Ambulatory blood pressure monitoring in obese children: role of insulin resistance

OBJECTIVES: To investigate the relationship between ambulatory blood pressure (ABPM) parameters and insulin resistance in obese children. METHODS: A population of 56 obese prepubertal children was recruited for the study. They underwent ABPM, an oral glucose tolerance test and complete physical examination, including adiposity indexes such as body mass index (BMI), skinfolds, waist-to-hip ratio (WHR) and fat mass. RESULTS: The standard deviation score for BMI was significantly correlated with 24-h systolic blood pressure (SBP) (r = 0.30; P = 0.02) and diastolic blood pressure (DBP) (r = 0.29; P = 0.03), daytime SBP and DBP (r = 0.28; P = 0.04 and r = 0.32; P = 0.02), night-time SBP and DBP (r = 0.32; P = 0.01 and r = 0.27; P = 0.04). Fat mass was correlated with 24-h SBP (r = 0.46; P = 0.005), daytime SBP (r = 0.40; P = 0.01) and night-time SBP (r = 0.49; P = 0.03). No correlations were found between ABPM parameters and WHR. Furthermore, significant correlations were found between insulin resistance indexes, such as the homeostasis model assessment of insulin resistance and quantitative insulin-sensitivity check index, and 24-h DBP (r = 0.34; P = 0.01 and r = -0.29; P = 0.03), daytime DBP (r = 0.35; P = 0.009 and r = -0.34; P = 0.01) and daytime SBP (r = 0.32; P = 0.02 and r = -0.27; P = 0.04). Only 24-h and daytime DBP remained correlated with insulin resistance after adjustment for obesity. The analysis of the circadian rhythm of blood pressure revealed that 24 out the 56 children were non-dippers. CONCLUSIONS: The results of the present study indicate that adiposity and insulin resistance have an important role in influencing blood pressure in obese children, and also show a high prevalence of non-dipping phenomenon. This is of particular relevance because blood pressure tracks from childhood into adulthood and an already early-life high blood pressure is associated with an increased cardiovascular risk.     

Factors influencing white-coat effect

BACKGROUND: The transient blood pressure (BP) rise during clinical visits is usually referred to as white-coat effect (WCE). The aim of the present study was to investigate factors that may influence the WCE. METHODS: A total of 2004 subjects underwent office BP measurements and 24-h ambulatory BP monitoring (ABPM) on the same day. The WCE was estimated as the difference between office and average daytime ambulatory BP (ABP). According to the office and daytime BP values, the study population was divided into normotensives (NTs), white-coat hypertensives (WCHs), masked hypertensives (MHTs), and sustained hypertensives (SHTs). Statistical analyses were performed using one-way analysis of variance and multiple linear regression models. RESULTS: The mean systolic and diastolic WCE was 9 +/- 16 and 7 +/- 12 mm Hg, respectively. In the entire group of patients, multiple linear regression models revealed independent determinants of systolic WCE in the following rank order: office systolic BP (SBP) (beta = 0.727; P < 0.001), female gender (beta = 0.166; P < 0.001), daytime SBP variability (beta = 0.128; P < 0.001), age (beta = 0.039, P = 0.020), and smoking (beta = 0.031, P = 0.048). A 1.0 mm Hg increase in daytime SBP variability correlated with an increment of 0.589 mm Hg (95% confidence intervals, 0.437-0.741) in the systolic WCE. The regression analyses for diastolic WCE revealed the same factors as independent determinants. A 1.0 mm Hg increase in daytime diastolic BP (DBP) variability was independently associated with an increment of 0.418 mm Hg (95% confidence intervals, 0.121-0.715) in the diastolic WCE. CONCLUSIONS: Factors such as gender, age, smoking, office BPV and daytime BPV may exert an important influence on the magnitude of the WCE.     

Low nocturnal blood pressure is associated with reduced cerebral blood flow in the cohort "Men born in 1914"

BACKGROUND:

“Men born in 1914” is a population-based cohort study of the epidemiology of cardiovascular and cerebral disease. Little is known about how diurnal variation in blood pressure (BP) levels influence cerebral perfusion in very elderly populations.

