Transcatheter aortic valve thrombosis: the relation between hypo-attenuated leaflet thickening, abnormal valve haemodynamics, and stroke

Aims The presence of hypo-attenuated leaflet thickening (HALT) and/or reduced leaflet motion on multi-detector row computed tomography (MDCT) has been proposed as a possible marker for early transcatheter aortic valve thrombosis. However, its association with abnormal valve haemodynamics on echocardiography (another potential marker of thrombosis) and clinical outcomes (stroke) remains unclear. The present study evaluated the prevalence of HALT on MDCT and abnormal valve haemodynamics on echocardiography. In addition, the occurrence of ischemic stroke and/or transient ischemic attack (TIA) was assessed. Methods and results A total of 434 patients (mean age 80+/-7 years, 51% male) who underwent transcatheter aortic valve replacement (TAVR) were evaluated. Transcatheter valve haemodynamics were assessed on echocardiography at discharge, 6 months, and thereafter yearly (up to 3 years post-TAVR). The presence of HALT and/or reduced leaflet motion was assessed on MDCT performed 35 days [interquartile range 19-210] after TAVR in 128 of these 434 patients. Possible TAVR valve thrombosis was defined by mean transvalvular gradient >= 20mmHg and aortic valve area (AVA)<= 1.1cm(2) on echocardiography or by the presence of HALT or reduced leaflet motion on MDCT. The occurrence of ischemic stroke/TIA at follow-up was recorded. HALT and/or reduced leaflet motion was present in 12.5% of 128 patients undergoing MDCT, and was associated with a slightly higher mean transvalvular gradient (12.4 +/-8.0 mmHg vs. 9.4+/-4.3 mmHg; P=0.026) and smaller AVA (1.49+/-0.39 cm(2) vs. 1.78+/-0.45 cm(2), P = 0.017). Only one patient with HALT on MDCT revealed abnormal valve haemodynamics on echocardiography. At 3-year follow-up, abnormal valve haemodynamics on echocardiography were observed in 3% of patients. HALT on MDCT and abnormal valve haemodynamics on echocardiography were not associated with increased risk of ischemic stroke/TIA. Conclusion On MDCT, 12.5% of patients showed HALT or reduced leaflet motion, whereas only one of these patients had abnormal valve haemodynamics on echocardiography. Neither HALT nor increased transvalvular gradient were associated with stroke/TIA.