Outcomes of Warfarin Therapy for Bioprosthetic Valve Thrombosis of Surgically Implanted Valves: A Prospective Study.

OBJECTIVES: The aim of this study was to assess the efficacy of warfarin in the treatment of bioprosthetic valve thrombosis (BPVT) of surgically implanted valves.

BACKGROUND: There are limited data about treatment outcomes for BPVT.

METHODS: This was a prospective study of patients with suspected BPVT of surgically implanted valves who received warfarin therapy at the Mayo Clinic from January 2013 to January 2016. BPVT score was calculated using previously described echocardiographic criteria. One point was assigned for each criterion: a 50% increase in prosthetic gradient within 5 years of implantation, increased cusp thickness, and abnormal cusp motion.

RESULTS: Fifty-two patients were enrolled in the study (mean age 61 ± 18 years, 34 men [66%]). The mean follow-up duration from presumed BPVT was 86 ± 24 weeks. Prosthesis positions were aortic in 31 patients (60%), mitral in 17 (32%), pulmonary in 2 (4%), and tricuspid in 2 (4%). Positive responses (defined as a 50% reduction in prosthesis gradient) occurred in 43 patients (83%) within 11 weeks (interquartile range [IQR]: 6 to 22 weeks) of anticoagulation with warfarin. Nine patients (17%) did not respond to warfarin, and these patients underwent surgical valve replacement (n = 5), transcatheter valve replacement (n = 1), and intervention (n = 3). BPVT scores were calculated for 48 patients (92%) with good-quality echocardiographic images; 9 had BPVT scores of 2, and 39 had BPVTs score of 3. A BPVT score of 3 predicted a positive response to anticoagulation therapy with sensitivity of 88% and specificity of 93%.

CONCLUSIONS: A trial of anticoagulation was effective in 83% of patients with suspected BPVT, and most patients responded within 3 months. BPVT score was predictive of response to therapy and should be considered during patient selection.