OBJECTIVES:

To study the association between systolic (SBP) and diastolic BP (DBP) levels, during the day and at night, expressed through 24 h ambulatory BP monitoring (ABPM) and regional cerebral blood flow (rCBF) disturbances.

METHODS:

A cross-sectional study from a population-based cohort of 108 men 81 years of age (born in 1914) was performed in an out-patient university clinic. Cerebral blood flow measurements using ^99mTc-hexamethylpropyleneamine oxime single photon emission computed tomography and 24 h ABPM were performed. Eleven men were excluded due to incomplete ABPM data.

RESULTS:

Mean DBP at night for each tertile was correlated to rCBF for the medial temporal right (P=0.012) and left (P=0.039) regions. Also, DBP during the day was correlated to the medial temporal right region (P=0.025). When analyses were stratified for DBP during the day, subjects with high DBP during the day (greater than 70 mmHg) showed a stronger association between low medial temporal right rCBF and low mean DBP at night (r=0.32, P=0.009) compared with subjects who had a lower daytime DBP. A corresponding positive correlation was noted for the medial temporal left region and daytime SBP, whereas a negative correlation was noted for frontal left region blood flow and SBP at night.

CONCLUSIONS:

A significant association was seen between low BP levels, especially at night, and rCBF in subjects with otherwise normal daytime DBP that may indicate a risk for nocturnal cerebral ischemia.     

老老年人群动态血压参数与动脉僵硬度的相关性

目的探讨老老年人群动态血压参数与动脉僵硬度的相关性。方法筛选年龄≥80岁的老老年人238例,以血压≥160/95 mm Hg(1 mm Hg=0.133 kPa)为标准,分为高血压组(134例)和对照组(104例),并进行臂-踝脉搏传导速度(baPWV)和24 h动态血压监测。用Pearson分析动态血压各参数与动脉僵硬度的相关性。结果高血压组baPWV高于对照组(P<0.05)。高血压组偶测收缩压,24 h、昼间和夜间收缩压、舒张压、脉压,收缩压负荷及舒张压负荷均高于对照组.夜间收缩压下降率、舒张压下降率低于对照组,差异有统计学意义(P<0.05,P<0.01)。baPWV与偶测血压;24 h收缩压、舒张压、脉压;昼间收缩压、舒张压、脉压、心率;夜间收缩压、舒张压、脉压;收缩压负荷、舒张压负荷呈正相关(P<0.05,P<0.01),而与夜间收缩压下降率呈负相关(P<0.01)。结论高血压是老老年人群动脉僵硬度增加的一个重要因素,动脉僵硬度与动态血压、脉压、心率及血压负荷相关。     

原发性高血压患者血压变异性及昼夜节律与左室肥厚的关系

目的 探讨原发性高血压患者血压变异性及血压昼夜节律与心室肥厚的关系.方法 连续入选2010 年8 月至2012 年1 月,于中国医科大学附属第一医院心血管内科住院的原发性高血压患者共93例,根据超声心动图测量指标计算所得的左心室重量指数(LVMI)分为左心室肥厚(LVH)组与无LVH 组;再根据24 h 动态血压监测获得的结果分为血压晨峰组与无血压晨峰组,杓型血压组与非杓型血压组.分析比较24 h 血压、白昼和夜间血压均值、血压变异性、血压昼夜节律及晨峰与心室肥厚的相关性.结果 ①与无LVH 组相比,LVH 组24 小时收缩压(24 h SBP)、24 小时舒张压(24 h DBP)、白昼收缩压(dSBP)、白昼舒张压(dDBP)、夜间收缩压(nSBP)和夜间舒张压(nDBP)均升高,P<0.01;LVH 组24 小时平均收缩压标准差(24 hSSD)高于无LVH 组,P<0.05,但两组24 小时平均舒张压标准差(24 h DSD)无差别;与无LVH 组相比,LVH组夜间收缩压标准差(nSSD)和夜间舒张压标准差(dDSD)升高,P<0.01;但白昼收缩压标准差(dSSD)和白昼舒张压标准差(dDSD)无差别.②血压晨峰组LVMI 高于无血压晨峰组,P<0.05;血压晨峰组LVH 比率也高于无血压晨峰组,P<0.01;与无血压晨峰组相比,血压晨峰组24 h SBP、dSBP 和nSBP 均增高,P<0.05,但两组24 h DBP、dDBP 和nDBP 无差别.③杓型血压组LVMI 低于非杓形血压组,P<0.05;杓型血压组LVH 比率低于非杓形血压组,P<0.01;与非杓形血压组相比,杓型血压组nSBP、nDBP 均降低,P<0.01;而两组24 hSBP、24 h DBP、dSBP、dDBP 差异无统计学意义.结论 原发性高血压患者LVH 的发生与血压变异性和血压晨峰密切相关.具有血压晨峰的患者和血压昼夜节律消失的非杓型高血压患者更易出现LVH.     

