Natural History of Leaflet Thrombosis After Transcatheter Aortic Valve Replacement: A 5‐Year Follow‐Up Study

Background Subclinical leaflet thrombosis, characterized by hypoattenuated leaflet thickening (HALT) on multidetector computed tomography, is common after transcatheter aortic valve replacement (TAVR). Because little is known about the long‐term natural history of subclinical HALT, we aimed to investigate this in patients who underwent TAVR without using additional anticoagulation. Methods and Results We retrospectively evaluated patients who underwent TAVR with the Edwards SAPIEN‐XT at our institute between October 2013 and December 2015. Patients were grouped according to the presence or absence of HALT within 1 year after TAVR (HALT and No‐HALT groups). The primary outcome, defined as the composite of all‐cause mortality, heart failure readmission, and ischemic stroke, was compared. Valve performance was assessed over time by transthoracic echocardiography. Among 124 patients (men: 29.1%; median age, 85 years), 27 (21.8%) showed HALT on multidetector computed tomography within 1 year after TAVR. No patient required additional anticoagulation for treating HALT because of the absence of valve‐related symptomatic deterioration. During the median follow‐up period of 4.7 years (interquartile range, 4.0–5.6), the rate of primary outcome and valve performance was not statistically different between the 2 groups (37.0% versus 38.1%; log‐rank test P =0.92; mean pressure gradient, 9 mm Hg [8–14 mm Hg] versus 10 mm Hg [7–15 mm Hg]; P =0.51, respectively). Conclusions Approximately 20% of patients after TAVR had HALT within 1 year; however, that did not change the risk of subsequent adverse cardiovascular events or the valve performance with statistical significance for up to 5 years despite no additional anticoagulation therapy.