Speed of CAD Diagnosis

ROTTERDAM — A tiered cardiac computed tomography (CT)–based protocol that includes myocardial perfusion imaging (MPI) is a faster and more efficient alternative to standard functional testing in patients with stable angina, while reducing rates of unnecessary procedures, results of the CRESCENT-II trial suggest.

The protocol, comprising calcium scanning and CT angiography (CTA) if calcium was present, followed by dynamic MPI in those with greater than 50% stenosis on CTA, significantly reduced the rate of invasive coronary angiography without a class 1 indication for revascularization compared with functional testing (primarily exercise electrocardiography) at 6 months (1.5% vs 7.2%; P = .035).

The overall rate of invasive angiography was similar in both groups, while the proportion of patients with a revascularization indication was higher with the CT protocol (88% vs 50%; P = .017).

Furthermore, the proportion of patients who required further testing was more than halved with the tiered CT protocol compared with functional testing (13% vs 37%; P < .001).
The findings, published online December 13 in JACC: Cardiovascular Imaging, extend those of previous studies, including SCOT-HEART, in which CTA helped reclassify coronary artery disease (CAD) and angina diagnoses and resulted in more focused treatment than standard clinical care in patients with new-onset chest pain.

It is not clear, however, whether this results in improvements in hard clinical endpoints.

For example, the PROMISE study of over 10,000 symptomatic patients indicated no significant impact on clinical outcomes with CTA vs functional testing in patients suspected of having CAD.

In contrast, a recent meta-analysis suggested that CTA is associated with significantly fewer myocardial infarctions than is standard functional stress testing in patients suspected of having CAD and acute or stable chest pain, albeit with more downstream invasive procedures.

Lead author, Dr Marisa Lubbers (Erasmus MC, Rotterdam, the Netherlands), told theheart.org | Medscape Cardiology that it would not be expected that the efficiencies gained in CRESCENT-II would translate into improved outcomes.

She explained it is „hard to improve hard outcomes like deaths and myocardial infarction“ because the overall survival of outpatients with chest pain is very high due to few events and even fewer deaths.

CRESCENT-II was therefore focused „especially on improving efficiency, like the time to diagnosis and the number of downstream diagnostic tests necessary to reach a diagnosis,“ Lubbers said.

Results of the CRESCENT-I trial[2] showed that adding calcium scanning into a tiered CT strategy was safe and effective. However, the ability of the strategy to assess the hemodynamic importance of angiographic lesions was limited.

Source: https://www.medscape.com/viewarticle/891084?nlid=120031_3922&src=WNL_mdplsnews_180112_mscpedit_card&uac=101287BR&spon=2&impID=1533111&faf=1