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United States Patent 3,874,388
King ,   et al. April 1, 1975

SHUNT DEFECT CLOSURE SYSTEM

Abstract

A method and apparatus for closing off a septal defect or shunt in the intravascular system or the great vessels including a pair of opposed, umbrella-like elements locked together in face-to-face relationship on opposite sides of the septal defect, thereby closing it. The dual umbrella-like closure elements are sequentially applied and joined together via an outer catheter inserted into the interior of the heart by means of the jugular vein in the neck or a vein in the groin along with other associated operative elements used within the outer catheter, thereby eliminating the need for open-heart surgery to correct a septal defect or shunt as was heretofore required. For a ventricular septal defect a single umbrella-like element is used which is temporarily held in place by an operative element which is subsequently removed.


Inventors: King; Terry D. (New Orleans, LA), Mills; Noel L. (New Orleans, LA)
Assignee: Alton Ochsner Medical Foundation (New Orleans, LA)
Appl. No.: 05/331,559
Filed: February 12, 1973


Current U.S. Class: 606/232 ; 606/213
Current International Class: A61M 25/00 (20060101); A61B 17/00 (20060101); A61F 2/24 (20060101); A61b 017/04 ()
Field of Search: 128/334R,335,348,351,1R 138/89,91,92,93,94

References Cited

U.S. Patent Documents
2493326 January 1950 Trinder
2799273 July 1957 Oddo
3334629 August 1967 Cohn
3397699 August 1968 Kohl
3540431 November 1970 Mobin-Uddin
3574865 April 1971 Hamaker
3592184 July 1971 Watkins et al.
3671979 June 1972 Spyridon
3675639 July 1972 Cimber

Other References

Hunter et al., - Annals of Surgery - Feb. 1970, Vol. 171, No. 2, pp. 315-320. .
King et al., - Surgery - Dec. 1953, Vol. 34, pp. 1100-1116. .
Hufnagel et al., - The Bulletin - Georgetown Med. Cen. (Vol. IV, No. 5, pp. 137-139) 1951. .
Mills et al., - Supplement I to Circulation, (Vols. XLIII and XLIV, pp. 1-111), 5/1971..

Primary Examiner: Truluck; Dalton L.
Attorney, Agent or Firm: Pugh & Laiche

Claims



What is claimed as invention is:

1. A shunt defect closure apparatus for closing off a shunt defect in the septum of for example the intravascular system comprising:

mechanical expansion means having an initial size substantially smaller than the diameter of the shunt defect to be closed during its preliminary handling and a final size substantially larger than the diameter of the shunt defect when it is positioned over and across the shunt defect to permanently close it off after being expanded to its larger size, said expansion means comprising a dual set of umbrella-like structures for placement on opposite sides of the shunt defect, the umbrella-like structures having central hub means for connecting said dual set of umbrella-like structures together through the shunt, each said umbrella-like structures including a series of relatively hard, strut-like members emanating out from said central means in at least a generally perpendicular, radial direction when said expansion means is in its final size and in at least a generally parallel, axial direction when said expansion means is in its initial size; and

operative means removably connected with said expansion means for at least temporarily holding the said expansion means on to the shunt defect after at least one of said umbrella-like structures has been expanded out to its final size.

2. The apparatus of claim 1 wherein said umbrella-like structure comprises a series of supporting struts with flexible material suspended between said struts, said struts being moveably attached to a centrally located support element for movement from a closed position to an open position or vice versa.

3. The apparatus of claim 1 wherein said operative means includes an obturator wire having attaching means at it distal end for temporarily attaching said obturator wire to one of said umbrella-like structures

4. The apparatus of claim 3 wherein said operative means further includes an outer catheter serving as a conduit for placing both said umbrella-like structures through the body adjacent to the shunt, said outer catheter having a diameter substantially greater than said obturator wire, said one of said umbrella-like structures being transported through said outer catheter by means of being mounted on the distal portion of said obturator wire and pushing said obturator wire with said one of said umbrella-like structures means thereon through said outer catheter.

5. The apparatus of claim 1 wherein each said umbrella-like structures includes an expanse of relatively flexible material extending between said strut-like members to thereby at least substantially close off the spaces between said strut-like members.

6. The apparatus of claim 1 wherein said umbrella-like structures have their undersides in opposing relationship to each other and said strut-like members are made of resilient material and resiliently bear inwardly toward the opposing umbrella-like structure, thereby securing the opposing umbrella-like structures to the septum.

7. The apparatus of claim 1 wherein said strut-like members include at their distal tips barb-like means emanating from their underside in a direction at least generally perpendicular thereto for bearing against the septum when each of said umbrella-like structures is moved toward the septum.

8. The apparatus of claim 1 wherein said operative means includes an obturator wire having attaching means at its distal end for temporary connection to one of said umbrella-like structures and wherein said first one of said umbrella-like structures has a central hub having a connection for temporary connection to said obturator wire; and wherein said second umbrella-like structure has a central sleeve which can slide over said obturator wire, said central hub and said central sleeve having locking means for locking them together in opposing fashion when on opposite sides of the shunt.

9. The apparatus of claim 8 wherein said locking means comprises a male-female connection between said central hub and said central sleeve, the exterior of said connection means of said central hub forming the male member and the interior of said sleeve forming at least in part the female orifice.

10. The apparatus of claim 9 wherein said male member includes a projection on its mating surface and said female orifice includes an indentation for further mating with said projection and locking the hub and sleeve together.

