Significance of white-coat hypertension in older persons with isolated systolic hypertension: a meta-analysis using the International Database on Ambulatory Blood Pressure Monitoring in Relation to Cardiovascular Outcomes population

The significance of white-coat hypertension in older persons with isolated systolic hypertension remains poorly understood. We analyzed subjects from the population-based 11-country International Database on Ambulatory Blood Pressure Monitoring in Relation to Cardiovascular Outcomes database who had daytime ambulatory blood pressure (BP; ABP) and conventional BP (CBP) measurements. After excluding persons with diastolic hypertension by CBP (≥90 mm Hg) or by daytime ABP (≥85 mm Hg), a history of cardiovascular disease, and persons <18 years of age, the present analysis totaled 7295 persons, of whom 1593 had isolated systolic hypertension. During a median follow-up of 10.6 years, there was a total of 655 fatal and nonfatal cardiovascular events. The analyses were stratified by treatment status. In untreated subjects, those with white-coat hypertension (CBP ≥140/<90 mm Hg and ABP <135/<85 mm Hg) and subjects with normal BP (CBP <140/<90 mm Hg and ABP <135/<85 mm Hg) were at similar risk (adjusted hazard rate: 1.17 [95% CI: 0.87-1.57]; P=0.29). Furthermore, in treated subjects with isolated systolic hypertension, the cardiovascular risk was similar in elevated conventional and normal daytime systolic BP as compared with those with normal conventional and normal daytime BPs (adjusted hazard rate: 1.10 [95% CI: 0.79-1.53]; P=0.57). However, both treated isolated systolic hypertension subjects with white-coat hypertension (adjusted hazard rate: 2.00; [95% CI: 1.43-2.79]; P<0.0001) and treated subjects with normal BP (adjusted hazard rate: 1.98 [95% CI: 1.49-2.62]; P<0.0001) were at higher risk as compared with untreated normotensive subjects. In conclusion, subjects with sustained hypertension who have their ABP normalized on antihypertensive therapy but with residual white-coat effect by CBP measurement have an entity that we have termed, "treated normalized hypertension." Therefore, one should be cautious in applying the term "white-coat hypertension" to persons receiving antihypertensive treatment.     

Assessment of long-term antihypertensive treatment by clinic and ambulatory blood pressure: data from the European Lacidipine Study on Atherosclerosis

OBJECTIVES: Information on the features of long-term modifications of clinic and 24-h ambulatory blood pressure (ABP) by treatment is limited. The present study aimed to address this issue. METHODS: Ambulatory BP monitoring and clinic BP (CBP) measurements were performed at baseline and at yearly intervals over a 4-year follow-up period in 1523 hypertensives (56.1 +/- 7.6 years) randomized to treatment with lacidipine or atenolol in the European Lacidipine Study on Atherosclerosis (ELSA). RESULTS: CBP was always greater than ABP, while reductions in all BP values (greater for CBP than for ABP) were on average maintained throughout 4 years, CBP changes showing limited relationship with ABP changes (r = 0.14-0.27). BP reductions by treatment during daytime and night-time were correlated (r = 0.63-0.73). BP normalization was achieved in a greater percentage of patients for CBP (41.7%) than for ABP (25.3%), with systolic BP control being always less common than diastolic BP control. BP normalization was more frequent at single yearly visits than throughout the 4 years. Twenty-four-hour BP variability was reduced by treatment over 4 years in absolute but not in normalized units. CONCLUSIONS: The present study provides the best evidence available on long-term effect of antihypertensive treatment on both ABP and CBP. On average, ABP was sustainedly reduced by treatment throughout the follow-up period, but 24-h BP was more difficult to control than CBP. In several patients, ABP control was unstable between visits, the percentage of patients under control over 4 years being much less than that of those controlled at each year. Treatment induced a reduction in absolute but not in normalized BP variability estimates. This has clinical implications because of the prognostic importance of ABP mean values and variability.     

Masked Hypertension Assessed by Ambulatory Blood Pressure Versus Home Blood Pressure Monitoring: Is It the Same Phenomenon?

