Statistical Analysis
Pre-operative and post-operative echocardiography were compared using the 2-tailed paired t test for peak transvalvular gradient across the AV. Statistical significance was set at P < 0.05. Overall freedom from reoperation was determine by Kaplan-Meier analysis and is expressed as the percentage of patients who remained event free. If patients had multiple re-operations, the number of days to the first re-operation was used for the analysis. If patients had no listed re-operations, it was assumed that the material was alive at the date of censorship.