause irreversible brain damage, or, may even be fatal.

In light of the short period of time during which brain tissue can survive without blood supply, there is significant importance to providing suitable means for preventing even small sized embolic material from entering the internal carotid artery, so as to prevent brain damage, or, even death.

The size of the filaments that make up the deflecting and filtering element, and the
Porosity Index thereof, defined hereinafter, are major features of the deflecting device of the present invention, as explained herein, below. By contrast, in venous blood filters currently known in the art, no particular attention has been given to the size of the filaments. It is noted that embolic material in venous blood is made up of only blood clots, while in arterial blood, it is necessary to deal with emboli featuring different materials, such as blood clots and atherosclerotic plaque debris, etc.. Accordingly, in order to provide efficient filtering means, a blood deflecting and filtering element should be of fine mesh.

However, a fine mesh blood filter has a higher tendency toward occlusion.

It is also be noted that the flow ratio between the ICA and the ECA is about 3: 14: 1. This flow ratio indicates the significantly higher probability of embolic material flowing into the ICA rather than into the ECA. However, the ECA is a relatively non-hazardous artery because it supplies blood to superficial organs in the face and head, which are not life supporting and which receive blood supply from collateral blood vessels.

Therefore, embolic material reaching these organs does not cause substantial damage to a subject.

In two copending patent applications of the same applicant hereof, PCT/IL00/00145 and PCT/IL00/00147, the teachings of which are incorporated-by reference as if fully set forth herein, there are described implantable stroke preventing devices. Preferred embodiments of the device of the present invention feature improvements over those disclosed in the aforementioned copending patent applications, with respect to relative simplicity and reduced cost of manufacturing, and, in flexibility of internal positioning.

Manufacturing braided stents and prostheses is known in the art. For example, in the disclosures of WO 97/16133, EP 804909, EP 895761, and, WO 99/55256, the teachings of which are incorporated by reference as if fully set forth herein, there are described methods of manufacturing braided stents. Such braided stents present various advantages. However, they are all made for the purpose of preventing stenosis and for supporting blood vessels. The relatively large mesh sizes employed, and, the thickness and shape of the stent struts, make them unsuitable for use as a deflecting and filtering element for deflecting embolic material.

There is thus a need for, and it would be highly advantageous to have an implantable integral device (deflecting device) and corresponding method for deflecting embolic material in blood flowing at an arterial bifurcation, thereby reducing the risk of embolic material entering the internal carotid artery of a subject, and, reducing the risk of blood clots occurring in the subject.

SUMMARY OF THE INVENTION
The present invention relates to an implantable integral device and corresponding method for deflecting embolic material in blood flowing at an arterial bifurcation. The implantable integral device, referred to as the deflecting device, featuring a unique expandable dual diameter coil element having a portion, referred to as a deflecting and filtering element, integral with the coil element, for deflecting the embolic material while filtering the blood flowing at the arterial bifurcation, reduces the risk of embolic material entering the internal carotid artery of a subject, and, reduces the risk of blood clots occurring in the subject.

It is thus an object of the present invention to provide an implantable integral device for deflecting embolic material in blood flowing at an arterial bifurcation, which is suitable for positioning within a blood vessel supplying blood to the brain, and further suitable to deflect embolic material that would have flowed into the internal carotid artery, to flow into the external carotid artery, thereby preventing entry of the embolic material into the internal carotid artery, thus, preventing extracranial embolus to occlude small intercranial arteries in the brain.

It is another object of the present invention to provide a method for treating a subject suffering from embolic disease or another condition associated with embolic material, or, aneurysms, by selectively occluding passage of embolic material into the internal carotid artery. It is another object of the invention to provide a method for preventing conditions associated with embolic material. It is another object of the present invention to provide a method of manufacturing the deflecting device of the present invention. Other objects of the invention are apparent throughout the following description.

The implantable integral device, or, deflecting device, of the present invention, featuring an expandable dual diameter coil element having a portion integral with the coil element, for deflecting the embolic material, while filtering the blood flowing at the arterial bifurcation, functions as an intravascular carotid artery stent-like device, designed especially to prevent anterior circulation strokes occurring due to proximal sources of embolic material.

In a first aspect of the present invention, the implantable integral device is positioned in the vicinity of an arterial bifurcation for causing embolic material in blood flowing toward a first branch of the bifurcation to be deflected into a second branch of the same bifurcation, by way of an integral part, such as a deflecting and filtering element, suitable to deflect the embolic material to the blood flowing toward the second branch, while filtering the blood flowing toward the first branch. The deflecting device features a coiled sheet portion having a contracted state with a first diameter, in which at least partial overlap of two opposing ends of the deflecting device exists, and an expanded state having a second diameter greater than the first diameter.

According to a preferred embodiment of the present invention, the implantable integral device is designed for positioning in the vicinity of a bifurcation of an artery leading to, or located in, the common carotid artery (CCA) on the one hand, and leading to a non-vital artery on the other hand, featuring a deflecting and filtering element suitable to deflect the embolic material in blood flowing toward the CCA, into the non-vital artery, while filtering blood flowing toward the CCA. The deflecting device features a coiled sheet portion having a contracted state with a first diameter in which at least partial overlap of two opposing ends of the deflecting device exists, and an expanded state having a second diameter greater than the first diameter.

In a preferred embodiment of the deflecting device according to the present invention, a portion, referred to as a deflecting and filtering element, integral with the coil element of the deflecting device, has openings, preferably, in a range of between about 100 um to about 700 urn, and, more preferably, in a range of between about 100 urn to about 400 um. In an open or expanded state, the deflecting device has a diameter, preferably, in a range of between about 5 mm to about 35 mm, and, more preferably, in a range of between about 5 mm to about 30 mm, and, in a closed or contracted state, a diameter, preferably, in a range of between about 1 mm to about 4 mm, and, more preferably, in a range of between about 1 mm to about 3 mm.

Different geometrical shapes, configurations, and, sizes, of wires can be used for constructing the deflecting device and elements thereof. According to a preferred embodiment of the present invention, the wires constituting the coil element body of the deflecting device have a cylindrical configuration with a circular cross-section diameter, preferably, in a range of between about 100 um to about 1500 um, and, more preferably, in a range of between about 100 um to about 200 um, while the wires of the deflecting and filtering element have a diameter, preferably, in a range of between about 20 um to about 75 um, and, more preferably, in a range of between about 20 gm to about 40 um.

According to other embodiments of the present invention, the cross-section of the wires can have other geometrical shapes and configurations, for example, elliptical, square, or, rectangular.

The deflecting device of the invention can be made of any suitable material. For instance, the filaments can be made of a material selected from among 316L stainless steel, superelastic Nitinol, ElgiloyTM, and mixtures of different metals and alloys.

