Cardiac scan nearly halves future risk of heart attack in patients with chest pain, finds study

Investigating patients with stable chest pain using coronary computed tomographic angiography (CTA) nearly halves their risk of death due to coronary heart disease or of non-fatal myocardial infarction over the next five years, a study has shown.1 This was first randomised trial to investigate adding this type of scan to standard care.

“This relatively simple heart scan ensures that patients get the right treatment,” said lead author David Newby, from the British Heart Foundation Centre for Cardiovascular Science at the University of Edinburgh.

“This is the first time that CT guided management has been shown to improve patient outcomes with a major reduction in the future risk of heart attacks,” he said. “This has major implications for how we now investigate and manage patients with suspected heart disease.”

The open label trial randomly assigned 4146 patients with stable chest pain who had been referred to one of 12 cardiology clinics across Scotland to receive either standard care plus CTA or standard care alone. They were followed up for a median of 4.8 years, giving a total of 20 254 patient years of follow-up.

Results, reported in the New England Journal of Medicine, showed that the rate of either death from coronary heart disease or non-fatal myocardial infarction was 41% lower in patients undergoing CTA compared with those managed with standard care (2.3% versus 3.9%, hazard ratio 0.59, 95% confidence interval 0.41 to 0.84, P=0.004). This was driven almost entirely by a lower rate of non-fatal myocardial infarction.

Rates of invasive coronary angiography and coronary revascularisation were higher in the CTA group in the first few months, but overall rates were similar at five years. Patients who were scanned, however, were more likely to be started on preventive therapies than the standard care group (odds ratio 1.40, 95% confidence interval 1.19 to 1.65) and angina drugs (1.27, 1.05 to 1.54).

“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. This change in management resulted in fewer clinical events in the CTA group,” the research group wrote.

In an accompanying editorial, Udo Hoffman from Massachusetts General Hospital and James Udelson from Tufts Medical Center, both in Boston, USA, said, “The information provided by a diagnostic test can resonate therapeutically beyond making a correct diagnosis of coronary artery disease.”2

Limitations of the study, which was funded primarily by the Scottish Government Chief Scientist Office, included its open label design, which may have led to ascertainment bias. But the researchers thought that this was mitigated by the primary endpoint being composed of hard clinical events. In addition, they did not collect data on lifestyle changes made by participants during follow-up, and thresholds for initiating preventive therapies have fallen since the trial was completed.