高血压患者24h动态血压的昼夜规律及变异性研究

目的 探讨原发性高血压（EH）患者血压昼夜规律及血压波动程度即变异性的临床意义.方法 回顾分析65例EH患者24 h动态血压（24 h ABPM）监测报告.将65例EH患者分为两组：一组为高血压伴左心室肥大（LVH）30例,另一组为高血压不伴左心室肥大35例.选择同期健康体检者30名为正常血压对照组.对下列参数进行分析：①24 h平均收缩压（24 h SBP）与舒张压（24 h DBP）;②白昼平均收缩压（dSBP）与舒张压（dDBP）;③夜间平均收缩压（nSBP）与舒张压（nDBP）;④24 h收缩压标准差（24 h SSD）与舒张压标准差（24 h DSD）;⑤白昼收缩压标准差（dSSD）与舒张压标准差（dDSD）;⑥夜间收缩压标准差（nSSD）和舒张压标准差（nDSD）;⑦夜间/白昼平均收缩压比值（nSBP/dSBP）与舒张压比值（nDBP/dDBP）.结果 高血压伴LVH组与正常对照组或高血压无LVH组比较,24 h各时间段的血压均值及血压变异性差异有统计学意义（P＜0.01）,血压昼夜（清醒/睡眠）规律性不明显,nSBP/dSBP比值显著高于对照组（P＜0.01）.高血压无LVH组与正常对照组比较,血压均值差异有统计学意义（P＜0.01）,血压大多有较明显昼夜（清醒/睡眠）变化规律,血压变异性比较除白昼收缩压变异性有明显差异外,其余差异无统计学意义.结论 高血压不合并靶器官损害时,血压的变异性不显著,有明显昼夜规律性;高血压合并靶器官损害时,血压的变异性增大,无明显昼夜规律性,nSBP/dSBP比值明显增高.利用这些指标可评估高血压患者是否有靶器官损害,以便更有效地控制血压,减少并发症.     

Differences in exercise blood pressure response between dipper and non-dipper elderly patients with essential hypertension

We evaluated the circadian variation and exercise stress response patterns of blood pressure (BP) in elderly patients with essential hypertension. Ambulatory BP monitoring for 48 hours every 30 minutes, and treadmill exercise test using a Bruce protocol at PM 3 to 5 were performed in 49 untreated patients with hypertension. Mean daytime (awake), and night-time (sleeping) systolic BP (SBP) and diastolic BP (DBP) values were analyzed by reviewing the patients' diaries, and the nocturnal reduction rate (NRR) of SBP and DBP were calculated according to the following formula. NRR (%) = [(daytime mean-nighttime mean)/daytime mean] x 100. The patients were divided into two groups according to the presence (dipper, n = 25) or absence (non-dipper, n = 24) of a reduction in both SBP and DBP during the night by an average of more than 10% of the daytime BP. Mean values of SBP and DBP measured over 48 hours in the dipper and non-dipper groups were similar. Responses of SBP to dynamic exercise at 2 to 5 minutes in the non-dipper group were significantly smaller than those in the dipper group (p < 0.05). Non-dipper patients with hypertension responded to dynamic exercise stress with smaller increases in SBP than did those in the dipper group. The differences in BP responses to exercise may affect the circadian blood pressure profile in dipper and non-dipper elderly patients with essential hypertension.     

