Unstable angina due to spontaneous left internal mammary artery dissection seventeen years after coronary artery bypass graft surgery: A case report and literature review

A 64 year-old male was admitted to the emergency department for multiple episodes of chest pain at rest. His cardiac history began seventeen years before when a coronary artery bypass grafting (CABG) was performed. This included left internal mammary artery (LIMA) graft to left anterior descending artery (LAD) and saphenous vein graft (SVG) to the diagonal branch. Since then the patient was subjected to numerous percutaneous coronary angioplasties on LAD, circumflex artery and SVG. The last angiographic control showed LIMA graft patency. The coronary angiography showed LAD, circumflex and right coronary artery occlusion and LIMA graft critical stenosis with evidence of dissection. Then, the lesion was crossed and intravascular ultrasound (IVUS) evaluation was performed to investigate the extent of the dissection. IVUS demonstrated dissection with an intramural hematoma and presence of intimal tear. Therefore, a coronary angioplasty with multiple direct drug eluting stents implantation completed with post-dilatation was performed. Good angiographic and IVUS results were achieved. Spontaneous LIMA graft dissection is a rare condition. We reported the ninth case in literature and the one with the highest latency period between CABG and LIMA graft dissection. This situation may lead to an acute coronary syndrome, an unstable angina in our report, therefore prompt treatment, percutaneous or surgical, is decisive. Spontaneous arterial graft dissection is sometimes seen in women, especially in the post-partum period, it usually occurs during the fifth and sixth decade in patients affected by arterial hypertension, vasculitis, connective tissue disorders or atherosclerotic disease.