High prevalence of myocardial perfusion abnormalities on positron emissiontomography in asymptomatic persons with a parent or sibling with coronary artery disease

Background-We hypothesized that asymptomatic persons with a parent or sibli ng with coronary artery disease (CAD) have myocardial perfusion defects on positron emission tomography (PET) as markers of early CAD. Methods and Results-After medical and family histories were recorded, 90 su bjects underwent rest-dipyridamole cardiac PET perfusion imaging, including 18 index cases (a subject with CAD documented by PET and arteriography), 3 2 asymptomatic adults without known CAD who had a parent or sibling with CA D among these index cases, 30 asymptomatic subjects with comparable coronar y risk factors without CAD or a family history of CAD, and 10 volunteer con trol subjects with no risk factors and no family history. PET perfusion ima ges were quantified with automated software for size of abnormalities as pe rcent of the cardiac image outside 95% CIs of normal controls and for sever ity as the lowest quadrant average relative activity. Of asymptomatic subje cts with a parent or sibling with CAD (first-degree relatives), 50% had dip yridamole-induced myocardial perfusion defects that involved greater than o r equal to5% of the cardiac image outside normal 95% CIs with or without ot her risk factors. The size of perfusion defects was larger in first-degree relatives than in control subjects (11+/-13% versus 1+/-1%, P=0.02) and lar ger than in asymptomatic subjects with comparable risk factors but no famil y history of CAD (11+/-13% versus 5+/-6%, P=0.02). Conclusions-This study documents the presence of quantitative, statisticall y significant, dipyridamole-induced myocardial perfusion abnormalities on P ET in 50% of asymptomatic persons with a parent or sibling with CAD, indepe ndent of other risk factors, indicating preclinical coronary atherosclerosi s.