Acute mitral regurgitation following giant coronary artery aneurysm resection: a case report

Abstract Background Giant coronary artery aneurysms carry a high risk of rupture, thrombosis, and distal embolization. When percutaneous coronary intervention is not feasible in symptomatic cases, surgical resection combined with coronary artery bypass grafting is recommended. However, surgical ligation can interrupt flow to downstream branch arteries and precipitate regional myocardial ischemia. Case presentation In a 70-year-old woman with coronary artery disease, coronary angiography showed a 20-mm aneurysm with 90% stenosis of the proximal left anterior descending (LAD) artery, 90% stenosis of the first diagonal branch (D1), and 100% occlusion of the left circumflex (LCx) artery. To resect the aneurysm and perform on-pump beating coronary artery bypass grafting, we used a free gastroepiploic artery graft to the LAD artery and a saphenous vein graft (SVG) from the ascending aorta to the LCx artery, with a piggyback anastomosis between the two grafts. After LAD artery aneurysm resection, acute severe mitral regurgitation and left ventricular dysfunction developed during weaning from cardiopulmonary bypass. Transesophageal echocardiography revealed a posteriorly directed eccentric mitral regurgitant jet with leaflet tethering, suggestive of acute anterolateral papillary muscle dysfunction. Because D1 ischemia was suspected to be contributing to the papillary muscle dysfunction and hemodynamic instability, an additional sequential SVG anastomosis to D1 was created, which resolved the mitral regurgitation and stabilized hemodynamics. Conclusions Ligation of a giant proximal LAD aneurysm can markedly alter coronary flow and precipitate unrecognized ischemia, including ischemia affecting the papillary muscle or broader myocardial territories. Because such perfusion dependence cannot be identified reliably on preoperative imaging, surgeons should be prepared to promptly revise the revascularization strategy and consider mechanical circulatory support if hemodynamic instability occurs.