Multicenter invasive validation of the Venous Excess Ultrasound Score (VExUS) in patients referred for pulmonary hypertension.

BACKGROUND: The Venous Excess Ultrasound (VExUS) score is increasingly used to assess systemic venous congestion, yet direct validation against invasively measured right atrial pressure (RAP) in pulmonary hypertension (PH) remains limited. RESEARCH QUESTION: How accurate is the VExUS score to predict RAP in patients with established or suspected PH? METHODS: We conducted a multicenter observational study across 7 Italian reference centers including patients referred for PH and undergoing a VExUS assessment and right heart catheterization within 1 hour. A VExUS score was calculated with a 0 to 3 grading based on inferior vena cava (IVC) diameter and collapsibility, and Doppler assessment of hepatic, portal, and intrarenal venous flow patterns. The diagnostic performance of VExUS for identifying elevated RAP thresholds was compared with echocardiographic estimates based on IVC diameter and inspiratory collapse and RA surface areas using a multivariable analysis followed by receiver operator curves (ROC) calculations. Subgroup analyses were performed across pulmonary hemodynamic phenotypes (normal hemodynamics vs pre- vs postcapillary PH). RESULTS: The study included 145 patients with pre-capillary PH, most of whom with pulmonary arterial hypertension (PAH), 21 with post-capillary PH, and 21 with no PH. The VExUS score showed a strong graded association with RAP, with mean RAP increasing across VExUS grades (0: 3.9 mmHg; 1: 8.4 mmHg; 2: 13.5 mmHg; 3: 15.8 mmHg; p<0.001). The VExUS score demonstrated excellent discrimination for elevated RAP >12 mmHg (AUC 0.97, 95% CI 0.94-0.99), with higher diagnostic performance than isolated echocardiographic markers and performance comparable to echocardiographic RAP estimation. These findings were consistent across hemodynamic phenotypes.