11. A shunt defect closure apparatus for closing off a shunt defect in the septum of for example the intravascular system comprising:

mechanical expansion means having an initial size substantially smaller than the diameter of the shunt defect to be closed during its preliminary handling and a final size substantially larger than the diameter of the shunt defect when it is positioned over and across the shunt defect to permanently close it off after being expanded to its larger size, said expansion means comprising at least one umbrella-like structure for placement on one side of the shunt, said umbrella-like structure having central hub means of at least a generally cylindrical shape for having pressure applied to it along its longitudinal axis for forcing the distal, end portions of the underside of said umbrella-like structure against the septum to at least partially close the shunt, said umbrella-like structure being of a material that will be endothelialized into the septum; the main surface of the umbrella-like structure in its expanded size being at least substantially perpendicular and radial to said central hub means and hence to the central axis of the shunt; and operative means associated with said expansion means for at least temporarily holding said expansion means on to the shunt defect.

12. The apparatus of claim 11 wherein the underside of said umbrella-like structure has on its distal portions bearing means for bearing against the septum, the bearing direction being generally perpendicular to the main surface of said umbrella-like structure and hence parallel to the central axis of the shunt.

13. The apparatus of claim 11 wherein said umbrella-like structure in its final size includes a series of relatively hard strut-like members radially emanating out from said extended central means in a direction at least generally perpendicular thereto, the distal tips of said strut-like members including barb-like structures emanating in a direction at least generally perpendicular thereto, said barbs serving as said bearing means.

14. The apparatus of claim 11 wherein said umbrella-like structure includes an expanse of relatively flexible material extending between said strut-like members to thereby at least substantially close off the spaces between said strut-like members.

15. The apparatus of claim 11 wherein said strut-like members are made of resilient material and resiliently bear inwardly toward the septum when the umbrella-like structure is in its final size, thereby securing the umbrella-like structure to the septum.

16. A shunt defect closure apparatus for closing off a shunt defect in the septum of for exammvTHE INTRAVASCULAR system comprising:

mechanical expansion means having an initial size substantially smaller than the diameter of the shunt defect to be closed during its preliminary handling and a final substantially larger than the diameter of the shunt defect when it is positioned over and across the shunt defect to permanently close it off after being expanded to its larger size, said expansion means comprising at least one expansion structure being of a material that will be endothelialized into the septum and having an extended, main body with a facing side for contacting the septum surface around the shunt and being extended at least in part in a direction at least generally parallel to the septum surface, and extended central hub means centrally located within said main body and being extended in a direction at least generally perpendicular to the septum surface for having pressure applied to it along its extended direction for forcing the distal, end portions of the facing side of said expansion structure against the septum to at least partially close the shunt, the facing side of said expansion structure having on its distal portions anchoring means for anchoring said expansion structure to the septum, when said expansion structure is forced against the septum, said anchoring means comprising projections extending at least partially in a direction parallel to said extended central means and hence parallel to the central axis of the shunt and perpendicular to the septum surface.

17. The apparatus of claim 16 wherein said expansion structure is an umbrella-like structure having a series of relatively hard strut-like members radially emanating from said extended central means, and having projections at their distal ends, said projections being barb-like structures emanating in a direction at least generally perpendicular to the emanating direction of said strut-like members.

18. The apparatus of claim 17 wherein said umbrella-like structure includes an expanse of relatively flexible material extending between said strut-like members to thereby at least substantially close off the spaces between said strut-like members.

19. The apparatus of claim 17 wherein said strut-like members are made of resilient material and resiliently bear inwardly toward the septum when the umbrella-like structure is in its final size, thereby securing the umbrella-like structure to the septum.

20. The method of closing off a ventricular septal defect in the intravascular system comprising the following sequential steps:

a. providing a ventricular septal defect closure structure for closing off the ventricular septal defect comprising mechanical expansion means having an initial size substantially smaller than the diameter of the intravascular shunt defect to be closed and a final size substantially larger than the diameter of the septal defect for positioning over and across the septal defect to permanently close it off after being expanded to its larger size, said expansion means being made of a tissue compatible material which can be endothelialized into the septum; and operative means associated with said expansion means for at least temporarily holding the said expansion means on to the defect, said operative means incuding an obturator wire having attaching means at its distal end for temporarily attaching said obturator wire to said expansion means;

b. making a relatively small, minor incision or opening in the body and into a vein having access to the ventricle with the defect;

c. introducing the obturator wire with said closure structure attached to its distal end while in its smaller size into said opening and through the septal defect;

d. expanding said expansion means of said closure structure to its larger size;

e. using said obturator wire to position and attach said expansion means of said closure structure while in its larger size over and across the far side of the septal defect, closing the septal defect;

f. closing off said opening in the body with said obturator wire still attached to said expansion means;

g. allowing said expansion means of said closure structure to become endothelialized over a substantial period of time, further closing off the septal defect;

h. reopening the opening in said body and removing said obturator wire; and

i. permanently closing off said opening; whereby the shunt is permanently closed by substantially non-invasive or at least limitedly evasive techniques and without the substantial suturing of the shunt as practiced in the prior art.

21. The method of claim 20 wherein in step (b) the vein used for the opening is the external or internal jugular vein and the incision is made in the neck.

22. The method of closing off a shunt defect in the septum of for example the intravascular system comprising the following steps:

a. providing a shunt defect closure-structure for closing off the shunt defect comprising mechanical expansion means having an initial size substantially smaller than the diameter of the intravascular shunt defect to be closed and a final size substantially larger than the diameter of the shunt defect for positioning over and across the shunt defect to permanently close it off after being expanded to its larger size, said expansion means comprising at least one umbrella-like structure for placement on the side of the shunt, said umbrella-like structure including a central hub having a series of relatively hard, strut-like members emanating out from said central hub in at least a generally parallel, axial direction when said expansion means is in its initial size and a generally perpendicular, radial direction when said expansion means is in its final size, said umbrella-like structure being made of a tissue compatible material which can be endothelialized into the septum; and operative means associated with said expansion means for at least temporarily holding the said expansion means on to the shunt defect;

b. making an opening in the body;

c. introducing said closure structure while in its smaller size in proximity to the shunt to be closed by means of said opening;

d. expanding said umbrella-like structure of said closure structure to its larger size by expanding out said strut-like members;

e. permanently positioning and attaching said umbrella-like structure of said closure structure while in its larger size over and across the shunt, closing the shunt;

f. allowing said umbella-like structure of said closure structure to become endothelialized, further closing off the shunt; and

g. ultimately closing off said opening; whereby the shunt is permanently closed by substantially non-invasive or at least limitedly evasive techniques and without the substantial suturing of the shunt as practiced in the prior art.

