Acute pulmonary embolism unmasking underlying chronic thromboembolic pulmonary hypertension and iliac vein compression syndrome.

We describe the case of a 72-year-old gentleman who was referred to our institution for management of cardiogenic shock from a massive pulmonary embolism. Right heart catheterization revealed a low cardiac index and markedly elevated pulmonary pressures, suggested long-standing venous thromboembolic (VTE) disease that evolved into chronic thromboembolic pulmonary hypertension (CTEPH). The patient was cannulated to veno-arterial extra-corporeal membrane oxygenation and eventually treated with pulmonary embolectomy and thromboendarterectomy. Subsequently discovered inferior vena cava clot and left iliac deep vein thrombosis were treated with suction and mechanical thrombectomy. Intravascular ultrasound of the left lower extremity venous system identified iliac vein compression syndrome (IVCS) as the culprit of the patient's VTE and CTEPH. A left iliac stent was placed and the patient was discharged on Warfarin for anticoagulation. The case illustrates the rapidly expanding armamentarium for VTE treatment and proposes IVCS as a new, potentially underrecognized risk factor for CTEPH.