Clinical Outcomes and Definitions
We reviewed all relevant clinical outcomes including all-cause mortality, aortic valve reoperation, recurrent endocarditis, and New York Heart Association (NYHA) functional class. Operative mortality was defined as any death within 30 days, or at any time during the same hospital stay. Postoperative morbidity was defined as major adverse cardiac and cerebral events (stroke or myocardial infarction), respiratory failure (prolonged mechanical ventilation >48 hours, tracheostomy, or need for reintubation), acute renal failure requiring renal replacement therapy, and requirement of new permanent pacemaker. Long-term clinical outcome data including NYHA functional class, recurrence and reoperations were obtained for all patients by personal contacts via phone interviews and office visits. Residents/fellows and junior attending surgeons were considered as a primary surgeon only when they performed all or most of the key portions of the operation. Mean follow-up was 2.2 years (range: 0.1 to 9.1 years).