Prognostic implications of inferior vena cava haemodynamics in ambulatory patients with tetralogy of Fallot

Aims: Right atrial pressure (RAP) provides a composite measure of right ventricular diastolic dysfunction, right atrial compliance, and volume status, and these three variables are typically abnormal in adults with repaired tetralogy of Fallot (TOF). RAP is a well-established prognostic metric in patients with pulmonary hypertension, and recent data suggest that RAP is associated with clinical outcomes in TOF. The purpose of this study was to determine the role of inferior vena cava (IVC) haemodynamics (size and collapsibility) for the assessment of RAP and its potential application for risk stratification and prognostication in the TOF population. Methods and results: Adult TOF patients with echocardiographic assessment of IVC haemodynamics were divided into patients with (derivation cohort, n = 256) and without (validation cohort, n = 492) cardiac catheterization data. We assessed the correlation between IVC haemodynamics, RAP, and disease severity indices [arrhythmias, peak oxygen consumption (VO₂), and heart failure hospitalization] in derivation cohort and compared it with the correlations in the validation cohort. IVC haemodynamics correlated with RAP (r = 0.52, P < 0.001), with disease severity indices {atrial arrhythmias [area under the curve (AUC) 0.81], ventricular arrhythmias [AUC 0.67], heart failure hospitalizations [AUC 0.78], and peak VO₂ [r = 0.53]}, and with transplant-free survival in the derivation cohort. Similar correlations between IVC haemodynamics, disease severity indices, and transplant-free survival were also observed in the validation cohort. Conclusions: These findings suggest that IVC haemodynamics can potentially be used for risk stratification and prognostication in TOF patients and can complement the current risk models that are based predominately on right ventricular volumes and systolic function.