ABSTRACT
Since the first description of left main coronary artery (LMCA) disease in a patient who died from cardiogenic shock secondary to acute myocardial infarction by James Herrick in 1912, there have been tremendous advancements in the treatment of LMCA disease. The LMCA arises from the mid-portion of the left aortic sinus of Valsalva, below the sinotubular junction of the aortic root. Traditionally, angiographic diameter stenosis of 50" has been considered a cut-off for significant LMCA disease. However, the conventional coronary angiogram is only a lumenogram and has critical limitations in assessing lesion morphology and plaque characteristics. Fractional flow reserve (FFR) is a pressure wire-based index used to identify ischaemia-producing coronary stenosis and is simply expressed as the ratio between the mean pressure of the aorta and the mean pressure distal to the stenosis in the maximal coronary hyperaemic condition. Patients with normal left ventricular function are usually tolerant of brief global ischaemia during the balloon occlusion.
