Increased arterial vascular tone during the night in patients with essential hypertension

Abstract

The time-dependent incidence of cardiovascular events points to an important role of chronobiology for arterial properties. To evaluate arterial properties in patients with essential hypertension, we assessed arterial vascular tone during sleep at night in patients with essential hypertension and normotensive control subjects. Vascular tone was continuously quantified by the reflective index obtained by non-invasive digital photoplethysmography and an algorithm for continuous, investigatorindependent, automatic analysis of digital volume pulse. During the first half of the night, the reflective index was significantly higher in 31 patients with essential hypertension compared to 30 normotensive control subjects (30.070.2 vs 28.870.2; P ¼ 0.001). In patients with essential hypertension, the reflective index significantly increased from 30.070.2 in the first half (from 2301 to 0230) to 30.770.2 in the second half (from 0231 to 0600) of the night (n ¼ 31; P ¼ 0.027). In normotensive control subjects the reflective index also significantly increased from 28.870.2 in the first half of the night to 30.270.2 in the second half of the night (n ¼ 30; P ¼ 0.001). An increase of the reflective index tone indicated systemic vasoconstriction as confirmed by cold pressure tests and a significant correlation between arterial vascular tone and sympathetic nerve activity measured by microneurography from the peroneal nerve. Photoplethysmographic determination of arterial vascular tone demonstrated a significant increase of systemic arterial vascular tone in patients with essential hypertension during the first half of the night compared to normotensive control subjects.

Nasal continuous positive airway pressure: influence on digital volume pulse in obstructive sleep apnoea patients

“…In these studies, sympathetic activity was derived from measurements of muscle sympathetic nerve activity. Previous experimental studies from our group already indicated that an elevated sympathetic nerve activity measured by microneurography from the peroneal nerve results in an increased reflective index [18]. In the present study, we confirmed that apnoea increased the reflective index in a similar way to vasoconstriction induced by the cold-pressure test.…”

“…This area covers the diastolic shoulder region to the dicrotic wave, which is in part formed by pulse waves reflected back from peripheral vascular sites of impedance mismatch. As indicated in our previous studies, short-term changes of the reflective index reflect vasoconstriction or vasodilatation [18,19]. Earlier studies from our group indicated that the reflective index shows a significant positive correlation with invasively determined systemic vascular resistance by pulmonary artery catheter (Spearman correlation, r50.64, p,0.01, n520).…”

“…The reflective index was determined according to SCHOLZE et al [18] with minor modifications. Digital volume pulse waves were measured by the transmission of red and infrared light through the finger pulp of the third digit using a conventional pulse oximeter with a sampling frequency of 300 Hz, which is then further processed by the internal software at a frequency of 25 Hz.…”

Metabolic Risk Factors Are Associated With Stiffness Index, Reflection Index and Finger Skin Temperature in Children

“…41 RI at rest reflects the current state of arterial tone, 16,17 and a lower RI is an indicator of more relaxed arteries. Also FST reflects blood flow 42, 43 and is regulated by sympathetic tone, 44 which relates FST to RI and endothelial function, 45 but not to SI. 16,17 Thus, a higher FST is also a marker of more open peripheral blood flow.…”

Arterial Hypertension Determined by Ambulatory Blood Pressure Profiles

“…Systemic arterial vascular tone is increased in patients with essential hypertension during the night compared with normotensive control subjects. This increased vascular tone might contribute to the well-known changes of arterial structure in essential hypertension and eventually lead to cardiovascular disease (22).…”