In another aspect, the present invention includes a method for preventing embolic material flowing in blood toward a first branch of an arterial bifurcation from entering into the first branch, comprising implanting upstream to the bifurcation a deflecting and filtering element suitable to deflect the embolic material flowing in the blood to a second branch. The deflecting device features a coiled sheet portion having a contracted state with a first diameter, in which at least partial overlap of two opposing ends of the deflecting device exists, and, an expanded state having a second diameter greater than the first diameter.

According to a preferred embodiment of the present invention, the method is for preventing the embolic material in blood flowing in the CCA from accessing the ICA, comprising implanting in the vicinity of a bifurcation of an artery leading to, or located in, the common carotid artery (CCA) on the one hand, and leading to a non-vital artery on the other hand, a deflecting and filtering element suitable to deflect the embolic material in the blood flowing toward the CCA, into the non-vital artery, while filtering the blood flowing toward the CCA. The deflecting device comprises a coiled sheet portion having a contracted state with a first diameter, in which at least partial overlap of two opposing ends of the deflecting device exists, and an expanded state having a second diameter greater than the first diameter.

According to a preferred embodiment of the present invention, the deflecting and filtering element is implanted in the vicinity of the bifurcation of the common carotid artery (CCA) into the internal carotid artery (ICA) and the external carotid artery (ECA).

The present invention further includes a method for preventing cerebralvascular diseases or their recurrence, comprising implanting in the vicinity of a bifurcation of an artery leading to, or located in, the common carotid artery (CCA) on the one hand, and leading to a non-vital artery on the other hand, a deflecting and filtering element suitable to deflect embolic material in blood flowing toward the CCA, into the non-vital artery, while filtering the blood flowing toward the CCA, the deflecting device featuring a coiled sheet portion having a contracted state with a first diameter, in which at least partial overlap of two opposing ends of the device exists, and, an expanded state having a second diameter greater than the first diameter.

In one particular embodiment, the deflecting and filtering element is implanted in the vicinity of the bifurcation of the common carotid artery (CCA) into the internal carotid artery (ICA) and the external carotid artery (ECA).

For instance, the deflecting and filtering element can be positioned in the carotid bifurcation, its proximal end in the common carotid artery (CCA) and the distal end in the external carotid artery, thus, functioning by filtering blood at the ICA orifice and by deflecting embolic material particles to the external carotid artery (ECA) territory. Another possible location is the brachiocephalic bifurcation, deflecting embolic material particles to the right subclavian artery (the right hand), for preventing access to the right CCA.

The deflecting device may be combined with a conventional stent, for example, for the treatment of bifurcation lesions, where a stent is positioned in the side branch and the deflecting device in the main branch, wherein the conventional stent is deployed at the internal carotid artery and addresses local stenosis. The insertion and deployment techniques are similar to those employed in connection with a conventional stent. Bilateral procedures can be performed during the same session without increased risk, thus enabling deployment of bilateral carotid divertors. Moreover, the deflecting and filtering element of the deflecting device is similarly effective in deflecting embolic material above a certain size, irrespective of the composition of the embolic material.

Given that embolic matter may be composed of thrombotic material, platelet-fibrin particles, cholesterol, atheroma, or, calcified particles, such a mechanical diversion or deflection has an inherent advantage of being general to any embolic composition.

In a further aspect, the present invention is directed to the prevention of the occurrence, or, the recurrence, of cerebralvascular diseases, particularly of stroke, comprising preventing embolic material in blood flowing in the CCA from accessing the
ICA, by deflecting the embolic material into blood flowing into the ECA. Prevention of the cerebralvascular disease is achieved by implanting, permanently, in the vicinity of the bifurcation of the common carotid artery (CCA) into the internal carotid artery (ICA) and the external carotid artery (ECA), a deflecting device including an integral part, such as a deflecting and filtering element, according to the present invention.

It is emphasized, that while throughout this specification particular reference is made to the bifurcation of the CCA into the ICA, this is done for the sake of brevity only, whereby the invention is in no way limited to this specific location. The invention can be advantageously implemented at any other suitable bifurcation of blood vessels as existing, for instance, in the leg.

Thus, according to the present invention, there is provided an implantable integral device for deflecting embolic material in blood flowing at an arterial bifurcation, comprising an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of the coil element, and an expanded state having a second diameter greater than the first diameter, wherein a portion of and integral with the coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation, while filtering the blood flowing toward the first branch of the arterial bifurcation.

According to another aspect of the present invention, there is provided a method for deflecting embolic material in blood flowing at an arterial bifurcation, comprising the steps of : (a) providing an implantable integral device featuring an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of the coil element, and an expanded state having a second diameter greater than the first diameter, wherein a portion of and integral with the coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation, while filtering the blood flowing toward the first branch of the arterial bifurcation;

and (b) implanting and deploying in a vicinity of the arterial bifurcation the implantable integral device.

According to another aspect of the present invention, there is provided a use of an implantable integral device in the manufacture of a medical device for deflecting embolic material in blood flowing at an arterial bifurcation, for preventing the occurrence of a condition associated with the embolic material in a subject, comprising implanting and deploying the implantable integral device at an arterial bifurcation of the subject, the implantable integral device comprising an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of the coil element, and an expanded state having a second diameter greater than the first diameter,

wherein a portion of and integral with the coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation, while filtering the blood flowing toward the first branch of the arterial bifurcation of the subject.

According to another aspect of the present invention, there is provided a use of an implantable integral device in the manufacture of a medical device for deflecting embolic material in blood flowing at an arterial bifurcation, for treating a subject with a condition associated with the embolic material, comprising implanting and deploying the implantable integral device at an arterial bifurcation of the subject, the implantable integral device comprising an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of the coil element, and an expanded state having a second diameter greater than the first diameter,

According to another aspect of the present invention, there is provided a method for deflecting embolic material in blood flowing at an arterial bifurcation, for preventing the occurrence of a condition associated with the embolic material in a subject, comprising the steps of :

(a) providing an implantable integral device featuring an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of the coil element, and an expanded state having a second diameter greater than the first diameter, wherein a portion of and integral with the coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation, while filtering the blood flowing toward the first branch of the arterial bifurcation; and (b) implanting and deploying in a vicinity of the arterial bifurcation of the subject the implantable integral device.

According to another aspect of the present invention, there is provided a method for deflecting embolic material in blood flowing at an arterial bifurcation, for treating the occurrence of a condition associated with the embolic material in a subject, comprising the steps of (a) providing an implantable integral device featuring an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of the coil element, and an expanded state having a second diameter greater than the first diameter, wherein a portion of and integral with the coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation,

while filtering the blood flowing toward the first branch of the arterial bifurcation; and (b) implanting and deploying in a vicinity of the arterial bifurcation of the subject the implantable integral device.

