ALLOGRAFT AORTIC-VALVE REPLACEMENT - LONG-TERM FOLLOW-UP

Aortic valve replacement using an allograft aortic valve has been performed on 804 patients. From December 1969 to May 1975, 124 patients received a nonviable allograft valve sterilized by incubation with low-dose antibiotics and stored for weeks by refrigeration at 4 degrees C (series 1). From June 1975 to January 1994, 680 patients received viable allograft valves, now cryopreserved early within 2 hours of collection from transplant recipient donors, 6 hours for multiorgan donor valves and 23 hours (mean) for autopsy valves from donor death. The 30-day mortality was 8.9% +/- 5% (95% confidence limits) for series I and 2.8% +/- 1% (95% confidence limits) for series II. Actuarial patient survival including hospital mortality at 15 years was 56% +/- 5% for series I and 62% +/- 5% for series II. The probability of a thromboembolic event was low, freedom at 15 years being 95% +/- 1% for patients receiving allografts with or without associated coronary bypass procedures and 81% +/- 5% for patients having allografts with other associated procedures (eg, mitral valve operations). Actuarial freedom from endocarditis was similar for the two series, 91% +/- 3% (series I) and 94% +/- 2% (series II) at 15 years. The freedom from valve incompetence, from reoperation for all causes, and from structural deterioration demonstrated clearly the inferiority of the 4 degrees C stored allograft valves. For structural deterioration as identified clinically, at reoperation and at death, freedom from this event at 15 years was 45% +/- 6% for series I and 80% +/- 5% for series II (p value for the difference is 0). The attrition rate appears highest in young patients and in those not receiving a viable cryopreserved valve. An important immunologic response can be unfavorable in some young patients, producing valve deterioration. But for the majority of patients, the viable cryopreserved allograft valve offers low morbidity with a good extended lifestyle and is superior to the 4 degrees C stored valve.