Short-term and long-term outcome in low body mass index patients undergoing cardiac surgery

Objective: We sought to assess the effect of low body mass index (BMI) on short- and long-term outcomes following cardiac surgery. Methods: This is a retrospective review of a prospectively collected departmental database over a 6-year period. Patients were eligible for the study if the BMI was <25 kg/m2. All morbidities, length of hospital stay, and short- and long-term mortality were reviewed. Results: There were 704 patients divided into low (n = 71) and normal (n = 633) BMI. Postoperative pulmonary complications were higher in the low BMI group compared to the normal BMI group (24% vs. 11%, P < 0.001) with a higher incidence of in-hospital mortality (10% vs. 5%). Using multiple logistic regression, low BMI was an independent risk factor for in-hospital mortality. The 1-, 3-, and 5-year survivals for the low group were 90%, 78%, and 70% compared to 94%, 86%, and 81% in the normal BMI group. Conclusion: Low BMI is associated with increased morbidity and mortality following cardiac surgery. Risk scoring systems should utilize the BMI in the preoperative risk assessment with special attention to low BMI. © 2009 The Japanese Association for Thoracic Surgery.