Left Main Coronary Artery Compression due to Pulmonary Artery Dilatation complicated by Acute Biventricular Dysfunction: a case report

Background Left main coronary artery (LMCA) compression by a dilated pulmonary artery is one of the lesser known but severe complications in the setting of severe pulmonary hypertension (PH). This phenomenon can lead to critical myocardial ischemia and poses unique diagnostic and therapeutic challenges. Case Summary A 36-year-old female with PH due to peripheral pulmonary arterial stenoses presented with significant dyspnea and exercise intolerance. Echocardiography revealed mild biventricular systolic dysfunction. Right heart catheterization confirmed severe precapillary PH, while coronary computed tomography angiography demonstrated a dilated pulmonary artery compressing the proximal LMCA. Invasive coronary angiography confirmed a sub-occlusive LMCA stenosis, but during the procedure the patient developed refractory cardiogenic shock with biventricular failure. LMCA percutaneous coronary intervention (PCI) with a single drug-eluting stent was performed with the assistance of mechanical circulatory support (MCS). After the procedure, the ventricular function gradually improved, the patient was weaned from MCS by day 2 and discharged after 10 days. Discussion LMCA compression in PH is often underdiagnosed due to its nonspecific symptoms. However, early recognition is crucial as it significantly impacts outcomes by preventing the progression to biventricular dysfunction and reducing the risk of sudden death. Management typically requires a multidisciplinary approach, with PCI often being the treatment of choice due to the high surgical risk in PH patients and the peculiar etiology of the stenosis secondary to extrinsic compression instead of luminal atherosclerosis. In this case, the use of MCS was essential in stabilizing the patient and enabling successful PCI.