Inclusion Criteria:
* Before any study-specific procedure, including assessments for screening, the appropriate written informed consent must be obtained.
* ≥ 18 years of age at the time of signing informed consent.
* Ischemic heart disease requiring coronary artery bypass grafting (multi-vessel coronary artery disease or coronary anatomy not suitable for percutaneous coronary intervention) and/or aortic valve disease scheduled for aortic valve replacement, irrespective of other concomitant valve surgery.
Exclusion Criteria:
* Active treatment with GLP-1 agonists
* Obstructive hypertrophic cardiomyopathy, active myocarditis, constrictive pericarditis, untreated hypothyroidism or hyperthyroidism or history of or active acute pancreatitis.
* Acute (i.e. off hours, within hours surgery), Sub-acute surgery (i.e. the following days) are eligible.
* Known allergy towards Exenatide/Byetta or albumin (vehicle).
* On the urgent waiting list for a heart transplant (UNOS category 1A or 1B, or equivalent). Patients on the non-urgent waiting list for a heart transplant (UNOS category 2 or 7, or equivalent) are eligible for inclusion in the study.
* Recipient of any major organ transplant (e.g. lung, liver, heart)
* Receiving or has received cytotoxic or cytostatic chemotherapy and/or radiation therapy for treatment of a malignancy within 6 month before randomization or clinical evidence of current malignancy, with the following exceptions: basal or squamous cell carcinoma of the skin, cervical intraepithelial neoplasia, prostate cancer (if stable localized disease, with a life expectancy of \> 2.5 years in the opinion of the investigator)
* Currently enrolled in, or at least 30 days not yet elapsed since ending participation in other investigational drug trial(s) for the treatment of diabetes or malignant obesity investigating the use of GLP-1 agonists or receiving other investigational agent(s). Concomitant participation in other non-pharmacological trials is not an exclusion criterion.
* Recent (within 3 months) history of alcohol or illicit drug abuse disorder, based on self-report.
* Pregnant, based on investigator evaluation (e.g., positive human chorionic gonadotropin test) or currently breast feeding.
* Any condition (e.g., psychiatric illness) or situation that, in the investigator's opinion, could put the subject at significant risk, confound the study results, or interfere significantly with the subject's participation in the study.
* Previous participation in the trial.