BACKGROUND: Masked hypertension is defined as normal clinic blood pressure (CBP) and elevated out-of-clinic blood pressure assessed using either self-monitoring of blood pressure (BP) by the patients at home (HBP) or ambulatory BP (ABP) monitoring. This study investigated the level of agreement between ABP and HBP in the diagnosis of masked hypertension. METHODS: Participants referred to an outpatient hypertension clinic had measurements of CBP (two visits), HBP (4 days), and ABP (24 h). The diagnosis of masked hypertension based on HBP (CBP <140/90 mm Hg and HBP > or =135/85) versus ABP (CBP <140/90 and awake ABP > or =135/85) was compared. RESULTS: A total of 438 subjects were included (mean age +/- SD, 51.5 +/- 11.6 years; 59% men and 41% women, 34% treated and 66% untreated). Similar proportions of subjects with masked hypertension were diagnosed by ABP (14.2%) and HBP (11.9%). In both treated and untreated subjects, the masked hypertension phenomenon was as common as the white coat phenomenon. Among 132 subjects with normal CBP, there was disagreement in the diagnosis of masked hypertension between the HBP and the ABP method in 23% of subjects for systolic and 30% for diastolic BP (kappa 0.56). When a 5-mm Hg gray zone for uncertain diagnosis was applied to the diagnostic threshold, the disagreement was reduced to 9% and 6% respectively. CONCLUSIONS: Similar proportions of subjects with masked hypertension are detected by ABP and HBP monitoring. Although disagreement in the diagnosis between the two methods is not uncommon, in the majority of these cases the deviation of the diagnostic BP above the threshold in not clinically important. Both ABP and HBP monitoring appear to be appropriate methods for the detection of masked hypertension.     

Variability of diurnal changes in ambulatory blood pressure and nocturnal dipping status in untreated hypertensive and normotensive subjects

An absent or diminished blood pressure (BP) fall during sleep (so-called "nondipping") has been associated with a higher risk of cardiovascular complications, but the long-term reproducibility of dipper status and the relationship between diurnal changes in BP and perceived sleep quality have not been previously documented in untreated hypertensive patients. Ambulatory BP (ABP) and dipping status were examined in 79 subjects (69 hypertensives and 10 normotensives) at 0, 6, and 12 months. Fifty-six percent of subjects had no change in their dipping status, the majority (53%) dipping normally on all three occasions. However, 44% of patients had variable dipping status, and normal nighttime dipping in BP was observed more often when patients perceived their sleep quality to be good during the period of ABP recording. These results highlight significant intrasubject variability in the diurnal fluctuations in ABP and dipper status, which may in part reflect day-to-day variations in sleep disturbance during ABP monitoring. Classifying hypertensive patients into dippers or nondippers on the basis of a single ABP recording is unreliable and potentially misleading.     

Relationship between daytime sleepiness and blood pressure in healthy older adults

BACKGROUND: Some sleep disorders have been linked to hypertension, but few studies have examined the relationship between daytime sleepiness and blood pressure (BP). This study attempted to determine whether scores on a short questionnaire assessing daytime sleepiness (Epworth Sleepiness Scale [ESS]) were associated with BP and could be used to predict hypertension after 5 years in healthy older adults who had not previously been diagnosed with hypertension. METHODS: A group of 157 healthy men and women 55 to 80 years of age completed an extensive medical examination, a series of psychosocial tests, and two 24-h ambulatory BP sessions. After 5 years the procedures were repeated in 133 (85%) of the subjects. Psychosocial variables and BP were compared in subjects scoring high (score of > or = 10) and low (< 10) on the ESS. RESULTS: Compared to individuals with low ESS sores, those scoring high had increased casual and sleep BP as well as higher systolic BP levels and diastolic BP variability during waking hours, and reported higher levels of anger, depression, anxiety, and intensity of psychological symptoms as well as lower defensiveness. Individuals with high ESS scores were more likely to be diagnosed with hypertension 5 years later. Groups with high and low ESS scores did not differ significantly on any other variables. CONCLUSIONS: The ESS, a simple measure of daytime sleepiness, identified individuals at risk for hypertension. Future studies should investigate the possibility that diagnosis and treatment of daytime sleepiness could aid in BP reduction and ultimately in decreased morbidity and mortality from cardiovascular disorders.     

