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 echo-cardiography. 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.