老年高血压病患者血压昼夜节律与动态的动脉硬化指数的关系

目的 探讨老年高血压病患者血压昼夜节律与动态动脉硬化指数的关系。方法 根据动态血压检测结果将112例老年高血压病患者分为杓形组(n=37)、非杓形组（n=45）和反杓形组（n=30）,并测定及计算动态动脉硬化指数（AASI）。结果 3组年龄,体质量指数,总胆固醇、三酰甘油、低密度脂蛋白胆固醇、高密度脂蛋白胆固醇、空腹血糖、病程和全天及白天平均收缩压、舒张压和脉压比较均无显著性差异。3组夜间平均收缩压、夜间平均舒张压、AASI比较有显著性差异（P<0.01）。结论 动态血压昼夜节律的改变与动态动脉硬化指数相关。     

Impact of blood pressure variability on cardiac and cerebrovascular complications in hypertension

BACKGROUND: The independent prognostic value of daytime and night-time blood pressure (BP) variability estimated by noninvasive 24-h BP monitoring is unclear. METHODS: We followed 2649 initially untreated subjects with essential hypertension for up to 16 years (mean, 6). Variability of BP was estimated by the standard deviation of daytime or night-time systolic BP (SBP) and diastolic BP (DBP). A BP variability either less than or equal to the group median or greater than the group median (12.7/10.4 mm Hg for daytime SBP/DBP and 10.8 and 8.9 mm Hg for night-time SBP/DBP) identified subjects at low or high BP variability. RESULTS: During follow-up there were 167 new cardiac and 122 new cerebrovascular events. The rate of cardiac events (x100 person-years) was higher (all P < .05) in the subjects with high than in those with low BP variability (daytime SBP: 1.45 v 0.72, daytime DBP: 1.29 v 0.91; night-time SBP: 1.58 v 0.62; night-time DBP: 1.32 v 0.85). The rate of cerebrovascular events was also higher (all P < .05) in the subjects with high than in those with low BP variability. In a multivariate analysis, after adjustment for several confounders, a high night-time SBP variability was associated with a 51% (P = .024) excess risk of cardiac events. The relation of daytime BP variability to cardiac events and that of daytime and night-time BP variability to cerebrovascular events lost significance in the multivariate analysis. CONCLUSIONS: An enhanced variability in SBP during the night-time is an independent predictor of cardiac events in initially untreated hypertensive subjects.     

The effect of 24 h blood pressure levels on early neurological recovery after stroke

OBJECTIVES: To assess the influence of 24 h blood pressure (BP) levels on functional recovery 1 week after stroke and the effect of antihypertensive therapy on 24 h BP levels. DESIGN: Prospective study of patients admitted to hospital over 1 year with first in a lifetime stroke who underwent 24 h BP and casual measurements. Setting. Medical wards in a teaching hospital. Subjects. Of 160 patients, 72 patients admitted to hospital within 24 h of stroke onset were investigated. Patients with conditions and therapy that interfered with autonomic and sympathetic function were excluded. Interventions. All subjects underwent 24 h BP and casual recordings on admission to hospital and at day seven after stroke. The mean 24 h, day and night systolic BP (SBP) and diastolic BP (DBP) and their differences (nocturnal BP dip) were recorded. Patients were divided into three groups according to whether they were taking antihypertensive therapy during the first week: (i) no therapy, (ii) therapy continued after stroke, and (iii) new therapy introduced. Main outcome measures. Functional recovery (Rankin Scale 0-1) and neurological improvement [Scandinavian Stroke Scale (SSS) >/=3 points] by 1 week of stroke. Change in circadian 24 h BP over 1 week. RESULTS: For each 10 mmHg difference between day and night time DBP, the odds for making a complete recovery were 4.63 (95% CI: 1.57-13.7, P=0.01). For each 10 mmHg difference between day and night SBP, the odds for making an improvement in neurological status was 2.24 (95% CI: 1.16-4.32; P=0.016). Significant falls in 24 h DBP (P=0.01), daytime SBP (P=0.005) and mean arterial BP (MABP) (P=0.04) over 1 week were demonstrated in patients who had just commenced antihypertensive therapy (P=0.001). CONCLUSION: An increase in day to night time BP change is favourable in short-term outcome after acute stroke. Significant falls in BP are more likely in patients started on antihypertensive therapy for the first time. Further research is required to understand the effects of circadian BP rhythm on stroke outcome.     

