Coronary artery calcification and myocardial perfusion in asymptomatic adults: the MESA (Multi-Ethnic Study of Atherosclerosis)

Abstract

Objectives: This study assessed the cross-sectional association between coronary artery calcification (CAC) and myocardial perfusion in an asymptomatic population.

Background: Clinical studies showed that the prevalence of stress-induced ischemia increased with CAC burden among patients with coronary heart disease (CHD). Whether an association between CAC and myocardial perfusion exists in subjects without a history of CHD remains largely unknown.

Methods: A total of 222 men and women, ages 45 to 84 years old and free of CHD diagnosis, in the Minnesota field center of the MESA (Multi-Ethnic Study of Atherosclerosis) were studied. Myocardial blood flow (MBF) was measured using magnetic resonance imaging during rest and adenosine-induced hyperemia. Perfusion reserve was calculated as the ratio of hyperemic to resting MBF. Agatston CAC score was determined from chest multidetector computed tomography.

Results: Mean values of hyperemic MBF and perfusion reserve, but not resting MBF, were monotonically lower across increasing CAC levels. After adjusting for age and gender, odds ratios (95% confidence intervals) of reduced perfusion reserve (<2.5) for subjects with CAC scores of 0, 0.1 to 99.9, 100 to 399, and > or =400 were 1.00 (reference), 2.16 (0.96 to 4.84), 2.81 (1.04 to 7.58), and 4.99 (1.73 to 14.4), respectively. Further adjustment for other coronary risk factors did not substantially modify the association. However, the inverse association between perfusion reserve and CAC attenuated with advancing age (p for interaction < 0.05).

Conclusions: Coronary vasodilatory response was associated inversely with the presence and severity of CAC in asymptomatic adults. Myocardial perfusion could be impaired by or manifest the progression to subclinical coronary atherosclerosis in the absence of clinical CHD.

Figure 1

(a) The first pass of an intravenous contrast agent bolus of gadolinium complex of diethylenetriamine pentaacetic acid (Gd-DTPA) through the right ventricle (RV) and left ventricle (LV) is shown in a short-axis view on 3 frames, out of a total of 50 for each slice, acquired by T1-weighted fast magnetic resonance imaging with a temporal resolution of 1 frame per heartbeat at each of 3 slice levels. (b) The myocardial signal enhancement in 1 of 8 myocardial sectors, located in the inferior wall, for baseline and hyperemia is analyzed by model-independent deconvolution with the respective arterial inputs, shown in c. The solid line in b represents the myocardial response calculated from the estimated tissue impulse response by convolution with the measured arterial input. SI = signal intensity.

Figure 2

Prevalence of reduced perfusion reserve (<2.5) across levels of coronary artery calcification in subjects with no clinical coronary heart disease, stratified by age group. Numbers in bars are the number of subjects with reduced perfusion reserve/total n of subjects in the respective coronary artery calcium score category. Error bars show the standard error for prevalence obtained by a bootstrap estimate.