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Published on: March 27, 2018
Long-Term Survival After On-Pump and Off-Pump Coronary Artery Bypass Grafting
John J Squiers1, Justin M Schaffer2, Jasjit K Banwait1
1Baylor Scott & White Research Institute, Plano, Texas.
Insights
Off-pump coronary artery bypass grafting (CABG) shows a slight increase in long-term mortality risk compared to on-pump CABG. However, this risk is reduced when off-pump CABG is performed by high-volume surgeons.
Area of Science:
- Cardiovascular Surgery
- Surgical Outcomes Research
- Health Services Research
Background:
- Off-pump coronary artery bypass grafting (CABG) has been debated regarding its long-term mortality risk compared to on-pump CABG.
- Surgeon volume is a potential factor influencing outcomes in complex surgical procedures like CABG.
Purpose of the Study:
- To evaluate the risk-adjusted long-term survival after off-pump versus on-pump CABG.
- To specifically assess the impact of surgeon volume (high-volume vs. low-volume) on long-term mortality after off-pump CABG.
Main Methods:
- Analysis of 1,235,089 isolated CABG procedures in Medicare beneficiaries from 2001 to 2015.
- Comparison of long-term mortality using Kaplan-Meier and log-rank analysis.
- Application of inverse probability of treatment weighting to adjust for confounding factors and surgeon volume.
Main Results:
- Off-pump CABG was associated with a statistically significant increased hazard for mortality compared to on-pump CABG (median survival difference: -134 days).
- Cox regression revealed an interaction between surgeon volume and mortality, with off-pump CABG hazard decreasing for high-volume surgeons (-84 days) and increasing for low-volume surgeons (-240 days).
Conclusions:
- Off-pump CABG presents a modest increase in long-term mortality risk compared to on-pump CABG.
- The increased mortality risk associated with off-pump CABG is mitigated when performed by high-volume surgeons.
Background:
Off-pump coronary artery bypass grafting (CABG) may be associated with increased hazard for long-term mortality as compared with on-pump CABG. We sought to evaluate risk-adjusted long-term survival after off-pump and on-pump CABG, particularly among high-volume and low-volume CABG surgeons.
Methods:
We evaluated 1,235,089 isolated CABGs (off pump = 209,085; on pump = 1,026,004) performed in Medicare beneficiaries from 2001 to 2015. Long-term hazard for mortality after off-pump versus on-pump CABG was compared with Kaplan-Meier and log-rank analysis among all CABG surgeons as well as among high-volume and low-volume CABG surgeons, before and after inverse probability of treatment weighting to adjust for confounding.
Results:
Among all surgeons, off-pump CABG was associated with a statistically significant hazard for mortality as compared with on-pump CABG before and after inverse probability of treatment weighting (median survival: off pump 9.8 years vs on pump 10.2 years; difference in median survival -134 days; log-rank P < .001). Cox regression analysis confirmed an interaction between surgeon volume and long-term mortality. The hazard for mortality associated with off-pump CABG was decreased among high-volume surgeons (difference in median survival -84 days; log-rank P < .001) and increased among low-volume surgeons (difference in median survival -240 days; long-rank P < .001).
Conclusions:
Off-pump CABG was associated with a significant, but clinically modest, increased hazard for mortality as compared with on-pump CABG. The hazard was reduced when off-pump CABG was performed by high-volume CABG surgeons.
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