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

Abstract

Background Multi-detector cardiac computed tomography (CT) allows for simultaneous assessment of aortic distensibility (AD), coronary atherosclerosis, and thoracic aortic atherosclerosis. Objectives We sought to determine the relationship of AD to the presence and morphological features in coronary and thoracic atherosclerosis. Methods In 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. Results Ascending 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 mmHg−110−3 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). Conclusions A 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.

Impaired aortic distensibility in hypothyroid patients with negative coronary angiograms: Simultaneous evaluation with 128-slice multiple row detector computed tomography

“…[2][3][4][5][6] Monitoring of aortic distensibility has been shown to be relevant for evaluating coronary artery disease progression and treatment choices. [7][8][9] Previous investigations regarding hypothyroidism and atherosclerosis have yielded contradictory results. Some studies have shown increased risk of atherosclerosis, 3 while others found no effect on atherosclerosis in cases of hypothyroidism compared with patients with normal thyroid function.…”

“…28 Disease in one vasculature may be indicative of disease in other vasculature. 9 Regardless of atherosclerosis location, the presence of atherosclerosis is associated with reduced aortic distensibility, and indicates higher cardiovascular event rates. 29 The strength of the present study came from the simultaneous finding of distensibility in the ascending aorta, proximal descending aorta and distal descending aorta as an early and objective marker of atherosclerosis, and evaluation of the coronary artery, using a single imaging modality.…”

“…For coronary plaque evaluation, a mean of three axial datasets per subject were reconstructed with a 512  512 pixel image matrix: slice thickness, 0.65 mm; increment, 0.4 mm. Aortic distensibility was calculated as previously described: 9 aortic distensibility ¼ maximum change in area= ðminimum area  pulse pressureÞ Pulse pressure was calculated from blood pressure measurements recorded in the supine position immediately prior to MDCT imaging. Aortic distensibility measurements were performed for the ascending aorta, proximal descending aorta and distal descending aorta.…”

“…Aortic distensibility can be objectively measured using MDCT or magnetic resonance imaging at any point along the thoracic aorta, and changes in distensibility in both the ascending and descending aorta have been shown in patients with atherosclerosis. 9,10 Aortic distensibility has also been shown to be inversely proportional to severity and presence of coronary artery disease. 11,12 With improved temporal and spatial resolution, 128-slice MDCT with retrospective electrocardiogram-gating allows accurate visualization of small-and large-calibre vasculature and their contractility throughout the cardiac cycle.…”

Noninvasive Imaging of Flow and Vascular Function in Disease of the Aorta

“…Similar to vascular aging, atherosclerosis adversely remodels the arterial wall leading to a loss of normal function. Atherosclerosis and calcification of the coronary arteries as well as the thoracic aorta was shown to be strongly associated with decreased gated CT derived distensibility in the aorta (76). This was further demonstrated in longitudinal evaluation of aortic distensibility by gated CT and coronary artery atherosclerosis which revealed parallel progression of coronary artery atherosclerosis and worsening aortic distensibility even after accounting for known risk factors including age (77).…”