WO2008072261A2

WO2008072261A2 - A medical device its use (s) and method (s) thereof

Info

Publication number: WO2008072261A2
Application number: PCT/IN2007/000598
Authority: WO
Inventors: Anil Madan Potdar
Original assignee: Anil Madan Potdar
Priority date: 2006-12-15
Filing date: 2007-12-17
Publication date: 2008-06-19
Also published as: WO2008072261A3

Abstract

The present invention provides a medical device for guiding the needle preferably for puncturing a wall or membrane within the body preferably atrial septum in the heart, and/or for measuring size of an aperture within body preferably in heart to the atrial septum, said device comprising a coiled wire coiled in convexo-concave or conical shape with proximal end at narrow end of the coil and a distal end at wide end of the coil; and a cable connected to the proximal end of the coiled wire to reach the coiled wire at predetermined place. The wire of the medical device on inserting into catheter accepts the elongation of the wire from the proximal end in a wave like manner and on releasing or reversing the medical device out from the catheter in vivo and/or in vitro, the wire winds up and assumes in its original convexo-concave or conical shape.

Description

A MEDICAL DEVICE ITS USE (S) AND METHOD (S) THEREOF FIELD OF THE INVENTION:

The present invention generally relates to a medical device, its use(s) and method(s) thereof. More particularly the present invention relates to a medical device for guiding the needle preferably for puncturing a wall or membrane within the body surface preferably atrial septum in the heart, and/or for measuring the width of an aperture within body surface, such as wall/membrane separating two cavities.

BACKGROUND OF THE INVENTION

Transseptal catheterization has been engaged to provide access to the left atrium by puncturing the atrial septum, since 1960,but with the development of the retrograde aortic approach, its use became less common. However, recently the transseptal catheterization is being employed more frequently, as preferred method for balloon Mitral Valvoplasty, avoiding valve injury in children, and in patients with prosthetic aortic valves. Moreover, due to an increase in number of left atrium radio frequency catheter ablations, the scope of the transseptal catheterization has grown tremendously.

In order to access the left atrium and locating the safe site and method to puncture the septum therewith was the object of immense research.

Traditional transseptal catheterization commences with entry via the right femoral vein using a 70-cm curved Brockenbrough needle. The needle is entered into the region of superior van cava with Mullins Dilator in combination. A wire is advanced into the region of superior vana cava, and the transseptal - dilator is advanced over the wire and then the wire is removed. The Blockenbrough needle is advanced under fluoroscopy. The needle is flushed with saline, and the needle hub connected to a pressure manifold. An arterial puncture is performed, and a pigtail catheter is advanced through the sheath to the aortic route, marking its position. The operator's right hand controls the movement of the Brokenbrough needle-direction indicator, while the left hand rotates the needle-dilator unit.

The needle and dilator are withdrawn as a unit under constant fluoroscopic guidance (observed from the left anterior oblique projection). When the unit is withdrawn, it proximal moves beneath the bulbs of the ascending aorta, and then moves medially, as the catheter jumps into the fossa ovalis. At this point, slight advancement of the unit will either bring it into the left atrium through a patient foramen ovale or cause it to be halted by a rim of limbus, which borders the superior edge of the fossa ovalis.

Ablation catheter positioning is traditionally guided by fluoroscopy and electrical recording from the catheter tip.

When satisfactory position of the dilator-needle unit is made out, the operator may smoothly and convincingly advance the Brockenbrough needle tip so that it punctures the fossa ovalis.

At this stage the confirmative test for the successful entry into the right atrium is: tracing left atrial pressure from the hub of the needle; withdrawing oxygenated blood from the tip of the needle. Subsequent to confirmation of the entry into the right atrium, the dilator is advanced over the needle into the left atrium while maintaining the needle in a fixed position. The needle can then be withdrawn from the dilator, with a syringe hooked to the hub of the sheath applying negative pressure to prevent entrainment of the air; the dilator is then flushed. Fluoroscopic imaging provides information about cardiac anatomy; however, such information is not a conclusive proof with respect to catheter position. When the fossa ovalis is difficult to locate the use of blind transceptal methodology involves the significant risks such as puncture of aorta, coronary sinus or left atrial free wall.

