Hemodynamic Comparison of the On-X and Top Hat Mechanical Aortic Valve Prostheses

• Published in: The Annals of thoracic surgery Vol. 118; no. 3; pp. 615 - 622
• Main Authors: Juarez-Casso, Fernando M., Cangut, Busra, King, Katherine S., Lee, Alex T., Stulak, John M., Schaff, Hartzell V., Greason, Kevin L.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.09.2024
• Subjects: Aged; Aortic Valve - diagnostic imaging; Aortic Valve - surgery; Aortic Valve Stenosis - surgery; Echocardiography; Female; Follow-Up Studies; Heart Valve Prosthesis; Heart Valve Prosthesis Implantation - methods; Hemodynamics - physiology; Humans; Male; Middle Aged; Prosthesis Design; Retrospective Studies
• ISSN: 0003-4975; 1552-6259; 1552-6259
• DOI: 10.1016/j.athoracsur.2024.04.003

There are limited data comparing hemodynamic valve function in mechanical aortic valve prostheses. This study compared the hemodynamic function of 2 commonly used mechanical aortic valve (AV) prostheses, the On-X (Artivion) and Top Hat (CarboMedics Inc) valves. This study was a retrospective analysis of 512 patients who underwent AV replacement with the On-X (n = 252; 49%) or Top Hat (n = 260; 51%) mechanical valves between 2011 and 2019. Patients were matched on the basis of selected variables. Echocardiographic data were collected preoperatively and postoperatively over a median follow-up of 1.39 years. A total of 320 patients were matched, 160 patients in each group. Despite being matched for left ventricular outflow tract diameter, patients in the Top Hat group received a greater prevalence of smaller tissue annulus diameter valves (≤21 mm) (83% vs 38%; P < .001). Patients in the On-X group had longer aortic cross-clamp times (78 minutes vs 64 minutes; P < .001) during isolated aortic valve replacement. Discharge echocardiography showed no difference in the AV area index between both groups (1.00 cm2/m2 vs 1.02 cm2/m2; P = .377). During longer-term echocardiographic follow-up, the AV area index remained stable for both valves within their respective tissue annulus diameter groups (P = .060). There was no difference between the 2 valves with respect to the AV area index at discharge, and hemodynamic function was stable during longer-term follow-up. The longer aortic cross-clamp time observed in the On-X group may indicate increased complexity of implantation compared with the Top Hat group.