Perioperative Endothelial Dysfunction in Patients Undergoing Major Acute Abdominal Surgery

The aim of the clinical study is: 1. to examine the association between postoperative endothelial function, indirectly measured by reactive hyperemia index, and major adverse cardiovascular events including myocardial injury and cardiac death within 30, 90 and 365 days of acute abdominal surgery. 2. to examine the association between postoperative endothelial function, indirectly measured by reactive hyperemia index, and non-cardiovascular complications including non-cardiac death within 30, 90 and 365 days of acute abdominal surgery. 3. to examine the importance of the postoperative blood glucose level and the pulmonary function for postoperative complications and death within 30, 90 and 365 days of acute abdominal surgery. 4. to examine the association between postoperative endothelial function, pulmonary function and blood glucose level 5. the qualitative part of the study will examine the postoperative subjective symptoms including acute and chronic pain, quality of recovery and functional status, depressive thoughts and post-traumatic stress disorder.