Outcomes of Hypoattenuating Leaflet Thickening Post-Transcatheter Pulmonary Valve Replacement

Transcatheter pulmonary valve replacement (TPVR) is a mainstay of therapy for right ventricular outflow tract dysfunction, especially in adult congenital heart disease.

This study aimed to assess the prevalence, characteristics, and clinical implications of hypoattenuating leaflet thickening (HALT) and hypoattenuation affecting motion (HAM) after TPVR.

This was a retrospective cohort study of TPVR performed from 2018 to 2024. Computed tomography angiography (CTA) assessed for HALT/HAM and echocardiography assessed valve gradients. Random forests for survival were used to assess the association between the rate of change in echocardiographic gradient and the time-related likelihood of HALT.

Of 106 patients with TPVR, 46 (39.6%) underwent CTA at 8.4 (6.1-24) (median [Q1-Q3]) months after TPVR. Twenty-six were in native right ventricular outflow tract, 12 were valve-in-valve, and 8 were in homografts. Eight patients (17.4%) had evidence of HALT ± HAM on CTA, 3 with valve deterioration. The median follow-up was 10 (2.4-23) months. No HALT/HAM was noted in patients on anticoagulation. Of the 5 with only HALT, one resolved, while one progressed. Three patients had HAM (6.5%), of which 2 had echocardiographic valve deterioration: one with mean gradient increase of 10 mm Hg, and one with ≥1-grade progression of regurgitation. All were treated with anticoagulation.

In this series of patients with TPVR, there was a 17.4% prevalence of HALT and 6.5% prevalence of HAM, with evidence of echocardiographic valve deterioration. Increases in valve gradients were associated with a higher likelihood of HALT. This is critical in adult congenital heart disease patients, where valve longevity is essential to reduce repeated interventions.