Relationship of ambulatory arterial stiffness index with blood pressure response to exercise in the early stages of hypertension

Submaximal exercise blood pressure and cardiovascular structure in adolescence

PURPOSE

Dynamic exercise results in increased systolic blood pressure (BP). Irrespective of resting BP, some individuals may experience exaggerated rise in systolic BP with exercise, which in adulthood is associated with risk of hypertension, and cardiovascular (CV) disease. It is unknown if exercise BP is associated with markers of CV structure during adolescence. We examined this question in a large adolescent cohort taking account of the possible confounding effect of body composition and BP status.

METHODS

4036 adolescents (mean age 17.8 ± 0.4 years, 45% male), part of a UK population-based birth cohort study completed a sub-maximal step-test with BP immediately post-exercise. Sub-samples underwent comprehensive echocardiography for assessment of cardiac structure; arterial structure including aortic pulse wave velocity (PWV) and carotid intima-media thickness; and assessment of body composition by dual-energy X-ray absorptiometry (DXA).

RESULTS

Each 5 mm Hg higher post-exercise systolic BP was associated with CV structure, including 0.38 g/m2.7 (95% CI: 0.29, 0.47) greater left-ventricular mass index (LVMI), and 0.04 m/s (95% CI: 0.03, 0.04) greater aortic PWV. Adjustment for age, total body fat, lean mass and BP status attenuated, but did not abolish associations with LVMI (0.14 g/m2.7 per 5 mm Hg of post-exercise systolic BP; 95% CI 0.21, 0.39) or aortic PWV (0.03 m/s per 5 mm Hg of post-exercise systolic BP; 95% CI: 0.02, 0.04).

CONCLUSION

Submaximal exercise systolic BP is associated with markers of CV structure in adolescents. Given the clinical relevance of exercise BP in adulthood, such associations may have implications for CV disease screening in young people and risk in later life.

Effects of Lifestyle Modification on an Exaggerated Blood Pressure Response to Exercise in Normotensive Females

BACKGROUND

This study was designed to examine the effects of a lifestyle modification on the improvement in an exaggerated systolic blood pressure (SBP) response to exercise in normotensive females.

METHODS

The subjects were 78 normotensive females with (n = 25) and without (n = 53) an exaggerated SBP response to exercise who were not taking any medications. An exaggerated SBP response to exercise was defined according to the criteria of the Framingham Study (peak SBP: ≥190 mm Hg). A lifestyle modification program consisting of aerobic exercise and diet counseling was conducted for 12 weeks. The brachial-ankle pulse wave velocity (baPWV), plasma nitrate/nitrite (NOx), plasma thiobarbituric acid-reactive substances (TBARS), high-sensitivity C-reactive protein, fibrinogen levels, and the white blood cell (WBC) counts were measured before and after 12-week intervention.

RESULTS

After 12-week intervention, the exercise-induced SBP elevation decreased in an exaggerated SBP response group (P < 0.05). In addition, the plasma NOx significantly increased, and the WBC counts and plasma TBARS decreased in an exaggerated SBP response group (P < 0.05). In an exaggerated SBP response group, a stepwise multiple regression analysis showed that the percent change in exercise-induced SBP elevation was independently associated with the percent changes in the plasma NOx level and baPWV (r2 = 0.647, P < 0.0001).

CONCLUSIONS

These results suggest that a lifestyle modification is considered to be important for reducing an exaggerated SBP response to exercise by improving the arterial stiffness and nitric oxide bioavailability.

Association of Thoracic Aorta Calcium Score With Exercise Blood Pressure Response and Clinical Outcomes in Elderly Individuals: Differential Impact of Aorta Calcification Compared With Coronary Artery Calcification

BACKGROUND

The structure of the aorta is considered to influence exercise systolic blood pressure (SBP) response, which, in turn, might impact upon adverse outcomes. The current study sought to investigate the relationship of aortic calcification and exercise SBP with adverse outcomes among elderly individuals.

