Thrombosis in Bioprosthetic Aortic Valves
What is the prevalence of reduced leaflet motion in bioprosthetic aortic valves, the association between reduced leaflet motion and strokes and transient ischemic attacks (TIAs), and the influence of anticoagulation on reduced leaflet motion?
The investigators analyzed data obtained from 55 patients in a clinical trial of transcatheter aortic valve replacement (TAVR) and from two single-center registries that included 132 patients who were undergoing either TAVR or surgical aortic-valve bioprosthesis implantation. They obtained four-dimensional, volume-rendered computed tomography (CT) scans along with data on anticoagulation and clinical outcomes (including strokes and TIAs).
Reduced leaflet motion was noted on CT in 22 of 55 patients (40%) in the clinical trial and in 17 of 132 patients (13%) in the two registries. Reduced leaflet motion was detected among patients with multiple bioprosthesis types, including transcatheter and surgical bioprostheses. Therapeutic anticoagulation with warfarin, as compared with dual antiplatelet therapy, was associated with a decreased incidence of reduced leaflet motion (0% and 55%, respectively, p = 0.01 in the clinical trial; and 0% and 29%, respectively, p = 0.04 in the pooled registries). In patients who were reevaluated with follow-up CT, restoration of leaflet motion was noted in all 11 patients who were receiving anticoagulation and in 1 of 10 patients who were not receiving anticoagulation (p < 0.001). There was no significant difference in the incidence of stroke or TIA between patients with reduced leaflet motion and those with normal leaflet motion in the clinical trial (2 of 22 patients and 0 of 33 patients, respectively; p = 0.16), although in the pooled registries, a significant difference was detected (3 of 17 patients and 1 of 115 patients, respectively; p = 0.007).
The authors concluded that reduced aortic-valve leaflet motion was shown in patients with bioprosthetic aortic valves.
This study reports that reduced aortic-valve leaflet motion, as identified on four-dimensional, volume-rendered CT, was observed in patients after TAVR or surgical AVR with a bioprosthetic valve. Therapeutic anticoagulation with warfarin, but not therapy with antiplatelet drugs appears to prevent and effectively treat this phenomenon. We need to better characterize and understand this observation to determine its frequency and evaluate its clinical implications.
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