Pulse pressure-III. Prognostic significance in four Chicago epidemiologic studies

Brachial-ankle pulse wave velocity compared with mean arterial pressure and pulse pressure in risk stratification in a Chinese population

BACKGROUND

Brachial-ankle pulse wave velocity (baPWV) can be easily measured in an observer-independent way, but lacks robust population-based validation in terms of fatal combined with nonfatal outcomes.

METHOD

To address this issue, we studied 4251 Chinese randomly recruited Gaoyou County (54.1% women; mean age, 52.1).

RESULTS

In the whole study population, mean values were 102.4 mmHg for mean arterial pressure (MAP), 51.1 mmHg for pulse pressure, and 14.8 m/s for baPWV. Over 4.4 years (median), 74 participants experienced a fatal or nonfatal cardiovascular event and 44 a stroke. In multivariable-adjusted Cox regression, standardized hazard ratios expressing the risk of a composite cardiovascular endpoint were 1.77 (95% confidence interval, 1.43-2.20), 1.37 (1.14-1.64) and 1.50 (1.26-1.78) for MAP, PP and baPWV, respectively; the corresponding hazard ratios for stroke were 1.82 (1.39-2.38), 1.39 (1.12-1.74) and 1.53 (1.25-1.89). baPWV did not add to the prediction of cardiovascular events or stroke by MAP (hazard ratios for baPWV, 1.25 and 1.27, respectively; P ≥ 0.053) but refined models including PP (hazard ratios, 1.42 and 1.45; P ≤ 0.0033). The optimized baPWV threshold, obtained by maximizing Youden's index (16.7 m/s), increased the integrated discrimination improvement over and beyond MAP (+1.27%; P = 0.021) and PP (+1.37%; P = 0.038) for the cardiovascular outcome, but not stroke, and increased the net reclassification improvement for both endpoints (≥42.2%; P ≤ 0.004).

CONCLUSION

With fatal and nonfatal cardiovascular and cerebrovascular endpoints as outcome, baPWV marginally increases risk stratification over and beyond MAP, but is a better predictor than PP. A threshold of 16.7 m/s might be used in Chinese populations.

Association of High Levels of Spot Urine Protein with High Blood Pressure, Mean Arterial Pressure and Pulse Pressure with the Development of Diabetic Chronic Kidney Dysfunction or Failure among Diabetic Patients. Statistical Regression Modeling to Predict Diabetic Proteinuria

INTRODUCTION

In research elevated Blood Pressure (BP) has been demonstrated to be a risk for the development of nephropathy and chronic renal disease (CKD) Or Diabetic Kidney Disease (DKD) among diabetics. However, no study has find correlation for the spot urine protein (UPr) excretion with elevated BP, Pulse Pressure (PP) and mean arterial pressure MAP). This technique was invented in the current study.

METHODS

10,270 were recruited for more than 12 years. Demographically, 43%, 38%, and 16% showed hypertension, nephropathy and chronic renal disease, respectively. UPr demonstrated significant correlations with systolic BP (SBP) and diastolic BP (DPB), MAP and PP (p < 0.0001 for all). SBP, DBP, PP and MAP, UPr were observed to be higher among the groups with nephroaphty and CKD/DKD with highly significant p-values (all p < 0.05). With logistic regression, odds ratio of hypertension (HTN) with nephropathy was observed to be 2.99 (95% CI 2.44 to 3.7; p < 0.0001); and odds ratio of HTN with CKD/DK was 7.1 (95% CI 4.3 to 11.84; p<0.0001), indicating that HTN significantly contributes to the development of nephropathy and CKD/DKD in diabetics.

RESULTS

Invented regression models for the excretion of UPr from the kidney with elevated SBP, DBP, MAP and PP were highly significant (p < 0.0001 for all); UPr = -138.6 + [1.347 × SBP] ; UPr = -93.4 + [1.62 × DBP] ; UPr = -149.5 + [1.922 × MAP] ; UPr = -41.23 +[1.541 × PP].

CONCLUSION

Current study is the first one to introduce this technique. These invented new equations can be used by physicians to estimate protein excretion in urine at bedside and outpatients departments for monitoring proteinuria and CKD/DKD.

Impact of ACE2 gene polymorphism on antihypertensive efficacy of ACE inhibitors

Angiotensin-converting enzyme 2 (ACE2), a newly discovered member of renin-angiotensin-aldosterone system, counterbalances the actions of angiotensin-converting enzyme. The objective of our study was to assess the association between rs2106809 polymorphism in ACE2 gene and the blood pressure response to ACE inhibitors in untreated hypertensive patients. After a 2-week, double-blind placebo run-in period, either benazepril or imidapril was administered for 6 weeks to 497 patients with mild to moderate essential hypertension. The achieved changes in BP were analyzed for their association with genotypes at ACE2 gene loci. In female hypertensive patients, the genotype frequency of ACE2 rs2106809 was 36.7%, 45.2% and 18.1% for CC, CT and TT genotypes, respectively. After 6 weeks of treatment, the reductions in diastolic blood pressure were significantly greater in female patients carrying the CC or CT genotype compared with those carrying the TT genotype (9.62±6.83 or 10.2±7.2 versus 6.81±6.31 mm Hg, respectively; P=0.045, analysis of variance (ANOVA)). Moreover, the reductions in mean arterial pressure were significantly greater in female patients carrying the CC or CT genotype compared with those carrying the TT genotype (12.1±7.5 or 12.0±7.9 versus 8.38±6.83 mm Hg, respectively; P=0.035, ANOVA). In male hypertensive patients, the genotype frequency of ACE2 rs2106809 was 58.1% and 41.9% for C and T genotypes, respectively. However, no association could be observed in males. We conclude that ACE2 rs2106809 is an important predictive factor of the response to antihypertensive treatment with ACE inhibitors in Chinese female hypertensive patients.

The effect of an e-health intervention designed to reduce prolonged occupational sitting on mean arterial pressure

OBJECTIVE

To evaluate the effect of a workplace health intervention designed to reduce prolonged occupational sitting on the mean arterial pressure (MAP) of desk-based employees.

