Patients with stable chest pain who were evaluated with coronary CT angiography (CTA) were significantly less likely to experience a heart attack or die from coronary heart disease (CHD) within five years compared to individuals who received standard testing, researchers reported in the New England Journal of Medicine.
The results of the SCOT-HEART study were also presented Aug. 25 at the European Society of Cardiology Congress in Munich.
Some 4,146 Scottish patients were randomized 1:1 to receive standard care plus CTA or standard care alone. At the five-year mark, 2.3 percent of patients in the CTA group and 3.9 percent of those in the usual care group met the primary endpoint of either death from CHD or nonfatal MI. The difference was mostly driven by the reduction of nonfatal MIs in the CTA group (2.1 percent versus 3.5 percent).
Although the rates of invasive coronary angiography and revascularization were higher in the CTA group in the first few months of follow-up, they evened out over the five-year period.
“Our findings suggest that the use of CTA resulted in more correct diagnoses of coronary heart disease than standard care alone, which, in turn, led to the use of appropriate therapies, and this change in management resulted in fewer clinical events in the CTA group than in the standard-care group,” wrote corresponding author David E. Newby, MD, with the University of Edinburgh, and colleagues.
The researchers found patients evaluated with CTA were 40 percent more likely to be prescribed preventive therapy and 27 percent more likely to be given antianginal therapy.
“Event rates in the two groups in the current trial were similar until diagnoses were confirmed and alterations in treatment were made after approximately 7 weeks, which suggests that the groups were similar at baseline and changes in outcomes occurred only once treatment interventions directed by CTA findings were initiated,” Newby et al. wrote. “We hypothesize that the immediate reductions in events were mediated through the use of aspirin and coronary revascularization procedures, and that longer-term benefits are attributable to lifestyle modification and statin therapy.”
According to the trial results, it would take 63 patients with stable chest pain being referred to CTA to prevent one heart attack over a span of five years.
But in a related editorial, two physicians suggested the difference between the SCOT-HEART and PROMISE studies—both of which evaluated CTA against other forms of testing for suspected coronary artery disease—lies in the comparator exams. PROMISE didn’t show a significant difference in outcomes at two years post-baseline, but nuclear or echocardiographic stress imaging was predominantly used in the non-CTA group. Only about 10 percent of patients in that study underwent exercise electrocardiographic (ECG) testing, which was performed in a majority of non-CTA patients in the SCOT-HEART study.
“One might conclude, then, that the CTA strategy was associated with fewer myocardial infarctions in the SCOT-HEART trial because of the suboptimal stress ECG comparator and because of the potentially suboptimal management that was based on that strategy,” wrote Udo Hoffmann, MD, MPH, and James E. Udelson, MD.
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.