Arterial stiffness and orthostatic blood pressure changes in untreated and treated hypertensive subjects

Carotid-femoral pulse wave velocity (PWV), an integrated marker of segmental aortic stiffness, was recently proposed as one of the underlying mechanisms inducing orthostatic hypotension in the elderly with marked arterial rigidity. We examined the relationship between PWV (Complior; Colson, Paris, France) and orthostatic blood pressure (BP) changes, measured repeatedly, over a wide range of age and arterial stiffness. Sixty-nine hypertensive subjects (age, 37 to 76 years; 39 untreated and 30 treated) were studied. BP, in both sitting and erect position, was measured at two occasions a few weeks apart, and in between PWV was assessed by means of pulse wave analysis. In untreated hypertensive subjects, the orthostatic alterations in systolic, but not in diastolic blood pressure (DBP), were inversely related to PWV, independently from age, gender, mean BP, and diabetes mellitus. The greater the aortic stiffness the larger was the systolic blood pressure (SBP) decrease during upraises. On the contrary, no such association was found between PWV and orthostatic changes of BP in treated hypertensive subjects. These results suggest the presence of a pathophysiological association between arterial stiffening and BP postural changes. Antihypertensive drug treatment, as well as other factors that have not been evaluated in the present study, might have modulated this association. However, it might be argued that a causal association between arterial stiffness – disturbed baroreflex sensitivity – postural BP changes, even in subjects without pronounced vascular aging or orthostatic hypotension, is implied.     

Predictors of controlled ambulatory blood pressure in treated hypertensive patients with uncontrolled office blood pressure.

Although some treated hypertensive patients have controlled 24-h ambulatory blood pressure (ABP) despite their uncontrolled office blood pressure (BP), the factors relating to the control of 24-h ABP remain unknown. We conducted a study to assess 24-h ABP and its association with other cardiovascular risk factors, including echocardiographic left ventricular hypertrophy (LVH), in elderly hypertensive patients (n =41) with uncontrolled office BP (>140/90 mmHg) during long-term medication. Although a majority of the patients had isolated elevation of office systolic BP (SBP), there was no significant relationship between office SBP and 24-h SBP, and about half of the patients had controlled 24-h ABP (125+/-8/69+/-6 mmHg). Patients with controlled 24-h ABP (125+/-8/69+/-6 mmHg) had similar office BP (150+/-6/77+/-5 vs. 150+/-7/79+/-7 mmHg), but lower left ventricular mass index (LVMI) (123+/-34 vs. 156+/-34 g/m(2)) and body mass index (BMI) (24.4+/-2.1 vs. 26.4+/-3.6 kg/m(2)) compared with those with uncontrolled 24-h ABP (149+/-13/78+/-7 mmHg). Multivariate analysis showed that LVMI and BMI were independently associated with controlled 24-h ABP, and the control status of 24-h ABP was highly dependent on the presence of LVH and obesity. Therefore, absence of LVH and obesity may be useful for predicting the level of control of 24-h ABP in treated patients whose office BP is uncontrolled without ABP measurements.     

Ambulatory blood pressure and the metabolic syndrome in normotensive and untreated hypertensive men

Background: Components of the metabolic syndrome are typically intercorrelated in epidemiologic studies and, when combined, predict type 2 diabetes and cardiovascular diseases. However, it remains unclear whether a single construct underlies the various components and which of the components are most closely associated with the underlying syndrome. Here, we use our confirmatory factor analytic model of the metabolic syndrome to examine the extent to which measures of ambulatory blood pressure, reflecting blood pressure variability throughout the day and night, may strengthen the association between blood pressure and the other components of the syndrome. Methods: Participants were a community sample of 358 men (248 with hypertension), ages 40-70, not receiving antihypertensive medications. Confirmatory factor analysis was employed to examine model fit and the strength of association between clinic and ambulatory blood pressure and the metabolic syndrome. Results: The blood pressure factor loaded significantly on the underlying metabolic syndrome but the strength of association was not as great (loading = 0.34, p < 0.01) as those observed for the obesity, insulin resistance and lipid factors. The factor loadings for the ambulatory measures (awake loading = 0.19; sleep loading = 0.16, p values < 0.01) were significant but smaller in magnitude than the loadings for clinic blood pressure. Conclusions: Both clinic and ambulatory measures of blood pressure are significantly associated with the underlying metabolic syndrome using confirmatory factor analytic methods. However, the strength of association appears greater for the clinic measures relative to the ambulatory measures in this study.     

