Cost-effectiveness of coronary artery bypass grafting plus mitral valve repair versus coronary artery bypass grafting alone for moderate ischemic mitral regurgitation

Abstract

Objective: The Cardiothoracic Surgical Trials Network reported that left ventricular reverse remodeling at 2 years did not differ between patients with moderate ischemic mitral regurgitation randomized to coronary artery bypass grafting plus mitral valve repair (n = 150) or coronary artery bypass grafting alone (n = 151). To address health resource use implications, we compared costs and quality-adjusted survival.

Methods: We used individual patient data from the Cardiothoracic Surgical Trials Network trial on survival, hospitalizations, quality of life, and US hospitalization costs to estimate cumulative costs and quality-adjusted life years. A microsimulation model was developed to extrapolate to 10 years. Bootstrap and deterministic sensitivity analyses were performed to address uncertainty.

Results: In-hospital costs were $59,745 for coronary artery bypass grafting plus mitral valve repair versus $51,326 for coronary artery bypass grafting alone (difference $8419; 95% uncertainty interval, 2259-18,757). Two-year costs were $81,263 versus $67,341 (difference 13,922 [2370 to 28,888]), and quality-adjusted life years were 1.35 versus 1.30 (difference 0.05; -0.04 to 0.14), resulting in an incremental cost-effectiveness ratio of $308,343/quality-adjusted life year for coronary artery bypass grafting plus mitral valve repair. At 10 years, its costs remained higher ($107,733 vs $88,583, difference 19,150 [-3866 to 56,826]) and quality-adjusted life years showed no difference (-0.92 to 0.87), with 5.08 versus 5.08. The likelihood that coronary artery bypass grafting plus mitral valve repair would be considered cost-effective at 10 years based on a cost-effectiveness threshold of $100K/quality-adjusted life year did not exceed 37%. Only when this procedure reduces the death rate by a relative 5% will the incremental cost-effectiveness ratio fall below $100K/quality-adjusted life year.

Conclusions: The addition of mitral valve repair to coronary artery bypass grafting for patients with moderate ischemic mitral regurgitation is unlikely to be cost-effective. Only if late mortality benefits can be demonstrated will it meet commonly used cost-effectiveness criteria.

Keywords: CABG; Cardiothoracic Surgical Trials Network; cost-effectiveness analysis; health care costs; ischemic mitral regurgitation; mitral valve; mitral valve repair; quality-adjusted life years.