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Heart scan cuts risk of CHD deaths and heart attacks, study finds

By Nicole MacKee
Coronary computed tomographic angiography (CTA) can significantly lower the risk of death from coronary heart disease (CHD) five years after diagnosis, researchers have told the European Society of Cardiology (ESC) Congress, held recently in Munich.

In a report of the five-year clinical outcomes of the SCOT-HEART (Scottish Computed Tomography of the Heart) trial, researchers said patients with stable chest pain whose symptoms had been investigated using CTA plus standard care had a 41% lower risk of death from CHD or nonfatal myocardial infarction than those who underwent standard care alone (including symptom assessment with exercise electrocardiography). The findings of the trial, which included more than 4000 patients, were also published in The New England Journal of Medicine.

Professor Joseph Selvanayagam, Professor of Cardiovascular Medicine at Flinders University, Adelaide, described this relative risk reduction as ‘quite spectacular’ given it was the result of an imaging test, not of a drug or another therapeutic intervention.

Professor Selvanayagam said that although ascertainment bias was a possibility, and the study did not have central event adjudication (both factors that may have skewed the results in favour of CTA), the improved clinical outcomes were most likely to be a result of earlier detection of CHD using CTA. He said this enabled more timely implementation of prevention measures, including lifestyle modification and drug therapy.

‘You are able to directly visualise the heart arteries with CTA, so you can tell whether a patient has early disease before the functional test becomes significant,’ he said.

The researchers also found that patients in the CTA arm had higher rates of invasive coronary angiography and coronary revascularisation in the first few months after diagnosis. However, at five years, the rates of these interventions were similar in the two groups.

Speaking to Cardiology Today, Professor Selvanayagam noted that in Australia stress echocardiography, nuclear stress perfusion studies and stress MRI were now more often used than exercise electrocardiography. However, he said, this should not alter the trial’s key message.

‘CTA should definitely be considered for low- to intermediate-risk patients with chest pain, where there is access to CTA,’ he said, adding that results needed to be followed up with lifestyle and medication intervention as appropriate.

‘It’s not just ordering the CT, of course, it’s following through on the result with the appropriate advice.’

Professor Selvanayagam said clinicians could also reassure patients about the safety of CTA, pointing to other research presented at the ESC Congress that found significantly lower radiation doses in modern scanners (Eur Heart J 2018: ehy546).
N Engl J Med 2018; 379: 924-933.