Dipping and variability of blood pressure and heart rate at night are heritable traits

BACKGROUND: Blunted nocturnal blood pressure dipping (NBPD) as well as high variability in blood pressure (BPV) and low variability in heart rate (HRV), are associated with increased cardiovascular morbidity and mortality. The aim of this study was to determine whether these traits are heritable. METHODS: We studied 260 healthy siblings without antihypertensive drugs from 118 Swedish families. The BPV and HRV were defined as the standard deviation of BP and heart rate values recorded during 24 h, daytime (6 am to 10 pm), and night-time (10 pm to 6 am). The NBPD was defined as the ratio between night-time and daytime BP. Heritability was estimated with a maximal likelihood method implemented in the Solar software package with and without adjustment for significant covariates. RESULTS: At night, significant heritability was found for systolic (33%, P < .05), diastolic (36%, P < .05), and mean (42%, P < .01) BPV. After covariate adjustment the corresponding heritability values were 23% (P = .08), 29% (P < .05), and 37% (P < .05). Daytime BPV was not heritable. The heritability of NBPD was 38% (P < .05) for systolic, 9% (P = .29) for diastolic, and 36% (P < .05) for mean BP, but after adjustment only systolic NBPD was significant (29%, P < .05). Heart rate was highly heritable both during daytime (57%, P < .001) and night-time (58%, P < .001), but the variability of heart rate, after adjustment, was only significant at night (37%, P < .05). CONCLUSIONS: Our data suggest that BPV and HRV are partially under genetic control and that genetic loci of importance for these traits could be mapped by linkage analysis.     

Temporal stability of twenty-four-hour ambulatory hemodynamic bioimpedance measures in African American adolescents

BACKGROUND: The reliability of ambulatory impedance cardiography has not been evaluated. OBJECTIVE: The purpose of this study was to determine the reproducibility of daytime and night-time ambulatory bioimpedance-derived measures of hemodynamic function in youth. METHODS: Thirty-five African American adolescents (ages 16.2+/-1.4 years, 14 girls, 21 boys) with high normal systolic resting blood pressure (BP) were evaluated twice, separated by a 2-month interval. Measures were collected using the AIM-8-V3 Wearable Cardiac Performance Monitor (Bio-impedance Technology, Inc., Chapel Hill, North Carolina, USA) and the Spacelabs ambulatory BP monitor 90207 (Spacelabs Inc., Redmond, Washington, USA) from 0600 h to midnight every 20 min and from midnight to 0600 h every 30 min in the natural environment. RESULTS: There were no significantly different means (P>0.15) between the two visits for daytime ambulatory heart rate (HR, r = 0.81), stroke volume (SV, r = 0.54), cardiac output (CO, r = 0.56), pre-ejection period (PEP, r = 0.59), left ventricular ejection time (LVET, r = 0.74), Heather Index (HI, r = 0.79), systolic BP (SBP, r = 0.79), diastolic BP (DBP, r = 0.66), mean arterial pressure (MAP, r = 0.65) and total peripheral resistance (TPR, r = 0.47). Overall means for night-time ambulatory HR (r = 0.76), SV (r = 0.49), CO (r = 0.45), LVET (r = 0.43), HI (r = 0.82), SBP (r = 0.65), DBP (r = 0.62), MAP (r = 0.63) and TPR (r = 0.20) were not significantly different between visits (P > 0.06). Mean differences (P < 0.01) were observed for PEP (r = 0.57). CONCLUSIONS: The findings demonstrate that across 2 months in youth daytime and night-time ambulatory bioimpedance-derived measures of HR, HI, SBP, DBP and MAP are highly repeatable and SV, CO, PEP and LVET are moderately repeatable. This methodology should prove useful in cardiovascular research and clinical care.     

