Left Main Coronary Artery

The left main is the first segment of the left coronary artery and supplies at least 75% of the left ventricular myocardium. The prevalence of significant left main stenosis is 5-10% in patients with symptoms of coronary artery disease and is historically categorized into “ostial”, “mid-shaft” or “distal” on the basis of angiography. Clinical presentation of unprotected significant left main coronary artery disease can range from asymptomatic patients to sudden death, being 1) low threshold angina pectoris or 2) acute coronary syndrome with chest pain at rest the most common clinical pictures. Historically, myocardial revascularization in patients with left main coronary artery disease has been surgically achieved with bypass grafting, although percutaneous revascularizazion with angioplasty and stenting has been widely recognised as a reasonable alternative whenever clinical comorbities and anatomical complexity allow feasibility. In this chapter, risk stratification of patients with left main coronary artery disease is discussed and registries and randomized trials of percutaneous coronary intervention versus coronary artery bypass graft are briefly reviewed. Finally, the role of invasive functional evaluation and imaging and technical aspects of percutaneous coronary interventions with drug-eluting stent implantation in patients with left main coronary artery disease are presented.