Cardiac and vascular consequences of pre-hypertension in youth

Arterial stiffness and pulse-pressure amplification in overweight/obese African-American adolescents: relation with higher systolic and pulse pressure

BACKGROUND

Obesity is associated with a higher systolic blood pressure (BP) and pulse pressure (PP) in African-American youths, increasing their risk for developing hypertension. However, it is unknown whether arterial stiffness and wave reflection are associated with a higher systolic BP and PP or with smaller PP amplification in overweight/obese (OW/OB) African-American adolescents.

METHODS

We measured carotid-femoral pulse wave velocity (CF-PWV), carotid-radial PWV (CR-PWV), the augmentation index (AIx) adjusted to a heart rate of 75 bpm (AI75), the augmentation pressure (AugP), PP amplification, and body composition in 227 healthy African-American adolescents (age, 16.9 ± 0.2 years; 54% male).

RESULTS

Adolescents who were OW/OB (n = 86, body mass index (BMI) ≥ 85th percentile) demonstrated 5%-6%, 13%-16%, and 2.5% higher aortic and brachial systolic BP, brachial and aortic PP, and mean arterial pressure (MAP), respectively (all P < 0.05), than adolescents of normal-weight (NW, n = 141, BMI < 85th percentile). The OW/OB adolescents had a 7% higher CF-PWV, 5% lower CR-PWV, and 3.5% lower PP amplification than the NW group (all P < 0.05), but no differences in AI75 or AugP. In the entire cohort after adjustment for age, sex, heart rate, height, and MAP, CF-PWV was positively correlated, and CR-PWV and PP amplification were negatively correlated, with total and abdominal/hip adiposity. Additionally, CF-PWV, AI75, and AugP were positively correlated with MAP and negatively correlated with PP amplification. CR-PWV, AI75, and AugP were negatively correlated with brachial and aortic PP.

CONCLUSIONS

Higher aortic stiffness is associated with smaller PP amplification with increasing adiposity in African-American adolescents. Whether a reduction in PP amplification predicts increased CVD risk in obese African-American adolescents requires further study.

Vascular inflammation and aortic stiffness relate to early left ventricular diastolic dysfunction in prehypertension

Prehypertension is characterized by an increased cardiovascular risk and by an increased prevalence of target organ damage compared with the pure normotensive state. The present study was designed to assess in prehypertensive subjects the possible relationships between early left ventricular dysfunction, vascular inflammation and aortic stiffness. The study population consisted of 31 untreated prehypertensive subjects (age: 34 ± 6 years, mean ± SD) and 31 age-matched pure normotensive controls. Left ventricular function was assessed by echocardiography, aortic distensibility parameters were derived from aortic diameters measured by ultrasonography, and high-sensitivity C-reactive protein was assessed by latex-enhanced reagent. Prehypertensive subjects displayed a significantly lower E/A ratio and a significantly greater deceleration time and isovolumetric relaxation time compared with normotensive controls. They also displayed aortic systolic diameter, diastolic diameter and mean aortic stiffness index beta significantly increased while systo-diastolic diameter change, mean aortic distensibility and aortic strain were significantly reduced compared with controls. Values of inflammatory markers were increased. At multiple regression analysis, E/A ratio was significantly related to high-sensitivity C-reactive protein and aortic stiffness index beta, after correction for age, left ventricular mass index and mean blood pressure (β coefficient = -0.49, overall r(2) = 0.24, p = 0.01 and β coefficient =-0.46, overall r(2) = 0.21, p = 0.02, respectively). Thus, in prehypertension, left ventricular dysfunction is significantly related to vascular inflammation and aortic stiffness, suggesting that early cardiac and vascular alterations may have an increased inflammatory process as a common pathophysiological link.

Impact of transcendental meditation on left ventricular mass in african american adolescents

Background. An early sign of ventricular remodeling is increased left ventricular mass (LVM) which over time may lead to left ventricular hypertrophy, the strongest predictor of cardiovascular morbidity and mortality, other than advancing age. Methods. 62 (30 TM; 32 CTL) African American adolescents (age 16.2 ± 1.3 years) with high normal systolic BP were randomly assigned to either 4-month Transcendental Meditation (TM) or health education control groups. The echocardiographic-derived measure of LVM index (LVMI = LVM/ht^2.7) was measured before and after the 4-month TM study and at 4-month followup. 2D-guided M-mode echocardiography using a Hewlett Packard 5500 echosonograph was used to determine LVMI. Results. The TM group exhibited a greater decrease in LVMI at 4-month followup compared to the CTL group (−2.6 versus +0.3 gm/ht^2.7, P < 0.04). The TM group exhibited a lesser increase in BMI at 4-month follow-up compared to the CTL group (0.2 ± 1.6 versus 1.1 ± 1.4, P < 0.03). Conclusion. These findings indicate that among a group of prehypertensive African American adolescents, 4 months of TM compared to heath education resulted in a significant decrease in LVMI, and these changes were maintained at 4-month follow-up.

Prehypertension in adolescents: risk and progression

In 2004, the National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents recommended a new designation of prehypertension for children with mildly elevated blood pressure (BP). This description was intended to help identify children most at risk for the development of persistent hypertension for whom targeted prevention programs would be most beneficial and was based largely on expert opinions and epidemiologic normal values. This review summarizes the knowledge that has been gained regarding the epidemiology and risk associated with prehypertension in adolescents since its inception and highlights future challenges in understanding and preventing the development of hypertensive disease in this population.

Pediatric ambulatory blood pressure monitoring: indications and interpretations

The prevalence of hypertension in children and adolescents is increasing, especially in obese and ethnic children. The adverse long-term effects of hypertension beginning in youth are known; therefore, it is important to identify young patients who need intervention. Unfortunately, measuring blood pressure (BP) is difficult due to the variety of techniques available and innate biologic variation in BP levels. Ambulatory BP monitoring may overcome some of the challenges clinicians face when attempting to categorize a young patient's BP levels. In this article, the authors review the use of ambulatory BP monitoring in pediatrics, discuss interpretation of ambulatory BP monitoring, and discuss gaps in knowledge in usage of this technique in the management of pediatric hypertension.