Cost and resource utilization associated with use of computed tomography to evaluate chest pain in the emergency department: the Rule Out Myocardial Infarction using Computer Assisted Tomography (ROMICAT) study

Abstract

Background: Coronary computed tomographic angiography (cCTA) allows rapid, noninvasive exclusion of obstructive coronary artery disease (CAD). However, concern exists whether implementation of cCTA in the assessment of patients presenting to the emergency department with acute chest pain will lead to increased downstream testing and costs compared with alternative strategies. Our aim was to compare observed actual costs of usual care (UC) with projected costs of a strategy including early cCTA in the evaluation of patients with acute chest pain in the Rule Out Myocardial Infarction Using Computer Assisted Tomography I (ROMICAT I) study.

Methods and results: We compared cost and hospital length of stay of UC observed among 368 patients enrolled in the ROMICAT I study with projected costs of management based on cCTA. Costs of UC were determined by an electronic cost accounting system. Notably, UC was not influenced by cCTA results because patients and caregivers were blinded to the cCTA results. Costs after early implementation of cCTA were estimated assuming changes in management based on cCTA findings of the presence and severity of CAD. Sensitivity analysis was used to test the influence of key variables on both outcomes and costs. We determined that in comparison with UC, cCTA-guided triage, whereby patients with no CAD are discharged, could reduce total hospital costs by 23% (P<0.001). However, when the prevalence of obstructive CAD increases, index hospitalization cost increases such that when the prevalence of ≥ 50% stenosis is >28% to 33%, the use of cCTA becomes more costly than UC.

Conclusions: cCTA may be a cost-saving tool in acute chest pain populations that have a prevalence of potentially obstructive CAD <30%. However, increased cost would be anticipated in populations with higher prevalence of disease.

Trial registration: ClinicalTrials.gov NCT00990262.

Keywords: acute coronary syndrome; chest pain; economics; multidetector computed tomography.

Figure 1

Alternate Scenarios. CAD = coronary artery disease; cCTA = coronary computed tomography angiography; D/C = discharge; ICA = invasive coronary angiography; MPI = myocardial perfusion imaging; Neg = negative; Trp = troponin.

Figure 2

cCTA Cost (Projected) Indexed. Costs were indexed by dividing the real-world costs the projected costs from each scenario within each subgroup (i.e., no plaque/no stenosis, plaque without stenosis, plaque with indeterminate stenosis, or plaque with significant stenosis) and reporting the percent. CAD = coronary artery disease; <50% CAD = <50% worst coronary stenosis (non-obstructive CAD); ≥50% CAD = ≥50% worst coronary stenosis (obstructive CAD). All scenarios differed significantly from actual cost, p < 0.001; all scenarios differed from each other, p < 0.001.

Figure 3

cCTA Cost (Projected) Discounted for Shorter ER Stay. A reduction in length of stay (LOS) has been modeled for patients with No CAD in all scenarios and for those with <50% CAD in Alternate Scenario A. CAD = coronary artery disease; <50% CAD = <50% worst coronary stenosis (non-obstructive CAD); ≥50% CAD = ≥50% worst coronary stenosis (obstructive CAD). All scenarios differed significantly from actual cost, p < 0.001; all scenarios differed from each other, p < 0.001.

Figure 4

Cost as a Function of Increasing Obstructive CAD Prevalence. With increasing prevalence of obstructive CAD (x-axis), the cost of care following imaging by cCTA increases due to increased diagnostic tests and medical therapies (y-axis). Depicted are the projected (modeled) costs for several large studies including the first randomized trial of cCTA for acute chest pain in the ED (Goldstein et al 2007), ROMICAT I, CT-STAT, and the ACRIN-PA trial. cCTA findings of prevalence of obstructive CAD have not been reported yet for ROMICAT II. As prevalence of ≥50% increases beyond 28% for the baseline scenario, 33% Alternate Scenario A, 30% Alternate Scenario B, and 28% Alternate Scenario C, the triage scenarios using cCTA for initial triage of possible ACS increase cost when compared to the actual data under usual care from the ROMICAT I trial. CAD = coronary artery disease.