Evolution of allograft aortic valve replacement over 13 years: results of 275 procedures.

OBJECTIVE: We describe our center's experience with the use of allografts for aortic valve or root replacement, illustrating the impact on outcome of the changes made in surgical and preservation techniques.

METHODS: Between 4/1987 and 1/2001 275 allografts were used in 267 consecutive patients to replace the aortic valve or root. All patients were prospectively followed over time. Mean patient age was 46 years (SD 16; range 0.06-83), male/female ratio was 201/74. Prior cardiac operations took place in 73 patients; 49 patients presented with active endocarditis. Pre-operative NYHA-class was III in 51%. Initially, the subcoronary technique was used (SC; N=95) while in recent years root replacement (ARR; N=180) became the technique of choice. Seven fresh (two pulmonary and five aortic) and 268 cryopreserved (four pulmonary and 264 aortic; 35 glycerol and 233 DMSO) allografts were implanted. Concomitant procedures took place in 133 (48%).

RESULTS: Operative mortality was 5.5% (N=15) and during follow-up (99% complete) 29 more patients died. Overall cumulative survival was 73% (95% CI 65-81%) at 9 years postoperative and significantly better for SC compared to ARR patients (P=0.005). Freedom from allograft-related reoperation (N=34) was 77% (95% CI 69-85) at 9 years, and worse in the SC compared to ARR group due to increased early technical failure (P=0.03). Freedom from reoperation for structural valve deterioration (SVD; N=22) was 81% (95% CI 73-89) at 9 years and did not differ between SC and ARR (P=0.51). Independent predictors of degenerative SVD were younger patient age (HR 0.93 with age as continuous variable; 95% CI 0.90-0.97), older donor age (HR 1.06 with age as a continuous variable; 95% CI 1.00-1.11), larger allograft diameter (HR 1.38; 95% CI 1.11-1.71) and the use of pulmonary allografts (HR 10.72; 95% CI 3.88-29.63). Calculated median time to reoperation for structural valve deterioration ranged from 23 years in a 65-year-old patient to 12 years in a 25-year-old.

CONCLUSIONS: Aortic valve replacement with allografts yields adequate midterm results. Although important changes have been made over the years to improve durability, allografts still have a limited life span especially in young patients.