Clinical significance of CT-detected hypoattenuated leaflet thickening after transcatheter aortic valve replacement: A systematic review and meta-analysis

BACKGROUND Hypoattenuated leaflet thickening (HALT) is a CT-detected finding increasingly recognized after transcatheter aortic valve replacement (TAVR), but its predictors, association with valve platform and antithrombotic regimen, and clinical significance remain uncertain. METHODS We performed a systematic review and meta-analysis of studies reporting HALT after TAVR. PubMed, Web of Science Core Collection, and the Cochrane Library were searched. Pairwise meta-analyses evaluated associations between HALT and patient characteristics, antithrombotic regimen, valve hemodynamics, and clinical outcomes. Network meta-analyses compared valve platform and valve size. RESULTS Fifty-nine studies including 16,269 patients were analyzed, with HALT observed in 1792 patients (11.0%). Most baseline patient characteristics were not associated with HALT. Compared with balloon-expandable valves, self-expanding supra-annular valves were associated with lower HALT risk, whereas self-expanding intra-annular and Lotus valves were associated with higher risk. Direct oral anticoagulants and warfarin did not differ in HALT risk, whereas oral anticoagulation was associated with lower risk than no oral anticoagulation. HALT was associated with a small increase in mean transvalvular gradient, but not with major clinical outcomes at short-term follow-up. CONCLUSION HALT after TAVR was associated mainly with valve platform and antithrombotic regimen rather than baseline patient characteristics. Its hemodynamic and clinical impact appeared limited, supporting individualized interpretation of this CT-detected finding. Further long-term follow-up studies are warranted to clarify the clinical sequelae of HALT and its potential impact on valve durability.