Coronary Artery Bypass Surgery and Percutaneous Coronary Revascularization: Impact on Morbidity and Mortality in Patients with Coronary Artery Disease

Abstract

Both percutaneous revascularization and coronary artery bypass surgery are very effective in relieving angina pectoris. The principal means by which revascularization alters survival prognosis appears to be a reduction in infarct size and infarct-related mortality, rather than a reduction in the incidence of infarction or unstable angina. Saphenous vein grafts have a limited durability, as evidenced clinically by the return of symptoms in surgically bypassed patients, often within 5 years, and the increased morbidity that follows. In contrast to saphenous vein grafts, internal mammary conduits are remarkably resistant to atherosclerosis, having 10-year patency rates of 80-95 %. The internal mammary artery performs best when used to bypass the left anterior descending coronary artery. Other arterial conduits used today include the radial artery and the inferior epigastric arteries. Thus, it is possible to perform multivessel revascularization without using a saphenous vein graft. Off-pump coronary bypass is generally equivalent to the standard procedure, but it reduces perioperative inflammation and morbidity and improves outcomes in selected high-risk patients. Atrial fibrillation is the most common complication of coronary artery bypass surgery, occurring in 25-30 % of patients. The risk of angiographic restenosis and need for repeat revascularization is markedly reduced in patients who receive stents that elute a variety of antiproliferative drugs into native coronary lesions, small vessels, and saphenous vein grafts, both after myocardial infarction and in patients with diabetes mellitus. Balloon angioplasty and stent-percutaneous coronary revascularization are effective forms of therapy for patients with non-ST-elevation myocardial infarction, unstable angina, or ST-elevation myocardial infarction aborting the acute event. For the treatment of stable angina, percutaneous therapy is principally for the control of angina. The risks and long-term efficacy associated with revascularization procedures must be weighed against the prognosis for survival and myocardial infarction that is estimated according to clinical, physiological, and anatomic criteria. Revascularization procedures do not alter the natural history of atherosclerosis, only the likelihood of surviving as the disease progresses. Therefore, every effort should be made to control risk factors for aberrant metabolism, including obesity, diabetes mellitus, hyperlipidemia, and smoking.