To effectively guide interventions aimed at reducing mortality in low-volume hospitals, the underlying mechanisms of the volume-outcome relationship must be further explored. Reducing mortality after major post-operative complications may represent one point along the continuum of patient care that could significantly impact overall hospital mortality.
To determine whether increased mortality at low-volume hospitals performing cardiovascular surgery is a function of higher post-operative complication rates or of less successful rescue from complications.
We utilized patient-level data on Medicare beneficiaries undergoing coronary artery bypass grafting, aortic valve repair, or abdominal aortic aneurysm repair. For each operation, we first divided hospitals into quintiles of procedural volume. We then assessed hospital risk-adjusted rates of mortality, major complications, and “failure to rescue” (i.e., case fatality among patients with complications) within each volume quintile.
Medicare fee-for-service beneficiaries age 65 to 99.
A total of 119,434 Medicare beneficiaries undergoing one of three major cardiovascular operations between 2005 and 2006.
Hospital procedural volume.
Main Outcome Measure
Hospital rates of risk-adjusted mortality, major complications, and failure to rescue.
For each operation, hospital volume was more strongly related to failure to rescue rates than to complication rates. For example, patients undergoing aortic valve replacement at very low-volume hospitals (lowest quintile) were 12% more likely to have a major complication than those at very high-volume hospitals (highest quintile), but 57% more likely to die if a complication occurs.
Conclusion and Relevance
High-volume and low-volume hospitals performing cardiovascular surgery have similar complication rates but disparate failure to rescue rates. While preventing complications is important, hospitals should also consider interventions aimed at quickly recognizing and managing complications once they occur.