The impact of hypo-attenuated leaflet thickening on haemodynamic valve deterioration following transcatheter aortic valve replacement

Background: Hypo-attenuated leaflet thickening (HALT) may occur following transcatheter aortic valve replacement (TAVR), however, it remains unclear if HALT is a predictor of haemodynamic valve deterioration (HVD). Aim: To determine the impact of HALT on the occurrence of HVD. Methods: We prospectively evaluated 186 patients for the presence of HALT at a median of 6 weeks following TAVR (Interquartile-range [IQR] 4–12 weeks). HALT depth and area were measured. HVD encompassed any of the following: mean gradient ≥20 ​mmHg with an increase in gradient ≥10 ​mmHg from baseline, Doppler velocity index reduction ≥0.1 or new moderate-to-severe valvular regurgitation. Routine echocardiograms at discharge, one month and annually, were assessed by echo-cardiologists that were blinded to the HALT status. Results: LT prevalence was 17.7% (33/186). HVD was present in 8.6% (16/186) at a median follow-up of 2 years (IQR 1–3); two required valve re-intervention and five required anticoagulation. HALT was the only independent predictor of HVD on multivariate analysis (OR 33.3, 95%CI 7.4–125). Patients with HALT were more likely to develop HVD, require repeat valve intervention and have higher trans-valvular gradients at up to 3-year follow-up. Patients with HALT had a median cumulative thickness of 2.9 ​mm (IQR 1.9–4.7) and area of 64.2 ​mm² (IQR 40.9–91.6). Thresholds for HALT in predicting HVD were a cumulative depth of 2.4 ​mm (Specificity 94.1%, Sensitivity 75.0%, AUC ​= ​0.87) and cumulative area of 28 ​mm² (Specificity 92.2%, Sensitivity 81.3%, AUC ​= ​0.86). Conclusion: HALT is an independent predictor of HVD, which exhibits specific depth and area thresholds to predict HVD. CT following TAVR may determine patients at risk of HVD.