The present invention successfully overcomes shortcomings and limitations of presently known stent, blood filtering, and, embolic material diverting, devices and techniques, for preventing stroke due to entry of embolic material into the internal carotid artery of a subject. The above, and other, characteristics, features, and, advantages, of the present invention, are better understood through the following illustrative and non-limiting detailed description of preferred embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

In the drawings:
Fig. 1A is a schematic diagram illustrating a sheet of perforated material used for constructing a first exemplary preferred embodiment of the expandable dual diameter coil element of the implantable integral deflecting device, in accordance with the present invention;
Fig. 1B is a schematic diagram illustrating an outer essentially rigid frame surrounding the perimeter of a meshed structure used for constructing a second exemplary preferred embodiment of the expandable dual diameter coil element of the implantable integral deflecting device, in accordance with the present invention;

Fig. 2A is a schematic diagram illustrating a perspective view of the first exemplary preferred embodiment of the implantable integral deflecting device, constructed from the expandable dual diameter coil element as a sheet of perforated material of Fig. 1A, in accordance with the present invention;
Fig. 2B is a schematic diagram illustrating a perspective view of the second exemplary preferred embodiment of the implantable integral deflecting device, constructed from the expandable dual diameter coil element as a rigid frame surrounding the perimeter of a meshed structure of Fig. 1B, in accordance with the present invention;

Fig. 3A is a schematic diagram illustrating a cross section view of the exemplary preferred embodiment of the deflecting device of Fig. 2A or Fig. 2B, in a closed, compressed, form, or, contracted state, prior to deployment, in accordance with the present invention;
Fig. 3B is a schematic diagram illustrating a cross section view of the exemplary preferred embodiment of the deflecting device of Fig. 2A or Fig. 2B, in an open, or, expanded state, in a first operative position of deployment, in accordance with the present invention;
Fig. 3C is a schematic diagram illustrating a cross section view of the exemplary preferred embodiment of the deflecting device of Fig. 2A or Fig. 2B, in an open, or, expanded state, in a second operative position of deployment, in accordance with the present invention;

Fig. 4A is a schematic diagram illustrating a side view of the exemplary preferred embodiment of the deflecting device of Fig. 2A or Fig. 2B, in a closed position, or, contracted state, on its way to reach an arterial bifurcation, prior to expansion into an artery, during inserting and positioning as part of a method for deployment, in accordance with the present invention;
Fig. 4B is a schematic diagram illustrating a side view of the exemplary preferred embodiment of the deflecting device of Fig. 2A or Fig. 2B, in a partially open position, or, partially expanded state, during expansion and positioning into an arterial bifurcation, during inserting and positioning as part of a method of deployment, in accordance with the present invention;

Fig. 4C is a schematic diagram illustrating a side view of the exemplary preferred embodiment of the deflecting device of Fig. 2A or Fig. 2B, in a fully open position, or, fully expanded state, following expansion and positioning into an arterial bifurcation, with deploying equipment free to be withdrawn as part of a method of deployment, in accordance with the present invention;
Fig. SA is a schematic diagram illustrating a side view of the exemplary preferred embodiment of the deflecting device of Fig. 2A or Fig. 2B, located at a bifurcation of the carotid artery, in accordance with the present invention; and
Fig. 5B is a schematic diagram illustrating a cross section view of the deflecting device and the carotid artery, corresponding to the A-A plane in the side view of Fig. 5A, in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention relates to an implantable integral device and corresponding method for deflecting embolic material in blood flowing at an arterial bifurcation. The implantable integral device, herein, referred to as the deflecting device, featuring a unique expandable dual diameter coil element having a portion, herein, referred to as a deflecting and filtering element, integral with the coil element, for deflecting the embolic material while filtering the blood flowing at the arterial bifurcation, reduces the risk of embolic material entering the internal carotid artery of a subject, and, reduces the risk of blood clots occurring in the subject. Herein, embolic material and blood clots are collectively and interchangeably referred to as'embolic material'.

The unique expandable dual diameter coil element of the implantable integral device of the present invention has a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of the coil element, and an expanded state having a second diameter greater than the first diameter, wherein a portion, that is, a deflecting and filtering element, integral with the coil element, deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation, while filtering the blood flowing toward the first branch.

It is to be understood that the invention is not limited in its application to the details of construction, arrangement, and, composition, of the components and elements of the implantable expandable stroke preventing device, or, to the details of the order or sequence of steps of operation or implementation of the method of manufacturing thereof, set forth in the following description, drawings, or examples. For example, the following description refers to preferred geometrical shapes, configurations, and, sizes, of the implantable integral device, and, elements and components thereof, such as the expandable dual diameter coil element and the deflecting and filtering element integral to the coil element, in order to illustrate implementation of the present invention.

In particular, for example, the deflecting and filtering element may be of different sizes, shapes, and, patterns, depending on specific flow parameters and/or requirements of a subject. Accordingly, the invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

The implantable integral device and corresponding method for deflecting embolic material in blood flowing at an arterial bifurcation, of the present invention, are herein disclosed for the first time, and are neither anticipated or obviously derived from the disclosures, PCT/ILOO/00145 and PCT/IL00/00147, of the same applicant hereof.

The implantable integral device and corresponding method for deflecting embolic material in blood flowing at an arterial bifurcation, according to the present invention, are better understood with reference to the following description and accompanying drawings.

Throughout the following description and accompanying drawings, like reference numbers refer to like elements.

Referring now to the drawings, Fig. 2A is a schematic diagram illustrating a perspective view of the first exemplary preferred embodiment of the implantable integral deflecting device of the present invention, herein, for brevity, generally referred to as deflecting device 20, constructed from an expandable dual diameter coil element 21, herein, for brevity, generally referred to as coil element 21, as a sheet of perforated material. For illustrative purposes, detailed structure of deflecting device 20, and, elements and components thereof, such as coil element 21, are not shown to scale.

In Fig. 2A, a portion 27 of and integral with the perforated sheet material as expandable dual diameter coil element 21, is structured and functions as a deflecting and filtering element, herein, generally referred to as deflecting and filtering element 27, as will be further explained with reference to Fig. 1A. In the first exemplary preferred embodiment of deflecting device 20 illustrated in Fig. 2A, expandable dual diameter coil element 21, is structured as a base plate, of sheet material with perforations or apertures 22.

Edges 23 of coil element 21 may be smoothed to remove edge effects, resulting in a gradually recessed inflowing portion. The sheet material of coil element 21 is coiled into a construction in which there is overlap between one end 24, and the other end 25, of the sheet material, and, therefore, of coil element 21. In this embodiment, as seen in Fig. 2A, end portion 24 is visible through aperture 26 in end portion 25. This embodiment is further illustrated in Fig. 3B, which is a cross-section view of Fig. 2A, taken along the A-A plane.

