Aortic valve allografts for mitral valve replacement.

Between May, 1967, and April, 1971, 122 patients underwent mitral valve replacement with fresh aortic valve allografts mounted on rigid support rings. The operative mortality rate was 6.6 percent. Current evaluation was obtained on all patients; the average postoperative follow-up interval for surviving patients is 4.8 years (range, 3.3 to 7.1). Survival rates 1, 2, and 5 years after mitral valve replacement are 89, 86, and 71 percent, respectively. The average functional class of 90 current survivors is 1.6, as compared to 2.9 preoperatively. Thirty-six thromboembolic episodes have occurred in 28 patients, generating a thromboembolism rate of 7 percent per patient year of analysis. Allograft valve dysfunction has occurred in 64 patients, requiring reoperation in 16 and causing death in two. The linearized valve dysfunction rate is 13 percent per patient year. Pathological examination of recovered allograft valves revealed predominantly leaflet fibrosis and calcification, acellular collagenous valve matrix, and infiltration with chronic inflammatory cells. The results of this long-term analysis indicate that mitral valve replacement with fresh aortic allografts provides significant functional improvement and an acceptably low rate of thromboembolism. However, the time-related rate of allograft valve dysfunction is unacceptably high and does not justify further clinical use of this type of bioprosthesis.     

Stented pulmonary valve allografts as tricuspid valve substitutes in sheep: Their macroscopic and microscopic decline

In sheep, stented pulmonary semilunar valves have been allografted as tricuspid valve substitutes and their biological behaviour has been followed postoperatively. Whereas there was initial pleasing function with normal cusp competence, by day 102 the cusps had retracted to partial incompetence. This process of valve decline was accentuated by day 150, and by day 241 was complete. Histological studies at day 150 showed cusp foreshortening, with scant nuclei and collagen looser than normal. These findings suggested that the mechanism causing the valve decline was a host to foreign body reaction rather than the usual histological pattern of graft rejection.     

Aortic allografts and pulmonary autografts for replacement of the aortic valve and aortic root

Background. Extensive experience has accumulated with the use of aortic and pulmonary autografts for replacement of the aortic valve and the aortic root. Three general techniques for insertion have been used: subcoronary (free-hand) valve implantation, mini- or inclusion-root implantation, and aortic root replacement. Thirty-day mortality for elective operations with all of these techniques has not exceeded 5%. Thromboembolic episodes have been rare, and endocarditis has occurred infrequently. Early hemodynamic performance has been excellent, without significant gradients or valve regurgitation in the majority of patients.

Methods and Results. Progressive aortic regurgitation has been observed with continued follow-up, and is the most important complication of both types of valves. Leaflet failure and technical problems are the major causes of reoperation for patients receiving aortic allografts. There is some evidence to suggest that the prevalence of these complications is lower with the root replacement technique than with the intraaortic implantation methods.

Conclusions. Reoperation for regurgitation of the neo-aortic valve is the major complication of the pulmonary autograft procedure. The incidence of reoperation appears to be lowest with the root replacement technique. Certain conditions (acute rheumatic fever, juvenile rheumatoid arthritis, systemic lupus, ankylosing spondylitis, Libman-Sachs endocarditis, and possibly a dilated aortic root) may be contraindications to the use of a pulmonary autograft. Reoperation on the pulmonary allograft that is used to replace the autograft may be necessary in up to 20% of patients at 20 years.     

Aortic valve lipoma

Cardiac lipoma (especially on the aortic valve) is extremely rare. We report a patient suffering from shortness of breath, chest pain, and recent presyncopal episodes who was found to have a mass on the aortic valve with mild aortic regurgitation. The patient had an uneventful aortic valve replacement.     

Aortic valve replacement in octogenarians

Background and Aims  

As our population ages and life expectancy increases the number of people aged over 80 and more referred for cardiac surgery is growing. This study sought to identify the outcome of aortic valve replacement (AVR) in octogenarians.     

Aortic reconstruction in patients with functioning renal allografts

Patients with functioning renal allografts requiring aortic reconstruction pose a considerable challenge to the vascular surgeon. A variety of strategies for renal allograft preservation during intervention have been described including hypothermia, indwelling shunts, cold renal perfusion, axillofemoral bypass, and endovascular stent-grafting. Reported here are two cases of successful aortic reconstruction utilizing standard open surgical techniques designed simply to minimize warm renal ischemia. The first case was that of a 55 year-old patient with a functional renal allograft originating from the right external iliac artery, who presented acutely with large symptomatic aortic and bilateral iliac artery aneurysms. He was treated with aorto-right femoral/left iliac bypass grafting. The right femoral anastomosis was performed first so that warm renal ischemia was limited to the 34 min required to perform the proximal end-to-end aortic anastomosis. The second case was that of a 44-year-old patient also with a transplanted kidney originating from the right external iliac artery. He presented with worsening hypertension, decreasing renal function, claudication, and severe aortoiliac occlusive disease. He was treated with aorto-left femoral bypass grafting via a retroperitoneal approach, followed by femorofemoral crossover bypass for retrograde perfusion of the kidney (total warm ischemia time 20 min). Both patients recovered uneventfully without a decrement in renal function and remain well on follow-up. It is concluded that standard open surgery without adjunctive shunts or bypasses remains a viable treatment option for these patients, provided warm renal ischemia can be minimized.     

Aortic valve sparing operations

Aortic valve sparing operations were developed to preserve the aortic valve in patients with ascending aortic aneurysm and aortic insufficiency or patients with aortic root aneurysm. There are 2 types of aortic valve sparing operations, remodeling of the aortic root and reimplantation of the aortic valve. The author believes that remodeling of the aortic root is more appropriate for older patients with ascending aortic aneurysm, dilated aortic sinuses, and normal aortic annulus, whereas reimplantation of the aortic valve is more appropriate for young patients with aortic root aneurysm in whom dilation of the aortic annulus is commonly associated. Although remodeling of the aortic root has been extensively used in patients with aortic root aneurysm, the long-term results are somewhat inferior to reimplantation in most series. The late results of aortic valve sparing operations have been excellent, and these operations have become an important addition to the surgical armamentarium to treat patients with proximal aortic aneurysms.