METHODS

This randomized controlled trial involved an experimental group who received an e-health intervention and a control group who did not. The 13-week intervention passively prompted participants to stand and engage in short bouts of office-based physical activity by interrupting prolonged occupational sitting time periodically throughout the workday. Mean arterial pressure was measured at pretest and posttest.

RESULTS

Between pretest and posttest the experimental group significantly reduced their MAP, whereas MAP in the control group did not.

CONCLUSIONS

A workplace e-health intervention designed to reduce prolonged occupational sitting was effective in decreasing MAP in desk-based employees.

Overall cardiovascular prognosis of isolated systolic hypertension, isolated diastolic hypertension and pulse pressure defined with home measurements: the Finn-home study

OBJECTIVE

The overall cardiovascular prognosis of isolated systolic hypertension, isolated diastolic hypertension and pulse pressure defined with home blood pressure (BP) measurements remains unclear.

METHODS

A prospective nationwide study was initiated in 2000-2001 on 1924 randomly selected participants aged 44-74 years. We determined home and office BP at baseline and classified the individuals into four groups according to their home BP levels: normotension, isolated diastolic hypertension, isolated systolic hypertension and systolic-diastolic hypertension. The primary endpoint was incidence of a composite cardiovascular event.

RESULTS

After a median follow-up of 11.2 years, 236 individuals had suffered a cardiovascular event. In multivariable Cox proportional hazard models, the relative hazards and 95% confidence intervals (CIs) for cardiovascular events were significantly higher in participants with isolated diastolic hypertension (relative hazard 1.95; 95% CI, 1.06-3.57; P=0.03), isolated systolic hypertension (relative hazard 2.08; 95% CI, 1.42-3.05; P<0.001) and systolic-diastolic hypertension (relative hazard 2.79; 95% CI, 2.02-3.86; P<0.001) than in participants with normotension. Home (relative hazard 1.21; 95% CI, 1.05-1.40; P=0.009 per 10 mmHg increase), but not office (relative hazard 1.10; 95% CI, 1.00-1.21, P=0.06) pulse pressure, adjusted for mean arterial pressure, was an independent predictor of cardiovascular risk.

CONCLUSION

Isolated diastolic and systolic hypertension defined with home measurements are associated with an increased cardiovascular risk. Close follow-up and possible treatment of these patients is therefore warranted. Home-measured pulse pressure is an independent predictor of cardiovascular events while office-measured pulse pressure is not, which fortifies the view that home BP provides more accurate risk prediction than office BP.

A core promoter variant of angiotensinogen gene and interindividual variation in response to angiotensin-converting enzyme inhibitors

INTRODUCTION

The polymorphic angiotensinogen (AGT) gene is one of the most promising candidates for essential hypertension. The aim of this study was to examine the association between the A-6G variant of the AGT gene and the blood pressure response to angiotensin-converting enzyme (ACE) inhibitors in hypertensive subjects.

METHODS

Five hundred and nine mildly to moderately hypertensive subjects received ACE inhibitors for six weeks after a two-week run-in period. AGT genotyping was performed by direct polymerase chain reaction amplification and deoxyribonucleic acid (DNA) nucleotide sequencing from peripheral blood.

RESULTS

The AA genotype, AG genotype, and GG genotype were present in 301 (59.1%), 186 (36.6%), and 22 (4.3%) of patients, respectively. As compared with patients carrying the AA or AG genotype, those carrying the GG genotype had significantly greater reductions in systolic blood pressure, diastolic blood pressure, pulse pressure and mean arterial pressure (p=0.007, 0.014, 0.027 and 0.005, respectively). Moreover, stepwise multiple linear regression analysis showed that the A-6G genotype was a significant predictor of systolic blood pressure and pulse pressure reductions (p=0.040 and 0.019, respectively).

CONCLUSION

Our study indicates that the A-6G variant of the AGT gene may be an important determinant of interindividual variation in the response to ACE inhibitors.

Clinical utility of ambulatory blood pressure monitoring in the management of hypertension

Accurate blood pressure (BP) measurement is essential for the diagnosis, monitoring and management of hypertension. However, conventional office-based BP readings have several limitations that include a low reproducibility, the white-coat effect and the existence of masked hypertension. These limitations can be addressed through the use of ambulatory BP monitoring. Because ambulatory monitoring provides measurements at specific time intervals throughout a 24-hour period, this technique represents a better picture of the normal fluctuations in BP levels associated with daily activities and sleep. In addition, end-organ damage associated with hypertension is more closely related to ambulatory BP than office BP measurements and ambulatory BP profile give better prediction of clinical outcome than conventional BP measurements.

Effect of interval training programme on pulse pressure in the management of hypertension: a randomized controlled trial

BACKGROUND

Pulse pressure (PP), might be a stronger determinants of cardiovascular risk.

OBJECTIVE

To investigate the effect of interval training program on PP in subjects with hypertension.

METHODS

Two hundred and forty five male patients with mild to moderate (Systolic Blood Pressure [SBP] between 140-179 & Diastolic Blood Pressure [DBP] between 90-109 mmHg) essential hypertension were age-matched and grouped into exercise and control groups. The exercise (work: rest ratio of 1:1) groups involved in an 8-weeks interval training programs of between 45-60 minutes, at intensities of 60-79% of HR max (maximum heart rate), while the control group remained sedentary during this period. SBP, DBP, VO2max and PP were assessed.

RESULTS

Findings of the study revealed significant correlation between PP and blood pressure; correlation of PP with SBP was much stronger (95% variance). Also, there was significant effect of the exercise training program on SBP, DBP and PP. Changes in VO2max also negatively correlated with changes in PP (r= -.285) at p<0.05.

CONCLUSION

Moderate intensity interval training programs is effective in the non-pharmacological management of hypertension and may prevent cardiovascular event through the down regulation of PP in hypertension.

Measurement of central aortic pulse pressure: noninvasive brachial cuff-based estimation by a transfer function vs. a novel pulse wave analysis method

BACKGROUND

The prognostic value of central aortic pulse pressure (PP-C) may have been underestimated due to its measurement inaccuracy. We aimed to investigate the accuracy of noninvasive brachial cuff-based estimation of PP-C by a generalized transfer function (GTF) or a novel pulse wave analysis (PWA) approach to directly estimate PP-C.

