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

Fernando M Juarez-Casso; Busra Cangut; Katherine S King; Alex T Lee; John M Stulak; Hartzell V Schaff; Kevin L Greason

doi:10.1016/j.athoracsur.2024.04.003

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

Ann Thorac Surg. 2024 Apr 16:S0003-4975(24)00287-X. doi: 10.1016/j.athoracsur.2024.04.003. Online ahead of print.

Authors

Fernando M Juarez-Casso¹, Busra Cangut¹, Katherine S King², Alex T Lee², John M Stulak¹, Hartzell V Schaff¹, Kevin L Greason³

Affiliations

¹ Department of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota.
² Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota.
³ Department of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota. Electronic address: greason.kevin@mayo.edu.

PMID: 38636685
DOI: 10.1016/j.athoracsur.2024.04.003

Abstract

Background: 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.

Methods: 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.

Results: 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).

Conclusions: 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.