Ambulatory blood pressure variability and brachial-ankle pulse wave velocity in untreated hypertensive patients

Blood pressure (BP) variability is estimated as the standard deviation of 24-h ambulatory BP. The present study was performed to determine the effect of the mean 24-h ambulatory BP values and standard deviations on arterial wall stiffness assessed by brachial-ankle pulse wave velocity (baPWV). Brachial-ankle pulse wave velocity, carotid intima-media thickness (IMT), urinary albumin excretion (UAE) and 24-h ambulatory BP were measured before the start of antihypertensive therapy in 203 newly diagnosed hypertensive patients (53.3+/-0.7 years old; clinic systolic/diastolic BP: 154+/-1/98+/-1 mm Hg), and univariate and multivariate regression analyses of these clinical and biological parameters were performed. Univariate regression analyses revealed a significant association between mean baPWV values and the standard deviations of ambulatory systolic/diastolic BP. Mean ambulatory systolic/diastolic BP values were also associated with UAE, and the standard deviations of ambulatory systolic BP were associated with maximum carotid IMT. Quintile analyses showed that patients with a mean 24-h ambulatory mean BP value and standard deviation below 110 and 20 mm Hg, respectively, had the lowest baPWV. Moreover, the multivariate regression analyses confirmed a significant correlation between baPWV and the standard deviation of 24-h ambulatory systolic BP. In conclusion, untreated hypertensive patients with a higher 24-h ambulatory systolic BP variability had stiffer arterial walls. Ambulatory systolic BP variability may be involved in stiffening of the arteries of hypertensive patients.     

Ambulatory blood pressure characteristics in normotensive and treated hypertensive older people

The objective of this study was to determine the normal values and characteristics of 24-h ambulatory blood pressure (ABP) and to describe the ABP level of treated hypertensive subjects in an older Finnish population. ABP was measured in 502 randomly selected subjects aged 64 years or over living in a Finnish municipality (mean age 70 years, range 64-87 years). A total of 211 subjects did not have blood pressure (BP) affecting medication. ABP measurements were taken every 30 min for 24 h, and the day- and night-time periods were diary-based. The results were that in untreated subjects, the average office BP was 134/82 +/- 16/9 (s.d.) mm Hg for men and 140/81 +/- 18/8 mm Hg for women. The 24-h average BP was 120/75 +/- 14/8 mm Hg (95th percentile upper limit 145/93 mm Hg) for men and 125/75 +/- 15/7 (95th = 154/89 mm Hg) for women. The daytime averages were 127/78 +/- 12/7 mm Hg (95th = 154/99 mm Hg) and 131/78 +/- 15/7 mm Hg (95th = 158/91 mm Hg) for men and women, respectively. The ABP daytime value of 130/83 mm Hg corresponded best to the office BP value of 140/90 mm Hg. All BP values were significantly higher in the treated hypertensive group compared to the normotensive group. Night-time BP was markedly lower than daytime BP, and no difference in circadian variability was found between the normotensive and hypertensive subjects. Both office and ambulatory BPs were significantly higher in women than in men. This study provides sex-specific normal values for ABP in a 64 to 87-year-old age group. The normal values of ABP were markedly lower than the office BP values. Hypertensives, even when treated, tended to have elevated values.     

