The CarboMedics supra-annular Top Hat valve improves long-term left ventricular mass regression.

Objective: The present study aimed to identify potential differences in hemodynamic performance between the supra-annular CarboMedics Top Hat valve and the intra-annular CarboMedics standard valve in terms of the long-term left ventricular mass reduction and transvalvular gradients.

Methods: We retrospectively reviewed a series of 186 consecutive patients who had undergone aortic valve replacement with a small size mechanical prosthesis at our institution from 2003 to 2013, receiving either a CarboMedics Top Hat valve (53 patients, valve size, 21 mm in 52.8% and 23 mm in 47.2%) or a CarboMedics standard prosthesis (133 patients, valve size, 19 mm in 14.3% and 21 mm in 85.7%).

Results: The in-hospital mortality was 9.4% and 11.3% in the Top Hat and standard groups, respectively (P = .71). The mean percentage of left ventricular mass reduction was greater in the Top Hat group (33% ± 15.8% vs 20.1% ± 16.6%, P < .001). The mean postoperative peak aortic gradient was lower in the Top Hat group (19.9 ± 8.9 vs 29.6 ± 8.6 mm Hg; P < .001). Spearman analysis showed a positive correlation between the indexed effective orifice area and the percentage of left ventricular mass reduction (Rho = +0.65, P = .02). The survival in the Top Hat group was 79.7% and 71.7% at 5 and 10 years, respectively. In the standard group, survival was 66.8% and 61.5% at 5 and 10 years, respectively (log-rank test, 0.19). Cox regression demonstrated severe myocardial hypertrophy (hazard ratio, 2.559; 95% confidence interval, 1.095-5.981) as one of the independent predictors of survival.

Conclusions: The Top Hat valve surpasses hemodynamically the intra-annular valve. We suggest the supra-annular Top Hat prosthesis can be especially recommended for patients with a small aortic root and severe myocardial hypertrophy.