Prognostic role of inferior vena collapsibility index in congenital heart disease: A validation study

Background: A recent study showed that inferior vena cava collapsibility index (IVCCI) <60% had better prognostic performance as compared to the American Society of Echocardiogram (ASE) criteria for estimating right atrial pressure (RAP). However, this study was based on a selected cohort of adults with congenital heart disease (CHD) that underwent right heart catheterization and limiting the generalizability of the results. The purpose of this study was, therefore, to validate the prognostic performance of IVCCI in a more representative sample of adults with CHD, which would in turn, improve generalizability of the results. Methods: Retrospective cohort study of adults with CHD that underwent echocardiogram at Mayo Clinic (2003−2021). Elevated RAP was defined as RAP >10 mmHg, and was estimated using IVCCI <60% or the ASE criteria (maximum IVC diameter < 2.1 cm and IVCCI <50%). Cardiovascular event was defined as heart failure hospitalization, heart transplant or cardiovascular death. Results: Of the 4029 patients, 754 (19%) and 601 (15%) had elevated RAP (RAP >10 mmHg) based on IVCCI <60%, and the ASE criteria, respectively. Of the 4029 patients, 374 (9%) had cardiovascular events during 7.6 (4.4–10.5) years of follow-up. IVCCI <60% was independently associated with cardiovascular events (adjusted HR 2.08, 95% CI 1.75–2.42; C-statistic 0.708, 95%CI 0.688–0.728), and provided improved prognostic performance as compared to the ASE criteria (C-statistic difference 0.036, 95%CI 0.017–0.055, P = 0.008). Conclusions: IVCCI had superior prognostic performance as compared to the ASE criteria.