Abstract
Background: Predicting intensive care unit length of stay and outcome following cardiac surgery is currently based on clinical parameters. Novel biomarkers could be employed to improve the prediction models. Methods: We performed a qualitative cytokine screening array to identify highly expressed biomarkers in preoperative blood samples of cardiac surgery patients. After identification of one highly expressed biomarker, growth differentiation factor 15 (GDF-15), a quantitative ELISA was undertaken. Preoperative levels of GDF-15 were compared in regard to duration of intensive care stay, cardio-pulmonary bypass time and indicators of organ dysfunction.Results: Preoperatively, GDF-15 was highly expressed in addition to several less highly expressed other biomarkers. After qualitative analysis we could show that preoperatively raised levels of GDF-15 was positively associated with prolonged ICU stay exceeding 48 h (median 713 versus 1041 pg/ml, p = 0.003). It was also associated with prolonged mechanical ventilation and rates of severe sepsis but not with dialysis rates or cardio-pulmonary bypass time. In univariate regression, raised GDF-15 levels were predictive of a prolonged ICU stay (OR 1.01, 95% Confidence Interval 1 – 1.02, p= 0.029). On ROC curves, GDF-15 was found to predict prolonged ICU stay (AUC= 0.86, 95% Confidence Interval 0.71 – 0.99, p= 0.003).Conclusion: GDF-15 showed potential as predictor of prolonged intensive care stay following cardiac surgery, which might be valuable for risk stratification models.
