ABSTRACT
Nowadays, noninvasive evaluation of dilatation changes of endothelium region under hyperaemia has attracted researchers' notice. But optimum conditions for inducing hyperaemia and proper mechanical parameters based on obstruction stress, obstruction time and time of ultrasonic survey after obstruction release were not reported. This study was designed to extract optimum biomechanical parameters for inducing hyperaemia in brachial artery. First, brachial artety of healthy men were forced under 0, 50, 100, 150, 200, 250 mm Hg for five minutes, and 60 seconds after obstruction release ultrasonic assessment was performed and according to maximum distensibility of brachial artery, optimum obstruction was extracted. Then brachial artery of healthy men were forced under optimum obstraction for 1, 2, 3, 4, 5 minutes and optimum obstruction time was extracted. For extracting the optimum time of ultrasonic assessment, brachial artery of healthy men were forced under optimum obstruction pressure and time and then ultrasonic assessment was done in 30, 45, 60, 75, 90 seconds after obstruction release. For extracting diameter changes of artery, maximum systolic velocity, minimum diastolic velocity, and also radial strain and distensibility, multi frames of B-mode and Doppler images were recorded on personal computer. According to ANOVA test, optimum parameters of inducing reactive hyperaemia for increasing distensibility of brachial artery were extracted. Hyperaemia under 150 mm Hg obstruction, for a duration of 4 minutes and 45 and 65 seconds after releasing are the best conditions for ultrasonic assessments. The application of optimum reactive hyperaemia protocol can provide a more accurate noninvasive evaluation of artries' biomechanical parameters