Study Looks at Subclinical Leaflet Thrombosis in Bioprosthetic Aortic Valves
FDA Alert Notes That Bioprosthetic Aortic Valves Remain Safe, Effective
Reduced aortic-valve leaflet motion may occur in patients after transcatheter aortic-valve replacement (TAVR) or surgical abortive-valve replacement with a bioprosthetic valve, and “could be associated with subclinical leaflet thrombosis,” according to results of a study published Oct. 5 in the New England Journal of Medicine.
The study looked at data from 55 patients enrolled in the PORTICO IDE clinical trial, and 132 patients enrolled in the RESOLVE and SAVORY registries – two single-center registries that include patients undergoing TAVR or surgical aortic-valve bioprosthesis implantation.
Results showed leaflet motion was noted on computed tomography in 22 of the 55 patients (40 percent) in the clinical trial, and in 17 of the 132 patients (13 percent) in the two registries. Further, therapeutic anticoagulation with warfarin, as compared with dual antiplatelet therapy, was associated with a decrease incidence of reduced leaflet motion (0 percent and 55 percent, respectively, P=0.01 in the clinical trial; and 0 percent and 29 percent, respectively, P=0.04 in the pooled registries).
The authors conclude that moving forward, “better characterization of this observation is needed to determine its frequency and evaluate its clinical effect.”
In a corresponding editorial comment, David R. Holmes Jr., MD, MACC, and Michael J. Mack, MD, FACC, note that “more information is urgently needed,” and pose a list of questions raised by the study, including the true incidence of reduced aortic-valve leaflet motion; if reduced leaflet motion is caused by thrombus formation on the leaflets; what the abnormality means clinically; and more.
Meanwhile, a related perspective from the U.S. Food and Drug Administration (FDA) notes, “We at the FDA believe that the available clinical evidence supports the conclusion that these valves remain safe and effective and that the findings to date concerning reduced leaflet motion have not changed the overall favorable benefit-risk balance for these valves when they are used for their approved indications.” The authors add that “if reduced leaflet motion is detected by imaging, treatment options should be discussed with the team of physicians responsible for the patient’s care.”
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