Cost-effectiveness of bilateral versus single internal thoracic artery grafts at ten years.

OBJECTIVES: Using bilateral internal thoracic arteries (BITA) for coronary artery bypass grafting (CABG) has been suggested to improve survival compared to CABG using single internal thoracic arteries (SITA) for patients with advanced coronary artery disease. We used data from the Arterial Revascularisation Trial (ART) to assess long-term cost-effectiveness of BITA grafting compared to SITA grafting from an English health system perspective. METHODS: Resource use, healthcare costs and quality-adjusted life-years (QALYs) were assessed across 10-years of follow-up from an intention-to-treat perspective. Missing data were addressed using multiple imputation. Incremental cost-effectiveness ratios were calculated with uncertainty characterised using non-parametric bootstrapping. Results were extrapolated beyond 10 years using Gompertz functions for survival and linear models for total cost and utility. RESULTS: Total mean costs at 10 years follow-up were £17,594 in the BITA arm and £16,462 in the SITA arm (mean difference £1,133 95% CI £239 to £2,026, p = 0.015). Total mean QALYs at 10 years were 6.54 in the BITA are and 6.57 in the SITA arm (adjusted mean difference -0.01 95% CI -0.2 to 0.1, p = 0.883). At 10 years BITA grafting had a 33% probability of being cost-effective compared to SITA, assuming a cost-effectiveness threshold of £20,000. Lifetime extrapolation increased the probability of BITA being cost-effective to 51%. CONCLUSIONS: BITA grafting has significantly higher costs but similar quality-adjusted survival at 10 years compared to SITA grafting. Extrapolation suggests this could change over lifetime.