Regionalization of cardiac surgery in the United States and Canada: geographic access, choice, and outcomes

Objective — To determine how regionalization of facilities for coronary artery bypass surgery (CABS) affects geographic access to CABS and surgical outcomes.

Design — Computerized hospital discharge records were used to measure hospital CABS volume and in-hospital post-CABS mortality rates. Relationships between surgical volume and age- and sex-adjusted mortality rates were compared using Chi-squared tests. Small-area analysis of the association between CABS rates and distances to nearest CABS hospital was performed using multivariate linear regression methods.

Setting — All nonfederal hospitals in New York, California, Ontario, Manitoba, and British Columbia.

Patients — All adult residents of the five jurisdictions who underwent CABS in a hospital in their jurisdiction from 1987 through 1989.

Results — In New York and Canada, approximately 60% of all CABS operations took place in hospitals performing 500 or more CABS operations per year, compared with only 26% in California. The highest mortality rates were found among California hospitals performing fewer than 100 CABS operations per year (adjusted 14-day in-hospital mortality was 4.7% compared with 2.4% in high-volume California hospitals, P<.001). The percentage of the population residing within 25 miles of a CABS hospital was 91% in California, 82% in New York, and less than 60% in Canada. Eliminating very low-volume (<100 cases per year) CABS hospitals in California would increase travel distances to a CABS hospital only slightly for a small number of residents. The Canadian degree of regionalization was not associated with lower CABS rates within provinces for populations living at more remote distances from the nearest CABS hospital.

Conclusion — Regionalization of CABS facilities in New York and Canada largely avoids the problem of low-volume outlier hospitals with high postoperative mortality rates found in California. New York has avoided the redundancy of facilities that exists in California while still providing residents a geographically convenient selection of CABS hospitals. Stricter regionalization in Canada may leave residents with a more narrow choice of facilities, but does not disproportionately affect access to surgery for populations living at remote distances from CABS facilities.