The said transseptal technique is revived through development of the intracardiac echocardiography or ICE. ICE employs an intravascular ultrasound imaging system such as the Boston Scientific Galaxy 2 to provide real time visualization of the right atrium fossa ovalis, aorta and left atrium, all of which must be considered in transseptal catheter positioning.

ICE allows the operator to obtain dynamic scans of interatrial septum and fossa ovalis during transseptal catheterization, reducing the risk of dangerous unwanted punctures and providing real time evidence of thrombus formation.

The ICE procedure employs a mechanical ultrasound catheter with single, large aparature, rotating transducer. The catheter provides a 360-degree lateral cross- section of the anatomy. Images are recorded on Galaxy 2 IVUS imaging system, allowing the operator to observe the complete chamber and adapt the procedure to patient specific anatomy.

The ICE probe is prepared by injecting 10cc of sterile water into the tip of the ultrasound atherter the probe is introduced through a sheath into the patient's superior vana-cava in addition to the wire. On the imaging system anatomy of the right atrial system- in particular the nature of the intra-atrial septum is analyzed.

The ICE catheter can be positioned to for fossa ovalis imaging, with the transducer serving as an additional fluoroscopic marker of the fossa ovalis transseptal puncture site. If abnormal or deviated patient anatomy does not easily allow this positioning, an angled sheath can be advanced and torqued to bring the ICE catheter into the correct position.

However ICE technology is highly expensive because of the exorbitant cost of the equipments such as ultra sound catheter. It requires a special instrument with an additional skilled medical person to operate the same. Furthermore this technique requires comparatively bigger puncture in the femoral vein to enable the insertion of the entire assembly into the heart. And the prerequisite set up is also a time consuming process.

In the transseptal catheterization, more particularly while puncturing the septum, fossa ovalis is considered to be 'right spot' to access the left atrium. However experience shows that position of intended septal puncture varies for each anticipated procedure and need not lie at fossa ovalis, which is frequently displaced or inaccessible. So in cases where traditional catheterization methods using fluoroscopic technique fails to detect the fossa ovalis ;operator is left with no other option rather than the adoption of 'unsighted puncture method', which in turn maximizes the probability of the effectuation of the risk involved in the said process.

Therefore, when the traditional method fails to locate the fossa ovalis under the guidance of fluoroscopic techniques; medical device and method to locate the exact central/middle portion of the atrial septum is the cause of research. This would include the ablation of the risk of inadvertent puncturing of the aorta, coronary sinus or left atrial free wall.

The atrial septal defect is required to be measured while carrying transcatheter closure by balloons of various sizes. The problem in using balloon is that the method becomes time consuming and requires expensive balloon. Further, as balloon sizes are fixed, it may require using one or two balloon to measure the size of the hole to be closed.

SUMMARY OF THE INVENTION:

It is an aspect of the present invention to provide a medical device which can be used either for guiding the needle preferably for puncturing a wall or membrane within the body surface preferably atrial septum in the heart or for measuring the size of an aperture within body surface such as wall or membrane separating two cavities more particularly atrial septum.

In accordance with present invention it is further aspect to provide method(s) for puncturing of a wall or membrane within the body surface more particularly atrial septum within the heart.

In accordance with present invention it is it is still further aspect to provide a method for measuring the width of an aperture within body surface such as wall or membrane separating two cavities more particularly the atrial septal defect or hole.

In one embodiment, the present invention provides a medical device for guiding the needle preferably for puncturing a wall or membrane within the body preferably atrial septum in the heart, and/or for measuring size of an aperture within body preferably in heart to the atrial septum, said device comprising a coiled wire coiled in convexo-concave or conical shape with proximal end at narrow end of the coil and a distal end at wide end of the coil; and a cable connected to the proximal end of the coiled wire to reach the coiled wire at predetermined place. The wire of the medical device on inserting into catheter accepts the elongation of the wire from the proximal end in a wave like manner and on releasing or reversing the medical device out from the catheter in vivo and/or in vitro, the wire winds up and assumes in its original convexo-concave or conical shape.

In other embodiments, the present invention provides a method for guiding the needle preferably for puncturing a wall or membrane within the body preferably atrial septum in the heart, and a method for measuring size of an aperture within body preferably in heart to the atrial septum using the device of the above embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the embodiments of the invention are generally described in the context of these drawings, it should be understood that it is not intended to limit the scope of the embodiments of the invention to these drawings.