Fig. 1A is a schematic diagram illustrating a sheet of perforated material used for constructing the first exemplary preferred embodiment of expandable dual diameter coil element 21 of deflecting device 20 illustrated in Fig. 2A. Coil element 21 is provided with a plurality of perforations or apertures 22. Perforations or apertures 22 are provided in order to permit growth of cells from the arterial walls onto the surface of coil element 21 of deflecting device 20, so as to incorporate deflecting device 20 therewith and to prevent pathological damage to the arterial walls.

Fig,. 1B is a schematic diagram illustrating an outer essentially rigid frame 30 surrounding the perimeter of a meshed structure used for constructing a second exemplary preferred embodiment of expandable dual diameter coil element 21 of deflecting device 20 illustrated in Fig. 2B. The meshed structure and its mesh dimensions may be of any suitable type, shape and sizes, for example, as used in conventional coronary stents.

In a preferred embodiment of the present invention, meshed structure of coil element 21 of Fig. 1B is made of braided material. The technique of flat braiding is well known in the art and is not described here. In another embodiment of the invention, it is possible to construct deflecting device 20 from a sheet of braided material. In this case, the flat braid is coiled into a deflecting device similar to that shown in Fig. 2B. In yet another embodiment of the present invention, the flat braid is manufactured from a shaped memory alloy, which can be formed into a cylindrical shape and processed to retain the desired shape.

In deflecting device 20, a portion 27 of and integral with coil element 21, for coil element 21 as a perforated sheet material (Figs. lA and 2A) or as a rigidly framed mesh structure (Figs. 1B and 2B), is either replaced by, or supplemented with, a substantially equivalently sized portion of a finely meshed zone, herein, generally referred to as deflecting and filtering element 27, the physical requirements from which will be further described below. This finely meshed zone is the zone that, when deflecting device 20 is coiled and introduced into an artery, is positioned in front of aperture 54 of junction 52 (Fig. 5A), and thus forms deflecting and filtering element 27.

Actual shape, size, and, dimensions, of deflecting and filtering element 27 as a finely meshed zone is such that deflecting and filtering element 27 covers an entire inlet of an aperture of an arterial junction, in general, and, such that it covers the entire aperture or inlet 54 to internal carotid artery (ICA) 40 of carotid arterial bifurcation zone 52 (Fig. 5A), in particular.

Preferably, portion or deflecting and filtering element 27, of and integral with coil element 21, of deflecting device 20, has mesh size openings, preferably, in a range of between about 100 um to about 700 u, m, and, more preferably, in a range of between about 100 um to about 400 um, in order to effectively prevent an undesirable amount of dangerous embolic material flowing in the blood, from entering the internal carotid artery (ICA 40, Fig. SA) in the region of an arterial bifurcation (arterial bifurcation zone 52, Fig.

5A). In general, in deflecting device 20, the open area of perforations or apertures 22 of the perforated sheet material as the first exemplary preferred embodiment of coil element 21 (Figs. 1A and 2A), and, the open area or mesh size of the meshed structure of the second exemplary preferred embodiment of coil element 21 (Figs. 1B and 2B), are significantly larger than the mesh size openings of deflecting and filtering element 27 of coil element 21 required for deflecting the embolic material in blood flowing at the arterial bifurcation.

Deflecting device 20 is made of a material having an elasticity suitable for expanding from a contracted position in which it is deployed through the vasculator of a subject for preventing and/or treating a condition associated with embolic material in blood flowing at an arterial bifurcation, and expanded by means well known in the art, as will be further explained hereinafter with reference to Figs. 4A through 4C.

Deflecting device 20 is schematically shown in the coiled position in which it is deployed, in Fig. 3A. In the situation depicted in Fig. 3A, dual diameter coil element 21 of deflecting device 20 is fully coiled or contracted, so that its total'coiled', or, first, diameter is substantially smaller than the total'expanded', or, second, diameter of dual diameter coil element 21 of deflecting device 20 in an expanded position. In the coiled or contracted position, end portions 24 and 25 do not necessarily need to be close to one another, and may be far apart, as shown in Fig. 3A.

Fig. 3B is a schematic diagram illustrating a cross section view of the exemplary preferred embodiment of deflecting device 21 of Fig. 2A or Fig. 2B, in an open, or, expanded state, in a first operative position of deployment. In this open, or, expanded, first operative position, opposing end portions 24 and 25 of coil element 21 partially overlap.

Fig. 3C illustrates a preferred embodiment of the present invention in which the diameter of a blood vessel (for example, common carotid artery 38, as shown in Fig. 5A) where deflecting device 20 is to be positioned is greater than the diameter of deflecting device 20 in a fully expanded state. In this situation, end portions 24 and 25 of deflecting device 20 do not overlap at all, and a gap 29 is formed between them. This situation is permissible, as long as gap 29 lies against a wall of a blood vessel in which it is placed, and not against an opening to another blood vessel.

This further illustrates the flexibility of expandable dual diameter coil element 21 of deflecting device 20 of the present invention, whereby deflecting device 20 can be used in conjunction with various blood vessel diameters, by automatically self-adjusting to unpredictable situations during deployment.

Deployment of deflecting device 20 in this manner is preferred because the double wall resulting from overlapping of ends portions 24 and 25 of coil element 21 of deflecting device 20, which would otherwise reduce blood flow, is absent, thereby, reducing stenosis.

Radio opaque markers 28 (for example, as shown in Figs. 1A and 1B, in Figs. 2A and 2B, and, in Figs. 4A, 4B, and, 4C) are preferably provided and located at strategic positions, for example, on the perimeter, of coil element 21, which serve to aid a physician in the proper positioning of deflecting device 20 within an artery, especially within the region or vicinity of an arterial bifurcation in a subject having a condition associated with embolic material. Markers 28 are visible under radiographic equipment. Other markers can also be provided, according to known teachings in the art. For instance, markers 28 can be gold points that may be used to position coil element 21 of deflecting device 20 also with respect to rotation around a longitudinal axis of deflecting device 20.

Preferably, deflecting device 20 has an essentially cylindrical shape with its body, that is, coil element 21, generally serving as an anchoring portion. An anchoring portion is a portion of deflecting device 20 that firmly contacts inner walls of an artery, in general, and inner walls of the external carotid artery at the common carotid arterial bifurcation, in particular. Such contact causes a growth of arterial wall into the net-like configuration of coil element 21 of deflecting device 20, and strongly anchors deflecting device 20 to an artery, thus preventing accidental displacement of deflecting device 20. The physiological processes leading to such anchoring are well known in the art, and are therefore not discussed herein in detail, for the sake of brevity.

Introduction, insertion, and, deployment, of deflecting device 20 and elements thereof, including coil element 21, and, deflecting and filtering element 27, of the present invention are illustrated in Figs. 4A-4C. As known to a person having ordinary skill in the art, employing a self-expandable stroke preventing device is more convenient in many cases, because of normally significant mobility of the neck of a subject. This self-expandable feature and property provides for better anchoring of deflecting device 20 in the region of a bifurcation zone at an arterial junction of a subject.

