Abstract 9429: The Impact of Hypo-Attenuated Leaflet Thickening on Valvular Haemodynamics and Structural Valve Deterioration Following Transcatheter Aortic Valve Replacement

Abstract

Introduction: Hypo-attenuated leaflet thickening (HALT) has been described following transcatheter aortic valve replacement (TAVR). It is unclear if HALT impacts prosthetic haemodynamics or predicts structural valve deterioration (SVD). Hypothesis: HALT predicts SVD. Methods: We prospectively evaluated 186 patients who had undergone TAVR with 320-slice CT imaging for the presence of HALT, defined as hypo-attenuation of bioprosthetic leaflets. HALT depth (thickness) was the greatest depth in the sagittal view and HALT area was the greatest area in the axial view. SVD was defined as at least one of mean gradient ≥20 mmHg, increase in gradient ≥10 mmHg from baseline and at least moderate valvular regurgitation. Echocardiograms at discharge, one month and annually were assessed by cardiologists blinded to HALT status. Results: LT prevalence was 17.7% at a median CT scan of 6 weeks (IQR 4-12). SVD occurred in 8.6% at a median follow-up of 2 years (IQR 1-3); two required valve re-intervention, five required anticoagulation that reversed moderate-severe gradient and nine had mild-moderate gradient that were closely monitored. Patients with HALT were more likely to develop SVD (39.3% vs 1.9%, p<0.01), repeat valve replacement (6.1% vs 0%, p = 0.03) and higher valvular gradients throughout follow-up (up to 3-years). HALT affected 1 leaflet in 17 cases, 2 leaflets in 13 cases and 3 leaflets in 3 cases. Patients with HALT had a median cumulative thickness of 2.9 mm (IQR 1.9-4.7) and a median area of 64.2 mm2(IQR 40.9-91.6). Threshold for the occurrence of SVD with HALT characteristics were cumulative depth of 2.4 mm (Spec. 94.1%, Sens. 75.0%, AUC=0.87) and cumulative area of 28 mm2 (Spec. 92.2%, Sens. 81.3%, AUC=0.86). Conclusions: HALT was associated with SVD, repeat valve intervention and higher valvular gradients following TAVR. HALT depth and area were strong predictors of SVD. CT following TAVR may determine patients at-risk of SVD.