Fig.1 shows frontal view of the medical device.

Fig.2 shows the side view of the medical device.

DESCRIPTION OF THE INVENTION:

Figures 1 & 2 show frontal view and side view of the medical device (100) according to the present invention. The medical device (100) comprises a coiled wire (110) and a cable (120) attached to the coiled wire.

According to the present invention, the coiled wire (110) has convexo concave or conical shape with a proximal end (112) at narrow end of the coiled wire (110) and a distal end (114) at wide end of the coiled wire (110). The distal end (114) forms a circle in combination with the end coil of wire. The distal end of the wire is a blunt end.

According to the present invention, the coiled wire of the medical device on inserting into catheter accepts the elongation of the wire from the proximal end in a wave like manner and on releasing or reversing the medical device out from the catheter in vivo and/or in vitro, the wire winds up and assumes in its original convexo-concave or conical shape. The coiled wire has coiled length of about 1 centimeter (10mm) and uncoiled length of about upto 30 centimeter (300mm). The diameter of the end coil of the coiled wire is between 30 and 50 millimeter (including 30 and 50 millimeter). The coiled wire has constant pitch. Alternatively it may have varying pitch. The coiled wire is formed of a selected from the group of consisting of titanium, stainless steel, nitinol and the like.

The cable is made of the known materials similar to the materials of the guiding wires used today and the cable are connected to the proximal end of the coiled wire fixedly by known means such as welding. According to the present invention, the proximal end (112) is connected with the cable (120) off centrally to form an aperture (116) centrally that extends convexo-concavely or conically along the longitudinal axis of the coiled wire from narrow end to wide end of the coiled wire (110).

According to the present invention, the medical device as described herein above can be used for guiding the needle preferably for puncturing a wall or membrane within the body surface more particularly atrial septum in the heart.

An advantage of medical device of the present invention is that the medical device guides the needle so as to ensure puncturing into the middle portion of the atrial septum, which may be fossa ovalis and ablates the risk of inadvertent puncturing of the aorta, coronary sinus, or left atrial free wall. For this purpose the present invention provides a method for guiding the needle to ensure puncturing the middle portion of the atrial septum In this method, for guiding the needle for the transseptal puncture, the catheter comprising the medical device according to the present invention is directed through femoral vein in the heart, more particularly via inferior vena cava into the right atria under the constant fluoroscopic monitoring. The medical device contained into the catheter and as soon as the catheter enters right atria, the cavity therein let the medical device to be opened up in its normal shape. Under the fluoroscopic monitoring the medical device is advanced towards the atrial septum and thereupon adjusted on the atrial septum. Once located on the atrial septum, its position can be visualized by the fluoroscopic technique. As shown in figure 1 the medical device has an aperture within the inner most ring of the coil. Subsequent to the positioning of the medical device on the septum the needle is delivered to the right atria via superior van cava through a catheter. The central or middle aperture of the coil of the medical device can be visualized on the fluoroscopic monitor. The needle is then positioned appropriately to pass through the central aperture of coil of the medical device and perforated in to the atrial septum. According to the present invention, the medical device guides needle to pass substantially along longitudinal central axis of the coiled wire thereby guiding the needle preferably for puncturing or perforating the atrial septum. Successful perforation in the centre of the IAS can be made out with the help of various scientific norms such as pressure tracing method or by contrast injection method.

The medical of the present invention device can also be used for measuring the size of an aperture within body surface, such as wall/membrane separating two cavities more particularly the width of the hole in the atrial septum of the heart. For this purpose the present invention also provides a method. In this method, catheter containing the medical device is introduced via right atrium through the atrial septum into the left atrium. Once into the left atrium the coil is released which regains its normal shape. Now the coil is gently tugged with the help of the cable of the medical device towards the right atria whereby the individual circular rings of the size just about less than the diameter of the aperture within the atrial septum get subtly pulled out of the hole or aperture of the atrial septum. The medical device may be gently tugged again to ensure the effective transition of the said spiral rings. The diameter of the largest individual ring of the coil of the said medical device that has passed out of the atrial septum into the right atria and the diameter of the next successive larger ring (that can not surpass the septum) defines the size of the atrial septal hole as the distance between the two adjacent coil is between 0 mm and 5 mm (includes 0 and 5 mm) and the pitch is constant. From the individual diameter of these two rings the width of the atrial septal defect or hole can be inferred to be not less than the diameter of the largest ring that has passed out of the septum and not more than the diameter of the next successive larger ring which can not surpass the septum one can easily find out the size of the deice require to occlude the hole in the septum atrial.