Fig. 4A shows deflecting device 20 in its folded position or contracted state, Fig.

4B shows deflecting device 20 during the first stage of expansion, and, Fig. 4C shows deflecting device 20 in a fully expanded state. Deflecting device 20 is supported on a guide wire 112, which is used to introduce and guide deflecting device 20 to a pre-determined or desired location, preferably, an arterial bifurcation, in a subject. In the folded position or contracted state, deflecting device 20 is covered with a covering envelope 113, which is preferably made of polymeric material, for keeping deflecting device 20 in the folded or contracted state. Envelope 113 is connected to a retraction ring 114, which is pulled away from deflecting device 20 by a mechanism (not shown), but, well known in the art of stent deployment.

Referring now to Fig. 4B, when ring 114 is pulled away in the direction of the drawn arrow, envelope 113 is pulled away with it, uncovering a portion 115 of deflecting device 20. Since envelope 113 no longer constrains portion 115 to remain in the folded or contracted state, and, since the normal, operating, position of deflecting device 20 is expanded, portion 115 starts expanding to its normally operative, expanded state. This process is completed in Fig. 4C, when envelope 113 has been completely removed and deflecting device 20 is in its fully expanded position or state.

In the normally operative, expanded state, for example, as illustrated in Fig. 4C, radially directional elastic forces of the expandable property of expandable dual diameter coil element 21 (Figs. 1A, 1B, 2A, 2B, 3A, and, 3B), operate to keep coil element 21 and therefore, deflecting device 20, expanded, whereby, anchoring of deflecting device 20 in its location is less susceptible to undesired displacement as compared to deployment of balloon expanded stents. Following completion and positioning of deflecting device 20, guide wire 112 is withdrawn from the subject, as in any other similar stent deployment procedure.

Other methods of deploying deflecting device 20 of the present invention are well known to a person having ordinary skill in the art. As another example, envelope 113 (Figs. 4A and 4B) could be constructed by sewing a sleeve (not shown) using an open stitch. After positioning deflecting device 20 in the proper location, the end of such a thread, of which the sleeve is sewn, is pulled back fraying the material and allowing deflecting device 20 to expand, as shown in Fig. 4C.

Fig. 5A illustrates a carotid artery portion, generally designated 36, in which the common carotid artery (CCA) is designated 38, the internal carotid artery (ICA) is designated 40, and, the external carotid artery (ECA) is designated 42. Blood (without a reference number) flowing throughout carotid artery portion 36 is indicated in Fig. 5A by the space between all other designated arteries and deflecting device elements and components.

Deflecting device 20 is positioned within arterial bifurcation zone 52, with deflecting and filtering element 27 extending opposite inlet 54 of ICA 40. Coil element 21, functioning as an anchoring or base plate of deflecting device 20 anchors against respective inner walls of common carotid artery 38 and of external carotid artery 42, respectively, with deflecting and filtering element 27 extending across inlet 54 of internal carotid artery 40.

In this position, embolic material, which is schematically illustrated as particles in blood flowing along flow lines 60 in Fig. 5A, flows or moves with the flowing blood into common carotid artery 38, and, upon contacting deflecting and filtering element 27, as a result of the fluid motion of the blood, for example, characterized by a range of the well known fluid mechanics parameter, the Reynolds number, Re, in particular, for a Reynolds number in the range of between about 200 and about 500, the embolic material particles are prevented from entering ICA 40, because the size of the particles is larger than the mesh size of deflecting and filtering element 27, whereby, the embolic material particles are thus deflected into external carotid artery 42 of arterial bifurcation zone 52.

Fig. 5B is a cross-section view taken along the A-A plane of Fig. 5A. Referring to
Figs. 5A and 5B, the gap 29 that results because the diameter of common carotid artery 38 is greater than the diameter, that is, the second diameter of coil element 21, of the fully expanded deflecting device 20 is clearly shown. This situation was previously discussed above with reference to Fig. 3C.

The importance of radio opaque markers 28 (Figs. 1, 2, and, 4 ; not shown in Fig. 5B) in the proper positioning of deflecting device 20 is clearly apparent here, since, for instance, if at least part of gap 29, faces inlet 54 of internal carotid artery 40 rather than wall 52 of external carotid artery 42, proper intended functionality of deflecting device 20 would be significantly limited.

As will be apparent to a person having ordinary skill in the art, expandable dual diameter coil element 21, and, therefore, deflecting device 20, of the present invention does not necessarily need to be self-expandable, whereby, coil element 21 of deflecting device 20 can be made of a non-self-expandable perforated sheet material (Figs. 1A and 2A), or, of a meshed structure (Figs. 1B and 2B), that is expandable under pressure supplied by a mechanism, such as by an implantable balloon, separate from, but, operative with, coil element 21, in particular, and, deflecting device 20, in general.

In this case, deployment of deflecting device 20 is carried out as for conventional stents, by placing deflecting device 20 in a coiled position or contracted state around an expandable balloon, following by expanding the balloon under pressure when deflecting device 20 reaches the desired location. This is a conventional procedure and is, therefore, not illustrated in the figures, for the sake of brevity.

Deflecting device 20 of the present invention can be constructed in a way very similar to conventional stents. A person having ordinary skill in the art is knowledgeable of the various materials and methods suitable to make deflecting device 20 of the present invention. For instance, deflecting device 20 can be made of a material selected from the group consisting of nitinol, polymeric material, stainless steel, and, combinations thereof.

Deflecting device 20 in the coiled position or contracted state can also be provided in a manner known to a person having ordinary skill in the art, for example, in a manner similar to that described in detail in PCT publication WO 99/48441, the contents of which are incorporated herein by reference, or, in any other suitable way.

Expandable dual diameter coil element 21 of deflecting device 20 of the present invention, can also be constructed using well known techniques of photochemical engraving, or, another etching process.

Preferably, portion 27, that is, deflecting and filtering element 27, of and integral with coil element 21, of deflecting device 20, has openings, preferably, in a range of between about 100 um to about 700 um, and, more preferably, in a range of between about 100 um to about 400 pm, in order to effectively prevent an undesirable amount of dangerous embolic material flowing in the blood, from entering the internal carotid artery (ICA 40, Fig. 5A) in the region of an arterial bifurcation (arterial bifurcation zone 52, Fig.

5A). The diameters of expandable dual diameter coil element, and therefore, of deflecting device 20 may somewhat vary, according to actual conditions associated with embolic material, of different subjects. Preferably, the first diameter of coil element 21 of deflecting device 20 in the coiled position or contracted state varies, preferably, in a range of between about 1 mm to about 4 mm, and, more preferably, in a range of between about 1 mm to about 3 mm, and, the second diameter of coil element 21 of deflecting device 20 in the open position or expanded state varies, preferably, in a range of between about 5 mm to about 35 mm, and, more preferably, in a range of between about 5 mm to about 30 mm.

