Iatrogenic anastomosis of the internal mammary artery with the great cardiac vein: The first documented case report in Palestine with a literature review.

An unintentional anastomosis of the left internal mammary artery (LIMA) to the great cardiac vein (GCV) is a rare complication of coronary artery bypass graft surgery (CABG), resulting in a left-to-right arteriovenous shunt. It may cause angina, arrhythmias, or right-sided heart failure, with symptoms sometimes delayed for years. Management varies based on symptoms and hemodynamic impact, ranging from conservative to surgical intervention. A 60-year-old male presented with recurrent exertional chest pain described as heavy, nonradiating, and relieved by rest. The pain was associated with nausea and sweating. He had a past medical history of ischemic heart disease, chronic obstructive pulmonary disease, hypertension, type 2 diabetes, hyperlipidemia, and a history of supraventricular tachycardia treated with ablation. He was a smoker and had previously undergone CABG in 2020. Electrocardiography revealed ST-segment depression in leads V4-V6 and T-wave inversion in inferior leads. Troponin was negative. Coronary angiography revealed an iatrogenic LIMA-GCV anastomosis instead of the intended left anterior descending (LAD), along with severe (95%) proximal LAD stenosis and additional mid-LAD disease. Echocardiography showed preserved left ventricular function (ejection fraction 60%). The patient underwent percutaneous transluminal coronary angioplasty with drug-eluting stents (Onyx 3.5/18 mm and Xience 2.5/18 mm) to the proximal and mid-LAD segments. No intervention was performed on the nondominant right coronary artery or the LIMA-GCV fistula during this admission. The patient experienced complete resolution of symptoms postintervention. The recovery was uneventful, and he was discharged on the second day of hospitalization. Iatrogenic aortocoronary arteriovenous fistula is a rare but important complication of CABG, which can lead to significant clinical symptoms. Early diagnosis through coronary angiography is crucial for guiding appropriate management. Although percutaneous intervention with drug-eluting stents effectively resolved the patient's angina by treating the native LAD stenosis, it is critical to recognize that this approach did not address the underlying LIMA-GCV fistula, which requires separate evaluation and management.