THE COST-EFFECTIVENESS ANALYSIS OF FIVE NON-INVASIVE CARDIAC IMAGING TECHNOLOGIES IN ONTARIO

Purpose: Stress echocardiography with contrast agent added when needed (stress contrast ECHO), cardiac computed tomography (CT angiography),and cardiac magnetic resonance imaging (cardiac MRI) are all relatively new options for non-invasive testing for suspected coronary artery disease. Our objective was to determine the relative cost-effectiveness of these newer cardiac imaging technologies, in comparison to more traditional modalities, such as stress echocardiography (stress ECHO) and single photon emission computed tomography (SPECT), for the diagnosis of patients with suspected coronary artery disease (CAD). Two patient populations were examined in Ontario: out-patients presenting with stable chest pain with an intermediate risk of CAD, and patients presenting to emergency and subsequently admitted to hospital with an acute chest pain syndrome, with low-intermediate risk of CAD.

Method: The analysis was conducted using a short term decision analytic model to determine the cost-effectiveness of each of the non-invasive cardiac imaging tests in diagnosing CAD in each of the two patient populations. The perspective was that of the Ontario Ministry of Health and Long-Term Care (MOHLTC). The primary outcome was incremental cost per accurate diagnosis of CAD, where accurate diagnosis was defined as true positive and true negative test results. To assist in determining the cost-effectiveness threshold, several willingness-to-pay (WTP) values were determined using current Ontario imaging utilization data. Sensitivity analyses were also conducted to explore feasibility and implementation issues associated with these technologies in Ontario.

Result: Stress contrast ECHO appeared to be the most cost-effective non-invasive diagnostic test for stable outpatients. At a WTP of approximately $1,400-$1,500 per accurate diagnosis of CAD, stress contrast ECHO was cost-effective when the prevalence of CAD was less than 55%; CT angiography was cost-effective at higher prevalence values. For acute inpatients, stress contrast ECHO was the most cost-effective at any prevalence. If stress contrast ECHO or CT angiography were unavailable, stress ECHO appeared to be the cost-effective option for stable outpatients, while SPECT appeared cost-effective for acute inpatients.

Conclusion: Stress contrast ECHO and CT angiography are consistently more economically attractive than competing technologies, and offer the potential for significant cost savings if used as replacement technologies for existing tests. Policy recommendations must also include safety issues (radiation exposure) as well as real world performance of new technologies.