In the October 5 issue of the NEJM a group of authors describe data evaluating possible subclinical leaflet thrombosis in bioprosthetic transcatheter and surgical valves. The investigation was initiated after the identification of reduced aortic-valve leaflet motion noted on computed tomography (CT) in a patient who had a stroke after transcatheter aortic-valve replacement (TAVR) in a clinical trial. 

 The authors analyzed data obtained from 55 patients in a clinical trial of TAVR and from two single-center registries that included 132 patients who underwent either TAVR or surgical aortic-valve bioprosthesis implantation. Ffour-dimensional, volume-rendered CT scans were obtained along with data on anticoagulation and clinical outcomes (including strokes and transient ischemic attacks [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 is identified in some  patients with bioprosthetic aortic valves, and that the condition resolved with therapeutic anticoagulation. The authors caution that the effect of this finding on clinical outcomes including stroke needs further investigation. 

1.Makkar RR, Fontana G, Jilaihawi H, Chakravarty T, Kofoed KF, de Backer O, Asch FM, Ruiz CE, Olsen NT, Trento A, Friedman J, Berman D, Cheng W, Kashif M, Jelnin V, Kliger CA, Guo H, Pichard AD, Weissman NJ, Kapadia S, Manasse E, Bhatt DL, Leon MB, Søndergaard L. Possible Subclinical Leaflet Thrombosis in Bioprosthetic Aortic Valves. N Engl J Med. 2015 Nov 19;373(21):2015-2024

2.Holmes DR, Mack MJ. Uncertainty and Possible Subclinical Valve Leaflet Thrombosis.N Engl J Med. 2015 Nov 19;373(21):2080-2082.