METHODS

Invasive high-fidelity right brachial and central aortic pressure tracings, and left brachial pulse volume plethysmography (PVP) waveforms from an oscillometric blood pressure (BP) monitor were all digitized simultaneously in 40 patients during cardiac catheterization. An aortic-to-brachial GTF and a PWA multivariate prediction model using the PVP waveforms calibrated to brachial cuff systolic BP (SBP) and diastolic BP(DBP) were constructed. Accuracy of the two methods was examined in another 100 patients against invasively measured PP-C.

RESULTS

The error of cuff PP in estimating PP-C was 1.8 ± 12.4 mm Hg. Application of the GTF on noninvasively calibrated PVP waveforms produced reconstructed aortic pressure waves and PP-C estimates with errors of -3.4 ± 11.6 mm Hg (PP-C = reconstructed aortic SBP - aortic DBP) and -2.3 ± 11.4 mm Hg (PP-C = reconstructed aortic SBP - cuff DBP), respectively. The observed systematic errors were proportional to the magnitudes of PP-C. In contrast, the error of the PWA prediction model was 3.0 ± 7.1 mm Hg without obvious proportional systematic error.

CONCLUSIONS

Large random and systematic errors are introduced into the PP-C estimates when PP-C is calculated as the difference between the estimated central SBP and central or cuff DBP. The accuracy can be improved substantially with the novel PWA approach.

Ophthalmodynamometric pressure in eyes with proliferative diabetic retinopathy measured during pars plana vitrectomy

PURPOSE

To measure ophthalmodynamometric pressure (ODP) during vitrectomy in patients with proliferative diabetic retinopathy (PDR).

DESIGN

Prospective, interventional, consecutive case series.

METHODS

This study included 75 eyes of 75 patients undergoing vitrectomy for PDR. After core vitrectomy, the intraocular pressure was gradually raised using a vented-gas forced-infusion system (VGFI), and the optic nerve head was continuously monitored through a planoconvex contact lens. When the central retinal artery or its branches on the optic nerve head showed pulsations, the pressure was recorded as ODP. Diastolic blood pressure (DBP) and systolic blood pressure (SBP) were measured at the time of ODP measurement. Multiple regression analysis was performed to investigate the relationship between ODP and various explanatory variables: DBP, SBP, age, gender, body mass index, presence of hypertension, serum hemoglobin A1c, serum total cholesterol, fasting plasma glucose, presence of rubeosis iridis, and severity of PDR.

RESULTS

ODP was 63.6 ± 11.5 mm Hg (range 15.5-84.4 mm Hg). The ODP significantly correlated with DBP (r=0.570, P<.0001) and the mean arterial blood pressure (r=0.522, P<.0001), but not with SBP (r=0.121, P=.303). Multiple regression analysis revealed that ODP had a significant correlation with DBP (P<.0001), presence of rubeosis iridis (P<.0001), and severity of PDR (P=.046).

CONCLUSIONS

We measured ODP using VGFI during vitrectomy in patients with PDR. The ODP was significantly associated with DBP. The ODP was lower in patients with rubeosis iridis and severe PDR.

A chromosome 11q quantitative-trait locus influences change of blood-pressure measurements over time in Mexican Americans of the San Antonio Family Heart Study

Although previous genome scans have searched for quantitative-trait loci (QTLs) influencing variation in blood pressure (BP), few have investigated the rate of change in BP over time as a phenotype. Here, we compare results from genomewide scans to localize QTLs for systolic, diastolic, and mean arterial BPs (SBP, DBP, and MBP, respectively) and for rates of change in systolic, diastolic, and mean arterial BPs (rSBP, rDBP, and rMBP, respectively), with use of the longitudinal data collected about Mexican Americans of the San Antonio Family Heart Study (SAFHS). Significant evidence of linkage was found for rSBP (LOD 4.15) and for rMBP (LOD 3.94) near marker D11S4464 located on chromosome 11q24.1. This same chromosome 11q region also shows suggestive linkage to SBP (LOD 2.23) and MBP (LOD 2.37) measurements collected during the second clinic visit. Suggestive evidence of linkage to chromosome 5 was also found for rMBP, to chromosome 16 for rSBP, and to chromosomes 1, 5, 6, 7, and 21 for the single-time-point BP traits collected at the first two SAFHS clinic visits. We also present results from fine mapping the chromosome 11 QTL with use of SNP-association analysis within candidate genes identified from a bioinformatic search of the region and from whole-genome transcriptional expression data collected from 1,240 SAFHS participants. Our results show that the use of longitudinal BP data to calculate the rate of change in BP over time provides more information than do the single-time measurements, since they reveal physiological trends in the subjects that a single-time measurement could never capture. Further investigation of this region is necessary for the identification of the genetic variation responsible for QTLs influencing the rate of change in BP.

Can we improve cardiovascular risk prediction beyond risk equations in the physician's office?

BACKGROUND AND OBJECTIVES

Beyond a global estimation of the cardiovascular risk through the assessment of major risk factors and their integration in dedicated risk scales or equations, the use of specific markers provides additive prognostic information at an individual level, including predisposing factors, which are not included in the risk equations as well as the individual susceptibility to their long-term exposure. However, the majority of these markers require specific devices and skills, which are not widely available in primary care.

METHODS

Some clinical and/or "low-cost" parameters are shown to be valuable risk markers, and their use could refine the risk estimation in a physician's office. Several epidemiologic studies suggest the heart rate, the pulse pressure and the ankle-brachial index are effective cardiovascular risk markers. The arms systolic pressure asymmetry could also be a useful marker of risk.

RESULTS AND CONCLUSIONS

Through a general review, the authors evaluate the potential of these clinical markers, including their use in combination for more accurate risk determination.

