Effective risk stratification of patients on the basis of myocardial perfusion SPECT is dependent on appropriate patient selection

Cost-effectiveness of myocardial perfusion SPECT and stress test according to coronary revascularization therapy, cardiac events and total mortality: Register of 8,496 patients

OBJECTIVE

The aim was to analyze the cost-effectiveness ratio (CER) of stress electrocardiogram (ES) and stress myocardial perfusion imaging (SPECT-MPI) according to coronary revascularization (CR) therapy, cardiac events (CE) and total mortality (TM).

MATERIAL AND METHODS

A total of 8,496 consecutive patients who underwent SPECT-MPI were followed-up (mean 5.3±3.5years). Cost-effectiveness for coronary bypass (CABG) or percutaneous CR (PCR) (45.6%/54.4%) according to combined electrocardiographic ischemia and scintigraphic ischemia were evaluated. Effectiveness was evaluated as TM, CE, life-year saved observed (LYSO) and CE-LYSO; costs analyses were conducted from the perspective of the health care payer. A sensitivity analysis was performed considering current CABG/PCR ratios (12%/88%).

RESULTS

When electrocardiogram and SPECT approaches are combined, the cost-effectiveness values for CABG ranged between 112,589€ (electrocardiographic and scintigraphic ischemia) and 2,814,715€ (without ischemia)/event avoided, 38,664 and 2,221,559€/LYSO; for PCR ranged between 18,824€ (electrocardiographic and scintigraphic ischemia) and 46,377€ (without ischemia)/event avoided, 6,464 and 36,604€/LYSO. To CE: the cost-effectiveness values of the CABG and CPR in presence of electrocardiographic and scintigraphic ischemia were 269,904€/CE-avoided and 24,428€/CE-avoided, respectively; and the €/LYSO of the CABG and PCR were 152,488 and 13,801, respectively. The RCE was maintained for the current proportion of revascularized patients (12%/88%).

CONCLUSIONS

Combined ES and SPECT-MPI results, allows differentiation between patient groups, where the PCR and CABG are more cost-effective in different economic frameworks. The major CER in relation to CR, CE and TM occurs in patients with electrocardiographic and scintigraphic ischemia. PCR is more cost-effective than CABG.

Systematic review of cost-effectiveness of myocardial perfusion scintigraphy in patients with ischaemic heart disease: A report from the cardiovascular committee of the European Association of Nuclear Medicine. Endorsed by the European Association of Cardiovascular Imaging

Coronary artery disease (CAD) is a major cause of death and disability. Several diagnostic tests, such as myocardial perfusion scintigraphy (MPS), are accurate for the detection of CAD, as well as having prognostic value for the prediction of cardiovascular events. Nevertheless, the diagnostic and prognostic value of these tests should be cost-effective and should lead to improved clinical outcome. We have reviewed the literature on the cost-effectiveness of MPS in different circumstances: (i) the diagnosis and management of CAD; (ii) comparison with exercise electrocardiography (ECG) and other imaging tests; (iii) as gatekeeper to invasive coronary angiography (ICA), (iv) the impact of appropriate use criteria; (v) acute chest pain, and (vi) screening of asymptomatic patients with type-2 diabetes. In total 57 reports were included. Although most non-invasive imaging tests are cost-effective compared with alternatives, the data conflict on which non-invasive strategy is the most cost-effective. Different definitions of cost-effectiveness further confound the subject. Computer simulations of clinical diagnosis and management are influenced by the assumptions made. For instance, diagnostic accuracy is often defined against an anatomical standard that is wrongly assumed to be perfect. Conflicting data arise most commonly from these incorrect or differing assumptions.

Appropriate use criteria for SPECT myocardial perfusion imaging: Are they appropriate for women?

BACKGROUND

Several studies have reported that women are more likely to receive inappropriate SPECT myocardial perfusion imaging (MPI), suggesting gender disparity in AUC determination. We investigated the impact of gender on the diagnostic and prognostic utility of AUC.

METHODS AND RESULTS

We analyzed a multi-site prospective cohort of 1511 consecutive patients (43.5% women) who underwent outpatient, community-based SPECT-MPI. Subjects were stratified into gender groups and appropriateness subgroups, and followed for 27 ± 10 months for cardiac death, myocardial infarction, and coronary revascularization. Women were more likely to receive inappropriate MPI (60.7% vs 33.8%, P < .001). Irrespective of appropriateness, women were less likely to have an abnormal MPI (6.1% vs 14.9%, P < .001), even after adjusting for clinical covariates [odds ratio = 0.40 (95% confidence interval = 0.26-0.60), P < .001]. Irrespective of appropriateness, women were at lower risk for MACE (composite of cardiac death, myocardial infarction, or coronary revascularization) after adjusting for clinical and imaging covariates [hazard ratio = 0.49 (95% confidence interval = 0.28-0.86), P = .01]. There was no interaction between gender and appropriateness group as a determinant of abnormal MPI or MACE (interaction P values ≥ .26), indicating that female gender was associated with similar relative risk of an abnormal MPI and MACE irrespective of appropriateness group. Abnormal MPI was similarly predictive of increased hazard of MACE in both genders, regardless of appropriateness (interaction P values ≥ .46).

CONCLUSION

In this multi-site cohort, there was no demonstrable gender-based differential impact of AUC on the diagnostic or prognostic utility of SPECT-MPI. The study validates the methods used in determining risk in the AUC algorithm and endorses the widespread application of AUC in men and women.