Exclusion criteria: patients with ambiguous food allergies that trigger shortness of breath, headache or flushing; patients> 85 years, previous cardiac surgery, patients who are in such bad condition that they cannot be asked to participate, patients who for linguistic or other reasons are unable to provide informed consent, severe renal failure with preoperative dialysis or calculated GFR <30 mL / min, patients requiring inotropic drugs or mechanical circulatory support (intra-aortic balloon pump) due to circulatory failure even before they enrolled in the study, patients who undergo surgery without the heart-lung machine (off-pump), patients who undergo concomitant Maze-procedure or surgery of ascending aorta.