Thickness and diameter of wire making up the body or coil element 21 of deflecting device 20 is preferably, in a range of between about 100 um to about 1500 um, and, more preferably, in a range of between about 100 um to about 200 pm, while that of wire used for constructing deflecting and filtering element 27 is preferably, in a range of between about 20 um to about 75 um, and, more preferably, in a range of between about 20 pm to about 40 um.

Of course, entire coil element 21, and, therefore, entire deflecting device 20, can also be constructed using wire of the same dimensions as that of deflecting and filtering element 27, whereby there would be no difference in mesh size between the body, that is, coil element 21, of deflecting device 20 and deflecting and filtering element 27, in which case, a strengthening mechanism, for example, ribs, may be required for proper performance during normal operation for treating a subject
Deflecting and filtering element 27 of deflecting device 20 of the present invention preferably fulfills certain pre-determined conditions, several of which are described herein below.

Various types of deflecting and filtering element 27, featuring different geometrical shapes, configurations, sizes, and, exhibiting desirable properties, may be constructed for fulfilling the following described conditions.

When testing deflecting device 20 of the present invention under physiological conditions in the carotid region of a subject, namely: Reav = 200-500,
BPM (heart beats per minute) = 40-180,
Womersley = 2-7, wherein Reav is the average Reynolds number of the blood flowing at an arterial bifurcation of the carotid region, and, Womersley is the dimensionless heart beat parameter, the following conditions should preferably be met by deflecting and filtering element 27, of coil element 21 of deflecting device 20 of the present invention:

(1) Reprox is, preferably, in a range of between about 0.3 to about 30, and, more preferably, in a range of between 0 and about 4, and, is also, preferably, equal to or less than 1, in accordance with creeping or Stokes'flow, and, (2) Shear Stress is in a range of between less than about 100 dyne/cm2 and greater than about 2 dyne/cm2, wherein Reprox is the Reynolds number for a single wire of which deflecting and filtering element 27 is made, and, the shear stress is measured at deflecting device 20. As known to a person having ordinary skill in the art, the smaller Reprox is, the better the performance of deflecting device 20.

However, deflecting device 20 may also operate at larger values of
Reprox than indicated above, whereby, the present invention is by no means limited to any specific value of Reprox
Deflecting device 20 according to the present invention is useful in a variety of cases. Some illustrative indications are listed below: (1) Embolic strokes from proximal sources. These are: - Atrial fibrillation (2.5 million in the U. S. A. in 1999) ; - Mechanical heart valve (225,000 procedures performed annually in the
U. S.); - Subjects at high risk for recurrent embolism for a certain period (S. B. E.); - Subjects at high risk for proximal emboli and absolute contraindications for anticoagulation; - Subjects at high risk for proximal emboli failing best medical treatment.

(2) In cases in where carotid stents are introduced to treat local stenosis, it is possible to introduce and deploy the deflecting device of the present invention during the same procedure if there are concomitant high risk proximal sources of emboli. These are, for instance: -Protruding Aortic arch atheroma (more than 1/3 of symptomatic subjects); - Severe carotid stenosis with concomitant cardiac disease; - Severe carotid stenosis in subjects undergoing heart surgery (5 % on the statistical basis of 600,000 coronary bypass surgeries).

All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

While the invention has been described in conjunction with specific embodiments and examples thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

Claims

WHAT IS CLAIMED IS: 1. An implantable integral device for deflecting embolic material in blood flowing at an arterial bifurcation, comprising an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of said coil element, and an expanded state having a second diameter greater than said first diameter, wherein a portion of and integral with said coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation, while filtering the blood flowing toward said first branch of the arterial bifurcation.

2. The device of claim 1, whereby said coil element is of a type selected from the group consisting of self-expandable, and, non-self-expandable, at the arterial bifurcation.

3. The device of claim 1, whereby said coil element is self-expandable at the arterial bifurcation.

4. The device of claim 1, whereby said coil element is expandable under pressure supplied by a mechanism operative at the arterial bifurcation.

5. The device of claim 1, whereby said coil element is expandable under pressure supplied by a mechanism separate from and operative with said coil element, at the arterial bifurcation.

6. The device of claim 1, whereby there is also said at least partial overlap of said two opposing ends of said coil element in said expanded state.

7. The device of claim 1, whereby there is no said at least partial overlap of said two opposing ends of said coil element in said expanded state, whereby a gap is formed between said two opposing ends of said coil element.

8. The device of claim 1, whereby said coil element is a perforated sheet material.

9. The device of claim 8, whereby said perforated sheet material features a plurality of perforations or apertures for permitting growth of cells from arterial walls onto surface of said coil element, thereby prevent pathological damage to said arterial walls of the arterial bifurcation.

10. The device of claim 1, whereby said coil element is a meshed structure.

11. The device of claim 10, whereby perimeter of said meshed structure is surrounded by an essentially rigid frame.

12. The device of claim 10, whereby said meshed structure is made of braided material.

13. The device of claim 10, whereby said meshed structure is made of flat braided material.

14. The device of claim 10, whereby said meshed structure is made of braided material manufactured from a shaped memory alloy.

15. The device of claim 1, whereby said portion of and integral with said coil element is a finely meshed zone functioning as a deflecting and filtering element, for said deflecting the embolic material in the flowing blood and for said filtering the flowing blood.

16. The device of claim 15, whereby said deflecting and filtering element replaces a substantially equivalently sized portion of said coil element.

17. The device of claim 15, whereby said deflecting and filtering element supplements a substantially equivalently sized portion of said coil element.

18. The device of claim 15, whereby open area of perforations or apertures of perforated sheet material as said coil element is significantly larger than mesh size openings of said deflecting and filtering element required for said deflecting the embolic material in the flowing blood.

19. The device of claim 15, whereby open area or mesh size of meshed structure as said coil element is significantly larger than mesh size openings of said deflecting and filtering element required for said deflecting the embolic material in the flowing blood.

20. The device of claim 1, whereby said first diameter of said coil element in said contracted state is in a range of between about 1 mm to about 4 mm.

21. The device of claim 1, whereby said second diameter of said coil element in said expanded state is in a range of between about 5 mm to about 30 mm.

22. The device of claim 1, whereby said first diameter of said coil element in said contracted state is in a range of between about 1 mm to about 4 mm, and, whereby said second diameter of said coil element in said expanded state is in a range of between about 5 mm to about 30 mm.

23. The device of claim 1, whereby said coil element is constructed from wires having cross-sections of variable geometrical shape and configuration selected from the group consisting of circular, elliptical, square, rectangular, and, combinations thereof.

