The lack of obstructive coronary artery disease on coronary CT angiography safely reduces downstream cost and resource utilization during subsequent chest pain presentations.

OBJECTIVE: The purpose of this study is to investigate the cost and resource use due to chest pain (CP) evaluations after initial coronary CT angiography (CCTA) stratified by coronary artery disease (CAD) burden.

METHODS: We examined 1518 patients referred for CCTA from January 2005 to July 2012 for downstream evaluation after CCTA during a median follow-up of 351 days. Results were stratified by CAD burden as quantified on CCTA into no CAD, nonobstructive CAD (<50% stenosis), or obstructive CAD (≥50% stenosis). The incidence of ischemic testing at the time of recurrent evaluation (defined as a composite of clinic visit, emergency department encounter, or ischemic testing after the index CCTA for CP, atypical CP, or angina defined by ICD-9 code), the testing modality used, and frequency of testing were abstracted and used to calculate the direct costs of downstream utilization. Major adverse cardiovascular events defined as all-cause mortality, nonfatal myocardial infarction, stroke, or revascularization >90 days from CCTA were abstracted using ICD-9 codes and Social Security Death Index query.

RESULTS: A total of 174 patients (11.5%) underwent evaluation for CP after index CCTA with a higher rate of subsequent clinical visits among obstructive CAD patients compared to those with nonobstructive CAD and no CAD (17.8% vs 13.9% vs. 7.5%; P < .001). A significant reduction in the incidence of repeat ischemic testing was observed in patients with no CAD and nonobstructive CAD (P = .002). This resulted in a lower per-patient cost in the nonobstructive CAD and no CAD patients (median [interquartile range 25-75]: $2952 [$307-2952] and $235 [$0-2880]) when compared with patients with obstructive CAD (median [interquartile range 25-75]: $5832 [$5498-17,459]; P < .001). Major adverse cardiovascular events were not different in the 90 patients that underwent repeat testing at the time of CP evaluation when compared with the 84 patients for whom testing was deferred.

CONCLUSION: Absence of CAD on initial CCTA was associated with lower costs and decreased downstream utilization compared to the presence of nonobstructive and obstructive CAD on CCTA during median follow-up of 351 days.