Endothelial function in sustained and white coat hypertension.
BACKGROUND
Endothelial dysfunction is a frequent finding in essential hypertension. The aim of this study was to assess endothelial function, by evaluating circulating nitric oxide metabolites, nitrate plus nitrite (NOx), and endothelium-dependent vasodilation (EDD), in white coat hypertension in comparison with sustained hypertension and normotension.


METHODS
We selected 22 sustained hypertensive, 22 white coat hypertensive, and 22 normotensive subjects matched for age, gender, body mass index, and occupation. Women were also matched for menopausal status. Subjects with smoking habit, dyslipidemia, and diabetes mellitus were excluded from the study. White coat hypertension was defined as clinical hypertension and daytime ambulatory blood pressure (BP) <135/85 mm Hg. Groups received for 2 days a low-nitrate diet before obtaining blood samples for laboratory measurements. The NOx levels were measured by using the Griess reagent after enzymatic conversion of all nitrate to nitrite. Subjects also underwent brachial artery study by ultrasonography to evaluate EDD and endothelium-independent vasodilation.


RESULTS
White coat hypertensive subjects had significantly higher levels of NOx than sustained hypertensive patients (30.8 +/- 12 v 22 +/- 8.5 micromol/L, P <.05) and significantly higher EDD (7.8% +/- 3.1% v 4.6% +/- 3.0%, P <.05). No significant difference was observed between white coat hypertensive and normotensive subjects regarding these parameters. Endothelium-independent vasodilation was not significantly different among sustained hypertensives, white coat hypertensives, and normotensives (18% +/- 4.2% v 18.3% +/- 3.9% v 18.6% +/- 4.8%, respectively, P = not significant).


CONCLUSIONS
Our data suggest that middle-aged white coat hypertensive subjects without other cardiovascular risk factors do not show endothelial dysfunction in contrast with sustained hypertensive patients.
Pierdomenico
Sante D
SD
Centro per lo Studio dell'Ipertensione Arteriosa, delle Dislipidemie e dell'Arteriosclerosi, Dipartimento di Medicina e Scienze dell'Invecchiamento, University Gabriele d'Annunzio, Via dei Vestini, 66013 Chieti Scalo (Chieti), Italy. pierdomenico@unich.it
Cipollone
Francesco
F
Lapenna
Domenico
D
Bucci
Anna
A
Cuccurullo
Franco
F
Mezzetti
Andrea
A
D000328:Adult; D018660:Blood Pressure Monitoring, Ambulatory; D015992:Body Mass Index; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009573:Nitrites / Q000097:blood*; D009819:Office Visits; D012016:Reference Values; D015203:Reproducibility of Results; D014463:Ultrasonography; D014664:Vasodilation
D009573:Nitrites