Plaque assessment by coronary CT angiography may predict cardiac events in high risk and very high risk diabetic patients: A long-term follow-up study

Highlights

• A not negligible portion of diabetic patients exhibited totally normal coronaries.

• Advanced parameters of plaque composition were associated with cardiac events.

• Elevated fibro-fatty plaque volume was the independent events predictor.

Abstract

Background and aims

The aim of the present study is to evaluate whether advanced coronary atherosclerosis analysis by CCTA may improve prognostic stratification among diabetic patients at high cardiovascular risk (CV risk).

Methods and results

The study population consisted of 265 consecutive diabetic patients at high CV risk who underwent CCTA for suspected CAD between January 2011 and December 2016. For every patients both traditional and advanced, qualitative and quantitative coronary plaque analysis were performed. The occurrence of cardiac death, ACS, and non-urgent revascularization were recorded at follow-up.

Among the 265 patients enrolled, 21 were lost to follow-up, whereas 244 (92%) had a complete follow-up (mean 45 ± 22 months) and were classified at high (n = 67) or very high cardiovascular risk (n = 177), according to ESC Guidelines. A total of 63 events were recorded (3 Cardiac Death, 3 NSTEMI, 8 unstable angina, 36 late non-urgent revascularization and 13 non-cardiac death) in 57 different patients. Elevated fibro-fatty plaque volume was the only predictor of events over age, gender and traditional risk factor when ACS and MACE were considered as end-points [HR (95% CI) 6.01 (1.65–21.87), p = 0.006 and 3.46 (2.00–5.97); p < 0.001].

Conclusion

The present study confirms the prognostic role of advance coronary atherosclerosis evaluation beyond risk factors and stenosis severity, even in diabetics. Despite the very high cardiovascular risk of study population, a not negligible portion (23%) of patients exhibited totally normal coronaries.

Introduction

Coronary artery disease (CAD) is the major cause of morbidity, mortality, and medical costs in patients with diabetes mellitus (DM), which is considered a CAD equivalent by European and American guidelines [1]. The American Diabetes Association gathered a panel of experts who reviewed the issue of CAD screening in patients with DM, with the aim of identifying high-risk subgroups and to improve their outcome with more aggressive modification of risk factors, medical surveillance, and revascularization [1]. Unfortunately, risk assessment is limited because angina is often absent, and stress tests, including nuclear and echocardiography stress imaging, demonstrated limited negative predictive value [2]. Although several coronary computed tomography angiography (CCTA) studies showed that patients with DM have higher prevalence of obstructive and nonobstructive CAD and fewer normal coronary arteries compared with nondiabetic patients [3], the European Society of Cardiology guidelines do not advise CCTA for risk assessment whereas the American College of Cardiology Foundation/American Heart Association guidelines for detection and risk assessment of stable CAD state that CCTA “may be appropriate” in asymptomatic patients with high global risk [4]. In the last years, some long-term observational studies with CCTA [[5], [6], [7]] underlined the role of this imaging modality in identifying both symptomatic and asymptomatic diabetic patients with high-risk coronary lesions and in improving their prognosis with appropriate and timely interventions. Because the CRONOS-ADM (Coronary CT Angiography Evaluation for Clinical Outcomes in Asymptomatic Patients With Type 2 Diabetes Mellitus) study provided additional evidence for the association between DM duration and the progression and severity of CAD as assessed by CCTA [8], some investigators suggested introducing screening for CAD with CCTA in all diabetic patients with a more than 10-year history of DM [9,10]. Moreover, some studies demonstrated an incremental prognostic utility of CCTA over coronary artery calcium score and traditional CAD risk factors in diabetic patients with a documented history of disease of at least 10–12 years [5,11]. Recently, growing amount of evidences documented as the CCTA identification of some high-risk coronary features, as positive remodeling (PR), low-attenuation plaques (LAP), small spotty calcifications and napkin ring sign, allows to improve the prognostic stratification with CCTA derived by the degree of stenosis alone [12], even in the subset of non-obstructive stenosis [13]. Finally, in the last year, large prospective multicenter studies showed that an advanced and comprehensive atherosclerosis quantification by CCTA resulted to be the most powerful predictor of cardiovascular events over lumen stenosis and clinical risk profile [14,15].

Therefore, the aim of the present study is to evaluate whether the advanced coronary atherosclerosis analysis by CCTA may improve the prognostic stratification among diabetic patients with at least 10 years of documented history of diabetes and high prevalence of major cardiovascular risk factors or target organ damage that underwent a clinically indicated CCTA for suspected CAD.