Gender-specific brachial artery blood pressure-independent relationship between pulse wave velocity and left ventricular mass index in a group of African ancestry.
OBJECTIVE
As it is uncertain whether arterial stiffness is related to left ventricular mass and left ventricle mean wall thickness independent of blood pressure measured at the brachial artery, we aimed to ascertain this effect in never-treated participants with a high prevalence of risk factors for large artery dysfunction.


METHODS
The conventional and ambulatory blood pressure-independent relations between indices of large artery function and either left ventricular mass or mean wall thickness were determined in 309 never-treated randomly recruited South Africans of African ancestry with prevalent risk factors for large artery changes [24% were hypertensive, 63% were overweight/obese, and 17% had diabetes mellitus or abnormal blood glucose control (glycosylated hemoglobin A1c > 6.1%)]. Large artery function was assessed from applanation tonometry performed at the carotid, radial and femoral arteries and central augmentation index and aortic pulse wave velocity (carotid femoral pulse wave velocity) derived from these measures. Left ventricular mass indexed for height (left ventricular mass index) and mean wall thickness were determined using echocardiography.


RESULTS
Pulse wave velocity was associated with left ventricular mass index (r = 0.67, P < 0.0001) and mean wall thickness (r = 0.61, P < 0.0001) in women, but not in men (r = 0.04-0.08) (P < 0.0001 for the interaction between pulse wave velocity and gender). On multivariate analysis with appropriate adjustments including either conventional systolic blood pressure, pulse pressure or mean arterial pressure, pulse wave velocity was independently associated with left ventricular mass index (partial r = 0.25, P < 0.005 after adjustments for systolic blood pressure) and with mean wall thickness (partial r = 0.17, P < 0.05 after adjustments for systolic blood pressure) in women, but not in men. With the inclusion of 24-h ambulatory rather than conventional systolic blood pressure, pulse pressure or mean arterial pressure in the regression equation, pulse wave velocity was similarly independently associated with left ventricular mass index (partial r = 0.39, P < 0.001 after adjustments for 24-h systolic blood pressure) and mean wall thickness (partial r = 0.33, P < 0.003 after adjustments for 24-h systolic blood pressure) in women, but not in men. Central augmentation index was not independently associated with left ventricular mass index or mean wall thickness. In women, the contribution of pulse wave velocity to left ventricular mass index or mean wall thickness independent of systolic blood pressure (standardized beta-coefficient for left ventricular mass index=0.37 +/- 0.13, P < 0.005) was equivalent to the contribution of systolic blood pressure (standardized beta-coefficient for left ventricular mass index = 0.38 +/- 0.13, P < 0.005). Moreover, after adjusting for clinic or ambulatory systolic blood pressure and other confounders, in women every one standard deviation increase in pulse wave velocity (2.1 m/s) translated into a 4.3 or 6.2 g/m increase in left ventricular mass index, respectively.


CONCLUSIONS
Arterial stiffness is associated with left ventricular mass index and left ventricle wall thickness independent of conventional or ambulatory blood pressure and additional confounders in a never-treated population sample of women, but not men, of African ancestry with prevalent risk factors for large artery dysfunction.
Libhaber
Elena
E
aCardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, South Africa bSchool of Medicine, University of the Witwatersrand, Johannesburg, South Africa.
Woodiwiss
Angela J
AJ
Libhaber
Carlos
C
Maseko
Muzi
M
Majane
Olebogeng Hi
OH
Makaula
Siyanda
S
Dessein
Patrick
P
Essop
Mohammed R
MR
Sareli
Pinhas
P
Norton
Gavin R
GR
D000328:Adult; D044383:Black People / Q000706:statistics & numerical data*; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001916:Brachial Artery / Q000502:physiology*; D004452:Echocardiography; D005260:Female; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging / Q000208:ethnology* / Q000503:physiopathology*; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000208:ethnology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D011673:Pulsatile Flow; D012307:Risk Factors; D017678:Sex Distribution; D013019:South Africa / Q000453:epidemiology