Acquired cardiovascular disease
Surgical volume and outcomes of off-pump coronary artery bypass graft surgery: Does it matter?

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Objectives

Coronary artery bypass grafting performed off-pump has emerged in recent years as a less morbid alternative to on-pump bypass grafting. However, the impact of hospital volume on the outcomes of off-pump relative to on-pump bypass grafting has not been evaluated.

Methods

We conducted a retrospective study of patients undergoing off-pump (n = 26,011) and on-pump (n = 99,344) coronary artery bypass grafting during 2000 through 2004 in 124 California hospitals, using the California Patient Discharge Database. Generalized linear mixed models were used to compare in-hospital mortality and postoperative complications in patients undergoing on-pump versus off-pump bypass grafting, accounting sequentially for differences in patient characteristics and hospital-level effects. The relative mortality and complication rates for patients undergoing on-pump versus off-pump coronary bypass were evaluated across hospital volume quartiles.

Results

Mean length of stay was lower for patients who underwent off-pump compared with on-pump bypass grafting (8.7 vs 9.6 days; P < .001), as were unadjusted mortality and complication rates (2.2% vs 3.3%; 10.1% vs 11.6%, respectively; P < .001). For hospitals in the highest percent off-pump bypass quartile, adjusted mortality and complication rates for patients having off-pump bypass were significantly lower than for the on-pump group (odds ratio [OR] = 0.50; 95% confidence intervals [CI], 0.41–0.61; OR = 0.73; 95% CI, 0.66–0.81, respectively; P < .001); by contrast, for hospitals in the lowest percent off-pump bypass quartile, mortality and complications were similar in off-pump and on-pump groups (OR = 1.10; 95% CI, 0.75–1.63; OR = 0.92; 95% CI, 0.72–1.16, respectively; P > .05).

Conclusions

Outcomes were significantly better for off-pump compared with on-pump coronary artery bypass grafting. Although the benefit of off-pump bypass grafting increased as the relative use of the procedure at a hospital increased, off-pump bypass grafting can be safely implemented across numerous hospitals.

CTSNet classification

27

Abbreviations and Acronyms

CABG
coronary artery bypass grafting
CI
confidence intervals
OR
odds ratio

Cited by (0)

For data acquisition, management, and analysis, this research was supported, in part, by an award (HFP 04-149) from the Health Services Research and Development Service, Veterans Health Administration, Department of Veterans Affairs. Dr Rosenthal is a Senior Quality Scholar, Office of Academic Affiliation, Veterans Health Administration. Dr Konety was supported by a Cardiovascular Interdisciplinary Fellowship (HL 07121) from the University of Iowa Hospital and Clinics, Division of Cardiovascular Diseases. Dr Konety had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

The views expressed in this article are those of the authors and do not necessarily represent the views of the Department of Veterans Affairs.

Drs Rosenthal and Vaughan-Sarrazin are supported by a grant (HFP 04-149) from the Health Services Research and Development Service, Veterans Health Administration, Department of Veterans Affairs. Dr Konety was supported by a Cardiovascular Interdisciplinary Fellowship (HL 07121) from the University of Iowa Hospitals and Clinics, Division of Cardiovascular Diseases.