Case report: Coronary artery bypass graft surgery for a diabetic patient

A 61-year-old man with diabetes mellitus, hypertension, dyslipidemia, and a remote history of cigarette use presented to the cardiology clinic for initial evaluation. Over the preceding 6 weeks, he noted onset of exertional fatigue associated with mild substernal chest heaviness that would resolve promptly with rest. He did not have symptoms of congestive heart failure and had no history of coronary artery disease, peripheral or cerebrovascular disease, or arrhythmia. His primary care physician had been treating him with aspirin, an angiotensin-converting enzyme (ACE) inhibitor, and metformin. He had recently been prescribed an HMG-CoA reductase inhibitor (statin drug) for modestly increased low-density lipoprotein (LDL) cholesterol and triglyceride levels. More recently, he had been prescribed sublingual nitroglycerin because of his chest discomfort; however, he had not yet taken any pills. His physical examination was notable only for an S4 gallop. He had no evidence of heart failure.

An office electrocardiogram showed sinus rhythm with borderline left ventricular hypertrophy without evidence of prior infarction or ischemia. Laboratory studies showed the following values: hemoglobin A1c, 6.8%; fasting glucose, 147 mg/dL; LDL cholesterol, 129 mg/dL; triglycerides, 230 mg/dL; and creatinine, 1.3 mg/dL. Coronary angiography showed a 90% stenosis of the proximal left anterior descending (LAD) coronary artery and a 75% stenosis of a large second obtuse marginal branch of the circumflex coronary artery. The ejection fraction was estimated to be 57% on ventriculography without wall motion abnormality. Although both coronary lesions appeared amenable to percutaneous coronary intervention, after detailed discussion with the patient, the decision was made to proceed with coronary artery bypass graft surgery based on the accumulated data suggesting improved long-term outcomes with a surgical versus percutaneous approach. The patient underwent uncomplicated two-vessel bypass surgery, which included a left internal mammary artery graft to the LAD and a saphenous vein graft to the obtuse marginal branch. The patient was discharged from the hospital on postoperative day 4 without complications. At the 1-year follow-up, the patient had no symptoms, was working full-time, and had no exercise limitations. He continued to take aspirin daily, an ACE inhibitor, a beta blocking agent, and statin therapy, along with metformin for glucose management.