To the Editor.
—Dr Grumbach and colleagues1 are to be commended for their creative study of coronary artery bypass surgery (CABS) outcomes, geographic access, and regionalization of health care in the United States and Canada. We found the study particularly thought-provoking with respect to the issues of access and regionalization of services for rural patients. The results clearly demonstrate a reduced mortality rate for CABS patients in hospitals of high procedural volume across different health care environments. However, the study raises significant questions regarding the indicators of quality that are most appropriate to measure in regionalized health care systems.Research suggests that the prevalence of coronary artery disease is as high in rural areas as it is in urban locales.2 If the rate of CABS is lower in rural locales, the issue of equitable access becomes an important health policy concern. This issue becomes even more important as