Extrinsic compression of the left main coronary artery (LMCA) by an enlarged pulmonary trunk has been reported in patients with pulmonary hypertension. We report the first case of symptomatic LMCA compression in a patient with pulmonary hypertension associated with diffuse parenchymal lung disease successfully treated with bilateral lung transplantation.
A 60-year-old man was referred to our center with pulmonary hypertension resulting from diffuse parenchymal lung disease due to beryllium exposure. He reported substernal chest pain during exercise. The pain was dull, radiated to the left arm, persisted throughout the day, and was associated with dyspnea on exertion. A resting myocardial perfusion scan with thallium-201 showed perfusion defects in the LMCA territory. Right heart catheterization revealed a right atrial pressure of 3 mm Hg, a right ventricular pressure of 76/2 mm Hg, a pulmonary artery pressure of 78/31 mm Hg, and a pulmonary artery occlusion pressure of 11 mm Hg. Coronary angiography showed a 70% smooth tapered narrowing of the LMCA without other coronary artery abnormalities (Figure 1). Computerized tomography (CT) of the chest revealed bilateral coarse fibrotic changes with traction bronchiectasis and honeycombing and a main pulmonary artery diameter of 4.7 cm. CT angiography revealed LMCA compression by the main pulmonary artery with no evidence of coronary artery atherosclerosis (Figure 2a, arrow = LMCA, P = pulmonary artery, A = aorta). Three months later, the patient underwent successful bilateral lung transplantation. Postoperatively, the patient had no recurrence of chest pain, and exercise stress testing with technetium99m-sestamibi revealed normal exercise performance and normal myocardial perfusion at a heart rate of 171. Follow-up CT angiography showed complete resolution of the LMCA compression (Figure 2b).
LMCA compression by an enlarged pulmonary artery may cause angina, left ventricular ischemia, and sudden death. LMCA compression has been reported in patients with idiopathic PAH, PAH associated with congenital systemic-to-pulmonary shunts, and pulmonary hypertension due to chronic thromboembolic disease (1–4). Although optimal management of this entity is unknown, successful treatment of LMCA compression has been reported after surgical correction of atrial septal defects (5), LMCA stenting (6), and pulmonary thromboendarterecomy with concurrent coronary artery bypass grafting (4). We report the first case of LMCA compression in association with pulmonary hypertension due to diffuse parenchymal lung disease with clinical, radiologic, and functional improvement after bilateral lung transplantation.
LMCA compression by an enlarged pulmonary artery may occur in pulmonary hypertension due to diffuse parenchymal lung disease and may be treated successfully with lung transplantation.
Caralee Caplan-Shaw, None.