The prognosis of patients with coronary artery disease is related to the extent of myocardium at risk. Proximal left anterior descending coronary artery (LAD) lesions often supply a high percentage of the left ventricular myocardium, compared to proximal lesions in the circumflex or right coronary arteries. A study reported that the prevalence of significant proximal LAD disease in stable patients undergoing diagnostic coronary catheterization was 7.2 percent in New York State and 13.4 percent in Ontario, Canada .
This topic will discuss both the choice between medical therapy and revascularization for treatment of proximal LAD disease in stable patients as well as the choice between coronary artery bypass graft surgery and percutaneous coronary intervention in those patients in whom revascularization is chosen. This discussion will focus on the outcomes of survival, myocardial infarction, and revascularization rates. Revascularization to improve angina refractory to medical therapy in patients for whom survival will not be improved is discussed separately. (See "Stable ischemic heart disease: Indications for revascularization" and "Stable ischemic heart disease: Overview of care".)
The management of patients with stable, nonproximal LAD disease is similar to disease identified in the circumflex and right coronary arteries. (See "Stable ischemic heart disease: Indications for revascularization" and "Bypass surgery versus percutaneous intervention in the management of stable angina pectoris: Recommendations".)
The discussion of coronary artery revascularization in the large subgroup of patients with diabetes is found elsewhere. (See "Coronary artery revascularization in patients with diabetes mellitus and multivessel coronary artery disease".)
DEFINITION OF SIGNIFICANT
For the purposes of this topic, significant disease of the proximal (proximal to and including the first major septal branch) left anterior descending coronary artery is present when coronary angiography reveals one or more obstructive lesions and one of the following criteria: