Wednesday Morning, May 5, 1954

9:00 A.M. Scientific Session: REGULAR PROGRAM.

31. The Surgical Correction of Mitral Insufficiency by Valvular Suturing.

Charles P. Bailey, W. L. Jamison (by invitation), H. T. Nichols (by invitation),

and A. Bakst (by invitation), Philadelphia, Pa.

The causes of clinical mitral insufficiency are classified. Some may be ignored. Some are presently incorrectable. Some may be alleviated by commissurotomy for associated mitral stenosis; the anterior commissure tends to retain full competence.

The reasons for the great frequency of incompetence in the posterior portion of the mitral valve are illustrated. It has been possible to devise a method of corrective suturing of this commissure with or without the addition of grafted tissue to correct an actual or relative lack of valvular substance.

Ninety-four of over 380 patients with proven mitral insufficiency have been definitely treated by valvular suturing by all developmental techniques with an over-all mortality of 27%. The newest technique utilizes a special "sewing machine" which obviates the former dangerous trans-ventricular approach. A mortality of 10% or less is expected.

The mitral stitcher consists of a flat instrument similar to our guillotine knives with an underbeak and a sliding spear-like knife three millimeters in width. This knife has a diagonal slot which picks up the suture as it punctures the valvular substance after the beak has been placed under the ventricular aspect of the valve cusp. By two passages of a right and left instrument, both valve leaflets are perforated and the sutures are applied through them. This non-living suture material is then replaced by strips of pericardium to form a living graft suture. This is done entirely through the auricular appendage.

32. The Surgical Correction of Mitral Insufficiency.

Dwight S. Harken, Harrison Black, Laurence B. Ellis (by invitation)

and Lewis Dexter (by invitation), Boston, Mass.

The pathology of mitral insufficiency and a morphologic classification are presented.

At the operating table the exploring finger can be inserted through the auricular appendage to the region of the mitral valve and block the regurgitant jet. This is commonly associated with prompt elevation of blood pressure, presumably due to increased aortic output. This simple demonstration of kinetic pathology and its correction affords a starting point for understanding some fundamental aspects of this peculiarly "self-aggravating" disease. Regurgitation from absolute leaflet insufficiency is followed by compensatory dilatation of the left ventricle. This in turn produces a larger mitral annulus, increasing relative leaflet insufficiency, further aggravating regurgitation, thus initiating a vicious cycle. Conversely, a lucite prosthesis can reverse this cycle. This simple maneuver at the operating table helps to emphasize the absolute necessity of preserving leaflet mobility.

Experience with mitral insufficiency spanning the past five years will be discussed. The place for simple valvuloplasty with improvement of leaflet mobility in combinations of stenosis and regurgitation is recognized. Forty-three baffle procedures of various types and the evolution of the current spindle baffle operation will be reviewed. The technique of inserting the spindle baffle will be demonstrated in moving pictures.

33. Four Years Clinical Experience with Internal Mammary Artery Implantation in the Treatment of Human Coronary Artery Insufficiency Including Additional Experimental Studies.

Arthur Vineberg, D. D. Munro (by invitation), Herman Cohen

(by invitation) and William Buller (by invitation), Montreal, Canada

In previous publications we have shown that the internal mammary artery after implantation into the left ventricular wall branches and forms anastomoses with the left coronary circulation. The value of this extra coronary blood source has been shown by survival ligation studies and by the experimental production and treatment of coronary artery insufficiency. One can measure the amount of blood delivered to the left ventricular myocardium by an implanted internal mammary artery. This may be of value in relation to the total work of the heart.

After implantation, the internal mammary artery forms mammary-coronary anastomoses in from 60 to 70 per cent of our animals. A pericardial vascular fat pad has been used to supplement the artery transplant. The fat is separated from the fibrous pericardium of the left ventricle and the latter entirely cut away. The epicardium is then removed from areas of the left ventricle after the internal mammary artery has been implanted. The vascular fat blanket is then applied to the left ventricle so that its vessels lie in direct contact with the ventricular muscle interspaces.

