Chronic Thromboembolic Pulmonary Hypertension Due to Popliteal Vein Aneurysm

Background: Venous thromboembolism (VTE) may present acutely as pulmonary embolism (PE), and its late complications include chronic thromboembolic pulmonary hypertension (CTEPH). PEs may arise from thrombi originating in a venous aneurysm, in rare cases of the popliteal vein. Case Presentation: A 77-year-old woman was referred to our hospital due to respiratory distress. Computed tomography revealed pulmonary thrombi and a thrombus in a popliteal vein aneurysm (PVA); PE was diagnosed. After 3 months of anticoagulant therapy (rivar-oxaban), her pulmonary hypertension showed little improvement. She underwent perfusion scintigraphy, which showed multiple perfusion defects, and Swan-Ganz catheterization. Mean pulmonary artery pressure was 26 mmHg. Pulmonary angiography revealed organized distal thrombi. Based on these findings, we diagnosed CTEPH due to recurrent formation of thrombi in the PVA. Conclusion: Asymptomatic PVA can lead silently to PE and CTEPH. The possibility of asymptomatic recurrent VTE should be considered in patients with pulmonary hypertension and PVA.