Distinctive clinical features of portopulmonary hypertension

Study objective: To differentiate the cardiopulmonary profile of portopulmonary hypertension (PPHTN) from that of primary pulmonary hypertension and chronic liver disease. Design: Retrospective survey. Setting: Tertiary care center. Patients: Thirty patients with cardiac catheterization-proven PPHTN were compared to 30 randomly selected patients with primary pulmonary hypertension alone and 30 patients with chronic liver disease alone necessitating consideration of liver transplantation (L-CONT). Interventions: All patients underwent right heart catheterization, echocardiography, ECG, chest radiography, pulmonary function tests, ventilation-perfusion scanning, and room air arterial blood gas measurements. Results: Patients with PPHTN exhibited elevated pulmonary pressures (mean pulmonary pressure, 48.6±2.1 mm Hg) and pulmonary vascular resistance (11.6±1.6 mm Hg/L/min/m²) with simultaneous elevation in the cardiac index (3.8±0.3 L/min/m²) and depression of systemic vascular resistance (24.9± 1.7 mm Hg/L/min/m²). Arterial blood gas measurements indicate that PPHTN exhibits a significant accentuation of the chronic respiratory alkalosis (PCO₂, 28.7±0.5 mm Hg) usually seen with chronic liver disease and pulmonary hypertension. In addition, patients with PPHTN have an increased alveolar-arterial gradient (27.0±2.7 mm Hg) when compared to patients with L-CONT, suggesting impaired gas exchange. Conclusions: PPHTN is associated with a unique clinical profile that possesses characteristics common to and exclusive of liver disease and primary pulmonary hypertension.