2.3.1. Flow-Mediated Dilation
Endothelial function was assessed by brachial FMD. The right brachial artery was scanned ~2–3 cm proximal to the antecubital fossa using a 12-MHz linear array Doppler ultrasound probe (LogiQ S7 expert, GE Medical Systems, Milwaukee, WI, USA) at an insonation angle < 60°. Following a 2 min baseline diameter and mean blood velocity recording, the occlusion cuff on the proximal forearm was rapidly inflated to 250 mmHg using an automated pump (E20, Hokanson, Bellevue, WA, USA). Following a 5 min occlusion period, the cuff was rapidly deflated while the diameter and mean blood velocity were continuously recorded for 3 min using open-source software (OBS Studio). Baseline and peak diameters were measured using an automated edge-detection software (Quipu Cardiovascular Suite, Pisa, Italy). Baseline diameter was measured as the average vessel diameter during the 2 min baseline, and peak diameter as the largest diameter detected post-occlusion. FMD is expressed as a percentage change from the baseline diameter: FMD% = ([peak diameter − baseline diameter]/baseline diameter) × 100.