As clinicians order more noninvasive cardiac imaging for patients with suspected ischemia, hospital admission rates and angiography rise.
Hospitals with higher noninvasive cardiac imaging rates for patients with suspected ischemia without acute myocardial infarction (AMI) are more likely to admit patients and perform angiography, according to a study published in JAMA Internal Medicine.
Researchers from Connecticut, New York, Georgia and Michigan designed a cross-sectional study to characterize hospital variation of noninvasive cardiac imaging and its association with further testing, interventions and outcomes.
The researchers used 2010 administrative data to identify 549,078 patients at 224 hospitals in the emergency room, observation unit or inpatient ward with:
• Initial evaluation of suspected ischemia
• At least one cardiac biomarker on day 0 or 1
• Principal discharge diagnosis for a common cause of chest discomfort, a sign or symptom of cardiac ischemia and/or comorbidity associated with coronary disease
The findings showed that the median hospital noninvasive imaging rate was 19.8 percent (10.9 percent to 27.7 percent). The median hospital imaging rates by quartile were Q1, 6.0 percent; Q2, 15.9 percent; Q3, 23.5 percent; Q4, 34.8 percent.
The Q4 hospitals had higher admission rates and intervention rates than Q1 hospitals, but had a lower yield of revascularization for noninvasive imaging and angiograms:
|Admission rates||32.1 percent||40.0 percent|
|Downstream coronary angiogram||1.2 percent||4.9 percent|
|Revascularization procedures||0.5 percent||1.9 percent|
|Revascularization for noninvasive imaging||7.6 percent||5.4 percent|
|Angiograms||41.2 percent||38.8 percent|
There were no differences by quartiles in readmission rates to the same hospital for AMI within two months. “Approximately 23 percent of variation in imaging use was attributable to the behavior of individual hospitals,” wrote the authors.
“Hospitals vary in their use of noninvasive cardiac imaging in patients with suspected ischemia who do not have AMI,” the authors concluded. “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.”