Ambulatory blood pressure variability is increased in diabetic hypertensives

The purpose of this study was to examine the possible difference in the 24-hr BP profile--including short-term BP variability, assessed as the standard deviation--between diabetic and non-diabetic hypertensives. We measured 24-hr ambulatory BP in 11 diabetic hypertensives (diabetic HT) and 10 non-diabetic hypertensives (non-diabetic HT) who were hospitalized for the educational program in our hospital and were under stable salt intake. Renal function and sleep apnea were also estimated. There were no significant differences in 24-hr systolic BP (141 mmHg vs. 135 mmHg, ns), daytime systolic BP (143 mmHg vs. 138 mmHg, ns), and nighttime systolic BP (135 mmHg vs. 130 mmHg, ns) between diabetic HT and non-diabetic HT. The values of 24-hr HR (69.7 beats/min vs. 65.2 beats/min, ns) and 24-hr HR variability (9.9 beats/min vs. 10.1 beats/min, ns) were also similar between the groups. Interestingly, diabetic HT had a significantly greater 24-hr systolic and diastolic BP variability than non-diabetic HT (18.2 mmHg vs. 14.5 mmHg, p < 0.05; 11.5 mmHg vs. 9.6 mmHg, p < 0.05, respectively). The values for creatinine clearance, urinary protein excretion, and apnea-hypopnea index were similar between the groups. Bivariate linear regression analysis demonstrated that fasting blood glucose was the primary determinant of 24-hr diastolic BP variability (r = 0.661, p < 0.01). Multiple stepwise regression analysis revealed that fasting blood glucose was a significant and independent contributor to 24-hr systolic BP variability (r = 0.501, p < 0.05). Taken together, these results demonstrate that BP variability is increased in diabetic hypertensives. Furthermore, it is possible that an elevation of fasting blood glucose may contribute to the enhanced BP variability in hypertensives.     

健康人和高血压、糖尿病患者动态心率血压双乘积和动态脉压分析

目的 探讨健康人和高血压、糖尿病患者的动态心率血压双乘积(ARPP)和动态脉压(APP)的昼夜变化.方法 正常组50例,年龄(60.0±10.3)岁;高血压组(轻、中度)58例,年龄(59.4±8.0)岁;糖尿病组(2型,未合并高血压及未接受胰岛素治疗)47例,年龄(61.0±8.5)岁.使用TM-2421动态血压仪监测记录24 h血压和心率.结果 余弦法分析证实,三组ARPP和APP均有明显的昼夜节律性变化(P＜0.05或0.01).高血压组和糖尿病组ARPP均值及节律调节中值明显高于正常组(P＜0.01),高血压组也明显高于糖尿病组(P＜0.01);高血压组APP均值及节律调节中值明显高于正常组和糖尿病组(仅调节中值)(P＜0.05或0.01).结论 ARPP和APP具有昼夜节律性变化,有临床诊断高血压的参考价值,糖尿病患者在临床确诊高血压前动态血压已发生明显改变.     

Endothelium-dependent vasodilatation in treated and untreated hypertensive subjects

It has repeatedly been shown that endothelium-dependent vasodilatation (EDV) is impaired in patients with untreated hypertension. The effect of antihypertensive treatment on EDV has, however, not been extensively investigated. In the present study, EDV and endothelium-independent vasodilatation (EIDV) were studied in 20 untreated and 41 treated hypertensive subjects and in 26 matched, normotensive controls by means of infusion of methacholine (MCh), 2 and 4 microg/min, evaluating EDV, and nitroprusside (SNP), 5 and 10 microg/min, evaluating EIDV, in the brachial artery. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. The vasodilatory action of MCh was impaired in untreated hypertensives compared with controls, with the response in the treated hypertensives in between the other two groups (p < 0.01 vs both of the other groups). EIDV, on the other hand, was enhanced in the treated hypertensives (p < 0.01), so that the MCh to SNP FBF ratio, an index of endothelial function, was attenuated in both treated and untreated hypertensives (0.97 +/- 0.24 and 0.96 +/- 0.15, respectively), compared with controls (1.27 +/- 0.29, p < 0.001). Both EDV and EIDV declined with increasing number of antihypertensive drugs used in the treated hypertensives (p < 0.05). In conclusion, the endothelial function index was found to be similarly depressed in both treated and untreated hypertensive subjects compared with normotensive controls. Antihypertensive therapy seems to improve the vasodilatory capacity in general rather than enhancing endothelial function.     