23. The method of claim 22 wherein in step (b) the opening in the body is made by making a relatively small, minor incision to gain access to a vein or artery of the blood circulatory system; and wherein in step (c) the introduction is made through said vein or artery.

24. The method of claim 22 wherein in step (a) in providing said expansion means there is further included the providing of a second umbrella-like structure having the same claimed features as the first umbrella-like structure for placement on the opposite side of the shunt from said first umbrella-like structure and steps (c) through (d) inclusive are each repeated for said second umbrella-like structure.

25. The method of claim 24 wherein in step (a) said operative means are provided by providing an outer catheter having a cross-sectional area smaller than the shunt and an obturator wire having a diameter substantially smaller than said outer cathether; and wherein in step (b) the opening in the body is made by making a relatively small minor incision to gain access to a vein or artery; and wherein in step (c) the introduction is made through said vein or artery and includes the following steps:

i. inserting said outer catheter through the incision into and through the vein/artery until its distal end is in juxtaposition to the shunt and, for said first umbrella-like structure, is passed through the shunt but, for the second umbrella-like structure, is located on the proximal side of the shunt; and

ii. moving said umbrella-like structures out of the distal end of said outer catheter.

26. The method of claim 25 wherein in step (c) there is further included in sub-step (ii) the steps of:

attaching said first umbrella-like structure to the distal end of said obturator wire and inserting the obturator wire with said first umbrella-like structure attached thereto in its initial size into and through the outer catheter until said first umbrella-like structure has emerged out of the distal end of said outer catheter;

and wherein the step (e) the underside of said first umbrella-like structure is pulled against the distal side of the septum.

27. The method of claim 25 wherein in step (a) in providing said second umbrella-like structure there is further included the providing of a central sleeve with a central orifice having a diameter greater than said obturator wire but less than said outer catheter; and wherein in step (c) there is further included in sub-step (ii) the steps of:

sliding said central sleeve of said second umbrella-like structure over said obturator wire and passing said second umbrella-like structure through said outer catheter while in its initial size until said second umbrella-like structure has emerged out of the distal end of said outer catheter;

and wherein in step (e) the underside of said second umbrella-like structure is pushed against the proximal side of the septum.

28. The method of claim 27 wherein in step (a) additional operative means are provided by providing a second, inner catheter having a diameter smaller than said outer catheter and having a central longitudinal opening along its length of a diameter larger than the diameter of said obturator wire and being slidable thereon and having a tip at its distal end; and wherein, in the step (e) for said second umbrella-like structure, the underside of said second umbrella-like structure is pushed against the proximal side of the septum by pushing the tip of said inner catheter against the central sleeve of said second umbrella-like structure.

29. The method of claim 28 wherein in step (a) the central hub of said first umbrella-like structure is provided with a centrally located, locking male member, the center of which serves as the connecting means for attaching the central hub to the distal end of the obturator wire; and wherein, the step (e) for said second umbrella-like structure, said inner catheter is used to push the central sleeve of said second umbrella-like structure so that its orifice, which then serves also as a female member, is pushed into the locking male member of said first umbrella-like structure, locking the two umbrella-like structures together.

30. The method of claim 28 wherein in step (a) the strut-like members of said second umbrella-like structure are provided with a set of elevating struts hingedly connected at one end to the strut-like members at a point removed from said central sleeve and at the other end to a centrally located, leading and elevating member; and wherein, in the step (d) for said second umbrella-like member, said second umbrella-like structure is expanded by pushing said central sleeve toward said elevating member by means of said inner catheter, causing said elevating struts to push said strut-like members out away from said central sleeve.
Description



BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an intravascular method and apparatus for closure of septal defects or shunts in the intravascular system or the great vessels by means of a positive mechanical structure applied by means of an outer catheter and other associated operative elements working within said outer catheter.

2. General Background

In order to gain a better understanding of the present invention and its particular application, it is noted that the heart is divided into four compartments or chambers, the two upper being the left and right atria and the two lower being the left and right ventricles. The atria are separated from each other by a muscular wall, the interatrial septum, and the vertrucles by the interventricular septum.

Either congenitally or by acquisition, abnormal openings, holes or shunts can occur between the chambers of the heart or the great vessels (interatrial and interventricular septal defects or patent ductus arteriosus and aorthico-pulmonary window respectively), causing shunting of blood through the opening. The deformity is usually congenital, resulting from a failure of completion of the formation of the septum, or wall, between the two sides during fetal life when the heart forms from a folded tube into a four-chambered, two unit system.

These deformities can carry significant sequelae. For example, with an atrial septal defect, blood is shunted from the left atrium of the heart to the right, producing an over-load of the right heart. In addition to left-to-right shunts such as occur in patent ductus arteriousus from the aorta to the pulmonary artery, the left side of the heart has to work harder because some of the blood which it pumps will recirculate through the lungs instead of going out to the rest of the body. The ill effects of these lesions usually cause added strain on the heart with ultimate heart failure if not corrected.

