Practice Update: Cardiology

EUROPEAN SOCIETY OF CARDIOLOGY CONGRESS 18

Functional imaging for suspected CHD can help avoid angiography Initial investigation of patients with suspected coronary heart disease using functional imaging rather than guideline-directed care resulted in significantly less unnecessary angiography, outcome of the Clinical Evaluation of MAgnetic Resonance imaging in Coronary heart disease 2 (CE-MARC 2) study shows.

J ohn Greenwood, PhD, of the University of Leeds, UK, said that the findings could exert an important impact on referral rates for invasive coronary angiography, and potentially healthcare costs. “Rates of invasive angiography are considered too high among patients with suspected coronary heart disease,” he said. “Our findings show that both cardiovascular magnetic resonance and myocardial perfusion scintigraphy significantly reduced rates of unnecessary angiography compared to guideline- directed care, with no penalty in terms of major adverse cardiovascular events. This suggests that functional imaging should be adopted on a wider basis, even in high-risk patient subgroups.” CE-MARC 2 included 1202 patients with suspected coronary heart disease from six UK centres. Patients were randomised to functional imaging-based investigation with either cardiovascular magnetic resonance (n=481), myocardial perfusion scintigraphy (n=481), or guideline- directed investigation (n=240) based on National Institute for Health and Care Excellence (NICE) guidelines. In the latter group, those with a pre-test likelihood of 10–29% (low risk for coronary heart disease based on age, gender, symptom characteristics, and clinical history) were scheduled for cardiac computed tomography. Those with a pre-test likelihood of 30% to 60% (intermediate risk) were scheduled for myocardial perfusion scintigraphy, and those with a high pre-test likelihood were sent directly to coronary angiography. The primary endpoint was unnecessary coronary angiography within 12 months, defined by the absence of significant stenosis as measured by fractional flow reserve or quantitative coronary angiography, with secondary endpoints of major adverse cardiovascular events, and positive angiography within this same time period. Twenty-two percent of the study population underwent coronary angiography within 12 months, with unnecessary angiography performed in 28.8% of the NICE guidelines group, 7.5% of the cardiovascular magnetic resonance group, and 7.1% of the myocardial perfusion scintigraphy group. The adjusted odds ratio of unnecessary angiography for the cardiovascular magnetic resonance group vs the NICE guidelines group was 0.21 (95% CI 0.12–0.34; P < 0.001), with no statistically significant difference between the cardiovascular magnetic resonance and myocardial perfusion scintigraphy groups. Among the three strategies, there was no difference in short-term major adverse cardiovascular events or positive angiography rates.

Dr Greenwood noted, “Worldwide, myocardial perfusion scintigraphy is the most commonly used test to assess suspected coronary heart disease, but cardiovascular magnetic resonance is increasingly recognised as conferring high diagnostic accuracy and prognostic value. Though the results of CE-MARC 2 showed no difference between the cardiovascular magnetic resonance and myocardial perfusion scintigraphy strategies in terms of unnecessary angiography rates, our original, 2012 CE-MARC study showed that cardiovascular magnetic resonance yielded higher diagnostic accuracy than myocardial perfusion scintigraphy, and, as published in 2016, as a stronger predictor of risk of major adverse cardiovascular events.” Dr Greenwood concluded, “These results show that broader use of functional imaging (cardiovascular magnetic resonance or myocardial perfusion scintigraphy), in low-, intermediate-, and high-risk patient groups, could reduce rates of invasive angiography that ultimately shows no obstructive coronary disease. In addition, CE-MARC and CE-MARC 2 further support cardiovascular magnetic resonance as an alternative to myocardial perfusion scintigraphy for the diagnosis and management of patients with suspected coronary heart disease.”

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PRACTICEUPDATE CARDIOLOGY