Coronary Artery-to-Pulmonary Artery Collaterals in Chronic Thromboembolic Pulmonary Hypertension

Bronchopulmonary collateral vasculature is a significant source of systemic blood flow in patients with chronic thromboembolic pulmonary hypertension (CTEPH).1 We present 2 cases of coronary artery-to-pulmonary artery (PA) collateral vessels, which have not been previously described in patients with CTEPH.A 40-year-old man with a history of deep venous thrombosis after parotidectomy for a benign lesion, recurrent strokes, and right-sided pulmonary embolism was evaluated for 5 years of progressive exertional dyspnea and suspected CTEPH. He had no known hereditary thrombophilia. Preoperative ventilation–perfusion scintigraphy demonstrated absent perfusion to the right lung and small defects in the left lower lobe (Figure 1). Pulmonary angiography confirmed occlusion of the proximal right PA with no distal flow (Figure 2; Movie I in the Data Supplement). His mean PA pressure was 35 mm Hg, pulmonary vascular resistance was 511 dyne/s per cm5, and cardiac index was 2.3 L/min per m2. Coronary angiography revealed a 4.6-mm diameter corkscrew vessel arising from the left circumflex artery and traveling to the right lung (Figure 3; Movie II in the Data Supplement). He had no significant coronary artery disease. The patient underwent bilateral pulmonary thromboendarterectomy (PTE; Figure 4), during which a small atrial septal defect was found and repaired. Collaterals were noted throughout the mediastinum, particularly around the aorta traversing toward the right lung and directly penetrating the right main PA. Final mean PA …