Thoracic Aortic Plaque Burden and Prediction of Cardiovascular Events in Patients Undergoing 320-row Multidetector CT Coronary Angiography

Abstract

Aim: Wide volume scan (WVS) coronary computed tomography angiography (CCTA) enables aortic arch visualization. This study assessed whether the thoracic aortic plaque burden (TAPB) score can predict major cardiovascular adverse events (MACE) in addition to and independently of other obstructive coronary artery disease (CAD) attributes.

Methods: This study included patients with suspected CAD who underwent CCTA (n=455). CCTA-WVS was used to assess CAD and the prognostic capacity of TAPB scores. Data analysis included the coronary artery calcification score (CACS), CAD status and extent, and TAPB score, calculated as the sum of plaque thickness and plaque angle at five thoracic aortic segments. The primary endpoint was MACE defined as a composite event comprised of ischemic stroke, acute coronary syndrome, and cardiovascular death.

Results: During a mean follow-up period of 2.8±0.9 years, 40 of 455 (8.8%) patients experienced MACE. In the Cox proportional hazards model adjusted for clinical risks (Suita cardiovascular disease risk score), we identified TAPB score (T3) as a predictor of MACE independent of CACS ＞400 (hazards ratio [HR], 2.91; 95% confidence interval [CI], 1.26-6.72; p=0.012) or obstructive CAD (HR, 2.83; 95% CI, 1.30-6.18; p=0.009). The area under the curve for predicting MACE improved from 0.75 to 0.795 (p value=0.008) when TAPB score was added to CACS ＞400 and obstructive CAD.

Conclusions: We found that comprehensive non-invasive evaluation of TAPB and CAD has prognostic value in MACE risk stratification for suspected CAD patients undergoing CCTA.

Keywords: Atherosclerosis; Coronary artery disease; Coronary computed tomography angiography; Ischemic stroke; Prognosis.

Fig.1. Schematic flow chart of the study process involving coronary angiography with 320-row multidetector computed tomography to image the aortic arch and coronary atherosclerosis

(A) First volume scan of the CCTA aiming at the heart and second volume scan aiming at the aortic arch. (B) Flow chart of participants in this study. CAD, coronary artery disease; CCTA, coronary computed tomography angiography; WVS, wide volume scan.

Fig.2. A representative case with thoracic aortic plaque burden score (T3) and obstructive coronary artery disease leading to stroke

(A) Coronary arteries with severe calcification (B) Vertical axis image of thoracic aorta, ascending aorta (B1), aortic arch (B2 and B3), and descending aorta (B4). (C) Brain magnetic resonance image. A 77-year-old female underwent CCTA-WVS to investigate the cause of chest pain upon physical effort; obstructive CAD was revealed in the proximal portion of the left anterior descending artery (A, yellow arrowhead). Furthermore, a reconstructed image of the CCTA-WVS demonstrated large and complex thoracic aortic plaques (B2 and B3), resulting in a thoracic aortic plaque score of 22 points (T3). One hundred and twenty-four days after the CCTA-WVS examination, the patient had neurological defects, including staggering gait. Brain magnetic resonance imaging revealed an acute infarct area in the right hypothalamus in the diffusion weighted image (C, red arrowhead). CAD, coronary artery disease; CCTA, coronary computed tomography angiography; WVS, wide volume scan.

Fig.3. Prevalence of coronary artery calcium score, coronary artery disease, and thoracic aortic plaque burden score according to the estimated 10-year risk of cardiovascular disease

(A) Prevalence of CACS category according to the estimated 10-year risk of cardiovascular disease (Suita CVD risk score). (B) Prevalence of the absence of CAD, non-obstructive CAD, and obstructive CAD according to the estimated 10-year risk of cardiovascular disease. (C) Prevalence of TAPB score (T1, T2, and T3) according to the estimated 10-year risk of cardiovascular disease. CACS, coronary artery calcium score; CAD, coronary artery disease; CVD, cardiovascular disease; TAPB, thoracic aortic plaque burden.

Fig.4. Cumulative event rates for major adverse cardiovascular events stratified by TAPB score

(A) Cumulative rates for MACE stratified by the TAPB score categories. (B and C) Cumulative rates for MACE stratified by the presence or absence of TAPB score in the third tertile (T3) and CACS ＞400 (B) or obstructive CAD (C). P-values were obtained using the log-rank test (A) TAPB scores, T3 vs. T1; (B) TAPB score T3 (+) and CACS ＞400 (+) vs. TAPB score T3 (-) and CACS ＞400 (-); (C) TAPB score T3 (+) and obstructive CAD (+) vs. TAPB score T3 (-) and obstructive CAD (-). CACS, coronary artery calcium score; CAD, coronary artery disease; MACE, major adverse cardiovascular events; TAPB, thoracic aortic plaque burden.

Fig.5. Receiver operating curve analysis in predicting major adverse cardiovascular events

(A) The AUC for TAPB score in the third tertile (T3) in predicting MACE was 0.717. (B) By adding the TAPB score (T3) on CACS ＞400, AUC in predicting MACE was improved from 0.632 to 0.751 (p value, 0.0009). Similarly, addition of the TAPB score (T3) significantly enhanced the AUC by (C) obstructive CAD (AUC, from 0.71 to 0.781; p value, 0.018), and (D) CACS ＞400 and obstructive CAD (AUC, from 0.75 to 0.795; p value, 0.008). AUC, area under the curves; CAD, coronary artery disease; MACE, major adverse cardiovascular events; TAPB, thoracic aortic plaque burden.