Functional compared to anatomical imaging in the initial evaluation of patients with suspected coronary artery disease: An international, multi-center, randomized controlled trial (IAEA-SPECT/CTA study)

Abstract

Objective To test the hypothesis that, in the initial evaluation of patients with suspected coronary artery disease (CAD), stress myocardial perfusion imaging (MPI) would result in less downstream testing than coronary computed tomographic angiography (CCTA).MethodsIn this international, randomized trial, mildly symptomatic patients with an intermediate likelihood of having CAD, and asymptomatic patients at intermediate risk of cardiac events, underwent either initial stress-rest MPI or CCTA. The primary outcome was downstream noninvasive or invasive testing at 6 months. Secondary outcomes included cumulative effective radiation dose (ERD) and costs at 12 months.ResultsWe recruited 303 patients (151 MPI and 152 CTA) from 6 centers in 6 countries. The initial MPI was abnormal in 29% (41/143) and CCTA in 56% (79/141) of patients. Fewer patients undergoing initial stress-rest MPI had further downstream testing at 6 months (adjusted OR 0.51, 95% CI 0.28-0.91, P = 0.023). There was a small increase in the median cumulative ERD with MPI (9.6 vs. 8.8 mSv, P = 0.04), but no difference in costs between the two strategies at 12 months.Conclusion In the management of patients with suspected CAD, a strategy of initial stress MPI is substantially less likely to require further downstream testing than initial testing with CCTA. Trial registration: clinicaltrials.gov identification number NCT01368770.Electronic supplementary materialThe online version of this article (doi:10.1007/s12350-016-0664-3) contains supplementary material, which is available to authorized users.

Comparison of mid‐ to long‐term clinical outcomes between anatomical testing and usual care in patients with suspected coronary artery disease: A meta‐analysis of randomized trials

“…Among the total included studies, 7 RCTs investigated the impact of CCTA strategy in patients with acute chest pain: the Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment (CT‐STAT) trial, the CT Coronary Angiography Compared to Exercise ECG (CT‐COMPARE) trial, the CATCH trial, the Prospective Randomized Outcome Trial Comparing Radionuclide Stress Myocardial Perfusion Imaging and ECG‐gated CCTA (PROSPECT), the Prospective First Evaluation in Chest Pain (PERFECT) trial, the study by Faisal Nabi et al, and the ACRIN‐PA 4005 trial . Five RCTs enrolled patients with stable chest pain: the Cardiac CT for the Assessment of Pain and Plaque (CAPP) trial, the Computed Tomography vs Exercise Testing in Suspected Coronary Artery Disease (CRESCENT) trial, the PROMISE trial, the SCOT‐HEART trial, and the International Atomic Energy Agency (IAEA)‐SPECT/CTA study . The mean or median follow‐up durations of the included studies varied significantly, ranging from 6 months to 42 months.…”

Acute chest pain evaluation using coronary computed tomography angiography compared with standard of care: a meta-analysis of randomised clinical trials

“…Our findings contrast with observations that CCTA-based strategy may result in a significant reduction in MI in stable chest pain patients 22 25 26. Use of stress electrocardiography as a comparator arm in some studies performed in outpatient settings may exaggerate the benefits of CCTA-based strategy due to relatively inferior performance of stress electrocardiography in ischaemia detection compared with stress imaging 27. Alternatively, detection of anatomic coronary artery disease (regardless of individual lesion severity) may prompt adjustment of medical regimen such as aggressive lipid-lowering therapy and lifestyle modification that decrease the long-term risk of acute coronary events 28.…”

Statistical issues associated with terminating a clinical trial due to slow enrollment

“…As noted by Karthikeyan et al, this was indeed a factor in the IAEA-SPECT/CTA study's failure to meet the target enrollment: only six of the planned 13 sites were approved to enroll participants. 4 Studies with stricter inclusion/exclusion criteria were also found to be more likely to be terminated for insufficient recruitment. 5 A primary concern for termination due to slow accrual is the potential loss of study power.…”

“…Note that the planned sample size for the IAEA-SPECT/CTA study was 500 subjects, which, assuming a 10% rate of loss to follow-up, would have led to 90% power to detect a significant difference in the primary endpoint, the rate of downstream testing. 4 Even though only 303 patients (60.6% of the target enrollment) were recruited, the study still had 83% power.…”