The Effects of a Neutrophil Elastase Inhibitor on the Postoperative Respiratory Failure of Acute Aortic Dissection

BACKGROUND: Postoperative respiratory failure is often encountered in patients suffering from acute aortic dissection (AAD) and is believed to be influenced by release of neutrophil elastase after cardiopulmonary bypass. Sivelestat is a specific neutrophil elastase inhibitor, and this study aims to evaluate the effects of sivelestat on postoperative respiratory failure due to AAD. METHODS AND RESULTS: Patients who were operated for AAD from January 2000 to April 2005 and who had less than 300 mmHg initial postoperative PaO (2)/FiO (2) were investigated retrospectively and divided into two groups. Group 1 (n = 9) received intravenous administration of sivelestat immediately after the operation, while Group II (n = 9) received no sivelestat. There were no significant differences between Group I and II with respect to patients' characteristics or background (age, body weight, operating time, cardiopulmonary bypass time, amount of bleeding, preoperative WBC number and initial PaO (2)/FiO (2)). Though patients in Group I showed a subtle improvement in certain parameters such as PaO (2)/FiO (2), A-aDO (2) and respiratory index (RI) over a 3-day observation period compared to those of Group II, there were no significant differences. Neither postoperative mechanical ventilation time nor ICU stay differed between Group I and II. However, Group I showed a significantly greater improvement in the ratio of RI to initial RI on the 3POD compared to that of Group II (61.6 +/- 44.2 % vs. 111.9 +/- 40.9 %, P = 0.02). CONCLUSION: Inhibiting the activity of the neutrophil elastase may attenuate the postoperative respiratory complications of patients with AAD.