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Tuesday, March 29, 2011

Multivessel Coronary Artery Disease

A 69-year-old man has been treated medically for chronic stable angina for 7 years. Over the past 6 months, he has been noticing some mild neck discomfort brought on by playing tennis. He has a 15-year history of type 2 diabetes mellitus. His medications are metoprolol, aspirin, atorvastatin, and insulin.

Results of the physical examination are unremarkable. An electrocardiogram shows a pattern of left ventricular hypertrophy. Cardiac catheterization is performed and shows 90% stenosis in the proximal left anterior descending coronary artery, 85% stenosis in the middle right coronary artery, and 70% stenosis in the proximal left circumflex coronary artery. The left ventricular ejection fraction at rest is 40%.

Which of the following treatments would offer this patient the greatest improvement in longevity?
A Begin clopidogrel
B Begin dipyridamole
C Coronary artery bypass graft surgery
D Implantable cardioverter-defibrillator

Key Points

* Coronary artery bypass grafting improves survival in patients with obstructive left main and/or three-vessel coronary artery disease and reduced ejection fraction.
* Coronary artery bypass grafting improves survival in comparison to percutaneous intervention in patients with diabetes mellitus and multivessel coronary artery disease.

Answer and Critique (Correct Answer = C)

This fit, elderly man with no contraindications to coronary revascularization has the clinical features (three-vessel coronary artery disease [CAD] and left ventricular dysfunction) that warrant an invasive treatment approach rather than simply adjusting his medications. Patients who have CAD with large zones of ischemia benefit the most from interventional approaches added to their existing medical treatment. Patients with obstructive left main CAD and/or three-vessel CAD with a reduced left ventricular ejection fraction (≤40%) or a moderate to large amount of myocardial ischemia have improved survival rates with coronary artery bypass grafting (CABG) in combination with medical therapy as compared with medical therapy alone. Patients with multivessel CAD and diabetes mellitus have better outcomes with CABG compared with percutaneous angioplasty. Thus, CABG is preferable to a percutaneous intervention in these patients.

The implantable cardioverter-defibrillator has emerged as an important prophylactic treatment option for reducing sudden cardiac death in selected patients with CAD. An ejection fraction ≤30% helps to identify patients likely to benefit from this procedure. In this patient, the ejection fraction was reduced but remained above 30%. In addition, in patients with an ejection fraction ≤30% who are being considered for an implantable cardioverter-defibrillator, CABG remains the primary treatment when multivessel CAD is present. Thus, placement of an implantable cardioverter-defibrillator is not the best choice for this patient.

1. Stone KE, Chiquette E, Chilton RJ. Diabetic endovascular disease: role of coronary artery revascularization. Am J Cardiol. 2007;99:105B-112B. [PMID: 17307063]

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