BACKGROUND: Subclinical leaflet thrombosis, as indicated by hypoattenuated leaflet thickening (HALT) on computed tomography (CT) imaging, remains a major concern owing to its potential impact on valve function and patient outcomes.

AIMS: We aimed to evaluate the association between HALT and clinical outcomes in patients undergoing valve-in-valve (ViV) transcatheter aortic valve implantation (TAVI) with balloon-expandable valves and to identify predictors of leaflet thrombosis.

METHODS: Consecutive patients who underwent ViV TAVI with balloon-expandable valves at the Cedars-Sinai Medical Center were retrospectively analysed. We analysed both pre- and postprocedural CT scans to identify predictors of HALT at 1 month after ViV TAVI and the association of HALT with clinical outcomes. The primary outcome was a composite of all-cause mortality, hospitalisation for heart failure (HF), or stroke at 3 years.

RESULTS: Among the 117 patients analysed, HALT was detected in 37 (31.6%). In the multivariable analysis, anticoagulation therapy (odds ratio [OR] 0.28, 95% confidence interval [CI]: 0.08-0.92; p=0.037) and greater transcatheter heart valve (THV) expansion at the minimum area level (OR 0.95, 95% CI: 0.91-0.99; p=0.026) were significant predictors of reduced HALT following ViV TAVI. While there was no significant difference in all-cause mortality between patients with and without HALT (OR 1.13, 95% CI: 0.42-3.02; p=0.8), those with HALT had a significantly higher incidence of the composite primary outcome (OR 2.31, 95% CI: 1.04-5.15; p=0.04).

CONCLUSIONS: HALT was frequently observed in patients who underwent ViV TAVI. Additionally, the presence of HALT correlated with a higher incidence of composite outcomes, including all-cause mortality, hospitalisation for HF, and stroke. Assessment of TRanscathetEr and Surgical Aortic BiOprosthetic VaLVe Dysfunction and Its TrEatment with Anticoagulation (RESOLVE; ClinicalTrials.gov: NCT02318342).