METHODS AND RESULTS

We retrospectively reviewed 702 elderly individuals (>65 years of age) without obstructive coronary artery disease (CAD; luminal stenosis <50%) who underwent coronary computed tomography (CT) and exercise treadmill testing. ΔSBPstage2 and ΔSBPpeak were defined as the difference in systolic blood pressure (SBP) between rest and stage 2 or peak exercise, respectively. Thoracic aortic calcium score (TACS) and coronary artery calcium score (CACS) were measured using CT scanning procedures. The primary endpoints were defined as all-cause death, admission for heart failure, obstructive CAD requiring coronary intervention, and stroke. In multivariable models, ΔSBPstage2 and ΔSBPpeak were positively related with log(TACS+1), even after adjusting for various clinical variables, baseline SBP, and CACS (P<0.001). During a median follow-up period of 65 months, there were 59 events (8.4%). In a multivariate Cox regression model, independent predictors for all events were age (hazard ratio [HR], 1.12; 95% CI, 1.05-1.19; P<0.001), dyslipidemia (HR, 1.96; 95% CI, 1.14-3.37; P=0.015), and the 4th quartile of TACS (HR, 1.24; 95% CI, 1.03-1.49; P=0.024). Among individual events, the 4th quartile of TACS was the only independent predictor for stroke (HR, 2.15; 95% CI, 1.09-5.13; P=0.044), whereas CACS ≥400 mm(3) was an independent predictor for obstructive CAD requiring intervention (HR, 7.04; 95% CI, 1.58-31.36; P=0.010).

CONCLUSIONS

Aortic calcification was related to SBP response during exercise and was an independent predictor for outcomes, especially stroke, regardless of resting SBP or CACS.

Effects of aliskiren- and ramipril-based treatment on central aortic blood pressure in elderly with systolic hypertension: a substudy of AGELESS

BACKGROUND

Systolic hypertension is the most common form of hypertension in elderly patients. There is increasing evidence that measurement of central aortic pressure (CAP) better accounts for cardiovascular risk than brachial blood pressure (BP). The Aliskiren for GEriatric LowEring of SyStolic hypertension (AGELESS) study in elderly patients with systolic hypertension showed that aliskiren-based therapy provided greater reductions in peripheral BP than ramipril-based therapy over 12 and 36 weeks of treatment. Here, we present CAP results in a substudy of elderly patients from the AGELESS study.

METHODS

This was a post hoc analysis of a 36-week, randomized, double-blind, parallel-group, active-controlled, optional-titration study in patients ≥65 years of age with systolic BP ≥140 mmHg. Changes in both central and peripheral BP and pulse pressure (PP) and changes in systolic and PP amplification ratios from baseline to the week 36 end point with aliskiren-based versus ramipril-based therapy were analyzed.

RESULTS

Of the 901 patients randomized in the overall study, 154 patients (aliskiren, n=78; ramipril, n=76) had CAP data. Numerically comparable reductions were seen for central aortic systolic pressure (CASP) in aliskiren-based therapy (baseline: 143.7±15.0; week 36: -20.3±16.2) compared with ramipril-based therapy (baseline: 147.9±11.9; week 36: -20.7±14.6). However, for the change in central aortic diastolic pressure, the least squares mean between-treatment difference (-3.6 mmHg [95% confidence interval, -6.76, -0.43; P=0.0263]) was in favor of aliskiren, while the other changes were comparable between the two groups with a trend in favor of aliskiren for CASP as well (-2.6 mmHg [95% confidence interval, -7.38, 2.19; P=0.2855)]. Correlation coefficients for change from baseline between CASP and systolic BP and between central aortic pulse pressure and PP (r=0.8, P<0.0001) were highly significant.

CONCLUSION

Aliskiren-based therapy provides comparable reductions in CASP to ramipril-based therapy. Although the results did not reach statistical significance, these findings, when coupled with those of the main study, suggest that aliskiren may offer effective control of central BP in elderly patients with systolic hypertension and may be a good alternative to ramipril.

Relationship between objectively measured physical activity and cardiovascular aging in the general population--the EVIDENT trial

BACKGROUND

Aging has been associated with an increase in arterial stiffness. We analyzed the relationship between regular physical activity and cardiovascular aging evaluated by the radial augmentation index (rAIx), ambulatory arterial stiffness index (AASI), pulse pressure (PP) and heart age in subjects without atherosclerotic disease.

METHODS

A cross-sectional study was performed including 1365 subjects from the EVIDENT trial (mean age 54.9±13.7 years; 60.3% women). As a measure of total volume of physical activity we used counts/minute recorded in an accelerometer (Actigraph GT3X) that participants wore for seven days, collecting data in 60-sec epochs, and respondents with ≥4 valid days were retained for the analysis. Arterial stiffness was evaluated using measures of rAIx, AASI, and central and peripheral PP on the B-pro device. rAIx was adjusted to 75 heart rate(rAIx75). Cardiovascular risk and heart age was estimated by the Framingham Risk Score.

