High Prevalence of Myocardial Perfusion Abnormalities on Positron Emission Tomography in Asymptomatic Persons with a Parent or Sibling with Coronary Artery Disease

Background: We hypothesized that asymptomatic persons with a parent or sibling 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 subjects underwent rest-dipyridamole cardiac PET perfusion imaging, including 18 index cases (a subject with CAD documented by PET and arteriography), 32 asymptomatic adults without known CAD who had a parent or sibling with CAD among these index cases, 30 asymptomatic subjects with comparable coronary risk factors without CAD or a family history of CAD, and 10 volunteer control subjects with no risk factors and no family history. PET perfusion images were quantified with automated software for size of abnormalities as percent of the cardiac image outside 95% CIs of normal controls and for severity as the lowest quadrant average relative activity. Of asymptomatic subjects with a parent or sibling with CAD (first-degree relatives), 50% had dipyridamole-induced myocardial perfusion defects that involved >/=5% of the cardiac image outside normal 95% CIs with or without other 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 larger than in asymptomatic subjects with comparable risk factors but no family history of CAD (11+/-13% versus 5+/-6%, P:=0.02).

Conclusions: This study documents the presence of quantitative, statistically significant, dipyridamole-induced myocardial perfusion abnormalities on PET in 50% of asymptomatic persons with a parent or sibling with CAD, independent of other risk factors, indicating preclinical coronary atherosclerosis.