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Surgical Swine Model of Chronic Cardiac Ischemia Treated by Off-Pump Coronary Artery Bypass Graft Surgery
Published on: March 27, 2018
Is the hospital volume-mortality relationship in coronary artery bypass surgery the same for low-risk versus
Laurent G Glance1, Andrew W Dick, Dana B Mukamel
1Department of Anesthesiology, University of Rochester Medical Center, School of Medicine and Dentistry, New York, Rochester 14642, USA. laurent_glance@urmc.rochester.edu
Insights
Low-risk patients gain the most benefit from high-volume centers for coronary artery bypass graft (CABG) surgery. High-risk patients also see improved outcomes at high-volume centers, though the benefit is less pronounced.
Area of Science:
- Cardiovascular Surgery
- Health Services Research
- Outcomes Research
Background:
- Evidence suggests an inverse relationship between coronary artery bypass graft (CABG) surgery mortality and procedure volume.
- The differential benefit of high-volume centers for CABG surgery across varying patient risk levels remains unclear.
Purpose of the Study:
- To investigate if patient risk modifies the association between CABG surgery volume and outcomes.
- To determine if all patients equally benefit from undergoing CABG at high-volume centers.
Main Methods:
- Retrospective cohort analysis of 20,078 CABG patients in New York State (1996 discharge data).
- In-hospital mortality was the primary outcome, analyzed as a function of procedure volume.
- Logistic regression modeling explored the interaction between patient risk and procedure volume.
Main Results:
- A significant interaction (p=0.01) was found between CABG procedure volume and patient risk.
- Low-risk patients experienced a greater reduction in mortality at high-volume centers compared to low-volume centers.
- High-risk patients also showed better outcomes at higher-volume centers, particularly those with >25% mortality risk.
Conclusions:
- Low-risk patients derive significant benefit from undergoing CABG surgery at high-volume centers.
- High-risk patients also experience improved outcomes at high-volume centers, though the benefit is less pronounced than for low-risk patients.
- Further validation using diverse regional databases is recommended before broader generalization.
Background:
There is evidence to support the existence of an inverse relation between mortality after coronary artery bypass graft (CABG) surgery and procedure volume. It is unclear whether all patients benefit equally from having CABG surgery performed at high-volume centers. The objective of this study was to determine whether the volume-outcome association for CABG surgery is modified by patient risk.
Methods:
This retrospective cohort analysis was conducted using data from the Cardiac Surgery Reporting System database on all patients (20,078) undergoing CABG surgery in New York State who were discharged in 1996. The main outcome measure was in-hospital mortality as a function of procedure volume after adjusting for severity of disease. Logistic regression modeling was used to explore the interaction between patient risk and procedure volume.
Results:
There is a significant interaction between procedure volume and patient risk (p = 0.01). The final model exhibits excellent discrimination (C statistic = 0.818) and goodness-of-fit (Hosmer-Lemeshow statistic = 6.02; p = 0.645). Very low (<0.5%) and low-risk (0.5%-2.0%) patients exhibit a greater reduction in CABG mortality than high (5.0%-10.0%) and very high risk (>10%) patients at high-volume centers relative to low-volume centers. Among the highest risk patients (>25% risk of mortality), higher risk patients have better outcomes at higher volume centers.
Conclusions:
For the vast majority of patients, low-risk patients benefit significantly more than high-risk patients from undergoing CABG surgery at high-volume centers instead of at low-volume centers. Low-risk patients benefit significantly more than high-risk patients from undergoing CABG surgery at high-volume centers instead of at low-volume centers. However, before generalizing these findings to other states, this study should be repeated using other regional population-based clinical databases.
