Significant, defined as a greater than 50 percent narrowing, left main coronary artery disease (LMCAD) is found in 4 to 6 percent of all patients who undergo coronary arteriography . When present, it is associated with multivessel coronary artery disease (MVCAD) about 70 percent of the time [2,3].
Most patients are symptomatic and at high risk of cardiovascular events, since occlusion of this vessel compromises flow to at least 75 percent of the left ventricle, unless it is protected by collateral flow or a patent bypass graft to either the left anterior descending or circumflex artery. Studies performed before revascularization with coronary artery bypass graft surgery (CABG) became the standard of care revealed a poor prognosis for these patients, with three-year survival as low as 37 percent . CABG, when directly compared to medical therapy, is associated with significantly better cardiovascular outcomes, including mortality .
Percutaneous coronary intervention (PCI) with stenting has generally been restricted to such patients considered inoperable or at high risk for CABG, or with prior CABG and at least one patent graft to the left anterior descending or circumflex artery (so-called "protected" left main disease). Graft patency is important in this setting in the event of acute or late closure after PCI. However, evidence is increasing to support the use of PCI with stenting in some cases. (See 'PCI versus CABG' below.)
Asymptomatic patients with left main lesions felt to not be hemodynamically significant should be managed with preventative therapies. Patients with anginal symptoms attributable to lesions elsewhere should be managed with therapies similar to those used in other patients with coronary artery disease. (See "Stable ischemic heart disease: Overview of care".)
This topic will discuss most aspects of the management of patients with LMCAD. The approach to patients with multivessel coronary artery disease without LMCAD is discussed elsewhere. (See "Bypass surgery versus percutaneous intervention in the management of stable angina pectoris: Recommendations".)