Frequency and clinical implications of fluid dynamically significant diffuse coronary artery disease manifest as graded, longitudinal, base-to-apex myocardial perfusion abnormalities by noninvasive positron emission tomography

Background-Diffuse coronary atherosclerosis is the substrate for plaque rup ture and coronary events. Therefore, in patients with mild arteriographic c oronary artery disease without significant segmental dipyridamole-induced m yocardial perfusion defects, we tested the hypothesis that fluid dynamicall y significant diffuse coronary artery narrowing is frequently manifest as a graded, longitudinal, base-to-apex myocardial perfusion abnormality by non invasive PET. Methods and Results-In this study, 1001 patients with documented coronary a rtery disease by coronary arteriography showing any visible coronary artery narrowing underwent rest-dipyridamole PET perfusion imaging. Quantitative severity of dipyridamole-induced, circumscribed, segmental PET perfusion de fects was objectively measured by automated software as the minimum quadran t average relative activity indicating localized flow limiting stenoses. Qu antitative severity of the graded, longitudinal, base-to-apex myocardial pe rfusion gradient indicating fluid dynamic effects of diffuse coronary arter y narrowing was objectively measured by automated software as the spatial s lope of relative activity along the cardiac longitudinal axis. Conclusions-In patients with mild arteriographic disease without statistica lly significant dipyridamole-induced segmental myocardial perfusion defects caused by flow-limiting stenoses compared with normal control subjects, th ere was a graded, longitudinal, base-to-apex myocardial perfusion gradient significantly different from normal control subjects (P=0.001) that was als o observed for moderate to severe dipyridamole-induced segmental perfusion defects (P=0.0001), indicating diffuse disease underlying segmental perfusi on defects; 43% of patients with or without segmental perfusion defects dem onstrated graded, longitudinal, base-to-apex perfusion abnormalities beyond +/-2 SD of normal control subjects, indicating diffuse coronary arterial n arrowing by noninvasive PET perfusion imaging.