Methods Endothelial function is determined in the brachial artery by flow-mediated dilation (FMD). Briefly, non-invasive examination of the radial artery of the non-dominant arm is performed with a 11 MHz (output 12 MHz) linear-array transducer connected to a Vivid E9. The transducer is connected to a flexible tripod to prevent movement of the probe. Images are recorded and saved every third second at end-diastole. Baseline radial artery diameter is recorded for one minute and defined as a mean from 20 images. A blood pressure cuff is placed around the upper part of the forearm, which is inflated to 30 mmHg above systolic pressure or 200 mmHg for 5 min. The diameter of the radial artery is continuously recorded for 3 min during hyperemia following deflation of the cuff. The three frames displaying maximum dilatation at end-diastole (triggered from the ECG) are used to calculate a mean diameter. All images are analyzed with Brachial analyzer (Medical Imaging Applications, Iowa City, IA, USA). FMD is calculated as a percentage increase in diameter from baseline diameter according to the following formula: diameter following cuff deflation-baseline diameter/baseline diameter x 100. All evaluations are performed blinded. A decrease in endothelial function is an established outcome of reperfusion injury.