CCTA Is Faster and Cheaper for Diagnosis of Chest Pain in ER

Reed Miller

September 21, 2011

September 20, 2011 (Royal Oak, Michigan) — Low-risk patients presenting to the emergency department with chest pain can be diagnosed more efficiently with coronary computed-tomographic angiography (CCTA) than myocardial perfusion imaging (MPI), results of trial published in the September 27, 2011 issue of the Journal of the American College of Cardiology suggest [1].

The Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment (CT-STAT) trial, led by Dr James Goldstein (William Beaumont Hospital, Royal Oak, MI), randomized 699 patients at 16 emergency departments to either CCTA or MPI. All of the patients had symptoms of ischemia but a normal or nondiagnostic rest ECG, no previous known coronary disease, a low TIMI score, and no other obvious indicators of acute coronary syndrome such as elevated biomarkers or arrhythmia. MPI is the standard test for this type of patient at most of the hospitals that participated in the trial.

Over the six months of follow-up, the patients imaged with CCTA were diagnosed 54% faster than those imaged with MPI (median 2.9 hours vs 6.3 hours, p<0.0001). The total costs of care were 38% lower with the CCTA group (median $2137 vs $3458, p<0.0001), even though the cost of each MPI test itself was only a little more than the cost of each CCTA ($538 vs $507). The diagnostic strategies made no difference in major adverse cardiac events (0.8% in the CCTA arm vs 0.4% in the MPI arm, p=0.29). The CCTA patients were also exposed to less radiation than the MPI patients (11.5 mSv vs 12.8 mSv, p=0.02).

Senior study investigator Dr Gilbert Raff (William Beaumont Hospital, Royal Oak, MI) told heartwire , "This study shows that CT is a reasonable option, so if your hospital is good at it, you should consider it for this population and it really does help." He also pointed out that CT can provide information on causes of chest pain other than coronary disease, such as pleural effusions or pulmonary embolism.

Goldstein et al caution that their study is not a formal cost-effectiveness analysis or an analysis of total downstream healthcare costs. They calculated the costs from the time the patient registered in the hospital to when they were either discharged or given a noninvasive diagnosis. The costs were estimated based on the Medicare cost-to-charge ratio, which relies on several assumptions. An accurate comparison of the societal costs of various alternative diagnostic strategies will require long-term studies of downstream healthcare resource utilization and cost-effectiveness analyses, the authors explain.

A Massive Trial With Multiple Comparisons Could Identify Best Approach

"The most important caveat is that many places do accelerated protocols that are faster than the stress tests that were done," Raff said. "For example, you could just do an ECG stress test, and only if the stress were positive, do an imaging study. That would be cheaper, and many people argue it is just as accurate." Future trials intended to identify the optimal evaluation strategy for specific patient subgroups should compare CCTA with multiple diagnostic protocols, including stress-ECG, rest-only and stress-only MPI, and stress echocardiography, he said.

"If we had multiple comparisons, then it would become a very much larger study and we just couldn't afford that. The ideal study would compare [CCTA] with everything," Raff said. He said the CT-STAT investigators are exploring opportunities to conduct a large, multicomparison study, which would be a "massive undertaking," costing between $8 million and $10 million. This proposed trial would be similar to the PROMISE study, except that it would focus on the acute chest pain population instead of the chronic stable angina population investigated in PROMISE.

In an accompanying editorial [2], Dr Michael Salerno (University of Virginia, Charlottesville) and colleagues write that "the CT-STAT trial provides additional evidence for the excellent negative predictive value of CCTA in patients at low risk for an ACS or at low-intermediate risk of having CAD as the cause of the chest-pain syndrome." They point out that the diagnostic utility of CCTA will probably improve in the future, with new techniques and technologies such as CCTA stress perfusion imaging and CCTA plaque characterization. Also, molecular imaging with positron-emission tomography may eventually be able to identify inflammation and vulnerable plaques, assessing both coronary anatomy and myocardial perfusion.

This study was funded by a research grant from Bayer Pharmaceuticals, but the authors state that Bayer did not design, conduct, analyze, or interpret this study, nor did it prepare or review this manuscript.

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