Endothelial dysfunction is a cardiovascular disease hallmark. After non-cardiac surgery, cardiovascular events correlate with surgical outcomes. Understanding the role of endothelial function in these events is crucial.

This research aims to study endothelial function and its association with cardiovascular events.

To study the presence of endothelial damage and its association with cardiac events, the investigators will perform an observational study to evaluate flow-induced dilatation of the brachial artery in patients scheduled for non-cardiac surgery.

After ethical review board approval, the investigators will select 200 patients admitted for non-cardiac surgery. After the patient written consent, the investigators will perform an ultrasound evaluation of the brachial artery flow-mediated dilatation. This will be performed before, during, and after surgery. A basal troponin level will be obtained and repeatedly measured in the three days after surgery.

The investigators will observe clinical outcomes one, 3, and 6 months after the hospitalization.

To observe 8% of events, for a 5% alpha and 80% power, 161 patients are needed for our study. The authors considered that to account for a loss of 10% of patients, a sample of 177 patients will be required. Considering no national or local incidence of cardiovascular events, we aim to complete a 200-patient selection.

Inclusion Criteria:

• Signed informed consent
• Patients 45 years or older

Exclusion Criteria:

• Refuse to participate in the study
• Myocardial injury or acute myocardial infarction less than two weeks ago
• Patients who expect less than 2 days of hospitalization
• Patients in whom the troponin elevation is attributed to a secondary cause (for example, sepsis, pulmonary thromboembolism, electrical cardioversion, etc.)
• Use of chemotherapy less than 2 weeks ago

Patients scheduled for non-cardiac surgery of 45 years old and older.