Abstract 6101: Cost Effectiveness of Cardiac Computed Tomography Compared to Myocardial Perfusion Imaging (MPI) as an Effective Gatekeeper to Cardiac Catheterization in the Evaluation of Asymptomatic Firefighters with an Abnormal Treadmill Test
To identify CAD among patients who fail treadmill tests, the traditional clinical care pathway is MPI, then invasive coronary angiography (ICA). In a retrospective cohort study, we compared the direct costs for detecting CAD using the traditional clinical care pathway and an alternative that incorporates MDCT, with coronary calcium score (CCS) followed by computed tomographic angiography (CTA) and ICA. Over a 2-year period, 3,950 Los Angeles, CA Firefighters underwent wellness/fitness exams at 6 contracted medical facilities. A total of 495 cases had abnormal treadmill tests and were referred for follow-up cardiology evaluation. All cases received CCS, followed by CTA for calcium scores >10, and ICA for abnormal CTA (>50% obstruction in at least one vessel). MPI results were estimated based on the prior year’s experience, with abnormal MPI receiving ICA. Costs to detect CAD were calculated for both the MPI and MDCT pathways based on results for the cohort and current Medicare reimbursement costs. Sensitivity analyses were performed by varying each of the clinical and cost components of the model to “low” and “high” levels and computing net costs. Most model inputs were varied by ±50% of baseline values to gauge the robustness of the results. Among 495 cases with abnormal treadmill tests, 146 (29.5%) would have required ICA due to abnormal MPI tests; 131 (26.9%) had abnormal CCS (>10) and went to CTA; 40 (8.1%) had abnormal CTA (>50% stenosis) and went to ICA. ICA showed 38 (7.7%) cases of CAD. The computed cost to detect CAD was $1,376 per case for the traditional route with MPI as gatekeeper and $503 per case for CCS as gatekeeper. All sensitivity analyses showed lower costs for the MDCT compared to MPI pathways. The net cost to ICA-confirmed diagnosis of CAD is substantially lower with MDCT compared to MPI as gatekeeper to ICA.