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Published on: March 27, 2018
Effect of institutional case volume on mid-term mortality after coronary artery bypass grafting surgery
Seohee Lee1, Eun Jin Jang2, Junwoo Jo3
1Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul National University Hospital, 101 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea.
Insights
Higher volume centers performing coronary artery bypass grafting (CABG) surgery are linked to better patient survival. This study found that high-volume centers significantly reduce mid-term mortality after CABG compared to low-volume centers.
Area of Science:
- Cardiovascular Surgery
- Health Services Research
- Outcomes Research
Background:
- The relationship between hospital case volume and patient outcomes after coronary artery bypass grafting (CABG) surgery remains a subject of debate.
- Understanding this association is crucial for optimizing patient care and resource allocation in cardiac surgery.
Purpose of the Study:
- To investigate the association between institutional annual CABG case volume and mid-term survival rates.
- To compare postoperative outcomes in patients undergoing CABG at high-volume versus low-volume centers.
Main Methods:
- A retrospective analysis of adult patients who underwent CABG between 2009 and 2016 using the Korean National Health Insurance database.
- Hospitals were categorized into low (<20 cases/year), medium (20-50 cases/year), and high (>50 cases/year) volume centers.
- Mid-term survival was assessed using logistic and Cox proportional hazard models, adjusting for relevant factors.
Main Results:
- A total of 22,575 CABG procedures were analyzed across 95 hospitals.
- High-volume centers performed the majority of cases (65.1%).
- One-year mortality rates were significantly lower in high-volume centers (6.5%) compared to medium (10.6%) and low-volume centers (15.2%). Both medium- and low-volume centers were identified as independent risk factors for increased 1-year mortality and poorer mid-term survival.
Conclusions:
- Higher institutional case volume for CABG is significantly associated with improved mid-term survival.
- Patients undergoing CABG at high-volume centers experience better outcomes, suggesting a volume-outcome relationship in cardiac surgery.
Objective:
The impact of center case volume on mid-term postoperative outcome after coronary artery bypass grafting surgery (CABG) is still controversial and requires investigation. The aim of this study was to compare mid-term survival after CABG according to the institutional annual CABG case volume.
Methods:
Adult patients (≥ 18 years) who underwent CABG from 2009 to 2016 were identified by searching National Health Insurance database of Korea for CABG procedure codes. Hospitals were classified into three groups based on annual case volume; low-volume centers (< 20 cases/year), medium-volume centers (20-50 cases/year), and high-volume centers (> 50 cases/year).
Results:
A total of 22,575 CABG were performed in 95 centers during the study period, and 14,697 (65.1%) cases performed at 15 high-volume centers, 5,262 (23.3%) cases at 26 medium-volume centers, and 2,616 (11.6%) cases at 54 low-volume centers. The overall 1-year mortality rate was the lowest in high-volume centers (6.5%), followed by medium-volume centers (10.6%) and low-volume centers (15.2%). Logistic regression identified medium-volume centers (adjusted OR 1.30 [95% CI 1.15-1.49], P < 0.01) and low-volume centers (adjusted OR 1.75 [95% CI 1.51-2.03], P < 0.01) as risk factors for 1-year mortality after CABG compared to high-volume centers. In the Cox proportional hazard model, low- and medium-volume centers were significantly risk factors for poor survival (adjusted HR 1.41 [95% CI 1.31-1.54], P < 0.01 and HR 1.26 [95% CI 1.17-1.35], P < 0.01 for low- and medium-volume centers, respectively).
Conclusions:
Higher institutional case volume of CABG was associated with lower mid-term mortality.