RESULTS

The median (IQR) of counts/min was 236.9 (176.3-307.8), rAIx75 90 (77-100), sleep PP 40 mmHg (33-47), central PP 39 mmHg (32-47) and heart age 57 years (45-73) and the mean±SD of the ASSI was 0.44±0.07. We found an inverse correlation between counts/minute and rAIx75 (r=-0.086; p<0.01), AASI (r=-0.146; p<0.001), heart age (r=-0.163; p<0.001) and peripherals PP. These associations were remained after controlling for potential confounders, except for rAIx75. In the multiple regression analysis, after adjustment, an inverse association persisted between counts/minute and AASI, sleep PP and heart age, but not with rAIx75. Accordingly, for every 100 higher counts/minute of accelerometer measures, both AASI and sleep PP would be lower by one measurement unit (beta=-0.979 and -1.031 respectively, p<0.001) and the estimated heart age by half year (beta=-0.525, p=0.023).

CONCLUSIONS

Regular physical activity was inversely associated with parameters related to advanced cardiovascular aging after adjustment for potentially influencing variables.

TRIAL REGISTRATION

Clinical Trials.gov Identifier: NCT01083082.

Impact of spironolactone on vascular, myocardial, and functional parameters in untreated patients with a hypertensive response to exercise

BACKGROUND

Although a hypertensive response to exercise (HRE) is associated with cardiac risk and masked hypertension (MHT), its mechanisms and appropriate treatment remain unclear. We investigated spironolactone as a treatment for abnormal vascular and myocardial stiffness in HRE.

METHODS

In this randomized, double-blind, placebo-controlled study of 115 patients (54 ± 9 years, 57% men) with an HRE (≥210/105 mm Hg in men; ≥190/105 mm Hg in women) but no prior history of hypertension or myocardial ischemia, MHT prevalence was 40%. Patients were randomized to spironolactone 25mg daily (n = 58) or placebo (n = 57) and underwent evaluation at baseline and 3 months with exercise echocardiography, VO2max, pulse wave velocity (PWV), exercise and central blood pressure (BP), and 24-hour ambulatory BP. Changes in left ventricular mass index (LVMI), Doppler-derived E/em ratio (LV filling pressure), and myocardial strain were assessed.

RESULTS

Baseline 24-hour systolic BP (SBP) was 133 ± 10 mm Hg and peak-exercise SBP was 219 ± 16 mm Hg. Peak systolic strain (0.3 ± 3.6% vs. -0.1 ± 3.2, P = 0.56), E/em (-1.1 ± 2.3 vs. -0.6 ± 1.7, P = 0.30), VO(2max) (0.4 ± 4.9 vs. -0.9 ± 4.1 ml/kg/min, P = 0.15), and adjusted PWV did not significantly change with treatment, despite reduction in exercise SBP, 24-hour SBP, and LVMI. The change in exercise E/em was of borderline significance (-0.3 ± 2.4 vs. 0.8 ± 2.8, P = 0.06) and became significant after adjustment for baseline differences (P = 0.01). Patients with higher LVMI significantly increased VO(2max) (1.1 ± 5.6 vs. -2.4 ± 4.4 ml/kg/min, P < 0.05) and reduced exercise E/e(m) (-0.7 ± 2.7 vs. 1.9 ± 2.8, P < 0.05).

CONCLUSIONS

In HRE patients without previous hypertension, short-term spironolactone reduced exercise BP, 24-hour ambulatory BP, LVMI, and E/e(m) but did not significantly alter exercise capacity or myocardial strain.

Exercise aortic stiffness: reproducibility and relation to end-organ damage in men

Resting aortic stiffness (pulse wave velocity; aortic PWV (aPWV)) independently predicts end-organ damage and mortality. Exercise haemodynamics have been shown to unmask cardiovascular abnormalities, otherwise undetectable at rest, but the response of aPWV to exercise has never been examined. This study aimed to develop a technique to measure exercise aPWV, determine reproducibility and relation to subclinical end-organ damage with aging. Healthy younger (n=17, 30±8 years) and older (n=18, 54±8 years) untreated men underwent cardiovascular assessment at rest and during low intensity semirecumbent cycling. Tonometry was used to assess aPWV and central blood pressure (BP). All participants underwent 24 h ambulatory BP (ABP) monitoring. Kidney function was assessed by estimated glomerular filtration rate (eGFR). Fifteen participants had testing repeated within 28±18 days. Exercise aPWV had good reproducibility (mean difference=-0.35±0.61 m s(-1), intraclass correlations=0.874, P<0.001) and was increased 26% above resting values in younger men (5.8±0.9 vs 7.3±1.6 m s(-1), P<0.001) and 19% above resting values in older men (6.3±1.0 vs 7.4±0.9 m s(-1), P<0.001). Exercise, but not resting, aPWV was significantly correlated with eGFR in older men (r=-0.633, P=0.005), and this was maintained after correction for age, body mass index and daytime systolic ABP (r=-0.656, P=0.008). Conversely, in younger men there was no significant association between eGFR and aPWV either at rest (r=-0.031, P=0.906) or during exercise (r=-0.117, P=0.655). Exercise aPWV is reproducible and significantly associated with kidney function in healthy older men. Further studies to determine the physiology and clinical relevance of raised exercise aPWV are warranted.

