PracticeUpdate Cardiology March 2019

EDITOR’S PICKS 11

Coronary Artery Plaque Characteristics Associated With Adverse Outcomes in the SCOT-HEART Study JACC: Journal of the American College of Cardiology Take-home message • Patients with suspected coronary artery disease underwent coronary CTA to evaluate the prognostic implications of adverse coronary plaque characteristics. At least one adverse plaque feature was seen in 34% of patients. Patients with adverse plaque had a threefold risk of coronary heart disease death or nonfatal myocardial infarction compared with those without adverse plaque. The risk of coronary heart disease death or nonfatal myocardial infarction was doubled in those with obstructive disease. The combination of obstructive disease and adverse plaque was associated with a 10-fold increase in coronary heart disease death or nonfatal myocardial infarction compared with normal coronary arteries. • Adverse coronary plaque characteristics increase the risk of coronary heart disease death or nonfatal myocardial infarction.

COMMENT By Stephan Achenbach Prof. Dr. med. T he SCOT-HEART trial is a 5-year follow-up trial that ran- domized 4146 patients with suspected coronary artery disease to receive initial management by exercise testing only (usually exercise ECG) or exercise testing and coronary CTA. It showed that the 5-year rate of myocardial infarction was slightly but significantly lower in the CT group than in the “stand- ard care” group (2.3% vs 3.9%). 1 Williams et al now publish a secondary analysis of this trial. In 1769 participants, coronary CTA datasets were examined for the presence of plaque with “adverse plaque features” (suggesting plaque vulnerability). These features included positive remode- ling and plaque with low CT attenuation (<30 HU). In the 5-year follow-up, it was indeed shown that patients with these plaque features had a higher risk of events (coronary heart disease death or myocardial infarction) than patients without: the rates were 4.1% versus 1.4%, corresponding to a hazard ratio of 3.01 (95% CI, 1.61–5.63; P=.001). At first sight, there is an impressively elevated risk (“factor of 3“) and a result that creates the impression that patients with adverse plaque features may be at high event risk. However, one has to be aware that plaques with adverse plaque features were found in 34% of these symptomatic patients and that, even with such plaque, the 5-year event rate was only 4.1%, meaning that 96% of patients with such plaque had no event. Hence, the positive predictive value is

extremely low; so, it is difficult to draw any conclusions regarding potential management if such plaque were found. It is interesting to see that very similar results were found by Ferencik et al, who analyzed the PROMISE population. 2 In these 4415 patients with suspected CAD who were followed for 3 years, the presence of adverse plaque was associated with a 6.4% risk of coronary events (as opposed to 2.4% in individuals without adverse plaque features). The usual limitations apply to both trials – rather low-risk patients with atypical symptoms and patients were treated knowing the CT results. Overall, interesting results, but another important confirmation that in stable, symptomatic patients, event rates are very low – as these trials demonstrate, low event rates are present even if high-risk plaque is detected. A single plaque with potential high- risk features is therefore usually no cause for undue alarm. References 1. SCOT-HEART Investigators, Newby DE, Adamson PD, Berry C, et al. Coronary CT angiography and 5-year risk of myocardial infarction. N Engl J Med 2018;379(10):924-933. 2. FerencikM, Mayrhofer T, Bittner DO, et al. Use of high-risk coronary atherosclerotic plaquedetection for risk stratification of patientswith stable chest pain: a secondary analysis of the PROMISE randomized clinical trial. JAMACardiol 2018;3(2):144-152.

Dr. Achenbach is Chairman of the Department of Cardiology at Friedrich-Alexander-Universität Erlangen-Nurnberg in Germany.

Abstract BACKGROUND Unlike most noninvasive imaging modalities, coronary computed tomography angiography can characterize subtypes of ath- erosclerotic plaque. OBJECTIVES The purpose of this study was to investigate the prognostic implications of adverse coronary plaque characteristics in patients with suspected coronary artery disease. METHODS In this SCOT-HEART (ScottishCOmputed Tomography of the HEART Trial) post hoc anal- ysis, the presence of adverse plaque (positive remodeling or low attenuation plaque), obstruc- tive disease, and coronary artery calcification within 15 coronary segments was assessed on coronary computed tomography angiography of 1,769 patients who were followed-up for 5 years.

RESULTS Among study participants (mean age 58 ± 10 years; 56% male), 608 (34%) patients had 1 or more adverse plaque features. Coro- nary heart disease death or nonfatal myocardial infarction was 3 times more frequent in patients with adverse plaque (n = 25 of 608 [4.1%] vs. n = 16 of 1,161 [1.4%]; p < 0.001; hazard ratio [HR]: 3.01; 95% confidence interval (CI): 1.61 to 5.63; p = 0.001) and was twice as frequent in those with obstructive disease (n = 22 of 452 [4.9%] vs. n = 16 of 671 [2.4%]; p = 0.024; HR: 1.99; 95% CI: 1.05 to 3.79; p = 0.036). Patients with both obstructive disease and adverse plaque had the highest event rate, with a 10-fold increase in coronary heart disease death or nonfatal myo- cardial infarction compared with patients with

normal coronary arteries (HR: 11.50; 95% CI: 3.39 to 39.04; p < 0.001). However, these associa- tions were not independent of coronary artery calcium score, a surrogate measure of coronary plaque burden. CONCLUSIONS Adverse coronary plaque char- acteristics and overall calcified plaque burden confer an increased risk of coronary heart dis- ease death or nonfatal myocardial infarction. Coronary Artery Plaque Characteristics Associated With Adverse Outcomes in the SCOT-HEART Study. J Am Coll Cardiol 2019 Jan 29;73(3)291-301, MC Williams, AJ Moss, M Dweck, et al. www.practiceupdate.com/c/79080

VOL. 4 • NO. 1 • 2019