الفهرس 
Definition and Incidence of LMCA DiseaseOnly 14 pages are availabe for public view
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Abstract
Angiographically significant LMCA stenosis is defined as luminal diameter stenosis ≥50%. Significant narrowing of the left main coronary artery puts the patient at high risk, since occlusion of this vessel, if unprotected by collateral flow or a patent bypass graft to either the left anterior descending (LAD) or the circumflex artery (LCX), compromises flow to approximately 75% of the left ventricle. The etiology of isolated and significant LMCA disease is not well understood. The few studies that have involved histologic examination of coronary vessels have reported atherosclerosis as the primary cause of LMCA stenosis. The finding of ST segment elevation in lead avR>v1 distinguished the LMCA group from the LAD group, the ST segment shift in lead AVR and inferior leads distinguished the LMCA group from the RCA group. Significant LMCA stenosis can present with any of clinical syndromes of CHD, high-risk NSTEMI and SCD being the most common clinical presentations. Coronary angiography has been accepted as the gold standard for the quantification of coronary artery disease, necropsy studies have shown that the severity of coronary artery stenosis in angiographically underestimated. Furthermore, lesions in specific locations (e.g., LMCA) are often difficult to assess angiographically. Intravascular ultrasound permits detailed, high-quality, cross-sectional imaging of the coronary arteries in vivo, coronary artery architecture, the major components of the atherosclerotic plaque, and the changes that occur in coronary arterial dimensions and anatomy with the atherosclerotic disease. Left main coronary arterial disease presents major issues for patients, families, and physicians and surgeons alike. From the earliest days of modern cardiology, the increased risk of morbidity and mortality associated with this location has been well understood. Attempts have focused on improved recognition of the condition and then development of treatment strategies to revascularize the patient. In the past in most regions of the world, surgical revascularization was the standard treatment of choice. This has been based on the excellent surgical results and also on the concern that restenosis after a percautanous approach might be fatal. With the advent of DES, the strategy for LMCA revascularization may change. Currently, trials are addressing the issue and randomize patients with LMCA stenosis to either a DES or a traditional surgical revascularization.