Prognostic superiority of daytime ambulatory over conventional blood pressure in four populations: a meta-analysis of 7,030 individuals

OBJECTIVE: To investigate the multivariate-adjusted predictive value of systolic and diastolic blood pressures on conventional (CBP) and daytime (10-20 h) ambulatory (ABP) measurement. METHODS: We randomly recruited 7,030 subjects (mean age 56.2 years; 44.8% women) from populations in Belgium, Denmark, Japan and Sweden. We constructed the International Database on Ambulatory blood pressure and Cardiovascular Outcomes. RESULTS: During follow-up (median = 9.5 years), 932 subjects died. Neither CBP nor ABP predicted total mortality, of which 60.9% was due to noncardiovascular causes. The incidence of fatal combined with nonfatal cardiovascular events amounted to 863 (228 deaths, 326 strokes and 309 cardiac events). In multivariate-adjusted continuous analyses, both CBP and ABP predicted cardiovascular, cerebrovascular, cardiac and coronary events. However, in fully-adjusted models, including both CBP and ABP, CBP lost its predictive value (P >or= 0.052), whereas systolic and diastolic ABP retained their prognostic significance (P or= 0.21). In adjusted categorical analyses, normotension was the referent group (CBP < 140/90 mmHg and ABP < 135/85 mmHg). Adjusted hazard ratios for all cardiovascular events were 1.22 [95% confidence interval (CI) = 0.96-1.53; P = 0.09] for white-coat hypertension (>or= 140/90 and < 135/85 mmHg); 1.62 (95% CI = 1.35-1.96; P < 0.0001) for masked hypertension (< 140/90 and >or= 135/85 mmHg); and 1.80 (95% CI = 1.59-2.03; P < 0.0001) for sustained hypertension (>or= 140/90 and >or= 135/85 mmHg). CONCLUSIONS: ABP is superior to CBP in predicting cardiovascular events, but not total and noncardiovascular mortality. Cardiovascular risk gradually increases from normotension over white-coat and masked hypertension to sustained hypertension.     

Effects of age on hypertensive status in patients with chronic kidney disease

OBJECTIVE: To evaluate effect of age on hypertensive status in chronic kidney disease (CKD). METHODS: We studied 459 prevalent CKD patients (stages 2-5, no dialysis), grouped by age (< 55, 55-64, 65-74, >or= 75 years), undergoing clinical blood pressure (CBP) and ambulatory blood pressure (ABP) measurement. RESULTS: Prevalence of diabetes, left ventricular hypertrophy and previous cardiovascular disease progressively increased with aging; glomerular filtration rate (GFR) and hemoglobin decreased. Achievement of CBP target decreased from 16% in patients < 55 years to 6% in those >or= 75 years (P = 0.023). ABP 24-h systolic rose while diastolic decreased, with a consequent pulse pressure increase from 45 +/- 8 to 65 +/- 14 mmHg (P < 0.0001). Age, proteinuria, diabetes, cardiovascular disease and anemia but not GFR predicted higher 24-h pulse pressure. CBP overestimated systolic/diastolic daytime ABP by 14 +/- 18/7 +/- 11 mmHg on average, a greater difference in older than younger groups (P < 0.005). Conversely, CBP night-time ABP difference did not vary among groups (24 +/- 20/16 +/- 11 mmHg). These age-dependent differences determined a rising prevalence of white-coat hypertension (from 19 to 40%, P = 0.001) and night/day ratio of at least 0.9 (from 43 to 66%, P = 0.0004). Age, diabetes, left ventricular hypertrophy and anemia but not GFR predicted nondipping status. Among the oldest patients, 13% had diastolic CBP below 70 mmHg, with 48% below the corresponding values of daytime (< 69 mmHg) or night-time ABP (< 60 mmHg). CONCLUSION: In CKD, prevalence of white-coat hypertension, nondipping status and potentially dangerous low diastolic ABP increases with aging. This suggests wider use of ABP monitoring in older patients and need for trials addressing identification of an age-specific blood pressure target.     

Ambulatory blood pressure is a better marker than clinic blood pressure in predicting cardiovascular events in patients with/without type 2 diabetes

BACKGROUND: The prognostic significance of ambulatory blood pressure (ABP) has not been established in patients with type 2 diabetes (T2DM). METHODS: In order to clarify the impact of ABP on cardiovascular prognosis in patients with or without T2DM, we performed ABP monitoring (ABPM) in 1,268 subjects recruited from nine sites in Japan, who were being evaluated for hypertension. The mean age of the patients was 70.4 +/- 9.9 years, and 301 of them had diabetes. The patients were followed up for 50 +/- 23 months. We investigated the relation between incidence of cardiovascular diseases (CVDs) and different measures of ABP, including three categories of awake systolic blood pressure (SBP <135, 135-150, and >150 mm Hg), sleep SBP (<120, 120-135, and >135 mm Hg), and dipping trends in nocturnal blood pressure (BP) (dippers, nondippers, and risers). Cox regression models were used in order to control for classic risk factors. RESULTS: Higher awake and sleep SBPs predicted higher incidence of CVD in patients with and without diabetes. In multivariable analyses, elevated SBPs while awake and asleep predicted increased risk of CVD more accurately than clinic BP did, in both groups of patients. The relationships between ABP level and CVD were similar in both groups. In Kaplan-Meier analyses, the incidence of CVD in nondippers was similar to that in dippers, but risers experienced the highest risk of CVD in both groups (P < 0.01). The riser pattern was associated with a approximately 150% increase in risk of CVD, in both groups. CONCLUSIONS: These findings suggest that ABPM is a better predictor of cardiovascular risk than clinic BP, and that this holds true for patients with or without T2DM.     