Study of representative periods of day-time and night-time levels of blood pressure

The aim of this study is to assess whether it is possible to shorten ambulatory blood pressure (ABP) monitoring while getting measurements that precisely reflect 24 hours and daytime blood pressure (BP). METHODS: three hundred and thirty six young male subjects aged: 21 +/- 2 y, height: 178 +/- 7 cm, weight, 75 +/- 12 kg, with normal or "borderline" BP (casual BP: 138 +/- 13/79 +/- 8 mmHg) participated in the study. BP was recorded in each, every 15 minutes on 24 hours with a Spacelabs 5200 device. Systolic and diastolic BP on 24-h, during the 9 a.m. - 8 p.m. period (daytime) and BP related to the different subperiods included between 15 minutes and 6 hours were calculated. BP values obtained from the 196 subperiods were correlated with 24-h, daytime ABP and causal BP. Results were classified according to the value of correlation coefficient, slope and intercept of regressions. RESULTS: no subperiod accurately predict 24-h systolic BP (SBP) or diastolic BP (DBP) (the best correlation are established with the subperiods: 7 p.m.-01 a.m. for SBP; r = 0.916, p less than 10(-9), y = 0.76 x + 30; and 06 a.m.-12 a.m. for DBP; r = 0.914, p less than 10(-9), y = 0.87 x + 9). Four 6 hours subperiods sampled between 09 a.m.-3 p.m. and 12 a.m.-6 p.m. predict alike and in a reasonable way the daytime BP (SBP: r = 0.971, p less than 10(-9), y = 0.94 x + 8; r = 0.973, p less than 10(-9), y = 0.91 x + 7. Best correlations with casual BP are moderate (SBP: r = 0.674, DBP: r = 0.588). COMMENTS: BP measurements of subperiods smaller or equal to 6 hours cannot accurately predict the average 24-h BP. This is related mainly to the night-time/daytime BP fluctuations. Daytime BP can be estimated with short-term monitoring but the duration must not be smaller than 6 hours.     

Rosiglitazone reduces office and diastolic ambulatory blood pressure following 1-year treatment in non-diabetic subjects with insulin resistance

OBJECTIVE: Rosiglitazone (RSG) has been reported to reduce blood pressure (BP) in patients with type-2 diabetes, but similar effects in non-diabetic people with insulin resistance is less clear. Our aim was to test the long-term BP-lowering effects of RSG compared with placebo. METHODS: We recruited participants for BP evaluation of RSG treatment from a larger intervention trial. Office BP was recorded in 355 non-diabetic subjects with insulin resistance randomized to receive either RSG or placebo for 52 weeks. Ambulatory BP monitoring (ABPM; Spacelab 90207) was performed in a subgroup of 24 subjects (RSG: n = 11; placebo n = 13). RESULTS: After 1 year, the office BP decreased by -3.1 mmHg systolic (p<0.05) and -3.8 mmHg diastolic (p<0.001) in the RSG group versus placebo. In patients treated with RSG, at 1 year there was a trend for a reduction from baseline for mean 24-h diastolic BP (DBP), daytime DBP and night-time DBP (-4.39, -5.26 and -2.93 mmHg, respectively). However, only daytime DBP was significantly lower in the RSG group compared with control (adjusted mean difference: -4.41 mmHg, p = 0.007). There was also a non-significant trend for a reduction in mean 24-h systolic BP (SBP), daytime SBP and night-time SBP (-2.70, -2.51 and -3.35 mmHg, respectively). CONCLUSIONS: RSG treatment for 1 year was associated with a small but significant decrease in diastolic 24-h ambulatory diastolic BP, and both systolic and diastolic office BPs in non-diabetic people with insulin resistance.     

Relationship between base blood pressure during sleep and health-related quality of life in healthy adults

There are many reports indicating that night time blood pressure (BP) is closely associated with target organ damage. However, BP in the waking period is influenced by physical activity and also by the psychological status. Recently, base BP (BP0: minimum and stable BP during sleep) has been reported to correlate with organ damage in hypertensives. However, little is known about the implications of BP0. We examined how BP0 is associated with BP, heart rate variability and health-related quality of life (HRQOL) in healthy subjects. One hundred and thirty-five participants, composed of 88 male and 47 female (age: 21-33 years) underwent a 24-h ambulatory BP monitoring (ABPM). Sympathetic nervous activity (ratio of low-frequency to high-frequency component: LF/HF) and parasympathetic nervous activity (high-frequency component: HF) were calculated by electrocardiogram monitoring. BP0 was calculated as previously reported. HRQOL was assessed by Medical Outcome Study Short-Forum 36-Item Health Survey. Base systolic BP (SBP0) positively correlated with 24-h systolic BP (SBP) (r=0.662, P<0.0001) and night time SBP (r=0.810, P<0.0001). SBP0 positively correlated with 24-h LF/HF (r=0.214, P<0.02) and night time LF/HF (r=0.326, P<0.001). Moreover, SBP0 negatively correlated with the scores of body pain (r=-0.223, P<0.02). Multiple linear regression analysis showed that SBP0 correlated with gender (P<0.01), night time LF/HF (P<0.04) and the scores of body pain (P<0.04). In conclusion, SBP0 correlated with BP, LF/HF and the scores of body pain (HRQOL). SBP0 may be a useful indicator for assessing 24-h BP, sympathetic nervous functions and HRQOL in healthy subjects.     