GENERAL DISCUSSION OF PRIOR ART AND PRESENT INVENTION

Heretofore these intracardiac or extracardiac septal defects have required relatively extensive surgical techniques for correction. In 1938 surgeons first seriously entered the field of attacking congenital heart disease when Gross reported the first ligation of a patent ductus arteriosus. Since that time rapid advances have allowed thoracic surgeons to close not only extracardiac congenital shunts but also shunts between the chambers of the heart. The modern era of extracorporeal circulation began in 1953 when Gibbon first closed an atrial-septal defect, using the heart-lung machine. To date the present method of closing intracardiac shunts, such as atrial-septal defects and ventricular-septal defects, entails the relatively drastic technique of open-heart surgery, requiring opening the chest or sternum and diverting the blood from the heart with the use of a cardiopulmonary bypass. The heart is then opened, the defect is sewn shut by direct suturing with or without a patch of synthetic material (usually of Dacron, Teflon, silk, nylon or pericardium), and the heart closed. The patient is then taken off the cardiopulmonary bypass machine, and the chest closed.

In place of direct suturing, it has been suggested that closures of interauricular septal defects could be made by means of a double "button" prosthesis, but open heart surgery was still required. See for example "Closure of Interauricular Septal Defects" by Charles A. Hufnagel, et al., The Bulletin Georgetown University Medical Center, Vol. IV, No. 5, Pp. 137-139, Feb.-Mar., 1951; which also cited Swan H.: "Experimental Closure of Interauricular Septal Defects" -- Symposium of Cardiovascular Research, National Institute of Health, Jan. 21, 1950, Washington, D.C. Additional work with such a button-type prothesis in open heart surgery was also apparently done by C.P. Bailey, M.D. (see Bailey, et al.: "Correction of Interventricular Septal Defects," Am. Surgery, 136, 919, 1952; and Bailey: "Surgery of the Heart," Lea and Febiger, Philadelphia, Pp. 366,1955) and by Yousif D. Al-Naaman, M.D., Department of Thoracic and Cardiovascular Surgery, University of Baghdad, Iraq.

Thus, prior to the present invention, it was only possible to repair septal defects or shunts through open-heart surgery, involving shunting the blood through an artificial pump-oxygenator (heart-lung machine) or at least supplanting the action of the heart itself (mechanical heart) while the heart is being repaired. Moreover, although excellent results have been obtained on simple septal defects by open-heart surgery, there is great risk in open-heart surgery in patients whose heart muscles have been under great strain for long periods of time.

In contrast to the relatively drastic technique of open-heart surgery, the system of the present invention closes off septal defects or shunts without the need of general anesthesia or opening of the chest. Instead the operative techniques employed in the present invention require only a small incision over a vein in the groin or neck under only local anesthesia, such as is carried out for many routine cardiac catheterizations.

Moreover, the catheter/closure system of the present invention allows a cardiologist to close a septal defect at the time of diagnostic cardiac catheterization, if desired. Because of the proposed size of the outer catheter used in the present invention, this would be most reasonably carried out after the age of 4 to 5 years.

In addition to a far superior, less drastic surgical procedure, the present invention achieves this by means of a unique, permanent catheter/closure system utilizing an expandible catheter/closure structure formed by relatively inexpensive, positive mechanical elements which are relatively simple and reliable in structure and made of readily available and proven materials. In the preferred embodiment of the present invention the catheter/closure structure includes either a single expandible umbrella-like element or an opposed pair of expandible umbrella-like elements, depending on the location of the septal defect.

It is noted that the term "catheter" as used herein refers to an instrument, generally tubular in shape, which is inserted into a body cavity, naturally or surgically opened. Several different catheters have been developed in the past, either for experimental research purposes or clinical application. The Mobin-Uddin catheter is one that is used for partial occlusion of the inferior vena cava to prevent pulmonary embolization. This catheter has been described in a publication by Drs. Kazi Mobin-Uddin and James R. Jude in an article entitled "A New Catheter Technique of Interruption of the Inferior Vena Cava for Prevention of Pulmonary Embolism," The American Surgeon, Volume 35, page 889, December 1969. See also U.S. Pat. No. 3,540,431 to Dr. Kazi Mobin-Uddin issued Nov. 17, 1970. A similar catheter technique, but using a balloon obstruction instead of an umbrella-type obstruction, is disclosed in the article "Experimental Balloon Obstruction of the Inferior Vena Cava" by Hunter, et al., Annals of Surgery, Vol. 171, No. 3, Pp. 315-320, February 1970.

Additionally, in experimental work performed by one of the co-inventors hereof, a cardiac catheter with an inflatable disc balloon for interim closure of left-to-right shunts through the ventricular septum was used. This catheter has been described in a publication by Dr. Noel L. Mills, et al., in an article entitled "Balloon Closure of Ventricular Septal Defect," Supplement I to Circulation, Vols. XLIII and XLIV, page I-111, May 1971. See also the article by Dr. Harold King et al., entitled "Experimental Surgical Repair of Ventricular Septal Defects," SURGERY, Vol. 34, pp. 1,100 - 1,116, December, 1953.

Diverse examples of other expandible and/or umbrella-like elements generally used in other types of surgical applications are found in the following U.S. Patents:

Patent No. Inventor(s) Title Issue Date __________________________________________________________________________ 2,493,326 J. H. Trinder "Tampon For Control 1/30/50 of Intractable Nasal Hemorrhages" 2,799,273 V. J. Oddo "Haemostatic Catheter" 7/16/57 3,334,629 B. D. Cohn "Occulsive Device 8/8/67 For Inferior Vena" 3,397,699 G. C. Kohl "Retaining Catheter 8/20/68 Having Resiliently Biased Wing Flanges" 3,592,184 David H. Watkins "Heart Assist Method 7/13/71 Erwin J. Klink And Catheter" 3,671,979 Spyridon "Catheter Mounted 6/27/72 Artificial Heart Valve For Implant- ing In Close Prox- imity To A Defective Natural Heart Valve" __________________________________________________________________________

However, as should be fully appreciated and understood from the detailed description of the preferred embodiments below, all of these diverse prior art catheters and umbrella-like elements, neither collectively nor individually, anticipate or make obvious the present, pioneering and far-reaching invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature and objects of the present invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawings, in which like parts are given like reference numerals and wherein:

FIG. 1A is a schematic illustration of the heart, partially cut away, showing the applied closure structure of the present invention closing off an atrial septal defect with two of the catheter operative elements of the catheter/closure system of the present invention being withdrawn; while

FIG. 1B is similar in perspective to FIG. 1A showing a typical atrial septal defect (ASD) prior to the application of the present invention.

