There is hospital variation in use of noninvasive cardiac imaging in patients with suspected ischemia who do not have acute myocardial infarction (AMI), and "hospitals with higher imaging rates did not have substantially different rates of therapeutic interventions or lower readmission rates for AMI, but were more likely to admit patients and perform angiography," according to a study published Feb. 10 in JAMA Internal Medicine.

According to the authors, "clinical guidelines often do no provide strong recommendations about which testing strategies should be applied to which patients among the clinically heterogeneous group that presents with suspected ischemia." Therefore, they sought to determine if "hospital use of noninvasive cardiac imaging was associated with patterns of downstream resource use."

The study looked at 549,078 patients at 224 U.S. hospitals, and hospitals were divided into four quartiles based on the proportion of patients who received noninvasive imaging tests, with quartile one as the lowest proportion and quartile four as the highest. Results showed a median hospital noninvasive imaging rate of 19.8 percent, with a range of 0.2 percent to 55.7 percent. Further, the quartile four hospitals had higher rates of admission, downstream coronary angiogram and revascularization procedures, and a lower yield of revascularization for noninvasive imaging and angiograms, when compared to quartile one hospitals.

The authors note that their findings "suggest that more frequent use of noninvasive cardiac imaging at a large, diverse group of hospitals in the U.S. was associated with greater rates of inpatient admission and use of invasive downstream diagnostic tests without evidence of a substantial effect on the use of therapeutic interventions or short-term outcomes." They add that since the hospitals with high imaging rates had a lower yield to angiogram and coronary revascularization, and had the same readmission outcomes compared with hospitals with low imaging rates, there is a "need to clarify the benefit to patients of higher rates of imaging use."

"We are documenting marked variation in the use of imaging that is very much related to where a patient seeks care," said Harlan Krumholz, MD, SM, FACC, co-author of the study. "We can no longer be indifferent to costs and consequences of variations in practice that are unrelated to the patient — it's time to determine which testing strategies are truly providing benefits for patients."

Keywords: Myocardial Infarction, Diagnostic Tests, Routine, Coronary Angiography, Health Services Needs and Demand