Lack of relationship between obesity and mortality or morbidity after coronary artery bypass grafting.

AIMS

Obesity has significant adverse effects on cardiovascular health. Conflicting results have been reported regarding relationships between body mass index (BMI) and outcomes after coronary artery bypass grafting (CABG). We compared outcomes of CABG patients by BMI categories.

METHODS

Isolated CABG performed between July 2010-June 2012 at Auckland City Hospital were categorised into four groups of BMI ≤25 (normal), >25-30 (overweight), >30-35 (obese) and >35 kg/m² (morbidly obese) retrospectively for analyses.

RESULTS

The four groups had 181(22.4%), 320 (39.6%), 205 (25.3%) and 103 (12.7%) patients respectively. Increasing BMI was associated with younger age (p<0.001) and increasing creatinine clearance (p<0.001). Obesity was associated with a higher proportion of patients of Maori or Pacific ethnicity and patients with more hypertension. Morbid obesity was associated with female sex, higher mean New Zealand Deprivation Index, diabetes, longer operation time and sternal wound infection. Thirty-day mortality (p=0.702), composite morbidity (p=0.904) and survival (p=0.112) during 1.4 ± 0.6 years of follow-up were similar across BMI categories.

CONCLUSION

Obesity was common and was present in over a third of patients undergoing CABG with 13% of the entire cohort being morbidly obese. Mortality and morbidity rates did not differ across BMI categories. Obesity should not be considered a risk factor for adverse outcomes after CABG and should not be a contraindication for surgery.