Risk factors for prolonged mechanical ventilation after total aortic arch replacement for acute DeBakey type I aortic dissection

Abstract

Background: EuroSCORE II is an objective risk scoring model. The aim of this study was to assess the performance of EuroSCORE II in the prediction of prolonged mechanical ventilation following total aortic arch replacement for acute DeBakey type I aortic dissection and evaluate the risk factors for prolonged mechanical ventilation.

Methods: Between February 2009 to February 2012, data from 240 patients who underwent total aortic arch replacement for acute DeBakey type I aortic dissection were collected retrospectively. Mechanical ventilation after the surgery longer than 48 hours was defined as postoperative prolonged mechanical ventilation. EuroSCORE II was applied to predict prolonged mechanical ventilation. A C statistic (receiver operating characteristic curve) was used to test discrimination of the model. Calibration was assessed with a Hosmer-Lemeshow goodness-of-fit statistic. Multiple logistic regression analysis was used to identify the final risk factors of prolonged mechanical ventilation.

Results: The overall mortality was 10%. The mean length of mechanical ventilation after total aortic arch replacement was 42.72 ± 51.45 hours. Total 74 patients needed prolonged mechanical ventilation. EuroSCORE II showed poor discriminatory ability (C statistic 0.52) and calibration (Hosmer-Lemeshow, p<0.05) in predicting prolonged mechanical ventilation. On multivariate analysis, independent risk factors for postoperative prolonged mechanical ventilation were age ≥ 48.5 years (p<0.001, OR=3.85), preoperative leukocyte count ≥ 13.5 × 10⁹/L (p<0.001, OR=4.05) and symptom onset before the surgery less than one week (p=0.002, OR=3.75).

Conclusions: EuroSCORE II could not predict prolonged mechanical ventilation following total aortic arch replacement for acute DeBakey type I aortic dissection. Preoperative high level of leukocyte, age and surgical period from symptom onset are risk factors for prolonged mechanical ventilation.

Keywords: Aortic arch replacement; Aortic dissection; EuroSCORE II; Leukocyte; Prolonged mechanical ventilation.