['To determine the relationship between severity of stenosis and hemodynamic significance in calcified coronary arteries.', 'Severity of stenosis is widely used to determine the need for revascularization but the effect of lesion calcification on hemodynamic significance is not well understood.', 'Two hundred consecutive patients undergoing fractional flow reserve (FFR) testing of an intermediate coronary lesion with a pressure wire and intravenous infusion of adenosine were studied. Coronary calcium was quantified based upon radiopacities at the site of the stenosis on cineangiography using the method of Mintz et al. (0\u2009=\u2009none or mild calcium, 1\u2009=\u2009moderate calcium, 2\u2009=\u2009severe calcium).', 'Mean age was 61\u2009±\u200911 years, 66% were males, 87.5% had hypertension, 44.5% had diabetes, and 20.5% were current smokers. The mean coronary stenosis by quantitative coronary angiography was 60\u2009±\u200912% and the mean FFR was 0.83\u2009±\u20090.08. There were 109, 45, and 46 patients classified as Calcium Score of 0, 1, or 2, respectively. Compared to those with no/mild or moderate calcification, patients with severe coronary calcium were older and more likely to have chronic kidney disease and pulmonary disease. The correlation between angiographic severity and FFR decreased as lesion calcification increased [calcium score\u2009=\u20090 (R'] Does angiographic severity correlate with fractional flow reserve in heavily calcified coronary arteries?