阻塞性睡眠呼吸暂停患者睡眠时高血压的发生

目的明确阻塞性睡眠呼吸暂停综合征（ＯＳＡＳ）患者清醒及睡眠时血压变化情况及对其影响的相关因素。方法１３例ＯＳＡＳ患者在桡动脉内留置导管监测血压并同步进行夜间睡眠多导生理仪连续记录，部分患者观察吸氧或经鼻（面）罩持续正压通气（ＮＣＰＡＰ）的治疗效果。结果（１）ＯＳＡＳ患者白天高血压发生率为４６％（６／１３）；白天无高血压的患者夜间一过性高血压发生率为８６％（６／７）；（２）ＯＳＡＳ患者夜间血压增高与低氧血症和呼吸暂停时间有关，与呼吸暂停指数（ＡＩ）无相关性（Ｐ＞０．０５）；（３）２例ＯＳＡＳ患者经吸氧治疗后，夜间血压波动仍存在，高血压未得到纠正；４例ＯＳＡＳ患者经ＮＣＰＡＰ治疗后，夜间血压波动消失。结论白天无高血压的ＯＳＡＳ患者夜间可反复出现一过性血压增高；ＯＳＡＳ患者夜间血压增高与低氧血症、呼吸暂停时间有关，但低氧血症不是引起夜间血压增高的主要因素；单纯吸氧不能纠正ＯＳＡＳ患者夜间血压增高，ＮＣＰＡＰ是纠正ＯＳＡＳ患者夜间血压增高的较好方法。     

Rate of morning increase in blood pressure is elevated in hypertensives

BACKGROUND: We applied a new logistic curve fitting procedure to ambulatory blood pressure (ABP) recordings to determine whether the rate of increase in systolic (SBP), mean (MBP) and diastolic blood pressure (DBP) and heart rate (HR) in the morning is related to the level of BP in subjects. METHODS: The rate of transition in the morning and evening period was determined using a six-parameter double-logistic equation applied to 528 ABP recordings from a cardiovascular risk assessment clinic. Based on daytime BP (MBP, SBP, or DBP), the upper quartile (UQ, n = 132) and lower quartile (LQ) were compared. RESULTS: Subjects in the UQ of daytime MBP were hypertensive and showed greater day-night differences compared to normotensive subjects in the LQ (29 +/- 1 mm Hg for MBP compared to 20 +/- 1 mm Hg). The rate of morning increase in SBP and DBP was 42% and 30% greater in UQ subjects compared to the LQ subjects (P < .05). The rates of evening decrease in all BPs were 69% to 84% greater in the subjects in the UQ. Similar results were obtained if subjects were divided according to daytime SBP or DBP. The rate of morning increase in MBP was correlated with daytime BP, but not night-time or 24 h MBP. CONCLUSIONS: The rate of morning increase in BP is greater in those subjects with the highest daytime BP. The exaggerated rate of morning increase in BP in this group, which were all hypertensive, may also be important for greater cardiovascular risk.     