FIG. 1C is a perspective view of the left and right umbrella-like closure elements used for an ASD in their open or erected positions;

FIG. 2A is a side view of the left umbrella-like closure element of the present invention in its collapsed position with the inner, central hub shown in phantom lines; while

FIGS. 2B and 2C are side, cross-sectional and end views, respectively, of the inner, central hub of the left umbrella-like closure element of FIG. 2A;

FIG. 3A is a side view of the right umbrella-like closure element of the present invention in its collapsed position with the inner, central sliding sleeve shown partially in phantom lines; while

FIGS. 3B and 3C are side, cross-sectional and end views, respectively, of the inner, central sliding sleeve of the right umbrella-like closure element of FIG. 3A;

FIG. 4 is a side view of a typical strut element used in the left and right umbrella-like closure elements of the present invention;

FIG. 5 is a perspective view of three of the catheter operative elements, concentrically assembled together, which are used in the method of the present invention;

FIG. 6 is a side, perspective view, partially cut away, of the catheter operative elements with the left umbrella-like closure element attached to the central one with the struts thereof partially opened, portions of the umbrella-like element, particularly the covering material, not being illustrated for simplicity purposes; while

FIG. 7 is similar to FIG. 6 with the exception of showing the right umbrella-like closure element being affixed to the central one of the catheter operative elements and showing an additional operative element, a control disc, positioned on the proximal end of the central catheter operative element;

FIG. 8 is a side view of the cone operative element used in the method of the present invention to initially close the umbrella-like elements prior to their insertion into the outer catheter operative element;

FIGS. 9A through 9K are side, schematic views of the inner heart structure illustrating the sequential steps of the method of the present invention as being applied to the closing of an atrial septal defect (ASD); while

FIGS. 10A and 10B are right and left end views, respectively, of the umbrella-like closure elements of the present invention after being applied and locked together to close off the artrial septal defect;

FIG. 11 is a side, cross-sectional view of the central hub and sleeve structures of the left and right umbrella-like closure elements locked together in a male-female relationship;

FIGS. 12A and 12B are side, cross-sectional and side, perspective views, respectively, of two other structures allowing two other alternative methods of opening or erecting the umbrella-like structure of the right umbrella-like closure element;

FIG. 13A is a schematic illustration of the heart, partially cut away, showing the applied closure structure of the present invention closing off a ventricular septal defect with an alternate method utilizing a single umbrella-like element being used; while

FIG. 13B is similar in perspective to FIG. 13A showing a typical ventricular septal defect (VSD) prior to the application of the present invention.

FIG. 13C is a perspective view of the single umbrella-like closure element used for a VSD in its open or erected position; while

FIG. 13D is a side view of the special obturator wire used in the alternative single umbrella technique;

FIG. 14A is a schematic illustration of the heart, partially cut away, showing the applied closure structure of the present invention closing off a patent ductus arteriosus (PDA) using a modified right or second umbrella-like closure element with the final catheter operative element of the catheter/closure system of the present invention ready to be withdrawn; while

FIG. 14B is similar in perspective to FIG. 14A showing a typical patent ductus arteriosus (PDA) prior to the application of the present invention.

FIG. 14C is a perspective view of the modified left and right or first and second umbrella-like closure elements used for a PDA in their open or erected positions;

FIG. 15A is a side view of a second basic embodiment of the right umbrella-like element of the present invention shown mounted on the obturator wire prior to its being applied to the shunt; while

FIG. 15B is a side view of the embodiment of FIG. 15A as it is being applied to the shunt and being pushed t o its locking position with the left umbrella-like element; while

FIG. 15C is a close-up, side view of the central portions of the umbrella-like closure elements in their final, locked position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Closure Structure and Operative Elements

The closure structure of the present invention must be expandible, fulfilling the special requirement of being a structure which has a first, smaller physical form while it is being inserted through a blood vessel and quite a different, second, larger form when placed in its final location closing and covering the septal defect or shunt. Additionally it must meet the several stringent mechanical requirements placed upon it, must reliably open at the desired time and place, and must effect a suitably tight closure of the defect or shunt in the heart system for a long period of time without any deterioration and without producing any unwanted side-effects either on tissue or blood. Many mechanical systems are conceivable to meet these requirements and a most suitable one has been developed and tested and comprises the preferred structural embodiment of the present invention, which will now for purposes of illustration and disclosure only be described in detail.

The closure structure of the preferred embodiment of the present invention, as illustrated in FIGS. 1C, 2 and 3, comprises a pair of opposed, umbrella-like elements 8, 9, a right element 8 having a central, tapered hub 84 and a second element 9 having a central, sliding sleeve 94.

