Appropriate Use Criteria for Cardiac Computed Tomography: Does Computed Tomography Have Incremental Value in All Appropriate Use Criteria Categories?

PURPOSE: Cardiac imaging expenditures have come under scrutiny, and a focus on appropriate use criteria (AUC) has arisen to ensure cost-effective resource utilization. Although AUC has been developed by clinical experts, it has not undergone rigorous quality assurance testing to ensure that inappropriate indications for testing yield little clinical benefit. The objective of the study was to evaluate the potential incremental prognostic value of coronary computed tomographic angiography (CCTA) in the different AUC categories. MATERIALS AND METHODS: Consecutive patients enrolled into a cardiac CT Registry were collated. Patient indications were reviewed and based on the 2010 AUC (appropriate, uncertain, and inappropriate). Patients were followed-up for death, myocardial infarction (MI), and late revascularization, with the primary composite endpoint being cardiac death, nonfatal MI, and late revascularization. The prognostic value of CCTA over clinical variables in each of the AUC categories was assessed. RESULTS: Indications for CCTA were appropriate, uncertain, and inappropriate in 1284 (66.5%), 312 (16.2%), and 334 (17.3%) patients, respectively. Rates of all-cause of death, cardiac death, nonfatal MI, and late revascularization were similar across patients with appropriate, uncertain, and inappropriate indications for CCTA. Moreover, in each AUC category, CCTA had incremental prognostic value over a routine clinical risk score (National Cholesterol Education Program) with hazard ratios of 9.98, 7.39, and 5.61. CONCLUSIONS: CCTA has incremental prognostic value in all AUC categories, even when the reason for the study was deemed "inappropriate." This suggests that CCTA may still have clinical value in "inappropriate" indications and that further quality assurance AUC studies are needed.

Appropriate Use Criteria for Cardiac Computed Tomography: Impact on Diagnostic Utility.

BACKGROUND: Appropriate Use Criteria (AUC) guidelines for cardiac computed tomography (CCT) were developed to limit testing to reasonable clinical settings. However, significant testing is still done for inappropriate indications. This study investigates the impact of AUC on evaluability of CCT to determine if inappropriate tests result in a greater proportion of nondiagnostic results. METHODS: Investigators reviewed the medical records of 2417 consecutive patients who underwent CCT at the University of Ottawa Heart Institute. We applied the 2010 AUC and classified them as appropriate, inappropriate, or uncertain. Unclassifiable tests, as well as those with uncertain appropriateness, were excluded from the final analysis. Cardiac computed tomography results were classified as diagnostic if (1) all coronary segments were visualized, evaluable, and without obstructive stenosis; or (2) obstructive coronary artery disease with greater than 50% diameter stenosis in at least 1 coronary artery. All other test results were considered nondiagnostic. RESULTS: Of the 1984 patients included in the final analysis, 1522 patients (76.7%) had indications that were appropriate, whereas the remaining 462 (23.3%) were inappropriate. Inappropriate tests resulted in a higher rate of nondiagnostic results compared with appropriate CCT (9.0% vs 6.2%, P = 0.034). Inappropriate tests also had significantly more studies with nonevaluable segments than appropriate tests (24.5% vs 16.4%, P < 0.001) and were more likely to reveal obstructive coronary disease than appropriate CCT (50.5% vs 32.7%, P < 0.001). CONCLUSIONS: Cardiac computed tomography done for inappropriate indications may be associated with lower diagnostic yield and could impact future downstream resource utilization and health care costs.