Out-of-office blood pressure in children and adolescents: disparate findings by using home or ambulatory monitoring

BACKGROUND: The validity of home blood pressure (HBP) measurements in children has not been evaluated, although in clinical practice such measurements are being used. This study compares HBP, with clinic (CBP) and daytime ambulatory blood pressure (ABP) in children and adolescents. METHODS: Fifty-five children and adolescents aged 6 to 18 years were evaluated with CBP (three visits), HBP (6 days), and daytime ABP. Mean age was 12.3 +/- 2.9 (SD) years, 33 boys. According to the Task Force CBP criteria, 26 were hypertensives, 6 had high-normal BP (hypertensive group), and 23 were normotensives (normotensive group). RESULTS: In the hypertensive group, CBP was 130.8 +/- 7.6/72.5 +/- 8.1 mm Hg (systolic/diastolic), HBP 118.9 +/- 6.3/73.7 +/- 6.7, and ABP 130.8 +/- 8.1/75.5 +/- 8.3. In the normotensive group, CBP was 112.8 +/- 8/63.1 +/- 6.3, HBP 106.7 +/- 8.4/67.2 +/- 5.2, and ABP 123.9 +/- 7.2/72 +/- 4.3. Strong correlations (P < .001) were observed between CBP-HBP (r = 0.73/0.57, systolic/diastolic), CBP-ABP (r = 0.59/0.49), and HBP-ABP (r = 0.72/0.66). In normotensive subjects, ABP was higher than both CBP and HBP for systolic and diastolic BP (P < .001). Furthermore, systolic HBP was lower than CBP (P < .01), whereas the opposite was true for diastolic BP (P < .05). In hypertensive subjects systolic HBP was lower than both CBP and ABP (P < .001), whereas CBP did not differ from ABP. For diastolic BP no differences were found among measurement methods. CONCLUSIONS: These data suggest that, in contrast to adults in whom HBP is close to the levels of daytime ABP, in children and adolescents HBP appears to be significantly lower than daytime ABP. Until more data become available, caution is needed in the interpretation of HBP in children and adolescents.     

Is "usual" blood pressure a proxy for 24-h ambulatory blood pressure in predicting cardiovascular outcomes?

BackgroundThe 24-h ambulatory blood pressure (ABP) is a stronger predictor of cardiovascular disease than conventional blood pressure (CBP), but it remains unclear how it compares with "usual" blood pressure (UBP), estimated after CBP has been corrected for regression dilution bias (RDB).MethodsWe compared the associations of cardiovascular mortality (n = 50), cardiovascular events (n = 101), and cardiac events (n = 71) with systolic CBP, UBP, and ABP over 13 years of follow-up (median) in 1,167 randomly selected Belgians. We estimated the correction factor to compute UBP from CBP at the midpoint of follow-up (6.5 years) in 723 untreated individuals without cardiovascular disease.ResultsCardiovascular disease increased across quartiles of systolic CBP, UBP, and ABP (P for trend 相似文献   

Predictive values of automated blood pressure measurement: what can we learn from the Japanese population - the Ohasama study

