Background and aim of the study: Aortic valve replacement can result in patient-valve mismatch and attenuated left ventricular remodeling. Using CarboMedics mechanical valves, we examined if the supraannular Top Hat prosthesis provided a size advantage over the intraannular valve.
Methods: Seventeen patients with aortic stenosis and aortic root < or = 23 mm were randomized to receive a CarboMedics supraannular Top Hat valve (n = 7) or an intraannular valve (n = 10). Doppler echocardiography was performed preoperatively, and after three months.
Results: There was no difference in aortic annulus size, but mean prosthesis size was significantly larger in the Top Hat group than in the intraannular group (25.00 mm versus 21.60 mm); the mean size improvement for Top Hat patients was 3.14 mm. After three months, all patients had excellent functional improvement and low transvalvular pressure gradients, with slightly higher effective valve opening area in the Top Hat group.
Conclusion: The supraannular Top Hat valve provides an advantage of one to two sizes over the intraannular valve, and improves the effective valve opening area. Both valves offer favorable hemodynamic performance and functional improvement.