Allograft aortic valve replacement: long-term follow-up

Area of Science:

• Cardiac Surgery
• Transplantation Immunology
• Biomaterials Science

Background:

• Aortic valve replacement (AVR) is a critical procedure for managing aortic valve disease.
• Allograft aortic valves have been utilized in AVR, with evolving preservation techniques influencing outcomes.
• Previous methods involved nonviable, refrigerated allografts, raising concerns about long-term efficacy.

Purpose of the Study:

• To compare the long-term outcomes of AVR using nonviable, refrigerated allografts versus viable, cryopreserved allografts.
• To evaluate differences in mortality, survival rates, thromboembolic events, endocarditis, and structural valve deterioration between the two allograft preservation methods.

Main Methods:

• Retrospective analysis of 804 patients undergoing AVR with allograft aortic valves.
• Series I (n=124): Nonviable allografts, sterilized and stored at 4°C for weeks.
• Series II (n=680): Viable allografts, cryopreserved within hours of collection.

Main Results:

• Series II demonstrated significantly lower 30-day mortality (2.8% vs. 8.9%) and improved 15-year actuarial survival (62% vs. 56%) compared to Series I.
• Freedom from structural deterioration at 15 years was markedly higher for cryopreserved allografts (80% vs. 45%).
• Thromboembolic events and endocarditis rates were low and comparable between series, with better freedom from valve incompetence and reoperation in Series II.

Conclusions:

• Early cryopreservation of viable allograft aortic valves significantly enhances long-term patient survival and reduces structural valve deterioration compared to older refrigeration methods.
• The findings underscore the superiority of cryopreservation in improving the durability and clinical performance of allograft valves for aortic valve replacement.
• Advancements in allograft valve preservation techniques are crucial for optimizing outcomes in cardiac valve surgery.