Effect of diet and exercise on pulse pressure and cardiac function in morbid obesity: analysis of 24-hour ambulatory blood pressure

Blood pressure is a major risk factor for cardiovascular events, although the role of pulse pressure, an independent predictor of arterial stiffness, has recently been emphasized. This study examines the baseline relationship between body mass index (BMI) and blood pressure indexes in 215 obese African Americans enrolled in a diet-exercise program. The subject population was 77% female, with a mean +/- SD age of 46.7+/-10.7 years and a mean BMI of 42.5+/-7.5 kg/m2. In addition, the authors prospectively examined the effect of weight loss on cardiovascular parameters in a subset of 25 participants. The results show a closer significant correlation between pulse pressure and BMI (b=1.97 kgm-1; p=0.001) than between systolic blood pressure and BMI (b=1.58 kgm-1; p=0.020). After 3 months of diet and exercise, average reductions were as follows: BMI, 4.2 kg/m2 (p<0.01); systolic blood pressure, 7.2 mm Hg (p<0.01); pulse pressure, 4.8 mm Hg (p<0.01); and cardiac output, 975 mL/min (p<0.01). Compliance index increased by 0.1 mL/mm Hg/m2 (p=0.03). The results highlight the potential value to cardiovascular health of a modest reduction in body weight in obese individuals.

Importance of arterial pulse pressure as a predictor of coronary heart disease risk in PROCAM

AIMS

To investigate pulse pressure (PP) as an independent predictor of coronary heart disease (CHD) risk.

METHODS AND RESULTS

On the basis of a 10-year follow-up of 5389 men aged 35-65 at recruitment into PROCAM, we used a proportional hazards model to calculate the effect of systolic blood pressure (SBP), diastolic blood pressure (DBP), and PP on CHD risk after correcting for age, high-density lipoprotein cholesterol, LDL cholesterol, triglycerides, smoking, diabetes, and family history of premature CHD. Increases of 10 mmHg in DBP, SBP, and PP were associated with an increased CHD hazard ratio (HR) of approximately 10%. When the group was divided into the age groups <50, 50-59, and >59 years, this relationship was seen in the age group 50-59 years for DBP, SBP, and PP and in men aged > or =60 for PP only (25% increase in HR). Overall, CHD risk in men with PP > or =70 mmHg was more three times that of men with PP <50 mmHg. This increased risk was not apparent at age <50 years, was greatest at age >60 years, and was also present in men who were normotensive at recruitment (SBP < or =160 mmHg, DBP < or =95 mmHg).

CONCLUSION

In older European men, increased PP is an important independent determinant of coronary risk, even among those initially considered normotensive.

Neural activity of the cardiac baroreflex decreases with age in normotensive and hypertensive subjects

OBJECTIVES

Baroreflex control of the heart rate is impaired in hypertensive subjects and decreases with age. The decrease in cardiac baroreflex sensitivity (BRS) is often ascribed to decreased distension of the pressure-sensing arterial wall segments. However, alterations in the sensing and processing of neural signals may be involved as well.

DESIGN

Conventionally, both vessel wall stiffness and the sensing and neural processing of the baroreflex are incorporated in the measure of pressure-derived BRS. We introduce stretch-derived BRS, which only considers the sensing and neural components of the baroreflex.

METHODS

To determine stretch-derived BRS in a non-invasive manner, we measured the spontaneously occurring low-frequency variations (range, 0.06-0.12 Hz) in the carotid artery diameter and the corresponding R-R interval fluctuations, and determined the associated transfer function. The stretch-derived BRS in a group of age-matched (age range, 25-72 years) normotensive (n = 20) and hypertensive (n = 21) subjects was compared.

RESULTS

In both subject groups the stretch-derived BRS decreased significantly with age. Moreover, the stretch-derived BRS of both groups was only different below 50 years of age.

CONCLUSIONS

The analysis of low-frequency fluctuations in the carotid artery diameter demonstrates that aging as well as hypertension are associated with impaired neural control of the baroreflex. Beyond 50 years of age the effect of hypertension cannot be distinguished from the effect of aging.

Pulse pressure, heart rate, and drug treatment of hypertension

Peak-systolic blood pressure (SBP) and end-diastolic blood pressure (DBP) have been considered the exclusive mechanical factors predicting cardiovascular (CV) risk in populations of normotensive and hypertensive subjects. The purpose of this review is to show that in addition to SBP and DBP, other hemodynamic indices that have particular relevance for coronary complications and originate from pulse pressure (PP) should be taken into account, namely brachial PP and, potentially, heart rate (HR). In normotensive and hypertensive populations, increased PP is an independent predictor for myocardial infarction, more powerful than SBP, even in hypertensive subjects under successful antihypertensive drug therapy. Increased HR is an additional CV risk factor, acting particularly through the presence of an enhanced PP x HR product. Such findings, observed during a period in which standard antihypertensive agents are known to reduce SBP and PP to a much lesser extent than DBP, require the development of intervention trials using drugs acting specifically on SBP, PP, and arterial stiffness.

Clinic, home and ambulatory pulse pressure: comparison and reproducibility

OBJECTIVE

Recent evidence suggests that pulse pressure (PP) is an independent predictor of cardiovascular risk. The objective of this study was to compare mean values and reproducibility of PP obtained in the clinic (CPP), at home (HPP) and with ambulatory monitoring (APP) and to evaluate potential implications for trials aiming to assess drug effects on PP.

METHODS

A total of 393 hypertensive subjects [mean age 51.5 +/- 11.5 (SD) years, 59% men, 35% treated] measured CPP (two visits), HPP (6 days) and APP (24 h). The reproducibility of PP was assessed using the SD of differences (SDD) between measurements in 133 untreated subjects who had repeated CPP (five visits), HPP (6 days) and APP measurements (two occasions).

RESULTS

There was no difference between mean CPP (51.0 +/- 13.3 mmHg) and HPP (50.2 +/- 11.0) whereas APP (48.8 +/- 8.4) was lower than both CPP [mean difference 2.3 +/- 10.3 mmHg; 95% confidence interval (CI), 1.2, 3.3; P < 0.01] and HPP (1.5 +/- 7.8; 95% CI, 0.7, 2.3; P < 0.01). The SDD between repeated measurements was about 10 mmHg for CPP (one visit), 5.2 mmHg for HPP (2 days) and 4 mmHg for APP (24-h). For a parallel comparative trial aiming to detect a difference of 3 mmHg PP in the effect of two drugs, 415 subjects would be required when using CPP, compared to 127 using HPP and 63 using APP.

