Appropriateness criteria developed in 2009 by the American College of Cardiology (ACC) and the American Society of Nuclear Cardiology (ASNC) performed "fairly well" for certain indications, reducing the number of inappropriate imaging exams, according to a study presented at ASNC's annual meeting in Denver last week.
Researchers from Danbury Hospital in Connecticut, led by Dr. Amit Dande, found that the guidelines resulted in more appropriately ordered SPECT myocardial perfusion imaging (MPI) studies (37%) for outpatients than inappropriately ordered studies (11%).
The study also found a similar proportion of abnormal studies among those ordered for appropriate and uncertain indications, suggesting that providers should lean toward testing for uncertain indications in four categories: asymptomatic patients and those who are postrevascularization, as well as for preoperative assessment and ischemic equivalent evaluation.
Dande and colleagues conducted their prospective research of outpatient MPI studies over a three-month period to determine the hospital's adherence to 2009 ACC/ASNC appropriateness criteria.
The study excluded cases in which indications were not addressed in the appropriateness criteria, such as revascularization with both coronary artery bypass surgery and percutaneous coronary intervention. The criteria also excluded patients who had a specific protocol, such being listed for transplant, or if adequate information was not available for classification.
Exams were then categorized as appropriate, inappropriate, or uncertain, with results collected and classified as normal, abnormal, or equivocal, based on results of myocardial perfusion imaging studies.
The researchers included a total of 265 exams in their final analysis, which found that the overall rate of inappropriate testing in the four indications was 21%. There were 55 inappropriately ordered exams: six studies (11%) that were abnormal, two equivocal studies (4%), and 47 normal studies (85%).
Of the 39 studies with uncertain appropriateness, 15 (38%) were deemed abnormal, with the remaining 24 (62%) judged as normal.
Of the 171 studies that were ordered appropriately, 63 (37%) were abnormal, one (1%) was equivocal, and 107 (62%) were considered normal.