The two umbrella-like closure elements 8, 9 of the preferred embodiment of the present invention have for example six material supporting struts 81, 91, respectively, each (note FIG. 4). Each strut 81, 91 has for example a length of 5.35 mm, with a 60.degree. angle between the struts 81, 91. The struts 81, 91 are made of a radiopaque material (not necessarily metallic), for example stainless steel, which have at the distal ends thereof small projections or barbs 83, 93, respectively, of for example 0.2 mm. length, which allow anchoring of the closure elements 8, 9 into the septum. Three holes are provided along the length of the struts 81, 91 -- hinge holes 86', 96'; tie eyes 87a, 97a for raising or lowering the struts 81, 91 by means of ties or lines 7; and suture eyes 87b, 97b for attaching the umbrella material 82, 92 to the struts 81, 91. The tie holes 87a, 97a are of sufficient size to allow the ties 7 to slide easily through them.

The struts 81, 91 are attached to the umbrella-like closure elements 8, 9 through a central hub 84 and a sliding sleeve 94, respectively, made of for example stainless steel. The surfaces of the hub 84 and the sleeve 94 are grooved (note FIGS. 2C and 3C) in such a manner to allow the struts 81, 91, respectively, to lie superficially in their surfaces without adding to the exterior bulk of the umbrella-like structures. The struts 81, 91 are movably attached to the hub 84 and sleeve 94 by hinge ring elements 86, 96, respectively, and there are included ring-like strut keepers 87, 97, respectively, to prevent the struts 81, 91 from opening, respectively, beyond 90.degree.. Each umbrella-like element 8, 9 is of small enough size to allow it to be placed within the outer, thin wall catheter 1 within which it is transported during application, as described more fully below.

Thin Dacron, Teflon, nylon, silastic, pericardium or silk, for example, routinely used to be close intercardiac defects in open-heart surgery, can be used for the umbrella sheet material 82, 92, although Dacron and silk are considered preferable. The material 82, 92 should be pliable and of sufficient strength and resiliency to open and close smoothly. Although the umbrella material 82, 92 could be fanfolded between the struts 81, 91, respectively, it is preferred that instead it be stretched or extended flat over the struts. It thus retains a certain amount of resiliency which further aids in opening the umbrellas 8, 9. The material 82, 92 is anchored centrally on the hub 84 and the sliding sleeve 94, respectively between the main body thereof and the strut keepers of 87, 97, respectively. Additionally small holes 87b, 97b are made in the struts 81, 91 so that, for example, Tycron sutures 87b', 97b' can be used to secure the umbrella material 82, 92, respectively, distally upon the struts 81, 91. Additionally, supplemental sutures 87a', can be used if desired to further secure the material 82, as the eyes 87a have not been found to be otherwise necessary.

The sliding sleeve 94 and the distal hub 84 are designed to lock securely together in opposed, facing relationship by means of an internal, central, male-female mechanism (note particularly FIG. 11). A typical structure for achieving this is illustrated particularly in FIG. 11 with supplemental reference to FIGS. 2B and 3B. The hub 84 includes a small member 84' projecting inwardly and having a locking plateau 85 on its outer surface. This mates with the female cavity formed within the inner portion 94' of the sleeve 94. The female cavity also includes a locking groove 95 for mating with the plateau 85.

To total external diameter of the hub 84 is for example 3.3 mm., and it has been engineered with grooves 89 so that the struts 81 are recessed within the surface and do not occupy any additional space within the outer catheter 1. The hub 84 is tapered slightly to a rounded, bullet-shape configuration at the distal end to a diameter of for example approximately 0.075 mm. The proximal end of the hub 84 is relatively blunt and has a central threaded orifice 80 for mating with the threaded end 31 of the obturator wire 3, described more fully below. The hub 84 can be for example 3 mm. in length.

Although it has not been found to be necessary, the central sliding sleeve 94 of the right umbrella 9 could have a flared or conical distal end in order to center it automatically with respect to the hub projection 84' as a prelude to sliding up over it and along it to the locked position. The bore 90 of the right sleeve 94 is considerably larger than the diameter of the obturator guide wire 3, described below, to allow for free movement thereon.

The operative elements of the closure catheter system of the preferred embodiment of the present invention comprise several parts: an outer catheter 1; an inner, locking catheter 2; an obturator guide wire 3; a loading cone 4; a manipulating T-piece 5; and a tie retracting and control disc 6 with a series of manipulating ties 7. Note particularly FIGS. 5, 7, 8 and 9J.

The outer, thin wall catheter 1, for example a No. 24 inch French size, is of sufficient length (for example 80-105 cm) to allow its manipulation into the heart area. The outer catheter 1 can be made from thin wall, woven Dacron or preferably polyvinyl material and has a gentle curve at the cardiac end to allow easy manipulation through a septal defect in the cardia area.

As shown in FIG. 5, inside the outer, thin wall catheter 1 is a second, radiopaque, inner catheter 2 which could be for example a No. 5 French size catheter of polyvinyl. It should be of sufficient length (for example 90-110 cm.) to protrude from the proximal end of the outer catheter 1 and has a rounded, cone-shape distal hub 21. The inner catheter 2 should be of a size to be quite mobile through the outer catheter 1.

Passing through the inner catheter 2 is an obturator guide wire 3 which can be for example 1.1 mm. or less in diameter and have a length of for example 200-350 cm. A removable, proximal T-piece 5 (note FIG. 9J) is used for rotational manipulation of the obturator wire 3. The T-piece is locked to the obturator wire 3 and is easily removable therefrom by means of a locking set screw 51 going through the central hub element 53. For gripping purposes an extention arm 52 is provided.

The cardiac or distal end 31 of the obturator wire 3 is threaded for approximately 1 mm. so that it may be screwed and unscrewed into the distal hub 84 of the left closing umbrella 8. The obturator wire 3 should be of sufficient flexibility to allow easy manipulation and can be for example made of a fixed core stainless steel spring material.

