Exercise Training Restores Baroreflex Sensitivity

Exercise Training Restores Baroreflex Sensitivity in Never-Treated Hypertensive Patients

Mateus C. Laterza; Luciana D.N.J. de Matos; Ivani C. Trombetta; Ana M.W. Braga; Fabiana Roveda; Maria J.N.N. Alves; Eduardo M. Krieger; Carlos E. Negrão; Maria U.P.B. Rondon
From the Heart Institute (InCor) (M.C.L., L.D.N.J.d.M., I.C.T., A.M.W.B., F.R., M.J.N.N.A., E.M.K., C.E.N., M.U.P.B.R.), University of São Paulo Medical School, São Paulo, Brazil; and the School of Physical Education and Sports (C.E.N.), University of São Paulo, São Paulo, Brazil

The effects of exercise training on baroreflex control of sympathetic nerve activity in human hypertension are unknown.
We hypothesized that exercise training would improve baroreflex control of muscle sympathetic nerve activity (MSNA) and heart rate (HR) in patients with hypertension and that exercise training would reduce MSNA and blood pressure (BP) in hypertensive patients. Twenty never-treated hypertensive patients were randomly divided into 2 groups: exercise-trained (n=11; age: 46±2 years) and untrained (n=9; age: 42±2 years) patients. An age-matched normotensive exercise-trained group (n=12; age: 42±2 years) was also studied.
Baroreflex control of MSNA (microneurography) and HR (ECG) was assessed by stepwise intravenous infusions of phenylephrine and sodium nitroprusside and analyzed by linear regression. BP was monitored on a beat-to-beat basis. Exercise training consisted of three 60-minute exercise sessions per week for 4 months. Under baseline conditions (before training), BP and MSNA were similar between hypertensive groups but significantly increased when compared with the normotensive group.
Baroreflex control of MSNA and HR was similar between hypertensive groups but significantly decreased when compared with the normotensive group.
In hypertensive patients, exercise training significantly reduced BP (P<0.01) and MSNA (P<0.01) levels and significantly increased baroreflex control of MSNA and HR during increases (P<0.01 and P<0.03, respectively) and decreases (P<0.01 and P<0.03, respectively) in BP.
The baseline (preintervention) difference in baroreflex sensitivity between hypertensive patients and normotensive individuals was no longer observed after exercise training. No significant changes were found in untrained hypertensive patients.
In conclusion, exercise training restores the baroreflex control of MSNA and HR in hypertensive patients. In addition, exercise training normalizes MSNA and decreases BP levels in these patients.

Keywords: hypertension • baroreflex sensitivity • sympathetic nerve activity • exercise • blood pressure

Hypertension, June, 2007,Vol.49, №6; p.1298.
© 2007 American Heart Association, Inc.

Pulse Pressure: Cardiovascular events

Predictive Utility of Pulse Pressure and Other Blood Pressure Measures for Cardiovascular Outcomes

William J. Mosley, II; Philip Greenland; Daniel B. Garside; Donald M. Lloyd-Jones
From the Bluhm Cardiovascular Institute (D.M.L.-J., P.G.), the Department of Medicine (W.J.M., D.M.L.-J., P.G.), and the Department of Preventive Medicine (D.M.L-J., D.B.G., P.G.), Feinberg School of Medicine, Northwestern University, Chicago, Ill.

