Background: The aim of the study was to investigate whether intravenous (iv) infusion of exenatide, a synthetic
GLP-1 receptor agonist, could provide a protective efect against myocardial ischemia-reperfusion injury after coronary artery bypass graft (CABG) surgery.
Methods: A sub study analysis of patients >18 years admitted for elective CABG and included in the ExSTRESS trial was conducted. Patients were randomized to receive either iv exenatide (1-h bolus of 0.05 µg min−1 followed by a constant infusion of 0.025 µg min−1) (exenatide group) or iv insulin therapy (control group) for blood glucose control (target range 100–139 mg dl−1) during the frst 48 h after surgical incision. All serum levels of troponin I measured during routine care in the Cardiac Surgery ICU were recorded. The primary outcome was the highest value of plasma concentration of troponin I measured between 12 and 24 h after ICU admission. The proportion of patients presenting an echocardiographic left ventricular ejection fraction (LVEF) >50% at the follow-up consultation was compared between the two groups.
Results: Finally, 43 and 49 patients were analyzed in the control and exenatide groups, respectively {age: 69 [61–76] versus 71 [63–75] years; baseline LVEF<50%: 6 (14%) versus 16 (32%) patients; on-pump surgery: 29 (67%) versus 33 (67%) patients}. The primary outcome did not signifcantly difer between the two groups (3.34 [1.06–6.19] µg l−1 versus 2.64 [1.29–3.85] µg l−1 in the control and exenatide groups, respectively; mean diference (MD) [95% confidence interval (95% CI)] 0.16 [−0.25; 0.57], p=0.54). The highest troponin value measured during the frst 72 h in the ICU was 6.34 [1.36–10.90] versus 5.04 [2.39–7.18] µg l−1, in the control and exenatide groups respectively (MD [95% CI] 0.20 [−0.22; 0.61], p=0.39). At the follow-up consultation, 5 (12%) versus 8 (16%) patients presented a LVEF<50% in the control and in the exenatide groups respectively (relative risk [95% CI] 0.68 [0.16; 2.59], p=0.56).
Conclusions: Postoperative iv exenatide did not provide any additional cardioprotective efect compared to iv insulin in low-risk patients undergoing scheduled CABG surgery.