OSA as a Remote Ischemic Preconditioning in Vascular Surgery

Ischemia and reperfusion (I/R) injury during abdominal aortic aneurysm (AAA) repair is inevitable and may lead to postoperative multi-organ failure. Remote ischemic preconditioning (short periods of ischemia in anticipation of longer period of ischemia) may act protectively against ischemia. Studies of ischemic preconditioning in patients with AAA are conflicting. Obstructive sleep apnea (OSA) is a sleep disordered breathing syndrome which may have a protective effect against ischemia. The investigators hypothesize that I/R injury will be less pronounced in patients who have OSA and that the extent of I/R injury will inversely correlate with OSA severity. Accordingly, the aim of this study is to compare postoperative complications and markers of I/R in patients undergoing elective AAA repair who do and do not have OSA.

Patients. Consecutive patients scheduled for elective aortobifemoral bypass (AAA and Leriche syndrome patients) will be recruited for this prospective, observational study. Polygraphy (PG). PG measurements will be done two nights before surgery using the Embletta system (Embla - Embletta MPR PG Sleep Data Recording System). STOP-BANG, Epworth questionnaire. Both questionnaires will be done the same day as polygraphy Cardiovascular complications will be assessed from the first 30 post-operative days Pulmonary complications will be assessed from the first 30 post-operative days Specific markers of I/R. T0 - before anesthesia induction T1 - 3 hrs after aorta de-clamping T2 - 12 hrs after aorta de-clamping T3 - 24 hrs after aorta de-clamping T4 - on the fifth post-operative day