Aortic valve replacement with stentless porcine aortic valve: a pioneer series

Durability of stentless porcine aortic valves is determined by the resistance of the cusps to mechanical fatigue and reactions by the host. This study examines the role of mismatch between the size of the valve and the diameter of the sinotubular junction on durability of the valve. A custom-made stentless porcine aortic valve designed for implantation in the subcoronary position was used for aortic valve replacement in 29 patients. There were 15 men and 14 women, with a mean age of 58 years (range 26 to 72 years). In addition to aortic valve replacement, 6 patients had mitral valve surgery, 10 patients had coronary artery bypass graft, 1 patient had closure of an atrial septal defect, and 1 had concomitant aortobi-iliac bypass graft. Follow-up time extended from 10.3 to 11.5 years and was complete. The selection of size of valve implanted was based solely on the diameter of the aortic annulus. Because the diameter of the sinotubular junction plays an important role in leaflet motion and valve competence, the size of valves was compared with the diameter of the sinotubular junction of the aortic roots where they were implanted. There was one operative death and five late deaths. There were no valve-related deaths. The actuarial survival at 10 years was 76%+/-5%. There were only two transient ischemic attacks and no strokes. One patient developed endocarditis 4 years' postoperatively and was successfully treated with aortic valve re-replacement. One patient with cardiomyopathy had heart transplantation. Thus, the stentless valve was at risk of failure in 21 patients. Nine patients developed echocardiographic evidence of valve dysfunction: seven had aortic valve re-replacement and two continue to be observed because the dysfunction is not severe. The function of the stentless valve remained normal in 12 patients. Patients with bioprosthetic valve dysfunction had a sinotubular junction 3.2+/-1.3 mm larger than the size of the valve, whereas patients with normal bioprosthetic valve function had a sinotubular junction 0.8+/-1.2 mm larger than the size of the valve (P = .01). The durability of stentless porcine aortic valve implanted in the subcoronary position is affected by discrepancies in diameters between the xenograft valve and the sinotubular junction of the aortic root. Sinotubular junction greater than the size of the stentless valve probably increases mechanical stress on the cusps and causes premature valve failure.