Reduction of peripheral flow reserve impairs endothelial function in conduit arteries of patients with essential hypertension.
BACKGROUND
A diminished flow reserve in resistance vessels is a hallmark of hypertensive microvascular disease. Hypertension is associated with structural alterations in the microcirculation and a reduced endothelium-dependent dilation in conduit arteries. Both have been demonstrated to predict future cardiovascular events.


OBJECTIVE
We hypothesized that a reduced peripheral flow reserve impairs endothelial function in upstream conduit arteries in patients with arterial hypertension.


METHODS
In 43 hypertensive patients (HT) and 38 normotensive controls (NT) endothelial function of the brachial artery was assessed by measurement of flow-mediated dilatation (FMD), using high-resolution ultrasound. Peripheral flow reserve (FR) was determined via measurements of forearm blood flow at rest and during increments of reactive hyperaemia, using venous occlusion plethysmography.


RESULTS
FMD was markedly impaired in HT (3.6 +/- 0.3%) as compared with NT (10.2 +/- 0.3%), whereas maximum brachial artery diameter following endothelium-independent dilatation was similar in both groups. In hypertensive patients FR was significantly reduced (HT, 3.2 versus NT, 6.0) during reactive hyperaemia after 5 min of ischaemia. FR was associated with FMD (r = 0.68, P < 0.01). Multiple stepwise regression analysis identified FR as a strong independent variable determining the extent of FMD (r2 = 0.46, P < 0.01). In HT the dose-response curve of FMD upon stepwise increases of FR was shifted significantly to the right. Normalization of FR improved FMD in HT by more than 60%.


CONCLUSIONS
In essential hypertension a reduced FR contributes to the endothelial dysfunction of upstream conduit arteries. These findings may have therapeutic and prognostic implications in patients with arterial hypertension.
Lauer
Thomas
T
Department of Medicine, Division of Cardiology, Pulmonary Diseases and Angiology, Heinrich-Heine-University, Duesseldorf, Germany.
Heiss
Christian
C
Preik
Michael
M
Balzer
Jan
J
Hafner
Dieter
D
Strauer
Bodo E
BE
Kelm
Malte
M
D000328:Adult; D000368:Aged; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000502:physiology; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000000981:diagnostic imaging / Q000503:physiopathology; D006973:Hypertension / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010991:Plethysmography; D011237:Predictive Value of Tests; D011379:Prognosis; D012039:Regional Blood Flow / Q000502:physiology*; D014463:Ultrasonography; D014655:Vascular Resistance / Q000502:physiology; D014664:Vasodilation / Q000502:physiology