Data are sparse regarding the actual predictive utility of pulse pressure and other blood pressure measures for cardiovascular events.
We included all of the participants from the Chicago Heart Association Detection Project in Industry who were free of cardiovascular disease and not receiving antihypertensive treatment at baseline (1967–1973).
Baseline blood pressure measures were assessed for predictive utility for fatal and nonfatal events over 33 years. Among 36 314 participants (mean age: 39±13 years; 43.4% women), there were 11 452 deaths: 745 were attributed to stroke, 2812 to coronary disease, and 599 to heart failure. Of the 16 393 participants who attained Medicare eligibility, 3050, 1367, and 2207 had 1 hospitalization for stroke, myocardial infarction, or heart failure, respectively.
In univariate analyses, hazards ratios for stroke death per SD of pulse, systolic, and diastolic pressure, respectively, were 1.49, 1.75, and 1.71. Likelihood ratio 2 (134.3, 302.0, and 232.6, respectively), Bayes information criteria values (15 142, 14 974, and 15 044, respectively), and areas under receiver-operating characteristic curves (0.59, 0.64, and 0.63, respectively) all indicated better predictive utility for systolic and diastolic compared with pulse pressure.
Results for coronary or heart failure death and stroke, myocardial infarction, or heart failure hospitalization were similar.
Pulse pressure had weaker predictive utility at all ages but particularly for those <50 years.
In this large cohort study, pulse pressure had predictive utility for cardiovascular events that was inferior to systolic or diastolic pressure.
These findings support the approach of current guidelines in the use of systolic and diastolic blood pressure to assess risk and the need for treatment.

Keywords: hypertension • pulse pressure • stroke • coronary heart disease • heart failure • prediction

Hypertension, June, 2007,Vol.49, №6; p.1256.
© 2007 American Heart Association, Inc.

Childhood growth and Development of hypertension

Childhood Growth and Hypertension in Later Life

Johan G. Eriksson; Tom J. Forsén; Eero Kajantie; Clive Osmond; David J.P. Barker
From the National Public Health Institute (J.G.E., T.J.F., E.K.), Department of Health Promotion and Chronic Disease Prevention, Diabetes Unit, Helsinki, Finland; the Department of Public Health (J.G.E.), University of Helsinki, Helsinki, Finland; MRC Epidemiology Resource Centre (C.O.), University of Southampton, Southampton General Hospital, Southampton, United Kingdom; and the Heart Research Center (D.J.P.B.), Oregon Health and Sciences University, Portland, Ore.

Few studies have examined the effects of both prenatal and postnatal growth on hypertension. We report on hypertension in 2003 people aged 62 years who were randomly selected from the Helsinki birth cohort and examined in a clinic.
Their heights and weights had been recorded serially up to age 11 years. A total of 644 had already been diagnosed with hypertension. Compared with normotensive people, they were obese and insulin resistant.
At birth they were thin and short, and they gained weight slowly up to age 2 years; thereafter they grew rapidly so that at age 11 years their body size was around the average. The odds ratio associated with each kilogram of birthweight was 0.42 (95% CI: 0.32 to 0.56); with each 10 kg of current weight it was 1.85 (95% CI: 1.66 to 2.05).
The blood pressures of another 802 people were classified as hypertensive under current definitions. They were overweight and had an atherogenic lipid profile. At birth they were short, and after birth they grew slowly so that at age 11 years they were short and thin. The odds ratio associated with each kilogram of weight at age 2 years was 0.75 (95% CI: 0.68 to 0.84); with each 10 kg of current weight it was 1.42 (95% CI: 1.28 to 1.57).
We conclude that 2 different paths of childhood growth precede the development of hypertension. We suggest that they lead to hypertension through different biological mechanisms and may respond differently to medication.

Keywords: hypertension • kidney • fetal programming • early growth • renin angiotensin system

Hypertension, June, 2007,Vol.49, №6; p.1415.
© 2007 American Heart Association, Inc.

Sleep blood pressure and Mortality

Predictors of All-Cause Mortality in Clinical Ambulatory Monitoring

Unique Aspects of Blood Pressure During Sleep

Iddo Z. Ben-Dov; Jeremy D. Kark; Drori Ben-Ishay; Judith Mekler; Liora Ben-Arie; Michael Bursztyn

From the Nephrology and Hypertension (I.Z.B.-D.), Epidemiology Unit (J.D.K.), and Mount-Scopus Internal Medicine Department (D.B.-I., J.M., L.B.-A., M.B.), Hadassah–Hebrew University Medical Center, Jerusalem, Israel

