Cost-Effectiveness of Revascularization Strategies: The ASCERT Study

Study Questions:

How cost-effective is coronary artery bypass grafting (CABG) relative to percutaneous coronary intervention (PCI) in the ASCERT (American College of Cardiology Foundation and the Society of Thoracic Surgeons [STS] Collaboration on the Comparative Effectiveness of Revascularization Strategies) study?

Methods:

ASCERT was a large observational study comparing the long-term effectiveness of CABG with PCI over 4-5 years. The ASCERT registry linked the Centers for Medicare and Medicaid Services (CMS) claims data to registry data from the CathPCI and STS databases. Costs for the index and observation period (2004-2008) were assessed by diagnosis-related group Medicare reimbursement rates for hospitalizations; costs beyond the observation period were estimated from average Medicare participant per capita expenditure using simulation techniques. Effectiveness was measured via mortality and life expectancy data. Both cost and effectiveness data were adjusted using propensity score matching with the incremental cost-effectiveness ratio (ICER) expressed as cost per quality-adjusted life year (QALY) gained.

Results:

The authors reported data on CABG patients (n = 86,244) and PCI patients (n = 103,549), ages ≥65 years, with two- or three-vessel coronary artery disease (CAD). Overall, the authors stated that “adjusted costs were higher for CABG for the index hospitalization, study period, and lifetime by $10,670, $8,145, and $11,575, respectively,” while “patients undergoing CABG gained an adjusted average of 0.2525 and 0.3801 life-years relative to PCI over the observation period and lifetime, respectively.” Thus, the life-time ICER of CABG compared to PCI was $30,454/QALY gained.

Conclusions:

The authors concluded that “over a period of 4 years or longer, patients undergoing CABG had better outcomes, but at higher costs than those undergoing PCI.” The ICERs reported here were stable under a variety of scenarios studied in sensitivity and subgroup analyses. They also are well within the thresholds deemed “societally” acceptable for payments for health care interventions.

Perspective:

This is the cost-effectiveness study for the well-known ASCERT registry that combined data from the two large observational registries for PCI and CABG with CMS claims data. The original study results were published in the New England Journal of Medicine. The cost data that are collected here do not include micro-cost data, but largely rely on hospitalization information. The findings are not too surprising, and seem consistent at least in direction with other reports from FREEDOM and SYNTAX. Although this will be an important addition to the literature, I continue to believe that these studies largely ignore the ‘complementary’ nature of PCI and CABG that exists today when the therapies are ideally used. For most patients, preferences for treatment options and anatomic differences play an important role in deciding between these two revascularization procedures. As in other areas, an approach that combines the judgment of interventional cardiologists, cardiac surgeons, and referring providers in a true ‘Heart Team’ is probably more important than these relative cost differences in ensuring high-quality care delivery.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Aortic Surgery, Interventions and Coronary Artery Disease

Keywords: Centers for Medicare and Medicaid Services (U.S.), Coronary Artery Bypass, Coronary Artery Disease, Cost-Benefit Analysis, Hospitalization, Life Expectancy, Percutaneous Coronary Intervention, Quality-Adjusted Life Years, Registries


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