Abstract 482: Increased Subclinical Atherosclerosis is Associated With Impaired Aortic and Coronary Artery Distensibility
Introduction: Atherosclerotic changes within the aortic and coronary artery wall can affect vessel wall distensibility. This study evaluates the relationship between the aortic (ADI) and coronary distensibility indices (CDI) measured by computed tomography (CT) and subclinical atherosclerosis measured as coronary artery calcium (CAC).
Methods: One hundred and sixteen subjects (age 59±6 years, 38% female) underwent CAC and CTA. Cross section area (CSA) of aorta and LAD coronary were measured 16 mm above the left main coronary ostium, and 5 mm distal to the LAD circumflex bifurcation, respectively. Aortic distensibility was defined as: ADI = (end systolic lumen CSA - End diastolic lumen CSA)/ (End diastolic lumen CSA x peripheral pulse pressure). Coronary distensibility was defined as: CDI = (early diastolic lumen CSA - mid diastolic lumen CSA)/ (mid diastolic lumen CSA x central pulse pressure). CAC was defined as CAC = 0, 1≤CAC≤99, and CAC≥100.
Results: The mean heart rate was 56±3 during CTA. ADI correlated significantly with CDI (r = 0.71, p = 0.001). Similarly, CDI and ADI decreased from CAC = 0 to 1≤CAC≤99 to CAC≥100 (p<0.05) (Figure⇓). After adjustment for age, gender and cardiac risk factors, the odds ratio of CAC≥100 was 3.64 in the lowest tertile of ADI, and 7.45 in the lowest tertile of CDI as compared to CAC = 0. Addition of CDI to ADI increased area under ROC curve from 0.7 to 0.9 to predict CAC≥100.
Conclusion: Significant subclinical atherosclerosis is associated with impaired aortic and coronary distensibility. Further studies are needed to evaluate the predictive value of concomitant low ADI and low CDI for identification o high risk coronary patients.