24. The device of claim 1, whereby said coil element is constructed from material selected from the group consisting of stainless steel, superelastic Nitinol, Elgiloy, mixtures of different metals and alloys, polymeric material, and, combinations thereof.

25. The device of claim 1, whereby thickness and diameter of wire used for constructing said coil element are in a range of between about 100 microns to about 1500 microns.

26. The device of claim 1, whereby thickness and diameter of wire used for constructing said coil element are in a range of between about 100 microns to about 200 microns.

27. The device of claim 15, whereby said deflecting and filtering element is constructed from wires having cross-sections of variable geometrical shape and configuration selected from the group consisting of circular, elliptical, square, rectangular, and, combinations thereof.

28. The device of claim 15, whereby said deflecting and filtering element is constructed from material selected from the group consisting of stainless steel, superelastic Nitinol, Elgiloy, mixtures of different metals and alloys, polymeric material, and, combinations thereof.

29. The device of claim 15, whereby thickness and diameter of wire used for constructing said deflecting and filtering element are in a range of between about 20 microns to about 75 microns.

30. The device of claim 1, whereby said coil element is positioned along inner walls of an artery of the arterial bifurcation.

31. The device of claim 1, whereby, for the arterial bifurcation being the common carotid arterial bifurcation, said coil element is positioned along inner walls of external carotid artery of the common carotid arterial bifurcation.

32. The device of claim 1, whereby said coil element is used for positioning said deflecting and filtering portion between arterial inner walls at an aperture of the arterial bifurcation.

33. The device of claim 1, whereby, for the arterial bifurcation being the common carotid arterial bifurcation, said coil element is used for positioning said deflecting and filtering portion between arterial inner walls located at aperture of inlet to internal carotid artery of the common carotid arterial bifurcation, thereby extending across and covering said aperture of said inlet to said internal carotid artery.

34. The device of claim 1, whereby said coil element supports and anchors said deflecting and filtering portion between arterial inner walls of an aperture of the arterial bifurcation.

35. The device of claim 1, whereby for the arterial bifurcation being the common carotid arterial bifurcation, said coil element supports and anchors said deflecting and filtering portion between arterial inner walls located at aperture of inlet to internal carotid artery of the common carotid arterial bifurcation, thereby extending across and covering said aperture of said inlet to said internal carotid artery.

36. The device of claim 1, whereby at least one radiographic opaque marker is located at a position on said coil element, for use in positioning said coil element within an artery at the arterial bifurcation.

37. The device of claim 36, whereby said at least one radiographic opaque marker is a gold point.

38. The device of claim 1, whereby radially directional elastic forces of said expandable coil element operate to maintain said coil element in said expanded state at the arterial bifurcation.

39. The device of claim 1, whereby the blood flowing at the arterial bifurcation is characterized by Reynolds number, Re, having a value in a range of between about 200 to about 500.

40. The device of claim 1, whereby, during the blood flowing at the arterial bifurcation, physiological conditions at the arterial bifurcation are characterized by Reynolds number, Re, having a value in a range of between about 200 and about 500, and, Womersley parameter having a value in a range of between about 2 and about 7.

41. The device of claim 15, whereby, during the blood flowing at the arterial bifurcation, said deflecting and filtering element is characterized by a wire Reynolds number having a value in a range of between 0 to about 30, in accordance with creeping or Stokes'flow.

42. The device of claim 15, whereby, during the blood flowing at the arterial bifurcation, said deflecting and filtering element is characterized by a wire Reynolds number having a value in a range of between 0 and about 30, in accordance with creeping or Stokes'flow, and, by a wire shear stress having a value in a range of between less than about 100 dyne/em and greater than about 2 dyne/cm2.

43. The device of claim 1, whereby the arterial bifurcation is in a region of the common carotid arteries.

44. The device of claim 1, whereby the arterial bifurcation is in a region of the common carotid arteries branching off to the internal carotid artery and branching off to the external carotid artery.

45. The device of claim 1, whereby, for the arterial bifurcation being the common carotid arterial bifurcation, said first branch is the internal carotid artery and said second branch is the external carotid artery.

46. The device of claim 1, whereby said first branch is a vital artery and said second branch is a non-vital artery.

47. A method for deflecting embolic material in blood flowing at an arterial bifurcation, comprising the steps of : (a) providing an implantable integral device featuring an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of said coil element, and an expanded state having a second diameter greater than said first diameter, wherein a portion of and integral with said coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation, while filtering the blood flowing toward said first branch of the arterial bifurcation ; and (b) implanting and deploying in a vicinity of the arterial bifurcation said implantable integral device.

48. The method of claim 47, whereby said coil element is of a type selected from the group consisting of self-expandable, and, non-self-expandable, at the arterial bifurcation.

49. The method of claim 47, whereby said coil element is self-expandable at the arterial bifurcation.

50. The method of claim 47, whereby said coil element is expandable under pressure supplied by a mechanism operative at the arterial bifurcation.

51. The method of claim 47, whereby said coil element is expandable under pressure supplied by a mechanism separate from and operative with said coil element, at the arterial bifurcation.

52. The method of claim 47, whereby there is also said at least partial overlap of said two opposing ends of said coil element in said expanded state.

53. The method of claim 47, whereby there is no said at least partial overlap of said two opposing ends of said coil element in said expanded state, whereby a gap is formed between said two opposing ends of said coil element.

54. The method of claim 47, whereby said coil element is a perforated sheet material.

55. The method of claim 54, whereby said perforated sheet material features a plurality of perforations or apertures for permitting growth of cells from arterial walls onto surface of said coil element, thereby prevent pathological damage to said arterial walls of the arterial bifurcation.

56. The method of claim 47, whereby said coil element is a meshed structure.

57. The method of claim 56, whereby perimeter of said meshed structure is surrounded by an essentially rigid frame.

58. The method of claim 56, whereby said meshed structure is made of braided material.

59. The method of claim 56, whereby said meshed structure is made of flat braided material.

60. The method of claim 56, whereby said meshed structure is made of braided material manufactured from a shaped memory alloy.

61. The method of claim 47, whereby said portion of and integral with said coil element is a finely meshed zone functioning as a deflecting and filtering element, for said deflecting the embolic material in the flowing blood and for said filtering the flowing blood.

62. The method of claim 61, whereby said deflecting and filtering element replaces a substantially equivalently sized portion of said coil element.

63. The method of claim 61, whereby said deflecting and filtering element supplements a substantially equivalently sized portion of said coil element.

64. The method of claim 61, whereby open area of perforations or apertures of perforated sheet material as said coil element is significantly larger than mesh size openings of said deflecting and filtering element required for said deflecting the embolic material in the flowing blood.

65. The method of claim 61, whereby open area or mesh size of meshed structure as said coil element is significantly larger than mesh size openings of said deflecting and filtering element required for said deflecting the embolic material in the flowing blood.

