Cost implications of initial computed tomography angiography as opposed to catheterization in patients with mildly abnormal or equivocal myocardial perfusion scans.

Background: Patients with mildly abnormal or equivocal myocardial perfusion imaging (MPI) scans undergo diagnostic angiography or receive medical management. However, current guidelines mandate different treatment goals for patients with known coronary artery disease (CAD), and catheterization is often required. Coronary computed tomography angiography (CCTA) may be an effective alternative to catheterization for patients at intermediate risk for CAD.

Objectives: The purpose of this study was to analyze the cost implications of CCTA before catheterization in patients with mildly abnormal or equivocal MPI scans.

Methods: Patients (n = 206) with mildly abnormal or equivocal MPI scans underwent 64-detector CCTA instead of catheterization at the discretion of a treating physician. Studies were evaluated by a trained reader, and results were classified as "no evident CAD," "nonobstructive CAD," or "potentially obstructive CAD." Cost data were analyzed based on actual reimbursements for CT angiography and cardiac catheterization. We modeled the costs of two clinical approaches. "Selective catheterization" involved catheterization only if CCTA showed potentially obstructive CAD. "Immediate catheterization" considered catheterization for all patients in the cohort. Sensitivity analysis was performed on multiple variables.

Results: Thirty-two percent of patients had potentially obstructive plaque on CTA. Selective catheterization saves $1454 per patient. Sensitivity analysis revealed cost savings to be preserved even if up to 81.5% of the patient cohort undergoes catheterization, as well as across wide ranges of procedural costs.

Conclusion: A strategy that uses CCTA as a gatekeeper to catheterization is cost saving as opposed to initial catheterization for patients with equivocal or mildly abnormal myocardial perfusion scans.