As shown in FIG. 7, a control disc 6 is provided for ease in manipulating and controlling the ties or suture lines 7. The disc can be made of stainless steel and is placed on the exterior, proximal portion of the obturator wire when needed. A series of hole pairs 61 are provided about the periphery of the disc for holding the ties 7. Although not illustrated, the holes 61 could be numbered or coded to the particular struts involved and an additional pair of holes can be provided for the retracting ties 7'. The ties 7, 7' can be made of for example monofilament nylon or 3-0 silk.

The final operative element is the loading cone 4, illustrated in FIG. 8. The loading cone 4 is provided to assist in the easy loading or insertion of the umbrella-like elements 8, 9 into the outer catheter 1. For example, as shown in FIG. 8, the left umbrella 8 threaded, onto the distal end 31 of the obturator wire 3 and in its open or partially opened position, is first inserted through the loading cone 4 which leads into the outer catheter 1. The cone 4 serves to close the umbrellas 8, 9 making them of a small enough size for insertion into the outer catheter 1.

The distance across the total closure structure from hub tip to sleeve tip once locked in place is only approximately 3.5 mm. The umbrella-like elements can be produced in diameter sizes of for example 10mm., 15 mm., 20 mm., 25 mm., 30 mm., and 35 mm., as desired or needed.

Thus, an effective and reliable embodiment is provided for a typical closure structure and associated operative elements. Of course many, other structures are possible, the variations being practically limitless. For example, rather than dual, opposed umbrellas, a single umbrella could be used as described more fully below with respect to the repair of a ventricular septal defect.

Additionally the means of expanding or opening the umbrella can be easily varied. For example as generally shown in FIG. 12A the struts 91' of the right umbrella can be mechanically forced open by appropriate shoulder and flange elements 97' as the sleeve 94a is pushed and locked into the hub 84. Alternatively, as generally illustrated in FIG. 12B, the struts 91" could be made of resilient, flexible material so that the umbrella will inherently or automatically open once it emerges from the outer catheter (note the movement of the phantom lined strut).

An additional, very effective, exemplary embodiment of the right umbrella is shown in FIGS. 15A-C in which the necessity of a tie wire system is eliminated. The umbrella 209 is similar in general structure to the right umbrella 9 except that in place of the tie wire system there is included a set of elevating struts 219' hingedly attached between the regular umbrella struts 291 and the elevating sleeve 294'. As shown in FIG. 15B, as the elvating sleeve 294' comes into contact with the hub 84, the umbrella becomes erected under the continuing pressure of the inner catheter 2 until it is locked into place as shown in FIG. 15C.

Finally, although an umbrella-type structure is thought to be particularly effective, other expansion systems i.e., the elements which initially have a relatively small size for insertion and positioning and which then expand to a relatively large size when in place, are possible and likewise nearly limitless. For example, in place of the umbrella elements, a balloon(s) or other inflatable structure(s) could be used.

Typical Method of Application

For purposes of illustration and disclosure purposes only, the method of application of the present invention will now be described in detail with respect to the closing of an atrial septal defect (ASD) with particular reference to FIGS. 1A-C and 9A-K.

In order to gain access to the heart, an incision is made in either the right or left groin under local anesthesia, and the femoral vein isolated. Standard catherization techniques are then utilized to confirm the presence of the ASD such as the one shown in FIG. 1B. Once confirmed, sizing of the ASD is then achieved by means of special but standard balloon catheters, and the appropriate size of umbrella-like closure elements 8, 9 are selected.

The initial closing/catheter assembly (note FIG. 5), i.e., elements 1, 2 and 3, the latter having the left umbrella 8 attached to its threaded end 31, is then inserted via the femoral vein into the heart under continuous flouroscopic control into the right atrium. With further advancing of the catheter assembly, it is placed in the left atrium (note FIG. 9A).

By manipulating the obturator wire 3, the distal hub 84 carrying the collapsed left umbrella 8 is advanced beyond the outer, thin wall catheter 1 into the left atrium (FIG. 9B). Once the left umbrella 8 is pushed beyond the tip of the outer, thin wall catheter 1, the umbrella 8 is initially unfolded by pushing the inner catheter 2 against the struts 81 and holding fast the obturator wire 3 (FIG. 9C), expanding the umbrella out in excess of the diameter of the outer catheter 1.

Then by pulling gently on the obturator wire 3, the umbrella 8 is pulled against the distal end 11 of the outer catheter 1, opening the umbrella 8 to its full 90.degree. position (FIG. 9D). The outer catheter 1 is then pulled back into the right atria and the umbrella 8 pulled snugly against the left atrial septum, with the distal barbs 83 being anchored against the septum (FIG. 9E).

Once the left umbrella 8 is firmly fixed, the inner catheter 2 is withdrawn and removed and the right umbrella 9 slid into the obturator wire 3 and loaded into the outer catheter 1 with the retraction ties 7 and retracting ties 7' in place on the struts 91 and sleeve 94, respectively, and the disc 6 (note FIG. 7). The collapsed right umbrella 9 is then pushed through and out the outer catheter 1 by means of the inner catheter 2 into the right atrium and positioned just superior to the inferior vena cava and right atrial junction (FIG. 9F). At this point the outer catheter 1 is withdrawn to allow the right umbrella 9 to lie freely upon the obturator guide wire 3 within the body of the right atrium.

As the inner catheter 2 is advanced and traction maintained on the elevating ties 7 and on the retracting sutures or ties 7', the right umbrella 9 is opened (FIG. 9G) and pushed snugly against the inter-atrial septum by means of the inner catheter 2. By fluoroscopic monitoring, it can be determined that all six struts 91 are at right angles. The inner catheter 2 is pushed further forward, forcing the sliding sleeve 94 of the right umbrella 9 to slide onto the left umbrella hub 84, locking the two together (FIG. 9H). A clicking sensation is felt through the obturator wire 3, and a click can be heard as the umbrellas 8. 9 are locked in place. Once in place the umbrellas 8. 9 are tugged gently with the obturator guide wire 3 to assure stability.

