How valid is the quantity and quality relationship in CABG surgery? A review of the literature.

Numerous analyses have identified an inverse relationship between case volume in coronary artery bypass graft (CABG) surgery and mortality, and have led some to call for the consideration of minimum-volume standards for open-heart surgery programs. These findings, however, have been questioned by studies that demonstrate a weak or absent association, and by the availability of risk-adjusted mortality data. There is also growing evidence that clinical care processes have greater impact on mortality than sheer numbers alone. Policy decisions that may address this issue in the future need to consider the impact of mandating referrals away from low-volume programs, including the negative financial and programmatic effect on hospitals and both the clinical and social ramifications for patients and families, particularly in rural regions of the country.