BACKGROUND: Measurements of ambulatory blood pressure (ABP) and of home blood pressure (HBP) as an adjunct to casual/clinic blood pressure (CBP) measurements are currently widely used for the diagnosis and treatment of hypertension. We have monitored a rural cohort of people from the population of Ohasama, Japan, with respect to their prognosis and have previously reported that ABP and HBP are superior to CBP for the prediction of cardiovascular mortality. One reason that CBP is a poor predictor of prognosis is that it incorporates several biases, including the white-coat effect. METHODS AND RESULTS: We examined the prognostic significance of white-coat hypertension for mortality and found that the relative hazard for the overall mortality of patients with white-coat hypertension was significantly lower than that for true hypertension. Short-term blood pressure variability has recently attracted attention as a cause of target-organ damage and cardiovascular complications. Our results confirmed that short-term blood pressure variability (as measured every 30 min) was independently associated with cardiovascular mortality. In addition, research has recently focused on isolated systolic hypertension and pulse pressure as independent risk factors for poor cardiovascular prognosis. The Ohasama study also clearly demonstrated that isolated systolic hypertension and increased pulse pressure, as assessed by HBP, were associated with an increase in the risk of cardiovascular mortality. Circadian blood pressure variation is characterized by a diurnal elevation and a nocturnal decline in blood pressure. We therefore compared morbidity from stroke between dippers (subjects who show an ordinal nocturnal dipping of blood pressure) and non-dippers (those with a diminished nocturnal dipping or nocturnal elevation of blood pressure [inverted dippers]) in the Ohasama study. The incidence of stroke increased with an increased length of observation in dippers using antihypertensive medication but not in non-dippers using antihypertensive medication. In contrast, the relative hazard for mortality increased in non-dippers and inverted dippers. These results suggest a cause-and-effect relationship for both dippers and non-dippers. CONCLUSION: The Ohasama study showed that the level and variability of hypertension as assessed by ABP and HBP are independent predictors of cardiovascular mortality. It also demonstrated an independent association between the prognosis of hypertension and each component of ABP and HBP, indicating the prognostic significance of these blood pressure measurements.     

Exposure to cadmium and conventional and ambulatory blood pressures in a prospective population study. Public Health and Environmental Exposure to Cadmium Study Group

This prospective population study investigated in a random sample of 692 subjects (age 20-83 years) how changing environmental exposure to cadmium influenced blood pressure (BP) and the incidence of hypertension. At baseline (1985 to 1989; participation rate, 78%) and follow-up (1991 to 1995; re-examination rate, 81%), blood pressure was measured by conventional sphygmomanometry (CBP; 15 readings in total) and, at follow-up, also by 24-h ambulatory blood pressure monitoring (ABP). Systolic/diastolic CBP at baseline averaged 128.4/77.3 mm Hg. At baseline, blood cadmium concentration (B-Cd) and urinary cadmium excretion (U-Cd) averaged (geometric means) 11.1 nmol/L and 10.2 nmol/24 h. Over 5.2 years (median follow-up), B-Cd fell by 29.6% and U-Cd by 15.2%. B-Cd fell less in subjects living closer to three zinc smelters and in premenopausal women. During follow-up, systolic CBP decreased by 2.2 mm Hg in men and remained unchanged in women, and diastolic CBP increased by 1.8 mm Hg in both sexes. No relationship could be demonstrated between the secular trends in CBP and B-Cd or U-Cd or between B-Cd or U-Cd at baseline and the incidence of hypertension. In addition, in cross-sectional analyses involving the average of all available CBP measurements in each participant or 24-h ABP at follow-up (mean, 119.1/71.4 mm Hg), blood pressure was not correlated with B-Cd or U-Cd. In conclusion, environmental exposure to cadmium was not associated with higher CBP or 24-h ABP or with increased risk for hypertension. The lesser fall in B-Cd in the residents living closer to the zinc smelters or in premenopausal women underscores the necessity to sanitize cadmium-polluted areas and to systematically reinforce the preventive measures to be adopted by exposed communities to reduce cadmium uptake.     

The ambulatory blood pressure in normotensive and hypertensive subjects: results from an international database

Objective: To delineate more precisely an operational threshold for making clinical decisions based on ambulatory blood pressure (ABP) measurement by studying the ABP in subjects who were diagnosed as either normotensive or hypertensive by conventional blood pressure (CBP) measurement.Subjects: Twenty-four research groups recruited 7069 subjects. Of these, 4577 were normotensive (systolic CBP ≤ 140 mmHg and diastolic CBP ≤ 90 mmHg) and 1773 were hypertensive (systolic CBP ≥ 160 mmHg and/or diastolic CBP ≥ 90 mmHg). Of the latter, 1324 had systolic and 1310 had diastolic hypertension.Results: Ninety-five percent of the normotensive subjects had a 24-h ABP below (systolic and diastolic, respectively) 133 and 82 mmHg. Of the patients with systolic hypertension, 24% had a 24-h systolic ABP of < 133 mmHg. Similarly, 30% of those with diastolic hypertension had a 24-h diastolic ABP of < 82 mmHg. The probability that hypertensive patients had a 24-h ABP below these thresholds was higher in women than in men, increased with age and was 2- to 4-fold greater if the CBP of the patient had been measured at only one visit and if fewer than 3 CBP measurements had been averaged to establish the diagnosis of hypertension. By contrast, for each 10-mmHg increment in systolic CBP, this probability decreased by 54% for the 24-h systolic ABP and by 25% for the 24-h diastolic ABP, and for each 5 mmHg increment in diastolic CBP it increased by 6 and 9%, respectively.Conclusion: The ABP distributions of the normotensive subjects included in the present international database were not materially different from those in previous reports in the literature. One-fifth to more than one-third of the hypertensive patients had an ABP which was below the 95th centile of the ABP in normotensive subjects, but this proportion decreased if the hypertensive patients had shown a higher CBP upon repeated measurement. The prognostic implications of elevated CBP in the presence of normal ABP remain to be determined.     

