Implanted size and structural valve deterioration in the Edwards Magna bioprosthesis

Abstract

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.

Keywords: Surgical aortic valve replacement (SAVR); patient-prosthesis mismatch (PPM); transcatheter aortic valve replacement (TAVR); valve durability.

Figure 1

Cumulative incidence of aortic valve reintervention. Among 2,100 patients with a bioprosthetic Magna aortic valve implant, a total of 116 prostheses were reintervened during follow-up, including 74 explants and 42 valve-in-valve procedures. The overall cumulative incidence of reintervention for any cause, accounting for competing events of death, VAD, and HT, were 1.2% at 5-year, 4.5% at 10-year, and 11.7% at 15-year. VAD, ventricular assist device; HT, heart transplant.

Figure 2

Cumulative incidence of aortic valve reintervention by index valve implant size. The overall cumulative incidence of reintervention for any cause, accounting for competing events of death, VAD, and HT, was not associated with the labeled valve size of the index Magna aortic valve implant. VAD, ventricular assist device; HT, heart transplant.

Figure 3

AV mean (A) and peak (B) gradients over time. Among patients with an index Magna AV implant, all available echo follow-up after surgery is shown with loess curves grouped by the occurrence of post-operative events. AV, aortic valve.