The prognostic value of sleep blood pressure reported by recent studies is variable.
Our aim was to examine the relationship of sleep blood pressure, measured by 24-hour ambulatory blood pressure monitoring, with all-cause mortality.
We studied a cohort of 3957 patients aged 55±16 (58% treated) referred for ambulatory monitoring (1991–2005).
Sleep, including daytime sleep, was recorded by diary. Linkage with the national population register identified 303 deaths during 27 750 person-years of follow-up. Hazard ratios (HRs) for mortality in Cox proportional hazards models that included age, sex, hypertension, and diabetes treatment were 1.32 (95% CI: 0.99 to 1.76) for awake hypertension ( 135/85 mm Hg), and 1.67 (95% CI: 1.25 to 2.23) for sleep hypertension ( 120/70 mm Hg).
By quintile analysis, the upper fifths of systolic and diastolic dipping during sleep were associated with adjusted HRs of 0.58 (95% CI: 0.41 to 0.82) and 0.68 (95% CI: 0.48 to 0.96), respectively.
In a model controlling for awake systolic blood pressure, hazards associated with reduced systolic dipping increased from dippers (>10%; HR: 1.0), through nondippers (0% to 9.9%; HR: 1.30; 95% CI: 1.00 to 1.69) to risers (<0%;>
Thus, in practice, ambulatory blood pressure predicts mortality significantly better than clinic blood pressure.
The availability of blood pressure measures during sleep and, in particular, the pattern of dipping add clinically predictive information and provide further justification for the use of ambulatory monitoring in patient management.

Keywords: ambulatory blood pressure monitoring • dipping • mortality • cohort • sleep blood pressure

Hypertension, June, 2007,Vol.49, №6; p.1235.
© 2007 American Heart Association, Inc.

Blood Pressure and Ischemic Brain Injury

Association of Ambulatory Blood Pressure With Ischemic Brain Injury

Gary L. Schwartz; Kent R. Bailey; Thomas Mosley; David S. Knopman; Clifford R. Jack, Jr; Vincent J. Canzanello; Stephen T. Turner From the Division of Nephrology and Hypertension (G.L.S., S.T.T., V.J.C.), the Department of Diagnostic Radiology (C.R.J.), the Department of Neurology (D.S.K.), and the Department of Health Sciences Research (K.R.B.), Mayo Clinic College of Medicine, Rochester, Minn; and the Department of Geriatric Medicine (T.M.), University of Mississippi, Jackson

Cerebral white matter hyperintensities on brain MRI (leukoaraiosis) are associated with increased risk of stroke and dementia.
To assess the relationships of blood pressure level and circadian pattern with leukoaraiosis, we obtained 24-hour ambulatory blood pressure recordings and brain magnetic resonance images in 343 white and 267 black adults who were members of sibships that had 2 siblings with essential hypertension.
In multiple linear regression models, factors associated with greater leukoaraiosis in both racial groups included age (P 0.002), homocysteine levels (P 0.006), and brain volume (P 0.008).
In blacks, ambulatory blood pressure measures associated with greater leukoaraiosis were higher awake, asleep, and 24-hour systolic and diastolic levels (P 0.009 for each).
In addition, there was a trend for smaller nocturnal declines in systolic and diastolic levels (ie, nondipping patterns) to be associated with greater leukoaraiosis, and all of these associations, except nondipping of diastolic level, remained or became significant after controlling for office blood pressure (P<0.05>
However, similar to findings in blacks, nondipping of systolic and diastolic ambulatory blood pressure levels were each associated with greater leukoaraiosis (P 0.008), and all of these associations remained or became significant after controlling for office blood pressure (P 0.009 for each).
Higher ambulatory blood pressure levels and a nondipping circadian pattern contribute to greater leukoaraiosis volume after controlling for office blood pressure.

Keywords: ambulatory blood pressure • leukoaraiosis • predictors • hypertension • target organ injury

Hypertension, June, 2007,Vol.49, №6; p.1228.
© 2007 American Heart Association, Inc.