Background and aims of the study: It has been shown that although stentless porcine aortic valves have better hemodynamic features than stented porcine valves, their long-term durability remains unknown. This study was undertaken to examine the long-term clinical outcome of aortic valve replacement (AVR) with stentless porcine aortic valves.
Methods: Between 1987 and 1989, custom-made stentless valves were implanted in 29 patients (mean age 58 years), and between 1991 and 1997, the Toronto SPV was implanted in 213 patients (mean age 63 years). In addition to AVR, one-third of the patients had coronary artery bypass. All patients were followed up at annual intervals and underwent Doppler echocardiography.
Results: There were two operative and 11 late deaths (four cardiac, seven non-cardiac). The actuarial survival rate was 89 +/- 4% at nine years. There were two strokes and seven transient ischemic attacks; freedom from thromboembolic complications was 92 +/- 4% at nine years. Two patients developed infective endocarditis, one early and one late; freedom from prosthetic valve endocarditis was 98 +/- 1% at nine years. Freedom from primary tissue failure was 85 +/- 8% at nine years. Seven patients required repeat AVR, because of endocarditis (two) and aortic insufficiency (five); freedom from repeat AVR was 82 +/- 8% at nine years. Periodic hemodynamic assessment by echocardiography indicated that the mean systolic gradients across the valve decreased during the first year of implantation, the valve effective orifice increased, and valve competence remained stable.
Conclusions: Stentless porcine aortic valves have provided excellent clinical results. These valves may suffer degenerative changes and fail at the same rate as stented porcine aortic valves but, because of their superior hemodynamic performance, they may enhance patients' survival by allowing complete regression of left ventricular hypertrophy and restoration of normal ventricular function.