Pelvic Vein Obstruction in Chronic Thromboembolic Pulmonary Hypertension: A Novel Association

Background: Pelvic venous obstruction (PVO), defined as greater than 50% stenosis or occlusion of pelvic veins, is a known risk factor for deep vein thrombosis (DVT). DVT is a known risk factor for chronic thromboembolic pulmonary hypertension (CTEPH), but the prevalence of PVO in CTEPH is unknown. Methods: This cross-sectional study at Temple University's tertiary referral center for Pulmonary Hypertension, Right Heart Failure, and CTEPH sought to identify the presence of PVO in patients with CTEPH who underwent cardiac catheterization, pulmonary angiography, and venography. Results: A total of 193 CTEPH patients were referred for pulmonary angiography, and among these, 148 underwent venography. PVO was identified in 65 (44%) patients. Lower extremity (LE) DVT was associated with PVO (p = 0.004). The severity of pulmonary hypertension was similar with and without PVO (mean pulmonary artery pressure 43.0 ± 10.3 mm Hg vs. 43.8 ± 12.4 mm Hg, p = 0.70), as was the need for pulmonary thromboendarterectomy (69.2% vs. 61.4%, p = 0.32). Conclusions: Pelvic vein obstruction is common and a novel clinical association in patients with CTEPH, particularly in patients with a history of LE DVT. PVO and its role in CTEPH warrants further study, including the potential role of revascularization to mitigate further risk.