Pulmonary artery aneurysms (PAAs) are rare with non-specific clinical presentation but may lead to serious complications such as pulmonary artery dissection, rupture and compression of the left main coronary artery (LMCA). Their complications and PAA association with pulmonary hypertension lead to significant morbidity and mortality. The standard treatment strategy is surgical correction of the aneurysm, however percutaneous coronary intervention in patients with clinically significant compression of the LMCA, due to PAA should be considered as a possible treatment approach. In this article, we present a case report of a 73-year-old with polymorbidity, presenting with an acute coronary syndrome, caused by extrinsic compression of the LMCA by PAA. Due to the high surgical risk, we adopted an endovascular approach with stenting of the compressed LMCA with successful restoration of the blood flow and clinical stabilization. In this case, a percutaneous coronary intervention proved to be a safe and effective treatment option for selected patients, who are at high operative risk.