CONCLUSIONS

These data suggest that although differences among mean values of CPP, HPP and APP are small, differences in their reproducibility are important and should be taken into account in the design of trials assessing drug effects on PP.

Isolated diastolic hypertension, pulse pressure, and mean arterial pressure as predictors of mortality during a follow-up of up to 32 years

OBJECTIVE

To compare mortality associated with various blood pressure components in middle-aged men during up to 32 years of follow-up.

DESIGN

A prospective cohort study.

SETTING

Helsinki, Finland.

PARTICIPANTS

We studied 3267 initially healthy men, aged 30-45 years, who participated in health check-ups from 1964 onwards.

MAIN OUTCOME MEASURES

Cox regression was used to relate baseline blood pressure components to all-cause (n = 701) and cardiovascular disease (CVD) mortality (n = 325).

RESULTS

Systolic (SBP) and diastolic (DBP) blood pressures, pulse pressure and mean arterial pressure singly predicted CVD mortality. With SBP 160 mmHg and DBP 90 mmHg as cut-off values, four blood pressure subgroups were identified: normotension (n = 1919), isolated systolic hypertension (ISH, n = 17), isolated diastolic hypertension (IDH, n = 1013), and combined systolic and diastolic hypertension (SDH, n = 318). IDH was subdivided into IDH-1 with SBP 140-159 mmHg (n = 667) and IDH-2 with SBP less than 140 mmHg (n = 346). With normotension as reference, only SDH and IDH-1 predicted CVD mortality [relative risk (RR) 2.71, 95% confidence interval (CI) 2.00 to 3.66, and RR 1.39, 95% CI 1.04 to 1.87, respectively]. Risk with IDH-2 (RR 1.14, 95% CI 0.77 to 1.69) was not statistically significant. SDH and IDH-1, but not IDH-2, were also associated with increased all-cause mortality risk. Use of antihypertensive medication did not explain the results.

CONCLUSION

These results demonstrate the often neglected role of SBP in predicting long-term CVD risk in middle-aged men. When SBP is less than 140 mmHg, IDH is not associated with significantly increased risk of mortality. Administrative guidelines, which affect population health, should also take due note of SBP.

Development of predictive models for long-term cardiovascular risk associated with systolic and diastolic blood pressure

Most existing risk prediction models have not considered the joint contribution of systolic and diastolic blood pressure to cardiovascular risk, and some suggest that there are thresholds below which further reductions of blood pressure yield no additional benefit. We developed multivariate risk prediction models that quantify the risk associated with both systolic and diastolic blood pressure and that can be used to infer the benefits of antihypertensive therapy in populations. Two large clinical trial cohorts, the Physicians' Health Study, composed of 22 071 males (mean age, 53.2 years; median follow-up, 13.0 years), and the Women's Health Study, composed of 39 876 females (mean age, 53.8 years; median follow-up, 6.2 years), were used to develop gender-specific predictive models via Cox regression. End points included myocardial infarction, stroke, coronary artery bypass, angioplasty, and cardiovascular death. Risk reduction estimates were derived by computing reductions associated with incremental lowering of systolic and diastolic blood pressures. In both populations, lower levels of blood pressure predicted lower event rates, with no evidence of a plateau or a J-shaped curve. In males, both systolic and diastolic blood pressures were significantly associated with events (P<0.001), whereas in females, only systolic blood pressure (P<0.001) predicted outcome after multivariate adjustment. Correction for measurement error in blood pressure increased risk estimates by approximately 50%. Differences in systolic blood pressure yielded greater relative risk reductions than did differences in diastolic blood pressure in a combined population of males and females. These predictive models may be useful for risk estimation associated with hypertension in similar populations and may also be used to infer the benefits of antihypertensive therapy.

Pulse pressure--a review of mechanisms and clinical relevance

The goal of this study was to review the origin, clinical relevance and treatment of pulse pressure (PP). Elevated PP is increasingly being recognized as a risk factor for cardiovascular, particularly coronary, disease. Pulse pressure is discussed in terms of both Windkessel and distributive models of the arterial circulation. Pulse pressure arises from the interaction of cardiac ejection (stroke volume) and the properties of the arterial circulation. An increased stiffness of the aorta and large arteries leads to an increase in PP through a reduction in arterial compliance and effects on wave reflection. A number of factors are known to influence arterial wall behavior and, therefore, PP. In addition to the effects of aging and blood pressure on arterial wall elasticity, there is some evidence that atherosclerosis, per se, amplifies these effects. Thus, the relationship between PP and coronary disease may be bidirectional. A number of dietary and lifestyle interventions have been shown to modify large artery behavior. These include aerobic exercise training and consumption of n-3 fatty acids. Conversely, strength training is associated with an increase in arterial stiffness and a higher PP. The effects of antihypertensive medication have been extensively studied, but many studies are difficult to interpret because of concomitant change in blood pressure, and to a lesser degree, heart rate. However a number of studies do suggest direct arterial wall effects, particularly for angiotensin-converting enzyme inhibitors. A distributed compliance model of the arterial circulation provides a framework for understanding the causes, effects and potential treatment of elevations in PP.

Systolic blood pressure, pulse pressure and arterial stiffness as cardiovascular risk factors

For many years systolic and diastolic blood pressure were the exclusive mechanical factors predicting cardiovascular risk in populations of normotensive and hypertensive individuals. However, if hypertension acts as a mechanical factor with deleterious consequences on the arterial wall, the totality of the blood pressure curve should be considered to evaluate the risk. The purpose of this review is to show that, in addition to systolic and diastolic blood pressure, other haemodynamic indexes with particular relevance for cardiac complications and that originate from pulsatile pressure should be taken into account, namely brachial pulse pressure and aortic pulse wave velocity. The main recent findings in normotensive and hypertensive populations are: (i) increased pulse pressure is an independent predictor of myocardial infarction, congestive heart failure and cardiovascular death, even in hypertensive patients undergoing successful antihypertensive drug therapy; (ii) increased aortic pulse wave velocity and increased carotid incremental elastic modulus are also both independent predictors of cardiovascular mortality, mainly in patients with end-stage renal disease and, to a lesser extent, in individuals with essential hypertension. Currently, increased pulse pressure and increased pulse wave velocity may be considered either as simple markers of an underlying vascular disease or as strong cardiovascular risk factors. The solution of this important question requires the development of specific intervention trials.