Risk of cardiovascular disease in relation to achieved office and ambulatory blood pressure control in treated hypertensive subjects

OBJECTIVE: We investigated the prognostic impact of 24-h blood pressure control in treated hypertensive subjects. BACKGROUND: There is growing evidence that ambulatory blood pressure improves risk stratification in untreated subjects with essential hypertension. Surprisingly, little is known on the prognostic value of this procedure in treated subjects. METHODS: Diagnostic procedures including 24-h noninvasive ambulatory blood pressure monitoring were undertaken in 790 subjects with essential hypertension (mean age 48 years) before therapy and after an average follow-up of 3.7 years (2,891 patient-years). RESULTS: At the follow-up visit, 26.6% of subjects achieved adequate office blood pressure control (<140/90 mm Hg), and 37.3% of subjects achieved adequate ambulatory blood pressure control (daytime blood pressure <135/85 mm Hg). Months or years after the follow-up visit, 58 patients suffered a first cardiovascular event. Event rate was lower (0.71 events/100 person-years) among the subjects with adequate ambulatory blood pressure control than among those with higher blood pressure levels (1.87 events/100 person-years) (p = 0.0026). Ambulatory blood pressure control predicted a lesser risk for subsequent cardiovascular disease independently of other individual risk factors (RR 0.36; 95% confidence intervals: 0.18 to 0.70; p = 0.003), including age, diabetes and left ventricular hypertrophy. Office blood pressure control was associated with a nonsignificant lesser risk of subsequent events (RR 0.63; 95% confidence intervals: 0.31 to 1.31; p = NS). In-treatment ambulatory blood pressure was more potent than pre-treatment blood pressure for prediction of subsequent cardiovascular disease. CONCLUSIONS: Ambulatory blood pressure control is superior to office blood pressure control for prediction of individual cardiovascular risk in treated hypertensive subjects.     

Study of untreated hypertensive subjects by means of continuous intra-arterial blood pressure recordings.

Continuous recording of intra-arterial blood pressure and electrocardiograms has been performed in 41 ambulant untreated essential hypertensive subjects for periods up to 48 hours. Statistical analysis of the results has revealed: (1) A group of patients who developed a persistent tachycardia during the day. This response was not observed in a control population free of overt cardiovascular disease. (2) Three different haemodynamic responses to day-time activities suggesting different mechanisms for the production of high blood pressures. No normal controls are available for these changes. (3) No differences in responses between patients defined as 'labile' and 'fixed' hypertensives.     

Ambulatory blood pressure monitoring in hypertensive adolescents

The purpose of this study was to determine the ability of ambulatory blood pressure monitoring to identify youths with chronic blood pressure elevation. Nineteen adolescent boys were studied, ten had 5-year average systolic or diastolic pressures above the 95th percentile, nine had normal pressure. A Del Mar Avionics Pressurometer III system recorded an average of 121 readings on each subject. The coefficients of variation for pressure were similar for hypertensive and normotensive individuals. During classes, eight of the ten hypertensive youths had elevated pressures in over half of the measurements. Also during these classes eight of ten hypertensive boys had average systolic or diastolic pressure above the 95th percentile, whereas only one of nine normotensive boys had average pressures above this level. We suggest that schooltime ambulatory pressures may be most useful in classifying the blood pressure trend in a youth.     

