Abstract 18799: Association of Long-term Risk Factor Levels with Coronary Artery Wall Remodeling Indices: The Chicago Healthy Aging Low-RISk Magnetic Resonance Angiography (CHARISMA) Study

Abstract

Background: Coronary artery wall remodeling (CAR) has recently been recognized as an important feature of atherosclerosis development. Long-term associations of risk factor (RF) burden with remodeling indices have not been described.

Methods: In 2009-11, we performed MR angiography in 440 randomly-selected participants (ppts) of the Chicago Healthy Aging Study, whose RFs had been measured in 1967-73. We examined association of aggregate burden of RFs with CAR indices measured by 1.5T MR imaging. Cross-sectional images of the proximal portions of the left main (LMCA, 1 slice), left anterior descending (LAD, 3 slices) and right (RCA, 3 slices) coronary arteries prescribed using coronary landmarks were acquired using a breath-hold, black-blood, ECG-gated, turbo spin echo sequence. RF burden at baseline was stratified into “Low Risk” (untreated cholesterol <200 mg/dL, untreated blood pressure <120/<80 mm Hg, not smoking and no diabetes) and “Not Low Risk,” including all others. Individual RF associations were also examined.

Results: Among 422 ppts with evaluable images, the mean age was 32±5 y at baseline and 71±5 y at follow-up; 65% were male and 84% white. By design, 154/422 (36.5%) had the Low Risk profile at baseline, but only 5.5% maintained it at follow up. The Table shows the CAR indices, stratified by Low Risk status at baseline. Mean and maximal wall thickness measures were significantly lower for ppts with Low Risk status at baseline in the LMCA and LAD, as was overall coronary wall area in the LAD. Associations were generally as expected for individual RFs and were particularly significant for baseline obesity.

Conclusions: These are the first data to examine long-term associations of RF burden with indices of coronary artery wall remodeling. These associations may explain part of the mechanism of the decades-long protection against development of clinical coronary events observed in individuals with the Low Risk profile in younger adulthood.