Systolic and diastolic blood pressure, pulse pressure, and mean arterial pressure as predictors of cardiovascular disease risk in Men

We compared systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and mean arterial pressure (MAP) in predicting the risk of cardiovascular disease (CVD), stratifying results at age 60 years, when DBP decreases while SBP continues to increase. We prospectively followed 11 150 male physicians with no history of CVD or antihypertensive treatment through the 2-year questionnaire, after which follow-up began. Reported blood pressure was averaged from both the baseline and 2-year questionnaires. During a median follow-up of 10.8 years, there were 905 cases of incident CVD. For men aged <60 years (n=8743), those in the highest versus lowest quartiles of average SBP (>/=130 versus <116 mm Hg), DBP (>/=81 versus <73 mm Hg), and MAP (>/=97 versus <88 mm Hg) had relative risks (RRs) of CVD of 2.16, 2.23, and 2.52, respectively. Models with average MAP and PP did not add information compared with models with MAP alone (P>0.05). For men aged >/=60 years (n=2407), those in the highest versus lowest quartiles of average SBP (>/=135 versus <120 mm Hg), PP (>/=55 versus <44 mm Hg), and MAP (>/=99 versus <91 mm Hg) had RRs of CVD of 1.69, 1.83, and 1.43, respectively. The addition of other blood pressure measures did not add information compared with average SBP or PP alone (all P>0.05). These data suggest that average SBP, DBP, and MAP strongly predict CVD among younger men, whereas either average SBP or PP predicts CVD among older men. More research should distinguish whether MAP, highly correlated with SBP and DBP, better predicts CVD.

Implications of pulse pressure as a predictor of cardiac risk in patients with hypertension

Previously we demonstrated that pulse pressure is a strong risk factor for coronary events in male hypertensive subjects in the MRC Mild Hypertension Trial, whereas stroke is best predicted by mean blood pressure. In this study, we have assessed the implications of this finding in the treatment of mild essential hypertension. We examined the relationship between diastolic blood pressure and both coronary disease risk and stroke when these events were predicted by the above blood pressure measures using an empirical linear model and multivariate logistic regression models that contained data from the MRC trial. Under these circumstances, the predicted stroke risk increased progressively with increasing values of diastolic blood pressure, but in both empirical and formal statistical models, the predicted risk of a coronary event exhibited a J-shaped relationship with diastolic blood pressure. These results suggest that if coronary event risk in mild essential hypertension is predicted by pulse pressure then it may increase at low values of diastolic blood pressure, in contrast to stroke risk, which declines continuously as diastolic blood pressure falls within the physiological range. This raises the possibility that different sequelae of hypertension are best predicted by different measures of blood pressure and that the effect of treatment on stroke and coronary events in some circumstances may be discordant.

A new approach to assessing antihypertensive therapy: effect of treatment on pulse pressure. Candesartan cilexetil in Hypertension Ambulatory Measurement of Blood Pressure (CHAMP) Study Investigators

BACKGROUND

A high pulse pressure is an independent cardiovascular risk factor. It has therefore been suggested that antihypertensive treatment should not only reduce systolic blood pressure (SBP) and diastolic blood pressure (DBP), but should also decrease pulse pressure (SBP minus DBP). In a previous analysis, we showed that two angiotensin II type 1 (AT1)-receptor blockers, candesartan cilexetil and losartan, differed in their effects in reducing SBP and DBP.

OBJECTIVE

To compare the efficacy of candesartan cilexetil and losartan according to a new approach--their effect on pulse pressure--and to describe the dose-effect relationship for SBP, DBP and pulse pressure, in a placebo-controlled study.

METHODS

After a 4-week placebo run-in period, 268 patients with mild-to-moderate hypertension were allocated randomly to groups to receive placebo, candesartan cilexetil (8 mg once daily) or losartan (50 mg once daily), for 4 weeks. The doses were then doubled to 16 and 100 mg, respectively, for the final 4 weeks of the study. Clinic blood pressure was measured 24 and 48 h after each dose of drug or placebo, and ambulatory blood pressure was monitored from 0 to 36 h after each dose, at baseline and after 4 and 8 weeks of treatment.

RESULTS

Candesartan cilexetil decreased ambulatory pulse pressure significantly (P < 0.05) more than did losartan during both daytime and night-time, and over the 24 h period after the previous dose. A different dose-effect relationship on SBP, DBP and pulse pressure was observed. The duration of action of candesartan cilexetil was greater than that of losartan. After a missed dose (i.e. approximately 24-36 h after the previous dose), mean ambulatory pulse pressure values after 4 and 8 weeks of treatment with candesartan cilexetil were lower than those observed with losartan (P < 0.005). Clinic pulse pressure measurements were consistent with these ambulatory measurements.

CONCLUSIONS

AT1 -receptor blockers differ both in their ability to reduce pulse pressure and in their duration of effect, candesartan cilexetil having a greater and more sustained effect than losartan. Different dose-effect relationships on SBP, DBP or pulse pressure were observed. Further prospective studies based on pulse pressure are needed to analyse the mechanism of reduction of pulse pressure and to determine its prognostic value.

Therapeutic studies and arterial stiffness in hypertension: recommendations of the European Society of Hypertension. The Clinical Committee of Arterial Structure and Function. Working Group on Vascular Structure and Function of the European Society of Hypertension

BACKGROUND

Increased pulse pressure and arterial stiffness are identified as predictors of cardiovascular risk in older hypertensive populations, particularly that of myocardial infarction. Because increased pulse pressure involves an increase in systolic (SBP) and a decrease in diastolic blood pressure (DBP), and because the former promotes cardiac hypertrophy and the latter alters coronary perfusion, a drug regimen reducing pulse pressure and decreasing arterial stiffness might further reduce cardiovascular risk. Under conventional treatment, normalization of DBP (< or = 90 mmHg) is not consistently associated with normalization of SBP (< or = 140 mmHg).

