Having completed his internship, Thomas N. P. Johns returned to the laboratory as William S. Halsted Fellow of 1947-48. The development of a technique for the production of an interatrial septal defect as a possible method of treatment of transposition of the great vessels had occurred during the year of his absence. We continued, however, to attempt to produce transposition, still without success.
One of his major efforts was in relation to the treatment of mitralvalve insufficiency, for which no satisfactory method of treatment had been developed. Usually caused by rheumatic inflammation of the mitral valve, leaflets become thickened and scarred. The chordae tendinae become involved and there is sufficient loss of motion to prevent the valve leaflets from approximating properly during systole. The edges of the leaflets are irregular and there is no standard contour shape or form to the orifice in the condition. Johns set out to make a prosthesis that would be mobile and at the same time conform to whatever shape or contour the valve's edges might have. He tried several materials -- inverted vein or pericardial sacs filled with blood and blood-filled sacs made of plastic film -- none of which worked satisfactorily.
Using a piece of polyvinyl sponge (Ivalon), he fashioned a prosthesis with an elliptical body with cylindrical extensions on each end for anchoring. The elliptical portion of the prosthesis was suspended between the commissures parallel to the apposing edges of the mitral valve leaflets (see figs. 38, 39, 40). The results were quite satisfactory, and the prostheses were well tolerated. Autopsies revealed that they had been properly placed and were still mobile. The prostheses were covered with endothelium with no thrombi attached.43 This was one of many steps taken before artificial circulation made open-heart procedures possible under direct vision. After completing his surgical residency in 1952, Dr. Johns went to the Medical College of Virginia as Assistant Professor of Surgery in 1953 and is currently in private practice in Richmond.
There was, and still is, much interest in and emphasis on coronary heart disease. Many investigators were at work in the attempt to increase the blood supply to the myocardium. We were evaluating the procedure of Dr. Claude Beck, of Cleveland, who attempted to increase the circulation in the myocardium by reversing the coronary blood flow through the coronary sinus. If this could be accomplished, blood could be supplied to