Vascular stiffness and endothelial dysfunction: Correlations at different levels of blood pressure.
Resistant hypertensive (RHTN) patients have endothelial dysfunction and aldosterone excess, which contribute to the development of resistance to antihypertensive treatment and cardiovascular complications. Biophysical forces within the arterial wall provide functional regulation of arterial stiffness. Carotid-femoral pulse wave velocity (PWV) and flow-mediated brachial artery dilation (FMD) can be used to evaluate vascular stiffness and endothelial function. Although both techniques have been used in several studies in hypertensive patients, it is unknown whether endothelial dysfunction is also associated with vascular stiffness in RHTN patients.


METHODS
One hundred and ninety-three consecutive subjects were divided in three groups: 44 RHTN, 35 well-controlled hypertensive patients (HTN) and 25 normal healthy volunteers (NT). FMD was measured by high-resolution ultrasound and PWV was calculated from measurements of the pulse transit time and the distance traveled by the pulse between carotid and femoral arteries.


RESULTS
No significant differences were observed in respect to body mass index, age or other biochemical variables among the three groups. FMD (NO-dependent) values were statistically different when comparing RHTN and well controlled HTN patients (respectively, 8.3 ± 4.7% and 10.1 ± 5.9%) and 12.3 ± 6.3% in normal subjects (p < 0.05). One-way analysis of variance (ANOVA) showed a significant difference in BP-adjusted PWV between RHTN and HTN (13.9 ± 1.0 and 11.5 ± 1.1 m/s, respectively; p < 0.05). FMD (NO-dependent) and PWV-adjusted values were strongly correlated in well-controlled HTN and NT subjects (r = - 0.74 and - 0.83, respectively). Although statistically significant, this correlation was lower in RHTN patients (r = - 0.43).


CONCLUSIONS
We found a close relationship among high BP levels, endothelial dysfunction and vascular rigidity in hypertensive patients, demonstrated by a significantly higher increase in carotid-femoral PWV and a decrease in brachial artery FMD in RHTN when compared with well-controlled hypertensive patients. Although this study was not designed to test the prognostic, the vascular damage differences observed between patients with controlled vs uncontrolled hypertension suggest that the latter group may have a worse cardiovascular prognosis, requiring prospective assessment tests.
Laboratory of Cardiovascular Pharmacology, Department of Medicine, University of Campinas (Unicamp), Campinas, SP, Brazil.
Valéria Nasser
VN
Figueiredo
Juan Carlos
JC
Yugar-Toledo
Luiz Cláudio
LC
Martins
Leandro Boer
LB
Martins
Ana Paula Cabral
AP
de Faria
Carolina
C
de Haro Moraes
Cristina
C
Sierra
Antonio
A
Coca
Heitor
H
Moreno
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001795:Blood Pressure Determination; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016022:Case-Control Studies; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D011446:Prospective Studies; D011673:Pulsatile Flow; D014463:Ultrasonography; D059289:Vascular Stiffness
D000959:Antihypertensive Agents; D009569:Nitric Oxide