Once the umbrellas 8, 9 are locked in place, the obturator wire 3 can be unscrewed from the distal hub 84, using the T-piece 5 on the proximal portion of the obturator wire 3, thus leaving in place the distal hub 84 with the right and left umbrellas 8, 9 locked in place (FIG. 9J). The obturator guide wires is thus unthreaded with the aid of the T-piece 5 from the left umbrella hub 84 and removed from the heart with the outer and inner catheters 1, 2 (FIG. 9K). Following this, the outer, thin wall catheter 1, the inner catheter 2 and the obturator wire 3 are completely withdrawn from the body.

Following installation of the closure structure, a diagnostic venous catheter can be introduced for the appropriate angiograms, dye curves and hydrogen electrode studies to confirm the effectiveness of the closure of the septal defect. The closure structures 8, 9 should be covered by endocardium within 6 to 8 weeks, and be thereby integrated into the heart's structure.

After completion of the operation, the vein and inguinal incision are closed.

Additional Methods of Application

For purposes of further illustration and disclosure, the method of application of the present invention will now be described in some detail with respect to the closing of a ventricular septal defect (VSD) with particular reference to FIGS. 13 A-C.

In order to gain access to the heart, an incision is made in the right neck over the external or internal jugular vein under local anesthesia. The jugular vein is isolated and venotomy is made for insertion of the outer catheter 1. Standard catherization techniques are then utilized to confirm the presence of the VSD such as the one shown in FIG. 13 B. Once confirmed, sizing of the VSD is then achieved by means of special but standard balloon catheters, and the appropriate size of the left umbrella-like closure element 8' is selected.

The outer catheter is inserted into the vein and subsequently passed into the right heart and manipulated across the ventricular septal defect into the left ventricle. Its position can be documented by obtaining an oxygen sample or passing an NIH catheter through the outer catheter into the left ventrical and doing a hand injection.

The proper size umbrella 8' similar in structure to the left umbrella 8 described above is loaded into the outer catheter and passed into the left ventricle and opened by using the inner catheter in the same manner as is carried out in closing the atrial septal defect as described above. The opened umbrella 8' is pulled snugly against the left side of the interventricular septum adjacent to the ventricular septal defect.

The outer and inner catheters are then removed from the body, leaving the obturator wire 3, and Silastic tubing 3' is passed over the guide wire 3 and subsequently into the heart to entirely cover the exposed guide wire 3.

By maintaining general pressure on the guide wire 3, the umbrella 8' is held tightly against the left side of the interventricular septum and thus closes the interventricular septal defect. The umbrella 8' is maintained in place by the barbs on the tips of the struts (like those described above) and by the obturator wire 3. Additionally the internal blood pressure system, which is greater in the left ventricle than the right (typically 90 min. Hg vs. 30 min. Hg), serves to help maintain the umbrella 8' over the VSD, closing it off.

The Silastic material 3' and the guide wire 3 are cut off at the appropriate lengths to allow anchoring them in the tissues of the right neck within the jugular vein. The incision is closed, and periodic checks are made of the umbrella 8' over the subsequent 15 minutes by fluoroscopy.

The patient is anticoagulated prior to the installation of the ventricular closing umbrella and is maintained on anticoagulation therapy for several weeks. After about 6 to 8 weeks and the umbrella 8' has been endothelialized, an incision is again made over the proximal end of the Silastic material 3' and guide wire 3 (quite close to the original incision in the neck). The guide wire 3 and Silastic outer covering 3' is isolated, and with the use of the T-piece 5 on the proximal end of the obturator wire 3, the latter is unscrewed and removed from within the heart and vascular system. The Silastic material 3' is of course removed simultaneously with the guide wire 3, and the incision closed leaving the VSD permanently closed.

Thus, the ventricular septal defect is closed with the use of only a single umbrella 8' with temporary anchoring by the guide wire 3 covered with the Silastic material 3 to prevent clotting and embolization.

To close a patent ductus arteriosus (PDA), for example like that shown in FIG. 14B, the same analogous method discussed with respect to the ASD of FIG. 1B and the steps of FIGS. 9 A-K can be used. However, because of the longer distance between the left and right outer walls of the PDA, modified aortic and pulmonary umbrella elements 108, 109 are used in place of the left and right umbrella elements 8, 9. The main modification is to extend further out the male member of the aortic umbrella 108 or alternatively the female member 194 (as illustrated in FIG. 14C). Otherwise the structure of the umbrellas 108, 109 can be identical to that disclosed in detail above with respect to the umbrellas 8, 9.

Finally, it is noted that it is advantageous to use the closure structures of the present invention even when open-heart surgery is necessary, as for example in the case of small babies. In such cases, the closure structures of the present invention can be applied through the open heart in a matter of a few minutes as opposed to the typical 30 to 40 minutes usually taken with standard suturing of the shunt as practiced in the prior art.

Thus atrial septal defects (FIG. 1) and in similar fashion ventricular septal defects (FIG. 13) and great vessel shunts (FIG. 14) are closed by non-invasive techniques. The closure catheter system of the present invention is efficient and with proper caution is safe. The addition of the opening and retracting ties 7, 7' greatly increases the safety of the device. Although it has not yet been found to be necessary to use the retracting eyes or holes 87a and ties for the left struts 81, they may be used if desired.

From past experience with cardiac surgery, stainless steel, particularly of the 300 series, which is the preferred material for all structural parts remaining in the heart, and materials such as Dacron, Teflon, nylon, percardium, Silastic and silk can be permanently inserted within the heart and tolerated without adverse effects. It is estimated that the heart will endothelialize the closure elements within 6 to 8 weeks as occurs after standard shunt closures using open-heart surgery.

Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirements of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.

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