Thirty cases of human coronary artery .insufficiency treated by internal mammary artery implant have been followed for from 3 months to 3½ years. The results have been encouraging. Angina pectoris slowly disappears after implantation. Improvement is steady and can be correlated with the time that the internal mammary artery is known to send out new branches. Exercise tolerance likewise improves and many patients previously totally disabled have returned to full time active occupations.

34. Anatomic, Physiologic and Surgical Considerations in Closure of Atrial Septal Defects in Man.

John W. Kirklin, Earl H. Wood (by invitation), Jesse E. Edwards (by invitation)

and Howard B. Burchell (by invitation), Rochester, Minn.

The various anatomic and physiologic features of atrial septal defects as seen at the Mayo Clinic are reviewed. In certain cases of atrial septal defect, the orifices of the right pulmonary veins are very near the defect. This permits some preferential shunting of blood from the right lung across the defect. In a few cases, there are actual anatomic anomalous pulmonary venous connections so that the veins from the right lung drain directly into the right atrium. Small and large right-to-left shunts are discussed.

Experience in 5 patients is reviewed, with surgical closure of the defect using an atrial well. There were no deaths. Some points of technic, including the use of a polyvinyl plastic sponge for closure of the defect, are reviewed. The technic employed in cases in which there is anomalous connection of the right pulmonary veins to the right atrium, as well as an atrial septal defect, is emphasized. Preoperative and postoperative data obtained at cardiac catheterization are presented in detail.

35. Aortic Arch Resection and Grafting for Aneurysm Employing an External Shunt.

Allan Stranahan, Ralph D. Alley (by invitation), William H. Sewell

(by invitation) and Harvey W. Kausel (by invitation), Albany, N. Y.

The procedure of choice in the surgical management of aneurysms of the intra-thoracic aorta is excision, with restoration of normal blood flow in the parent vessel. The application of this ideal in treating aneurysms which require temporary aortic occlusion, except for those complicating coarctation, has awaited the development of an adequate and safe means of diverting the blood flow during the period of aortic obstruction.

In two cases of aneurysm of the intrathoracic aorta treated by surgical excision and grafting, the aortic blood flow was diverted through a shunt of large caliber for periods of six hours and forty-five minutes and three hours and twenty minutes, respectively.

The first case was a fusiform and saccular leutic aneurysm of the entire intrathoracic aorta which was excised and replaced by a heterologous freeze-dried graft. The procedure was technically achieved but the patient expired during recovery from anesthesia as the result of hemorrhage from the pulmonary artery stump of an incidental pneumonectomy.

The second case is a classical post-traumatic saccular anerrysm of the first portion of the descending aorta accompanied by a patent ductus arteriosus, treated by partial aortic resection, homologous freeze-dried graft replacement, and division of the ductus.

The false preoperative estimate that the second case would be amenable to local excision and aortorrhaphy supports our thesis that a shunt and suitable graft should always be available when a case of intrathoracic aneurysm is explored.

36. Resection of the Thoracic Aorta with Replacement by Homograft for Aneurysms and Constrictive Lesions.

Denton A. Cooley and Michael E. DeBakey, Houston, Texas

Excision of aneurysms and constrictive lesions of the aorta provides the optimum method of treatment wherever conditions permit its satisfactory application. For sacciform aneurysms usually of the arch, excision of the lesion with lateral aortorrhaphy may be feasible; but for fusiform aneurysms, some large sacciform lesions, and many constrictive lesions, extirpation of the lesion requires sacrifice of a segment of aorta with restoration of continuity by aortic homograft. Application of this latter technic involves periods of temporary aortic occlusion for approximately one hour and tissues distal to the occlusion may suffer irreversible damage from anoxia. The central nervous system is most vulnerable; where the temporary occlusion is of the thoracic aorta, cerebral and spinal cord damage is likely to prevent a successful outcome. In constrictive lesions the collateral arterial circulation is well developed and prolonged aortic occlusion is easily tolerated.

This report deals with our experience with cases where lesions involved various areas of the thoracic aorta, including the distal portions of the arch and where segments up to 22.5 cm. in length were resected with restoration of continuity by aortic homograft. Certain technical aspects of the problem will be considered with particular reference to choice of approach, choice and preparation of the graft, and methods of prevention of central nervous system damage during temporary aortic occlusion, including the use of general body hypothermia for this purpose.