Increased mean arterial pressure response to dynamic exercise in normotensive subjects with multiple metabolic risk factors

Metabolic syndrome (MS) may influence vascular reactivity and might cause an excessive increase in blood pressure (BP) during dynamic exercise. We examined this hypothesis in 698 normotensive men (mean age: 43 years) free of cardiovascular disease, diabetes mellitus and renal disease. The response of BP to exercise was assessed by the mean arterial pressure (MAP) during bicycle ergometry. The MAP values were expressed as z-scores normalized to the relative increases in heart rate. High-normal BP, dyslipidemia and hyperglycemia were diagnosed according to the Japan-specific MS criteria. The z-score of MAP was significantly higher in subjects with high-normal BP (+0.57, P<0.001), dyslipidemia (+0.18, P<0.001) and hyperglycemia (+0.24, P<0.001) than in those without MS component (-0.38). In the high-normal BP subjects, the addition of dyslipidemia and/or hyperglycemia was associated with a progressive increase in the z-score of exercise MAP, whereas no such association was observed in the normal-BP subjects (P=0.033, two-way ANOVA). Multivariate regression analysis revealed that a greater number of MS components (β=0.102, P=0.010) was an independent determinant of increased MAP z-score after adjustment for potential confounders, including age (β=0.123, P<0.001), body mass index (β=0.145, P<0.001) and high-normal BP (β=0.410, P<0.001). These results suggest that accumulation of MS components may alter vascular structure and function and lead to the significant elevation of MAP during dynamic exercise even before clinical manifestation of arterial hypertension.

Cardiovascular responses to walking in patients with peripheral artery disease

PURPOSES

The study's purposes were to assess the cardiovascular responses during constant-load walking and to identify predictors of this response in peripheral artery disease (PAD) patients.

METHODS

Seventy-nine patients with PAD performed a constant-load treadmill test (2 mph, 0% grade). During the test, systolic blood pressure (BP), diastolic BP, and HR were obtained at the fourth minute to the last minute of exercise. Patients were also characterized by demographic measures, cardiovascular risk factors, baseline exercise performance, and vascular measures.

RESULTS

During constant-load walking, there was a significant increase (P < 0.01) in systolic BP (+12 ± 10 mm Hg), diastolic BP (+6 ± 9 mm Hg), and HR (+5 ± 5 bpm). The HR responses were negatively correlated with the ischemic window (r = -0.23, P < 0.05), expressed as an area under the curve of the resting ankle systolic BP and its recovery from a maximal graded treadmill test, and positively correlated with the HR during the first minute of recovery from the maximal graded treadmill test (r = 0.27, P < 0.05). The increase in cardiovascular variables during constant-load walking was greater in subjects with a higher body mass index and in men (P < 0.05).

CONCLUSIONS

Patients with PAD had an increased cardiovascular response during constant-load walking, and these responses were greater in obese patients and in men. The clinical implication is that PAD patients engaged in walking training programs, particularly men and those with obesity, require frequent assessment of cardiovascular parameters to avoid exaggerated increases in BP and HR during constant-load walking.

Insulin resistance, low cardiorespiratory fitness, and increased exercise blood pressure: contribution of abdominal obesity

