Aortic distensibility and its relationship to coronary and thoracic atherosclerosis plaque and morphology by MDCT: Insights from the ROMICAT Trial

BackgroundMulti-detector cardiac computed tomography (CT) allows for simultaneous assessment of aortic distensibility (AD), coronary atherosclerosis, and thoracic aortic atherosclerosis.ObjectivesWe sought to determine the relationship of AD to the presence and morphological features in coronary and thoracic atherosclerosis.MethodsIn 293 patients (53 ± 12 years, 63% male), retrospectively-gated MDCT were performed. We measured intraluminal aortic areas across 10 phases of the cardiac cycle (multiphase reformation 10% increments) at pre-defined locations to calculate the ascending, descending, and local AD (at locations of thoracic plaque). AD was calculated as maximum change in area / (minimum area × pulse pressure). Coronary and thoracic plaques were categorized as calcified, mixed, or non-calcified.ResultsAscending and descending AD were lower in patients with any coronary plaque, calcified or mixed plaque than those without (all p < 0.0001) but not with non-calcified coronary plaque (p ≥ 0.46). Per 1 mm Hg− 1 10− 3 increase in ascending and descending AD, there was an 18-29% adjusted risk reduction for having any coronary, calcified plaque, or mixed coronary plaque (ascending AD only) (all p ≤ 0.04). AD was not associated with non-calcified coronary plaque or when age was added to the models (all p > 0.39). Local AD was lower at locations of calcified and mixed thoracic plaque when compared to non-calcified thoracic atherosclerosis (p < 0.04).ConclusionsA stiffer, less distensible aorta is associated with coronary and thoracic atherosclerosis, particularly in the presence of calcified and mixed plaques, suggesting that the mechanism of atherosclerosis in small and large vessels is similar and influenced by advancing age.