THERAPEUTIC DESIGNS

In individuals older than 50 years, the goal of antihypertensive treatment should be, not only to decrease mean blood pressure (to less than 100 mmHg), but also to decrease pulse pressure (to less than 50 mmHg). Using appropriate pharmacological tools, trials should test whether an active decrease in arterial stiffness might produce an attenuation of the age-related increase in SBP and decrease in DBP, thus delaying the age-related increase in pulse pressure and decreasing further cardiovascular risk. This procedure requires concomitant non-invasive evaluations of aortic stiffness.

CONCLUSION

The studies that are required in hypertension should use two different approaches: novel titrations of conventional drugs to achieve a decrease in either SBP or pulse pressure, and development of new drugs acting selectively on the large artery wall, to facilitate the conduct of subsequent controlled trials.

Pulse pressure, arterial stiffness, and cardiovascular risk

Systolic and diastolic blood pressures are the exclusive mechanical factors usually considered as predictors of cardiovascular risk in populations of normotensive and hypertensive subjects at large. However, if hypertension is considered as a mechanical factor acting on the arterial wall with substantial deleterious consequences, the totality of the blood pressure curve should be considered in order to investigate the cardiovascular risk. The purpose of this review is to show that in addition to systolic and diastolic blood pressures, other hemodynamic indices that have particular relevance for cardiac complications and that originate from pulsatile pressure should be taken into account, with important consequences in cardiovascular epidemiology and in the pathophysiology of hypertensive end-organ damage.

Excess mortality associated with increased pulse pressure among middle-aged men and women is explained by high systolic blood pressure

OBJECTIVE

To assess the risk of death from coronary heart disease, stroke, all cardiovascular diseases and all-cause mortality associated with pulse pressure among the middle-aged population.

METHODS AND DESIGN

A prospective 15-year follow-up cohort study was conducted of two independent cross-sectional random samples of the population who participated in baseline surveys in 1972 or 1977. Each survey included a self-administered questionnaire with questions on smoking and antihypertensive drug treatment, measurements of height, weight and blood pressure and the determination of the serum cholesterol concentration. Multivariate analyses were performed by using Cox proportional hazard models.

SETTING

The provinces of North Karelia and Kuopio in eastern Finland

PARTICIPANTS

Men and women aged 45-64 years with no history of myocardial infarction or stroke at the time of the baseline survey were selected. In total 4333 men and 5270 women took part in this follow-up study.

RESULTS

The relative risk of coronary heart disease, stroke, cardiovascular disease and all-cause mortality increased with the increasing pulse pressure in individuals aged 45-64 years independent of the diastolic blood pressure level. Only in women with diastolic blood pressure > or = 95 mmHg was the relative risk of fatal stroke not statistically significant. After adjustment for systolic blood pressure, the positive association between mortality and increasing pulse pressure disappeared.

CONCLUSION

Increasing pulse pressure is a predictor of death from coronary heart disease, stroke, cardiovascular disease and all causes in men and women aged 45-64 years, but the increase in risk is entirely associated with the increase in systolic blood pressure.

Prognostic value of ambulatory blood pressure : current evidence and clinical implications

This article is a critical review of the available evidence on the prognostic value of ambulatory blood pressure (ABP). Several event-based cohort studies have shown that ABP improves cardiovascular risk stratification over and beyond traditional risk factors, including office BP. Most of these studies have been conducted in subjects with essential hypertension who were untreated at the time of execution of ABP monitoring; other studies have been conducted in subjects who were poorly controlled with treatment or in the general population. In these studies, ABP was examined as a continuous variable or with operational risk categories. Cardiovascular risk showed a direct and independent association with the observed ABP (systolic, diastolic, and pulse) and an inverse association with the degree of BP reduction from day to night. Cardiovascular risk was also directly associated with the difference between the observed value of ABP and that predicted from the office BP. White-coat hypertension versus ambulatory hypertension and dippers versus nondippers are 2 classifications based on arbitrary operational risk categories. A blunted or absent BP reduction from day to night, defined with ABP as a continuous variable or with operational thresholds, was also associated with a worse outcome regardless of the average value of ABP during the 24 hours. Overall, these studies indicate that ABP monitoring is particularly valuable to refine cardiovascular risk stratification in untreated subjects with office hypertension and in those with resistant hypertension. Intervention studies targeted at ABP are now needed.

Elevated systolic blood pressure as a cardiovascular risk factor

This paper reviews the evolution of attitudes toward the treatment and diagnosis of hypertension. In particular, there is a growing realization that elevated systolic pressure may be a more valuable measurement in evaluating and controlling hypertension than is generally acknowledged. A large number of epidemiologic studies in a wide variety of populations have revealed that systolic blood pressure exerts a stronger influence than diastolic blood pressure. The largest of these, the Framingham Heart Study, showed that in subjects with systolic hypertension, diastolic blood pressure was only weakly related to the risk of cardiovascular events, but in those with diastolic hypertension, the risk of these events was strongly influenced by the level of systolic pressure. Furthermore, cardiovascular event rates were found to increase steeply with systolic pressure and were higher in cases of isolated systolic hypertension than diastolic hypertension. Clinical trials produced similar results, again suggesting that a greater reliance should be placed on systolic pressure in evaluating the risk of cardiovascular problems. This review concludes that the health community needs to be reeducated to consider the importance of systolic and diastolic blood pressure in assessing appropriate management strategies for hypertensive patients.

