Post-TAVR Neo-Sinus Geometry and Impaired Ventricular Recovery Are Associated with Early Leaflet Thrombosis: First MDCT Insights from Vietnam

Background/Objectives: Leaflet thrombosis after transcatheter aortic valve replacement (TAVR), typically identified as hypoattenuated leaflet thickening (HALT) on multidetector computed tomography (MDCT), is increasingly recognized as an early manifestation of bioprosthetic valve dysfunction. However, factors associated with early HALT in Southeast Asian populations remain poorly characterized. The objective of this study was to characterize MDCT features of leaflet thrombosis and identify factors independently associated with early HALT after TAVR. Methods: In this two-center observational study, patients undergoing MDCT 1–3 months after TAVR were evaluated. Leaflet thrombosis was defined as HALT. Leaflet involvement, thrombus severity, anatomical distribution, and post-implantation geometric parameters were analyzed. Multivariable logistic regression identified factors associated with early HALT. Results: Among 65 patients, HALT was detected in 30.8%, predominantly as subclinical leaflet thrombosis (29.2%), whereas clinical valve thrombosis was rare (1.5%). Most cases involved one or two leaflets, with preferential involvement of the non-coronary cusp. Patients with HALT showed greater increases in transvalvular peak gradients, and a peak gradient increase ≥10 mmHg was more frequent than in patients without HALT (30.0% vs. 4.4%; p = 0.008). Severe RCA ostial eccentricity (grade 3–4) combined with a neo-sinus–RCA distance > 13 mm was independently associated with HALT (adjusted OR 5.52; p = 0.006). Lack of left ventricular ejection fraction improvement after TAVR was also independently associated with HALT (adjusted OR 4.44; p = 0.018), though given the limited number of HALT events (n = 20), these multivariable associations should be regarded as exploratory and hypothesis-generating. Conclusions: Early post-TAVR leaflet thrombosis is common and predominantly subclinical. CT-derived neo-sinus geometry and impaired ventricular recovery were independently associated with HALT, supporting the hypothesis that altered neo-sinus washout contributes to thrombus formation.