The performance of the supra-annular Top-Hat aortic valves compared to the standard Carbomedics valves

Background: The CarboMedics Top-Hat aortic valve prosthesis was designed to be implanted in a supra-annular position. This study aimed to compare the hemodynamic performance of the Top-Hat aortic prostheses versus the standard CarboMedics aortic valve prostheses. Methods: The study included 98 patients who had aortic valve replacement and were divided into two groups. Group A included 60 patients who had standard aortic valve prostheses, and Group B included 38 patients who had the Top-Hat aortic prostheses. The study endpoints were hospital outcomes, the effective orifice area, and the pressure gradient during a one-year follow-up. Results: There was no significant difference in the baseline echocardiographic data and risk factors between the groups. The patients who had Top-Hat aortic prosthesis were younger, with a mean age of 47.5 (44-55) years, and those who had the standard prosthesis were 53.5 (48-56) years old (P= 0.02). The cardiopulmonary bypass time was significantly less in the Top-Hat prosthesis group with an average of 78 min (75- 81) compared to 88 min (84- 95) in the other group (P ˂0.001). The effective orifice surface area was significantly larger in the group with Top-Hat prosthesis; 0.9 mm/m2 (0.88- 0.92) compared to 0.84 mm/m 2 (0.79- 0.87) for the standard aortic valve prosthesis group (P ˂0.001). The pressure gradient over the aortic valve decreased significantly postoperatively (coefficient -1.98 (-2.21- -1.75); P˂0.001). Patients with Top-Hat valves had significantly lower gradient (coefficient: -4.22 (-6.61- -1.82); P= 0.001), while age had no effect on the pressure gradient (coefficient: 0.1 ( -0.07- 0.27); P= 0.25). Conclusion: The Top-Hat CarboMedics prostheses could be superior to the standard CarboMedics aortic valve prosthesis regarding the effective orifice area and pressure gradient over the valve.