Endothelial function and peripheral vasomotion in the brachial artery in neurally mediated syncope

Abstract

SummaryBackground: Paradoxical peripheral vasodilation is one of the suspected mechanisms of neurally mediated syncope. Parasympathetic stimulation following sympathetic activation during orthostatic stress mainly contributes to this vasodilation.Hyporhesis: Since endothelial function modulates peripheral vascular tone, this study aimed to determine whether endothelial function and inappropriate peripheral vasomotion has a significant role in the pathogenesis of neurally mediated syncope.Merhods: To investigate whether endothelial function is augmented or whether abnormal peripheral vasomotion exits, flow-mediated dilation (FMD, endothelium-dependent vasodilation) and sublingual glyceryl trinitrate-induced dilation (0.3 mg, GTN-D, endothelium-independent vasodilation) were measured in the brachial artery in 16 patients with neurally mediated syncope, aged 33 f 10 years, by using highresolution ultrasound. All patients underwent positive head-up tilt testing. These measures were compared with those in 16 control subjects matched with the patients by age, gender, and

An Increased Endothelial‐Independent Vasodilation Is the Hallmark of the Neurally Mediated Syncope

“…17 -19 The cardiovascular response observed during this provocative test is characterized by the presence of a marked hypotension, typical of these patients, spontaneously occurring and amplified by nitroglycerine administration, which could be similar to the ultrasound pattern found at the evaluation of the endothelial dysfunction. 12,13 We found that the nitrate administration induced in all patients a higher endothelium-independent vasodilation, regardless of the type of neuromediated syncope induced by the tilt test; the vascular response to the nitrate administration was more pronounced, but without any statistically significant difference, in subjects with VD syncope.…”

Increased flow‐mediated vasodilation in cirrhotic patients with ascites: relationship with renal resistive index

“…FMD is reduced in patients with essential hypertension, atherosclerosis, diabetes and in cigarette smokers, all conditions characterized by a decreased production of endothelial NO (12, 24–26). In contrast, in neurally mediated syncope, a clinical condition of reduced vascular tone, FMD is paradoxically increased (27).…”

Endothelial dysfunction state in migraine headache and neutrally mediated syncope in children and young adults

“…Similarly, Takase et al . [ 7 ] showed that FMD in adult patients with neurally mediated syncope was significantly greater than those in controls. Furthermore, Galetta et al .…”

“…Besides, in describing pathophysiological basis of syncope, it has been hypothesized the modulation of endothelial function can be accompanied with an impairment of vascular tonicity of peripheral arteries leading to improper peripheral vasomotion which identified as the main pathogenesis of syncope. [ 7 ] Similar to the suggested basis for a migraine headache, an abnormal peripheral vasoreactivity has been shown to be associated with increased risk for syncope particularly in its neurally mediated type. [ 8 ]…”