Functional Testing Best for Detecting Coronary Artery Disease

Functional testing outperforms anatomical testing for detecting coronary artery disease (CAD) in low-risk patients, according to a new network meta-analysis.

“Currently available evidence indicates that both anatomical- and functional-based diagnostic strategies have no differential effect on the subsequent risk of myocardial infarction, but considerable differences exist in the need for further investigations and revascularizations,” said Dr. George C. M. Siontis from Bern University Hospital in Switzerland.

“Physicians should make their decision following appropriate risk stratification of their patients, based on local constraints for each diagnostic strategy and patients’ preferences,” he told Reuters Health by email.

Both functional and anatomical noninvasive tests are widely available and used according to locally available resources and expertise, Dr. Siontis and his colleagues write in The BMJ, online February 20. Randomized controlled trials have not provided conclusive evidence as to which strategy gives the best results for subsequent downstream testing or clinical outcomes.

To investigate, Dr. Siontis and colleagues used a network meta-analysis of 30 diagnostic randomized controlled trials, including more than 33,000 patients and six different imaging modalities.

Among patients with low-risk acute coronary syndrome, evaluation by stress echocardiography, cardiovascular magnetic resonance, or exercise electrocardiogram was significantly less likely to trigger referral to invasive coronary angiography than was coronary CT angiography.

Similarly, patients evaluated by cardiovascular magnetic resonance and stress echocardiography less frequently underwent subsequent revascularization than did those evaluated by coronary CT angiography.

Overall, a functional-testing strategy and cardiovascular magnetic resonance were significantly less likely than an anatomical-testing strategy to lead to referrals for invasive coronary angiography.

None of the strategies affected the rate of subsequent myocardial infarction.

For patients with suspected stable CAD, there was no clear discrimination between diagnostic strategies regarding the subsequent need for invasive coronary angiography, but differences between the strategies in the risk of myocardial infarction could not be ruled out.

“Appropriate risk stratification of each patient before the application of any diagnostic strategy is the key element for a successful diagnostic approach,” Dr. Siontis said. “Hybrid strategies (which have not been tested in clinical trials so far) may be useful in selected cases, whereas ongoing trials of other emerging technologies that noninvasively evaluate anatomical and functional lesion hemodynamics or myocardial perfusion may be proven useful.”

“Nevertheless,” he said, “any additional diagnostic test should be carefully evaluated in the context of its risk. Finally, it is of high importance for the physicians to identify those patients who require directly invasive assessment (high pre-test probability).”

Source: BMJ

FFRCT on par with invasive coronary angiography

 Coronary computed tomographic angiography (CTA) with fractional flow reserve (FFRCT) analysis might be a better alternative to invasive coronary angiography for patients with suspected coronary artery disease, a study suggests.

Care guided by CTA and selective FFRCT was associated with equivalent clinical outcomes and quality of life (QOL), and lower costs, compared with usual care over 1-year follow-up, according to investigators.

To determine the 1-year clinical, economic, and QOL outcomes of FFRCT use instead of usual care, researchers managed consecutive patients (mean age 61 years; mean pretest probability of coronary artery disease 49 percent) with stable, new onset chest pain by either usual testing (n=287) or CTA (n=297) with selective FFRCT (submitted in 201, analysed in 177). Of the patients, 581 (99.5 percent) completed 1-year follow-up.

The primary endpoints were adjudicated major adverse cardiac events (MACE; death, myocardial infarction, unplanned revascularisation), total medical costs, and QOL.

After follow-up, MACE events were infrequent, with 2 in each arm of the planned invasive group and 1 in the planned noninvasive cohort (usual care strategy).

In the planned invasive group, mean costs were 33 percent lower with CTA and selective FFRCT ($8,127 vs $12,145 usual case; p<0.0001). In the planned noninvasive cohort, mean costs did not differ when using an FFRCT cost weight of zero ($3,049 FFRCT vs $2,579; p=0.82), but were higher when using an FFRCT cost weight equal to CTA.

At 1 year, QOL scores improved, with similar improvements in both groups, apart from the 5-item EuroQOL scale scores in the noninvasive stratum (mean change of 0.12 for FFRCT vs 0.07 for usual care; p=0.02).

Researchers suggest further randomized trials to compare the clinical utility of FFRCT with invasive strategies for evaluation of patients with suspected coronary disease.