Economic Analysis: Alternative Diagnostic Strategies to Evaluate Chest Pain
Background: Diagnosis costs for cardiovascular disease waste a large amount of healthcare resources. The aim of the study is to evaluate the clinical and economic outcomes of alternative diagnostic strategies in low risk chest pain patients.
Methods: We evaluated direct and indirect downstream costs of 6 strategies: coronary angiography (CA) after positive troponin I or T (cTn-I or cTnT) (strategy 1); after positive exercise electrocardiography (ex-ECG) (strategy 2); after positive exercise echocardiography (ex-Echo) (strategy 3); after positive pharmacologic stress echocardiography (PhSE) (strategy 4); after positive myocardial exercise stress single-photon emission computed tomography with technetium Tc 99m sestamibi (ex-SPECT-Tc) (strategy 5) and direct CA (strategy 6).
Results: The predictive accuracy in correctly identifying the patients was 83,1% for cTn-I, 87% for cTn-T, 85,1% for ex-ECG, 93,4% for ex-Echo, 98,5% for PhSE, 89,4% for ex-SPECT-Tc and 18,7% for CA. The cost per patient correctly identified results $2.051 for cTn-I, $2.086 for cTn-T, $1.890 for ex-ECG, $803 for ex-Echo, $533 for PhSE, $1.521 for ex-SPECT-Tc ($1.634 including cost of extra risk of cancer) and $29.673 for CA ($29.999 including cost of extra risk of cancer). The average relative cost-effectiveness of cardiac imaging compared with the PhSE equal to 1 (as a cost comparator), the relative cost of ex-Echo is 1.5×, of a ex-SPECT-Tc is 3.1×, of a ex-ECG is 3.5×, of cTnI is ×3.8, of cTnT is ×3.9 and of a CA is 56.3×.
Conclusion: Stress echocardiography based strategies are cost-effective versus alternative imaging strategies and the risk and cost of radiation exposure is void.

Technological advances in cardiac imaging have led to dramatic increase in test utilization and in cardiovascular healthcare costs. Cardiac imaging is a major contributor to rising healthcare costs with estimates of more than 9.3 million myocardial perfusion procedures performed in 2002 in the United States (US) and a growth of 40% in the last 3 years. Each test represents a cost, as well as a potential risk, as biohazards and downstream long-term costs linked to radiation exposure should also be considered.

Several current tests for the diagnosis of coronary artery disease are more expensive and more accurate than traditional ex-ECG. Little information exists to guide the clinician about which test to order or to inform policy makers about which tests represent the best value. Despite several meta-analyses, the effectiveness of these procedures, defined using prognostic value each test's, has been reported in several observational studies, but limited comparative data are available in similarly at-risk populations.Substantial cost saving could be realized if health care policies allocate resource use on the basis of both clinical outcomes and cost effectiveness data and it would be necessary a combined clinical and cost effectiveness-driven testing strategy in patients with suspected coronary artery disease. Ex-ECG, stress myocardial SPECT with thallium (Th) or technetium (Tc), and more recently, PhSE, ex-Echo and CA have been used to detect unstable angina (UA) and to identify, among patients referred for suggestive coronary artery disease, those at risk of coronary events. Ex-ECG is considered the standard reference test to investigate the cause of chest pain that suggests coronary origin, where stress imaging testing (stress echocardiography, stress myocardial SPECT) and CA are the second and third choice. However, while the cost of ex-ECG is lower, the accuracy of other imaging tests is also claimed to be higher. This is a scenario where an economic evaluation could help in choosing a diagnostic test, since from the clinical point of view, is not enough that a test is marginally "better" than the other to justify its use: the extra-value should be proportional to the extra-cost and to the extra-risk.