Vitamin K antagonists and structural valve deterioration in bioprosthetic aortic valves

To evaluate the effect of postoperative vitamin K antagonist (VKA) exposure on structural valve deterioration (SVD) after bioprosthetic aortic valve replacement (AVR).

We retrospectively analysed 123 patients who underwent surgical bioprosthetic AVR between 2010 and 2025 with adequate echocardiographic follow-up. VKA exposure was recorded during follow-up; for the primary time-fixed Cox model, VKA exposure was defined as cumulative postoperative use ≥3 months (yes/no), and VKA was additionally evaluated as a time-varying covariate in a time-dependent sensitivity analysis. The primary endpoint was VARC-3-defined SVD; secondary endpoints were all-cause mortality, bioprosthetic valve failure, and reoperation/valve-in-valve.

Mean age was 71.3±6.1 years; 65% were male. Porcine and bovine bioprostheses accounted for 71.5% and 28.5% of implants. Median SVD-free survival was 2073 days (95% confidence interval [CI]: 0-4212) in VKA users, while the median was not reached in non-users; the difference was significant (logrank p=0.017). In the adjusted time-fixed Cox model, VKA exposure was associated with higher SVD risk (adjusted hazard ratio [aHR] 2.14; 95% CI 1.08-4.26; p=0.030). In a time-dependent sensitivity Cox model with VKA as a time-varying covariate, periods on VKA were similarly associated with higher SVD hazard (hazard ratio 2.16; 95% CI 1.10-4.23; p=0.025). Porcine bioprostheses were also independently associated with higher SVD risk (aHR 2.71; 95% CI 1.09-6.76; p=0.031).

After bioprosthetic AVR, VKA exposure and porcine bioprostheses were independently associated with SVD. Antithrombotic strategies should consider the potential long-term adverse effects of VKA in the context of prosthesis material and patient characteristics. Prospective multicenter studies are needed to confirm these findings.