Introduction: Cardiac computed tomography (CT) has emerged as a diagnostic technique beyond the evaluation of outpatient stable chest pain; however, as quality in imaging has only recently been defined by the American Heart Association, understanding the changing utilization of CT use may inform application of these standards. This study aims to characterize changes in cardiac CT utilization and for chest pain, assess the impact on downstream invasive testing over a 3 year time period.
Methods: 439 consecutive patients from July 2013 through June 2016 who had cardiac CT performed at an urban academic medical center were evaluated. Patient demographics and cardiac CT indications were reviewed from electronic medical records and archived cardiac CT reports. Cardiac CT indication categories included calcium scoring, outpatient chest pain, inpatient chest pain, electrophysiology applications, transcatheter aortic valve replacement (TAVR) and other. For patients who had cardiac CT for outpatient or inpatient chest pain, all records were reviewed to assess for further invasive cardiac catheterization. The studies were divided into three academic years.
Results: The average age of patients undergoing cardiac CT was 60 ± 14 years, 64% were male and 55% were white. Overall, there was a 34% increase in the utilization of Cardiac CT across the study period. There was a significant rise in CT for inpatient chest pain from 2% (2/123) to 14% (26/187; p=0.0002) from year one to year three of the study period. In addition there was a significant rise in CT for TAVR planning from 7% (8/123) in year one to 14% (26/187; p=0.04) in year three. The proportion of patients undergoing evaluation for outpatient chest pain and calcium scoring was relatively unchanged from year one to year three. There was a decrease in cardiac CT for electrophysiology applications from 33% (41/123) to 15% (28/187) from year one to year three (p=0.0001). Among patients who had cardiac CT for either inpatient or outpatient chest pain, 23% (29/123) patients had previous equivocal stress testing. Only 3 of these pts required further cardiac catheterization potentially preventing 90% (26/29)of patients from undergoing invasive cardiac catheterization.
Conclusion: Cardiac CT utilization is rising for inpatient chest pain and for TAVR planning. For 90% of the patients undergoing evaluation for chest pain, and 90% of patients with equivocal stress testing, cardiac CT potentially prevented need for further downstream invasive testing. This hypothesis-generating data has potential implications that may inform application of quality standards for TAVR and chest pain imaging. Further research is needed to disseminate the effect of cardiac CT on patient outcomes in this cohort.