66. The method of claim 47, whereby said first diameter of said coil element in said contracted state is in a range of between about 1 mm to about 4 mm.

67. The method of claim 47, whereby said second diameter of said coil element in said expanded state is in a range of between about 5 mm to about 30 mm.

68. The method of claim 47, whereby said first diameter of said coil element in said contracted state is in a range of between about 1 mm to about 4 mm, and, whereby said second diameter of said coil element in said expanded state is in a range of between about 5 mm to about 30 mm.

69. The method of claim 47, whereby said coil element is constructed from wires having cross-sections of variable geometrical shape and configuration selected from the group consisting of circular, elliptical, square, rectangular, and, combinations thereof.

70. The method of claim 47, whereby said coil element is constructed from material selected from the group consisting of stainless steel, superelastic Nitinol, Elgiloy, mixtures of different metals and alloys, polymeric material, and, combinations thereof.

71. The method of claim 47, whereby thickness and diameter of wire used for constructing said coil element are in a range of between about 100 microns to about 1500 microns.

72. The method of claim 47, whereby thickness and diameter of wire used for constructing said coil element are in a range of between about 100 microns to about 200 microns.

73. The method of claim 61, whereby said deflecting and filtering element is constructed from wires having cross-sections of variable geometrical shape and configuration selected from the group consisting of circular, elliptical, square, rectangular, and, combinations thereof.

74. The method of claim 61, whereby said deflecting and filtering element is constructed from material selected from the group consisting of stainless steel, superelastic Nitinol, Elgiloy, mixtures of different metals and alloys, polymeric material, and, combinations thereof.

75. The method of claim 61, whereby thickness and diameter of wire used for constructing said deflecting and filtering element are in a range of between about 20 microns to about 75 microns.

76. The method of claim 47, whereby said coil element is positioned along inner walls of an artery of the arterial bifurcation.

77. The method of claim 47, whereby, for the arterial bifurcation being the common carotid arterial bifurcation, said coil element is positioned along inner walls of external carotid artery of the common carotid arterial bifurcation.

78. The method of claim 47, whereby said coil element is used for positioning said deflecting and filtering portion between arterial inner walls at an aperture of the arterial bifurcation.

79. The method of claim 47, whereby, for the arterial bifurcation being the common carotid arterial bifurcation, said coil element is used for positioning said deflecting and filtering portion between arterial inner walls located at aperture of inlet to internal carotid artery of the common carotid arterial bifurcation, thereby extending across and covering said aperture of said inlet to said internal carotid artery.

80. The method of claim 47, whereby said coil element supports and anchors said deflecting and filtering portion between arterial inner walls of an aperture of the arterial bifurcation.

81. The method of claim 47, whereby for the arterial bifurcation being the common carotid arterial bifurcation, said coil element supports and anchors said deflecting and filtering portion between arterial inner walls located at aperture of inlet to internal carotid artery of the common carotid arterial bifurcation, thereby extending across and covering said aperture of said inlet to said internal carotid artery.

82. The method of claim 47, whereby at least one radiographic opaque marker is located at a position on said coil element, for use in positioning said coil element within an artery at the arterial bifurcation.

83. The method of claim 82, whereby said at least one radiographic opaque marker is a gold point.

84. The method of claim 47, whereby radially directional elastic forces of said expandable coil element operate to maintain said coil element in said expanded state at the arterial bifurcation.

85. The method of claim 47, whereby the blood flowing at the arterial bifurcation is characterized by Reynolds number, Re, having a value in a range of between about 200 to about 500.

86. The method of claim 47, whereby, during the blood flowing at the arterial bifurcation, physiological conditions at the arterial bifurcation are characterized by Reynolds number, Re, having a value in a range of between about 200 and about 500, and, Womersley parameter having a value in a range of between about 2 and about 7.

87. The method of claim 61, whereby, during the blood flowing at the arterial bifurcation, said deflecting and filtering element is characterized by a wire Reynolds number having a value in a range of between 0 and about 30, in accordance with creeping or Stokes'flow.

88. The method of claim 61, whereby, during the blood flowing at the arterial bifurcation, said deflecting and filtering element is characterized by a wire Reynolds number having a value in a range of between 0 and about 30, in accordance with creeping or Stokes'flow, and, by a wire shear stress having a value in a range of between less than about 100 dyne/cm2 and greater than about 2 dyne/cm2.

89. The method of claim 47, whereby the arterial bifurcation is in a region of the common carotid arteries.

90. The method of claim 47, whereby the arterial bifurcation is in a region of the common carotid arteries branching off to the internal carotid artery and branching off to the external carotid artery.

91. The method of claim 47, whereby, for the arterial bifurcation being the common carotid arterial bifurcation, said first branch is the internal carotid artery and said second branch is the external carotid artery.

92. The method of claim 47, whereby said first branch is a vital artery and said second branch is a non-vital artery.

93. Use of an implantable integral device in the manufacture of a medical device for deflecting embolic material in blood flowing at an arterial bifurcation, for preventing the occurrence of a condition associated with the embolic material in a subject, comprising implanting and deploying the implantable integral device at an arterial bifurcation of the subject, the implantable integral device comprising an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of said coil element, and an expanded state having a second diameter greater than said first diameter, wherein a portion of and integral with said coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation,

while filtering the blood flowing toward said first branch of the arterial bifurcation of the subject.

94. Use of an implantable integral device in the manufacture of a medical device for deflecting embolic material in blood flowing at an arterial bifurcation, for treating a subject with a condition associated with the embolic material, comprising implanting and deploying the implantable integral device at an arterial bifurcation of the subject, the implantable integral device comprising an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of said coil element, and an expanded state having a second diameter greater than said first diameter, wherein a portion of and integral with said coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation,

95. A method for deflecting embolic material in blood flowing at an arterial bifurcation, for preventing the occurrence of a condition associated with the embolic material in a subject, comprising the steps of : (a) providing an implantable integral device featuring an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of said coil element, and an expanded state having a second diameter greater than said first diameter, wherein a portion of and integral with said coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation, while filtering the blood flowing toward said first branch of the arterial bifurcation;

and (b) implanting and deploying in a vicinity of the arterial bifurcation of the subject said implantable integral device.

96. A method for deflecting embolic material in blood flowing at an arterial bifurcation, for treating the occurrence of a condition associated with the embolic material in a subject, comprising the steps of : (a) providing an implantable integral device featuring an expandable dual diameter coil element having a contracted state with a first diameter in which there is at least partial overlap of two opposing ends of said coil element, and an expanded state having a second diameter greater than said first diameter, wherein a portion of and integral with said coil element deflects the embolic material in the blood flowing toward a first branch of the arterial bifurcation into a second branch of the arterial bifurcation, while filtering the blood flowing toward said first branch of the arterial bifurcation;