Ambulatory blood pressure and metabolic abnormalities in hypertensive subjects with inappropriately high left ventricular mass

Appropriateness of left ventricular (LV) mass to cardiac workload can be evaluated by the ratio of observed LV mass to the value predicted for an individual's gender, height(2.7), and stroke work at rest (%PLVM). It is unclear which pathophysiological factors are associated with inappropriately high LV mass in hypertensive subjects. Adequate LV mass was defined by the 90% confidence interval (73% to 128%) of the distribution of %PLVM in 393 normal-weight normotensive subjects. In 185 hypertensive subjects (aged 56+/-11 years; 60% male, 29% black), according to %PLVM, 164 (88%) had adequate LV mass, 16 (9%) had inappropriately high LV mass (%PLVM >128%), and 5 (3%) had %PLVM <73% (low LV mass). Age, gender, smoking habit, proportion of never-treated subjects, total cholesterol, triglycerides, and creatinine levels did not differ significantly between subjects with adequate and inappropriately high LV mass. Body mass index, fasting glucose, and proportion of black subjects were higher (all P<0.05), while HDL cholesterol was lower (P<0.05) in subjects with inappropriately high LV mass. Blood pressure at the echocardiogram was comparable between subjects with adequate and inappropriately high LV mass, but the latter group had higher ambulatory blood pressure (P<0.01). Subjects with inappropriately high LV mass also had higher aortic root dimension and LV relative wall thickness and relatively lower LV systolic performance than those with adequate LV mass (all P<0.001). Larger aortic root diameter and lower systolic function were also found in hypertensive subjects with inappropriate LV hypertrophy compared with those with adequate LV hypertrophy. In an exploratory case-control study that compared subjects with low %PLVM with age-matched counterparts with adequate LV mass, low %PLVM was associated with lower body mass index, more favorable metabolic profile, and higher LV myocardial contractility. Higher body mass index, larger aortic root, and black race were independent correlates of increased %PLVM. Thus, in arterial hypertension, levels of LV mass inappropriately high for gender, cardiac workload, and height(2.7) are associated with higher body mass index, higher ambulatory blood pressure, larger aortic root diameters, and relatively low myocardial contractility.     

Ambulatory intra-arterial blood pressure in normal subjects

It has been suggested that ambulatory blood pressure monitoring is superior to casual cuff methods in predicting cardiovascular events, but lack of reference data from a normal population seriously limits this method's clinical applicability. We therefore performed 24-hour intra-arterial ambulatory blood pressure (BP) monitoring in 50 normal volunteers (cuff BP less than 140/90 mm Hg) whose ages ranged from 18 to 74 years. There were 30 men and 20 women in the study, but there was no significant difference between the sexes with respect to age, cuff BP, or body mass index. A diurnal variation in BP was observed, qualitatively similar to that seen in hypertensive individuals, including a prewaking BP rise. Mean daytime intra-arterial pressures differed little between the sexes (124/74 mm Hg for women and 127/76 mm Hg for men, p = NS), but was lower at night in women than in men (96/52 versus 102/59 mm Hg, respectively; p less than 0.02 for diastolic pressure). Based on this group of subjects, we defined the upper limit of normal daytime BP in both men and women as 150/90 mm Hg and the upper limit of mean nighttime BP as 130/80 mm Hg for men and 115/65 mm Hg for women. The lower nighttime pressures in women compared with their male counterparts with similar daytime pressures may explain why women appear to tolerate similar levels of BP better than men.     

接受降压治疗患者的压力波反射及中心动脉收缩压

目的 探讨接受降压治疗患者不同血压分级间压力波反射和中心动脉收缩压变化及不同种类降压药物与它们之间的关系。方法 从北京地区5100名自然人群中筛选出1371例接受降压治疗的高血压患者（其中男性679例,女性692例）,年龄33 ～ 87(47.2±11.5)岁。采用科林HEM-9000动脉反射波增强指数(AI)检测仪,用桡动脉张力测量法测量桡动脉AI及中心动脉收缩压。结果 桡动脉AI随血压水平的升高而逐渐增高(P＜0.01)。中心动脉收缩压低于相对应的肱动脉血压(P＜0.01)。多元线性回归分析显示,影响桡动脉AI的因素为：血管紧张素转换酶抑制剂（标准化β=-0.09,P＜0.05）、血管紧张素Ⅱ受体拮抗剂（标准化β=-0.07,P=0.01）、钙离子拮抗剂（标准化β=-0.12,P＜0.01）及利尿剂（标准化β=0.14,P=0.04）;而中心动脉收缩压受血管紧张素转换酶抑制剂（标准化β=-0.07,P=0.02）、血管紧张素Ⅱ受体拮抗剂(标准化β=-0.08,P=0.01)及钙离子拮抗剂（标准化β=-0.15,P＜0.05）的降压影响。结论 在接受降压治疗的患者中,积极有效降压可以减少波反射对心血管系统的不良作用,降压药物的选择应更加注重对动脉血管功能的改善。     

