Chidozie Ukpabi, Mercer University College of Pharmacy
Heart disease, including coronary heart disease (CHD), is the leading cause of death in the United States.  Myocardial perfusion scintigraphy (MPS) by single-photon emission computed tomography (SPECT) is the most commonly used test worldwide for the assessment of myocardial ischemia.  The diagnostic sensitivity of MPS SPECT ranges from 82% to 88% for exercise stress test and 88% to 91% for pharmacological stress nuclear myocardial perfusion imaging (MPI).  Previous trials have supported the wider adoption of cardiovascular magnetic resonance (CMR) for the diagnosis and management of stable CHD patients, due to a growing concern of cancer risk associated with ionizing radiation with SPECT. 
|Effect of Care Guided by Cardiovascular Magnetic Resonance, Myocardial Perfusion Scintigraphy, or NICE Guidelines on Subsequent Unnecessary Angiography Rates: The CE-MARC2 Randomized Clinical Trial |
|Design||Multicenter, 3-parallel group, randomized clinical trial; N= 1,202|
|Objective||To test in patients with suspected CHD, if CMR guided care is superior to National Institute for Health and Care Excellence (NICE) guidelines–directed care and MPS–guided care in reducing unnecessary angiography|
|Study Groups||UK NICE guidelines (n= 280); GMR guided care (n= 481); MPS guided care (n= 481)|
|Methods||Patients were allocated to one of five equally sized groups based on CHD pretest likelihood, following whether management was by NICE guideline–directed care (Group A), CMR-guided care (Groups B and C) MPS-guided care (Groups D and E). Patients randomized to the NICE guidelines group were scheduled for cardiac computed tomography (CCT) for patients with a pretest likelihood of 10% to 29%, MPS for patients with a pretest likelihood of 30% to 60% or sent directly to coronary angiography for patients with CHD pretest likelihoods of 61% to 90%. Unnecessary coronary angiography was defined as any unnecessary angiography occurring after a false-positive test result, patients with high CHD pretest likelihood sent directly to coronary angiography (NICE guidelines group only), and imaging results that were either inconclusive or negative but overruled by the responsible physician.|
|Duration||November 23. 2012 – March 12, 2016|
|Primary Outcome Measure||Protocol-defined unnecessary coronary angiography occurring within 12 months|
|Adverse Events||Common Adverse Events: N/A|
|Serious Adverse Events: N/A|
|Percentage that Discontinued due to Adverse Events: N/A|
|Study Author Conclusions||In patients with suspected angina, investigation by CMR resulted in a lower probability of unnecessary angiography within 12 months than NICE guideline–directed care, with no statistically significant difference between CMR and MPS strategies. There were no statistically significant differences in major adverse cardiac event rates.|
Minimization of risk and cost are just as important as intervention effectiveness in healthcare. Coronary angiography is an invasive procedure that is both higher in cost and poses more risk to patients than other interventions that are equally effective. The benefits of CMR over other diagnostic methods, as described in the trial, increase its usefulness and will more than likely impact current clinical guidelines. Decreasing the incidence of coronary angiography is therefore an important step towards reducing unnecessary risk and lessening financial burdens on patients.
- CDC. Leading causes of death. http://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm. Accessed October 1, 2016.
- Greenwood JP, Ripley DP, Berry C, et al. Effect of Care Guided by Cardiovascular Magnetic Resonance, Myocardial Perfusion Scintigraphy, or NICE Guidelines on Subsequent Unnecessary Angiography Rates: The CE-MARC 2 Randomized Clinical Trial. JAMA. 2016;316(10):1051-60.
- Fihn SD, Gardin JM, Abrams J, et al. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease: a report of the American College of Cardiology Foundation/American Heart Association task force on practice guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation. 2012;126(25):e354-471.
- Greenwood JP, Maredia N, Younger JF, et al. Cardiovascular magnetic resonance and single-photon emission computed tomography for diagnosis of coronary heart disease (CE-MARC): a prospective trial. Lancet. 2012;379(9814):453-60.