As the medical device of the present invention is simple device, it is relatively inexpensive to manufacture and low profile. Further as the medical device of the present invention does not contain any other material along with the device, it is not harmful which may be possible with the balloon. Further while performing an operation for measurement of the hole, no further preparation requires like balloon system.

While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A medical device for guiding the needle preferably for puncturing a wall or membrane within the body preferably atrial septum in the heart, and/or for measuring size of an aperture within body preferably in heart to the atrial septum, said device comprising:

a coiled wire coiled in convexo-concave or conical shape with proximal end at narrow end of the coil and a distal end at wide end of the coil; and

a cable connected to the proximal end of the coiled wire to reach the coiled wire at predetermined place,

wherein the wire of the medical device on inserting into catheter accepts the elongation of the wire from the proximal end in a wave like manner and on releasing or reversing the medical device out from the catheter in vivo and/or in vitro, the wire winds up and assumes in its original convexo- concave or conical shape.

2. A medical device as claimed in claim 1 further comprises an aperture at proximal end extending convexo-concavely or conically from narrow end to wide end to allow needle to pass substantially along longitudinal central axis of the coiled wire thereby guiding the needle preferably for puncturing a wall membrane within the body preferably atrial septum in the heart.

3. A medical device as claimed in claim 1 wherein said proximal end of the wire connected to the cable off-centrally.

4. A medical device as claimed in claim 1 wherein said distal end forms a circle in combination with the end coil of wire.

5. A medical device as claimed in claim 1 wherein said distal end of the wire is a blunt end.

6. A medical device as claimed in claim 1 wherein said wire has coiled length of about 1 centimeter and uncoiled length of about upto 30 centimeter.

7. A medical device as claimed in claim 1 wherein the diameter of the end coil of the coiled wire is between 30 and 50 millimeter.

8. A medical device as claimed in claim 1 wherein the coiled wire has constant pitch or varying pitch.

9. A medical device as claimed in claim 1 wherein the distance between the 2 adjacent coils preferably maintained between 0 mm and 5 mm.

10. A medical device as claimed in claim 1 wherein said coiled wire is formed of a selected from the group of consisting of titanium, stainless steel, nitinol and the like.

11. A method for guiding a needle preferably for puncturing a wall or membrane within the body preferably atrial septum in heart, said method comprising steps of:

introducing the coiled wire portion of a medical device as claimed in claim 1 into a catheter;

inserting the catheter in to the heart;

releasing coiled wire portion of the medical device in vivo, in order to regain its original shape;

visualizing and positioning of the medical device more particularly coiled wire appropriately on the atrial septum so as to equally covering the septum;

inserting the needle along with dilator-catheter combination in to the heart; positioning the needle exactly all the way through the aperture present at the center of the coiled wire on the central part of the atrial septum;

puncturing the atrial septum; and removing the needle and the medical device from the heart

wherein medical device guides the needle to puncture at central/middle portion of the atrial septum.

12. The method as claimed in claim 11 wherein the catheter comprising the medical device is introduced more particularly into the right atrium of the heart through the femoral vein.

13. The medical device as claimed in claim 11 wherein visualizing and positioning the medical device is carried by a fluoroscopic monitor.

14. A method for measuring the size of an aperture within body preferably in heart to the atrial septum, said method comprising steps of:

introducing the medical device into catheter;

inserting the catheter in to heart through the defective hole;

releasing of coiled wire of the medical device into the left atrium;

tugging the medical device gently; and

visualizing the smallest ring of the said coil, which has not been transferred from the left atrium into the right atrium; and

removing the medical device from the heart;

wherein the diameter of the largest individual ring of the coil of the said medical device that has been released through the atrial septum into the right atria and the diameter of the next successive larger ring that can not pass through the septum defines the size of the hole in the atrial septum of the heart.

15. The method as claimed in claim 14 wherein the distance between the two adjacent coils of the coiled wire of the medical device is negligible and preferably between 0 mm and 5 mm with or without constant pitch.

16. The method as claimed in claim 14 wherein visualizing the medical device is carried by a fluoroscopic monitor.