Abstract 14414: Bioprosthetic Valve Thrombosis: Different Time to Response to Warfarin in Mitral and Aortic Valves

Abstract

Background: Warfarin is known to be effective in the treatment of bioprosthetic valve thrombosis (BPVT). However, the time-course of response to anticoagulation has not been fully characterized. Hypothesis: We hypothesized that response to warfarin can differ depending on valve position. Methods: We retrospectively identified 45 patients with BPVT diagnosis between 2002 and 2019 that involved either the mitral (MV) or the aortic valve (AV) prostheses, all with eventual echocardiographic resolution with warfarin. BPVT involved AV in 26 (57.8%) patients and MV in 19 (42.2%). Mean gradients (MGs) were tracked starting from BPVT diagnosis until recovery, which was defined as MGs decreasing to initial post-implantation MGs, to 50% below MGs at BPVT diagnosis, or to < 20 mmHg in AV and < 5 mmHg in MV. Kaplan Meier analysis was used to compare recovery time between MV and AV. Duration is reported relative to the time of BPVT diagnosis. Results: Recovery was faster in MV than in AV patients treated with warfarin, with median time of 3.8 months in the AV and 1.8 months in the MV group, p < 0.001 (Figure 1). At 1 month follow up, 15.4% recovered in AV group and 21.1% in MV, p = 0.605. At 3 months, 38.5% recovered in the AV and 78.9% in the MV, p = 0.009. At 6 months, 57.7% of AV group recovered while 100% recovered in the MV group, p = 0.001. The longest time for recovery was 30 months in 1 AV patient. Conclusion: Recovery using warfarin tended to be faster in BPVT involving the MV compared with the AV. In our study, all patients with MV BPVT recovered by 6 months, while this only happened in half the patients with AV BPVT. This suggests that a longer duration of warfarin trial may be needed in the case of AV disease. This might also suggest that the pathogenesis may differ between the two valves.