Implanted size and structural valve deterioration in the Edwards Magna bioprosthesis

Background: The desire of patients to avoid anticoagulation, together with the potential of valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR), have resulted in the increasing use of bioprosthetic valves for aortic valve replacement (AVR). While patient-prosthesis mismatch (PPM) is known to be an adverse risk after AVR, few studies have addressed the effect of PPM on valve durability. This study evaluates the role of valve size and hemodynamics on long term durability after AVR with a Magna bioprosthesis. Methods: We performed a retrospective, single-center evaluation of patients who underwent a surgical AVR procedure between June 2004 through December 2022 using the Magna bioprosthesis. Perioperative information and long-term follow-up data were sourced from the institution's Society for Thoracic Surgeons Adult Cardiac Surgery Registry and outcomes database. Cumulative incidence of freedom from reintervention were estimated accounting for competing events. Group comparisons used Gray's test. Results: Among 2,100 patients, the mean patient age was 69 years (range, 22-95 years), of whom 98% had native aortic valve disease, 32.5% had concomitant coronary bypass grafting, and 19% had mitral valve surgery. Median follow-up was 5.8 (1.9-9.4) years, during which 116 reinterventions were performed, including 74 explants and 42 VIV procedures. Nine hundred and twenty-eight patients died prior to reintervention. Incidence of all cause reintervention was 1.2%, 4.5%, and 11.7% at 5, 10, and 15 years, respectively. Smaller valve size was associated with worse survival (P<0.001), but not with reintervention. Higher mean gradient at implant was associated with increased late reintervention [sub-distribution hazard ratio: 1.016; 95% confidence interval (CI): 1.005 to 1.028; P=0.0047, n=1,661]. Conclusions: While reintervention rates are low for the Magna prosthesis at 15 years, the analysis is confounded by the competing risk of death. PPM, as reflected physiologically by elevated post-operative valve gradients, portends an increased risk of intervention. Further study is necessary to elucidate the mechanism of early stenosis in patients who progress to reintervention.