Original Article|Articles in Press

Increasing obesity is associated with lower postoperative bleeding in coronary bypass patients

Published:March 16, 2023DOI:



      : Despite inherent comorbidities, obese cardiac surgical patients paradoxically had shown lower morbidity and mortality, although the nature of this association is still unclear. Thus, we intended in this large registry-based study, to investigate the impact of obesity on short- and long-term postoperative outcomes, with focus on bleeding and transfusion requirements.


      : Retrospective registry study.


      : Three university hospitals


      : A cohort of 12,330 prospectively compiled data from CABG patients operated between 2007-2020 was retrieved from the West Denmark Heart Registry.


      . The parameters were analyzed to assess the association between body mass index (BMI) and the selected outcome parameters.

      Measurements and main results

      : The crude data showed a clear statistically significant association in postoperative drainage from 637 (418-1108) ml in underweight patients with BMI < 18.5 kg/m2 to 427 (295-620) ml in severe obese patients with BMI ≥ 40 kg/m2 (P<0.0001, Kruskal-Wallis). Further, 50.0 % of patients with BMI < 18.5 received average 451 ml/m2 in red blood cell transfusions, compared to 16.7 % patients with BMI > 40 receiving 84 ml/m2. The obese groups were less often submitted to re-exploration due to bleeding and fewer received perioperative hemostatics, inotropes and vasoconstrictors. The crude data showed increasing 30-day and 6-month mortality with lower BMI, while the one-year mortality showed a V-shaped pattern, but BMI had no independent impact on mortality in logistic regression analysis.


      : Patients with high BMI may carry a protection to postoperative bleeding after cardiac surgery, probably secondary to inherent hypercoagulable state, while underweight patients carry a higher risk in bleeding and outcomes.

      Graphical Abstract



      ACS (Acute coronary syndrome), BMI (Body mass index), CABG (Coronary arterial bypass grafting), CPB (Cardiopulmonary bypass), CPR (Central Personal Register), CL (Confidence limit), ECC (Extra corporeal circulation), IQR (Interquartile range), ICU (Intensive care unit), INR (International normalized ratio), LMW (Low molecular weight), OR (Odds-ratio), PCI (, Percutaneous coronary intervention), RBC (Red blood cells), VTE (Venous thromboembolism), WDHR (Western Denmark Heart Registry)
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