Ambulatory monitoring of blood pressure (AMBP) in patients with primary hyperparathyroidism

The purpose of our study was to evaluate the behaviour of blood pressure (BP) by ambulatory monitoring of blood pressure (AMBP) in 53 patients with primary hyperparathyroidism (PHPT) compared to 100 essential hypertensive (EH) and 31 healthy subjects (HS). The correlations between calcium-phosphorus metabolism and haemodynamic parameters in all groups are included in the study. AMBP was performed using the oscillometric technique (Space-Labs, 90207, Redmond, WA, USA) and the following AMBP parameters were evaluated: average day time systolic (S) and diastolic (D) blood pressure (BP) and heart rate (HR) (when awake), average night time SBP, DBP and HR (when asleep) and average 24-h-SBP, DBP and HR. The definition of 'dipper' or 'non-dipper' subjects was established if night time SBP and DBP fall was >10% and <10%, respectively. In total, 25 PHPT patients (47.2%) were hypertensive (HT-PHPT) and 28 PHPT (52.8%) were normotensive (NT-PHPT). Mean 24-h-SBP and DBP obtained by AMBP was higher in HT-PHPT (P < 0.05) and EH (P < 0.05) than in NT-PHPT and HS. The multiple linear regression has shown that in PHPT-HT patients ionized calcium is an independent factor for the rise of 24-h-DBP values (r: 0.497; P < 0.05) and daytime DBP values (r: 0.497; P < 0.05). In 56% of HT-PHPT patients there is an absence of physiological BP nocturnal fall ('non-dipper'), which is statistically significant (P < 0.05) compared with 'non-dipper' EH patients (30%). In conclusion, in our study the prevalence of hypertension in PHPT was 47%. AMBP revealed that the 'non-dipping 'pattern was much higher in HT-PHPT patients in respect to EH patients.     

血压变异性与高敏C反应蛋白及颈动脉内膜中层厚度的关系

目的:探讨高血压患者血压变异性(BPV)与高敏C反应蛋白(hs-CRP)及颈动脉内膜中层厚度(IMT)的关系。方法:依据夜间收缩压标准差的三分位间距将126例高血压患者分为低BPV组、中BPV组和高BPV组。彩色多普勒超声仪测定IMT和颈动脉斑块,同时检测血浆hs-CRP和血管紧张素转化酶(ACE)。结果:高BPV组hs-CRP水平和IMT较低BPV组增加[hs-CRP:(3.78±3.63)mg/L∶(2.24±1.92)mg/L;IMT:(1.01±0.16)mm∶(0.91±0.17)mm;均P<0.05]。24h血压不达标亚组IMT较达标亚组明显增加[(1.00±0.19)mm∶(0.93±0.16)mm,P<0.05],而hs-CRP和ACE差异无统计学意义。IMT增厚者夜间收缩压标准差大于IMT正常组[(11.13±4.19)mmHg(1mmHg=0.133kPa)∶(9.69±3.24)mmHg,P<0.05]。IMT与24h平均收缩压(mSBP)、白天mSBP、夜间mSBP、夜间收缩压标准差、夜间舒张压标准差及LDL呈正相关(r分别为0.218、0.211、0.210、0.176、0.191、0.267,均P<0.05),多元线性回归分析显示IMT与24hmSBP及LDL有关。结论:高血压患者BPV与颈动脉IMT及hs-CRP密切相关。     

Comparison of valsartan and amlodipine on ambulatory blood pressure variability in hypertensive patients

We tested the hypothesis that calcium channel blockers (CCBs: amlodipine group, n = 38)) are superior to angiotensin receptor blockers (ARBs: valsartan group, n = 38) against ambulatory blood pressure variability (BPV) in untreated Japanese hypertensive patients. Both drugs significantly reduced ambulatory systolic and diastolic BP values. With regard to BPV, standard deviation (SD) in SBP did not change with the administration of either drug, but the ARB significantly increased SD in awake DBP (12 ± 4–14 ± 4 mmHg). The ARB also significantly increased the coefficients of variation (CVs)in awake and 24-h SBP/DBP (all P < 0.05), but amlodipine did not change the CV. CCB significantly reduced the maximum values of awake SBP (193 ± 24–182 ± 27 mmHg, P = 0.02), sleep SBP (156 ± 18–139 ± 14 mmHg, P < 0 .001), and awake and sleep DBP (P < 0.01 in both cases), but the ARB did not change the maximum BP values. In conclusion, a once-daily morning dose of CCB amlodipine was more effective at controlling ambulatory BPV than ARB valsartan, especially in reducing maximum BP levels.