Ambulatory pulse pressure: a potent predictor of total cardiovascular risk in hypertension

A wide pulse pressure (PP) is a marker of increased artery stiffness and high cardiovascular (CV) risk. To investigate the prognostic value of ambulatory PP, which is currently unknown, we studied 2010 initially untreated subjects with uncomplicated essential hypertension (mean age, 51.7 years; 52% men). All subjects underwent baseline procedures including 24-hour noninvasive ambulatory blood pressure (BP) monitoring. The mean duration of follow-up was 3.8 years (range, 0 to 11 years), and CV morbidity and mortality were the outcome measures. There were 200 major CV events (2.61 per 100 person-years), 36 of which were fatal (0.47 per 100 person-years). In the 3 tertiles of the distribution of office PP, the rate of total CV events (per 100 persons per year) was 1.38, 2. 12, and 4.34, respectively, and that of fatal events was 0.12, 0.30, and 1.07 (log-rank test, both P<0.01). In the 3 tertiles of the distribution of average 24-hour PP, the rate of total CV events was 1.19, 1.81, and 4.92, and that of fatal events was 0.11, 0.17, and 1. 23 (log-rank test, both P<0.01). After controlling for several independent risk markers including white coat hypertension and nondipper status, we found that ambulatory PP was associated with the biggest reduction in the -2 log likelihood statistics for CV morbidity (P<0.05 versus office PP). In each of the 3 tertiles of office PP, CV morbidity and mortality increased from the first to the third tertile of average 24-hour ambulatory PP (log-rank test, all P<0.01). Age, left ventricular hypertrophy, and nondipper status were independent predictors of CV mortality, and the further predictive effect of ambulatory PP (P<0.001) was marginally but not significantly superior to that of office PP and average 24-hour systolic BP. We conclude that ambulatory PP is a potent risk marker in essential hypertension. CV morbidity is more closely predicted by ambulatory than by office PP even after control for multiple risk factors.

Arterial mechanics predict cardiovascular risk in hypertension

Systolic and diastolic blood pressures are the exclusive mechanical factors considered as predictors of cardiovascular risk for members of populations of normotensive and hypertensive subjects. However, if hypertension is considered as a mechanical factor acting on the arterial wall with deleterious consequences, the totality of the blood pressure curve should be considered in order to investigate the risk. The purpose of this review is to show that in addition to systolic and diastolic blood pressures, other hemodynamic indexes with particular relevance for cardiac complications and that originate from pulsatile pressure should be taken into account, namely brachial pulse pressure, pulse pressure amplification, early wave reflections, and pulse wave velocity.

Increased systolic pressure in chronic uremia. Role of arterial wave reflections

To assess the role of arterial wave reflections in the mechanism of systolic hypertension and altered pulsatile arterial dynamics in patients with end-stage renal disease (ESRD), 79 ESRD patients were compared with 73 age-matched control subjects with normal renal function and similar mean blood pressure. Wave reflections were investigated from the carotid pulse contour recorded by applanation tonometry using a Millar micromanometer-tipped probe. Wave reflections were quantified as the ratio (augmentation index, %) of the height of the late systolic peak to the total height of carotid pulse wave. Travel time of the reflected wave was timed from the foot of the pressure wave to the foot of the late systolic peak. Systolic and pulse pressure were increased in ESRD patients (p less than 0.001) and was not attributable to differences in left ventricular ejection pattern. The augmentation index was increased in ESRD patients (23.2 +/- 15.0 versus 9.8 +/- 15.6%; p less than 0.001) in association with a shorter travel time of reflected wave (109 +/- 24 versus 131 +/- 30 msec; p less than 0.001). Multiple regression analysis showed two principal factors associated (p less than 0.001) with the increase in augmentation index and shortened travel time of reflected wave: increased aortic pulse wave velocity and smaller stature with shorter body height in ESRD patients. The study points to the role of arterial wave reflections in the mechanisms producing alterations in pulsatile arterial dynamics in ESRD and is the first, through the mechanisms of early wave reflections, to show in humans that the increase in systolic and pulse pressures is associated with lesser body size.

Pulsatile versus steady component of blood pressure: a cross-sectional analysis and a prospective analysis on cardiovascular mortality

Studies on the prognostic significance of blood pressure on cardiovascular disease have essentially investigated the levels of diastolic or systolic blood pressure. However, blood pressure may also be divided into two other components: steady (mean arterial pressure) and pulsatile (pulse arterial pressure). The relations of these two components with cardiovascular risk factors and cardiovascular mortality were investigated in 18,336 men and 9,351 women aged 40-69 years, who were followed up for a mean period of 9.5 years. However, the interpretation of the relations is complicated by the strong correlation existing between these two components. A principal component analysis was performed to obtain two independent parameters: a steady and a pulsatile component index, strongly correlated with mean and pulse arterial pressure, respectively. In the cross-sectional analysis, relations were stronger with the steady component index than with the pulsatile component index; an association was found between left ventricular hypertrophy and the pulsatile component index in both sexes. The survival analysis was not performed in women under 55 as only 11 cardiovascular deaths occurred in this group. The steady component index was a strong prognostic factor of all types of cardiovascular death in both sexes. In women, the pulsatile component index was positively correlated to death from coronary artery disease and inversely correlated to stroke. In conclusion, the steady component of blood pressure is a strong risk factor for cardiovascular death in both sexes; the pulsatile component could be a risk factor independent of the steady component in women older than 55 years.

Mortality associated with diastolic hypertension and isolated systolic hypertension among men screened for the Multiple Risk Factor Intervention Trial

The large cohort of white men (317,871) 35 to 57 years old at initial screening for possible enrollment into the Multiple Risk Factor Intervention Trial (MRFIT) was examined with regard to initial blood pressure levels and subsequent coronary heart disease (CHD), stroke, and all-cause mortality. The overall prevalence of isolated systolic hypertension (ISH), defined as systolic blood pressure (SBP) greater than or equal to 160 mm Hg and diastolic blood pressure (DBP) less than 90 mm Hg, was 0.67% among white men screened for MRFIT and increased with age (0.31% among 35- to 39-year-olds to 1.7% among 55- to 57-year-olds). The 6 year CHD and all-cause mortality rates in men over 50 were highest in those with ISH compared with both subjects with diastolic hypertension and those with normal pressure. The relative risk of death from stroke in those with ISH, compared with that in those with SBP less than 160 mm Hg and those with DBP less than 90 mm Hg, was 3.0 (95% confidence interval 1.3 to 6.8). In addition, at any level of DBP, the level of SBP appeared to be the major determinant of all-cause and CHD mortality. The determinants of ISH in individuals under 60 years of age as well as the possible efficacy of its treatment should be evaluated further.