Outcome after aortic valve replacement: comparison of homografts with mechanical prostheses.

BACKGROUND AND AIM OF THE STUDY

Aortic valve replacement (AVR) in younger patients is conventionally performed using a mechanical prosthesis (MP), although homograft (HG) implantation is an accepted alternative. This study compares, retrospectively, the follow up of these two dissimilar prostheses.

METHODS

Since 1990, a total of 147 Sorin Bicarbon MPs and 285 HGs have been implanted at the authors' institution, and compared statistically for survival, reoperation rate and valve-dependent complications. Only patients aged <70 years were included in the study.

RESULTS

The demographic parameters of both patient groups differed with regards to gender, age at the time of implantation, and duration of follow up. Survival was superior in the HG group (log-rank, p = 0.01). Sixteen of 42 late deaths in the MP group were valve-related due to cerebral infarction (n = 7), ventricular arrhythmias (n = 3), or ventricular failure (n = 6). Six of 24 deaths after HG implantation were valve-related (all prosthesis infections). The choice of valve type and patient age were independent risk factors in the multivariate analysis. Freedom from reoperation was superior after MP implantation (log rank, p = 0.007); in six MP patients the indications for redo surgery were prosthesis infection (n = 2) and paravalvular leak (n = 4). In 20 HG patients, redo surgery was required due to prosthesis infection (n = 12), stenotic degeneration (n = 2), regurgitation > grade II (n = 4), or paravalvular leak (n = 2). Age at the time of implantation and valve type were independent risk factors. Thromboembolic complications were mainly seen in MP patients (log rank, p <0.001): there were five ischemic infarctions and 11 transient ischemic attacks (TIAs) compared to three TIAs among HG patients. Cerebral bleeding was found in only 18 cases after MP implantation, and in no cases after HG implantation. In the multivariate analysis, the type of prosthesis was an independent risk factor.

CONCLUSION

As expected, these data confirm a longer time period without need for reoperation after MP implantation, but demonstrate a significantly higher survival and fewer complications after AVR with HG.