Home blood pressure is a better predictor of carotid atherosclerosis than office blood pressure in community-dwelling subjects.

An increase in the thickness of the intima-media (IMT) of the carotid artery is associated with an increased risk of cardiovascular morbidity and mortality. Hypertension is one of the underlying mechanisms for the progression of carotid atherosclerosis. However, office blood pressure (BP) has been shown to have only a weak association with carotid IMT. Since self-measured home BP has less variation than office BP, home BP could be a better predictor of carotid atherosclerosis. To explore this hypothesis, we compared the relationships between carotid IMT and office BP or home BP in a community-dwelling population. One-hundred and one community residents, aged 50 years or older and not taking any medication, were enrolled in this study. Morning home BP was measured according to the guidelines of the Japanese Society of Hypertension. The results were recorded for 2 weeks and averaged. Carotid atherosclerosis was defined as IMT > or =0.80 mm, which corresponds to the first quartile. Home systolic BP showed a more significant association with carotid IMT (r=0.422, p <0.0001) than with office systolic BP (r=0.021, p=0.027). Logistic regression analysis for the presence of carotid atherosclerosis further showed that the relative risk of hypertension defined using home BP (> or =135/85 mmHg) was 6.3 (95% confidence interval [CI]: 2.0 to 19.6), while that using office BP was 1.5 (95% CI: 0.5 to 4.2). These results suggest that home BP is a better predictor of the development of carotid atherosclerosis than office BP.     

Ambulatory blood pressure monitoring: dippers compared with non-dippers

Epidemiologic studies have demonstrated that the peak incidence of most types of cardiovascular disease follows a circadian (24 h) pattern. Ambulatory monitoring studies have documented a reproducible 24 h rhythm for blood pressure, characterized by a period of low values during sleep, an early-morning increase in pressures, and a plateau period while the individual is awake and active. Hypertensive patients who display the typical nocturnal decrease in blood pressure are termed 'dippers', whereas patients in whom the nocturnal decrease in blood pressure is absent or blunted are termed 'non-dippers'. The circadian rhythm may be influenced by demographic, neurohormonal, and pathophysiologic factors. The non-dipper profile appears to be of prognostic significance because it is associated with increased target-organ damage and a worsened cardiovascular outcome. Chronotherapy is a new pharmacologic concept whereby medication is delivered at a time and in a concentration that varies according to physiologic need during the dosing period. Of greatest interest is the reduction in blood pressure during the early-morning blood pressure surge, as that time is associated with an increased risk for myocardial infarction and stroke. Factors that may increase the early-morning blood pressure include activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system. In the near future, the benefits of a chronotherapeutic approach to the management of hypertension should be elucidated by large-scale outcome studies.     

原发性高血压合并脑微出血患者动态血压特征

目的 对原发性高血压（高血压）患者合并脑微出血的动态血压特征进行探讨.方法 选取80例高血压患者作为研究对象,并将其中有脑微出血的42例患者列为观察组,未合并有脑微出血的38例患者列为对照组.对两组患者的动态血压值进行观察和比较.结果 两组收缩压、舒张压比较,差异无统计学意义（P＞0.05）.两组的随测血压值均比24动态血压监测（ABMP）值高,差异有统计学意义（P＜0.05）.观察组的收缩压夜间下降率、舒张压夜间下降率均低于对照组,差异有统计学意义（P＜0.05）.结论 高血压患者的血压在夜间降低是引发脑微出血相关因素,因此在临床治疗期间,需对血压的动态节律变化加以注意.