The Effects of Obesity on Mortality Following Coronary Artery Bypass Graft Surgery: A Retrospective Study from a Single Center in China
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Published on: November 10, 2018
Mengwei Lv1,2, Fei Gao3, Ban Liu4
1Department of Cardiovascular Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China (mainland).
Insights
Higher body mass index (BMI) in patients undergoing coronary artery bypass graft (CABG) surgery is linked to lower short-term mortality. This "obesity paradox" suggests overweight and obese patients may have better outcomes after CABG.
Area of Science:
- Cardiology
- Surgical Outcomes
- Obesity Research
Background:
- Coronary artery bypass graft (CABG) surgery is a standard treatment for coronary artery atherosclerosis.
- Rising global obesity rates are linked to ischemic heart disease and other health issues.
- The impact of obesity on CABG outcomes requires further investigation.
Purpose of the Study:
- To examine the association between body mass index (BMI) and mortality in patients undergoing CABG surgery.
- To identify whether obesity influences short-term and long-term survival after CABG.
- To explore potential differences in outcomes between on-pump and off-pump CABG procedures.
Main Methods:
- Retrospective analysis of 1471 patients who underwent CABG surgery.
- Patients were categorized into normal weight, overweight, and obese groups based on BMI.
- Statistical analyses included logistic regression for 30-day mortality and Cox regression for long-term mortality.
Main Results:
- Thirty-day postoperative mortality was significantly lower in overweight (1.3%) and obese (0%) groups compared to the normal-weight group (5.0%).
- Increased BMI was an independent protective factor for 30-day mortality (OR=0.748, P<0.001).
- No significant correlation was found between BMI and long-term mortality, although overweight patients showed better long-term survival in the off-pump CABG subgroup.
Conclusions:
- An "obesity paradox" exists, where higher BMI is associated with reduced 30-day mortality after CABG.
- The protective effect of increased BMI on short-term mortality was more pronounced in the off-pump CABG subgroup.
- Further research is needed to understand the mechanisms behind the obesity paradox in CABG patients.
Abstract:
BACKGROUND Coronary artery bypass graft (CABG) surgery has become a routine surgical procedure for patients with occlusive coronary artery atherosclerosis. Worldwide, increasing levels of obesity are associated with ischemic heart disease and systemic comorbidities. This retrospective study from a single center in China aimed to investigate the effects of obesity on patient mortality following CABG surgery. MATERIAL AND METHODS Patients undergoing CABG (N=1471) were grouped according to body mass index (BMI) as normal weight (N=596), overweight (N=684), or obese (N=191). Baseline clinical characteristics and outcomes were recorded. Logistic regression analysis was performed for 30-day postoperative mortality. Kaplan-Meier survival curves were plotted, and Cox regression analysis investigated risk and protective factors for long-term mortality, with subgroup analysis for differences between on-pump and off-pump CABG groups. RESULTS The 30-day postoperative mortality was 5.0% in the normal-weight group, 1.3% in the overweight group, and 0% in the obese group. BMI was an independent protective factor for 30-day postoperative mortality (odds ratio=0.748; 95% confidence interval, 0.640-0.874; P<0.001). The 10-year mortality for the groups was 13.2% (normal), 7.8% (overweight), and 12.7% (obese). The >20-year mortality rates for the groups were 33.0% (normal), 41.5% (overweight), and 12.7% (obese). There was no significant correlation between BMI and long-term mortality. Being overweight had a protective effect against long-term mortality in the off-pump CABG subgroup. CONCLUSIONS An "obesity paradox" was identified in postoperative outcomes in patients following CABG surgery, with an increased BMI associated with reduced 30-day postoperative mortality. This association was more significant in the off-pump CABG group.