Individuals with insulin resistance and low cardiorespiratory fitness are frequently found to have an increased waist circumference and high exercise blood pressure. We tested the hypothesis that the relationships among insulin resistance, low cardiorespiratory fitness, and increased exercise blood pressure may be mediated by an elevated waist circumference. This study included 317 apparently healthy men and women (mean age: 34.8±12.8 years; mean body mass index: 26.1±5.2 kg/m(2)). Exercise blood pressure values were measured using a submaximal ergometer test evaluating physical working capacity. Plasma insulin and glucose levels were measured during a 3-hour oral glucose tolerance test. Multivariate regression analyses showed that waist circumference accounted for 32.8% (P<0.0001) and 45.1% (P<0.0001) of the variance in exercise systolic blood pressure in men and women, respectively. Participants were classified into tertiles according to either insulin response, measured during the oral glucose tolerance test, or fitness levels and then further subdivided into 2 subgroups using sex-specific waist circumference thresholds. Individuals with an increased waist circumference (≥94 cm and ≥80 cm for men and women, respectively) had higher exercise systolic blood pressure compared with individuals with low waist circumference, irrespective of their level of insulin resistance (10.6 versus 6.8, 12.2 versus 7.7, and 13.2 versus 8.7 mm Hg/metabolic equivalent, respectively, for the low, intermediate, and high tertiles; P<0.05) or fitness levels (13.1 versus 8.2, 12.0 versus 7.9, and 10.6 versus 7.1 mm Hg/metabolic equivalent, respectively, for the low, intermediate, and high tertiles; P<0.05). Individuals with a higher waist circumference have elevated exercise systolic blood pressure, regardless of their insulin sensitivity or level of cardiorespiratory fitness.

Metabolic syndrome and exaggerated blood pressure response to exercise in newly diagnosed hypertensive patients

Background: Running evidence supports a prognostic value of an exaggerated blood pressure response to exercise (EBPR). The impact of the metabolic syndrome (MS) on EBPR in hypertensive patients has not been investigated.

Design: A cross-sectional study in the setting of an outpatient hypertension clinic.

Methods: In total, 325 non-diabetic patients with newly diagnosed hypertension were divided into two groups based on the presence ( n = 95) or absence ( n = 230) of the MS as defined with NCEP-ATP III criteria. All subjects underwent ambulatory blood pressure monitoring, echocardiography and exercise treadmill testing.

Results: Hypertensive patients with MS exhibited higher prevalence of EBPR (by 17%, p = 0.002) and peak exercise systolic BP (by 10.4 mmHg, p = 0.001) irrespectively of confounders. Metabolic equivalents were higher in hypertensives with MS (by 0.6 ml/kg/min, p = 0.048), but the difference lost significance after adjusting for confounders, including body mass index. Logistic regression analysis identified the MS as an independent predictor of an EBPR ( p = 0.016). Hypertensive patients with MS had a 2.3-fold risk of exhibiting EBPR compared to those without MS. However, individual components of MS altogether as well as each one separately failed to predict EBPR.

Conclusions: Presence of MS in newly diagnosed hypertensive patients is associated with increased peak exercise BP and a higher frequency of EBPR over and above its separate elements.

Impaired exercise tolerance is associated with increased urine albumin excretion in the early stages of essential hypertension

BACKGROUND

Our aim was to investigate the relationship between impaired exercise capacity and albumin excretion level in the setting of never treated essential hypertension.

DESIGN AND METHODS

For this purpose, 338 consecutive essential hypertensives (52 ± 8.5 years, 227 males, office BP = 148.6/96.1 mmHg) performed a negative for myocardial ischemia, maximal treadmill exercise testing and were classified based on the gender specific median value of the amount of metabolic equivalents (METs) achieved (10.1 ml/kg/min for women and 11 ml/kg/min for men) as fit (n = 177) and unfit (n = 161). All the participants underwent 24-h ambulatory BP monitoring, complete echocardiographic study including left ventricular diastolic function evaluation and determination of albumin to creatinine ratio (ACR) on two non-consecutive morning spot urine samples.

RESULTS

Unfit hypertensives compared to the fit ones were older by 4.5 years (p < 0.001) and had greater waist circumference by 4.5 cm (p < 0.001), body mass index by 1.3 kg/m(2) (p = 0.001), 24-h pulse pressure by 3.0 mmHg (p = 0.005), ACR levels by 12.6% (p = 0.003) and prevalence of microalbuminuria (19.5% vs 10.3%, p = 0.007) while the differences in diastolic function indices lost significance after adjustment for confounders. By applying stepwise multivariate linear regression analysis in order to identify the predictors of METs, it was revealed that age (β = -0.338, p = 0.045), gender (β = 0.274, p = 0.045), body mass index (β = -0.230, p = 0.045) and logACR (β = -0.151, p = 0.004) were the only independent predictors of exercise capacity.

CONCLUSIONS

Increased ACR is associated with diminished exercise capacity in the early stages of essential hypertension independently from adverse cardiac adaptations, further elucidating the adverse prognostic role of albuminuria in this setting.