Role of Inferior Vena Cava Dynamics for Estimating Right Atrial Pressure in Congenital Heart Disease

Background: Inferior vena cava (IVC) size and collapsibility (IVC dynamics) are used for estimating right atrial pressure (RAP). However, the diagnostic performance of the American Society of Echocardiography IVC criteria for estimating RAP in patients with congenital heart disease are unknown. The purpose of this study was to assess the role of IVC dynamics for estimating RAP in adults with congenital heart disease. Methods: We conducted a retrospective study of adults with congenital heart disease that underwent cardiac catheterization and echocardiogram at Mayo Clinic (2003-2019). IVC diameter was measured at inspiration (IVC_min) and end-expiration (IVC_max), and IVC collapsibility index (IVC_CI) was calculated. Results: Based on 918 patients, we observed a good correlation between IVC_maxand invasive RAP (r=0.56, P<0.001); IVC_minand RAP (r=0.58, P<0.001); and IVC_CI(r=-0.72, P<0.001). There was excellent correlation between invasive RAP and estimated RAP using IVC_CI(r=0.80, P<0.001). We observed that IVC_CI<60% had superior diagnostic performance as compared with American Society of Echocardiography criteria (IVC_max>2.1 cm, area under the curve difference 0.15, P<0.001; IVC_CI<50%, area under the curve difference 0.09, P=0.008; combination of IVC_max>2.1 cm; and IVC_CI<50%, area under the curve difference 0.06, P=0.02). Estimated RAP >10 mm Hg based on IVC_CIhad comparable prognostic performance as invasive RAP but superior prognostic performance as the American Society of Echocardiography criteria. Conclusions: IVC_CI<60% was the best criterion to identify patients with elevated RAP. IVC_CIwas comparable to invasively measured RAP in its relation to prognosis. Further studies are required to determine whether the use of IVC_CIin clinical decision-making will improve clinical outcomes in this population.