Prognostic value of the variability in home-measured blood pressure and heart rate: the Finn-Home Study

The objective of the study was to assess the prognostic value of variability in home-measured blood pressure (BP) and heart rate (HR) in a general population. We studied a representative sample of the Finnish adult population with 1866 study subjects aged 45-74 years. BP and HR self-measurements were performed on 7 consecutive days. The variabilities of BP and HR were defined as the SDs of morning minus evening, day-by-day, and first minus second measurements. The primary end point was incidence of a cardiovascular event. The secondary end point was total mortality. During a follow-up of 7.8 years, 179 subjects had experienced a cardiovascular event, and 130 subjects had died. In Cox proportional hazard models adjusted for age, sex, BP/HR, and other cardiovascular risk factors, morning-evening home BP variability (systolic/diastolic relative hazard: 1.04/1.10 [95% CI: 1.01-1.07/1.05-1.15] per 1-mm Hg increase in BP variability) and morning day-by-day home BP variability (relative hazard: 1.04/1.10 [95% CI: 1.00-1.07/1.04-1.16] per 1-mm Hg increase in BP variability) were predictive of cardiovascular events. Morning-evening home HR variability (relative hazard: 1.07 [95% CI: 1.02-1.12] per 1-bpm increase in HR variability) and morning day-by-day home HR variability (relative hazard: 1.11 [95% CI: 1.05-1.17] per 1-bpm increase in HR variability) were also independent predictors of cardiovascular events. Greater variabilities of morning home BP and HR are independent predictors of cardiovascular events. Because the variabilities of home BP and HR are easily acquired in conjunction with home BP and HR level, they should be used as the additive information in the assessment of cardiovascular risk.     

动态血压监测与高血压病预后的关系

目的 :探讨动态血压 (ABP)及偶测血压 (CBP)与高血压预后的关系。方法 :2 2 0例原发性高血压患者入选时分别测量基础状态下ABP及CBP、并根据白昼舒张压水平分为高、中、低 3个亚组 (HL、ML、LL) ,然后长期随访观察与高血压病相关的心脑血管“事件”。结果 :平均随访 38个月 ,发生各类“事件”者 2 6例 ,单因素分析表明 :“事件”组各项ABP参数明显高于“非事件”组 (P <0 0 5～ 0 0 1) ,而 2组CBP间无显著差异 (P >0 0 5 )。LL、ML、HL 3个亚组中“事件”发生率分别为 2例 10 0人年、3 4例 10 0人年及 6 3例 10 0人年。多因素分析显示 :SBP节律、夜间SBP水平及总胆固醇 (CT)水平为高血压患者“事件”发生的独立危险因素 ,分别为RR =3 0 8、RR =1.2 6、RR =1.4 9(P <0 0 5～ 0 0 1)。结论 :ABP在判断高血压预后方面较CBP更具有临床意义 ,较高的ABP水平提示不良的预后 ,SBP节律、夜间SBP水平是预测高血压患者心脑血管“事件”及肾脏受损的独立危险因素     

Contributions of hypoxia and respiratory disturbance index to sympathetic activation and blood pressure in obstructive sleep apnea syndrome

Hypertension is a common finding among obstructive sleep apnea (OSA) patients, and is thought to be caused by sympathetic hyperactivity. The present study compares the contributions of the respiratory disturbance index (RDI) as a reflection of sleep fragmentation, and the magnitude of oxygen desaturation, to sympathetic activation as indexed by urinary norepinephrine concentrations, as well as to morning and evening blood pressure in sleep apnea syndrome patients. Data (polysomnography, blood pressure [BP], and urine catecholamines) of 38 consecutive OSA patients (age, 46 ± 14.5 years) were analyzed. Stepwise logistic regression analysis revealed that minimal oxygen saturation level (SaO₂min) was a significant predictor of both morning and evening norepinephrine levels, and that 37% of morning systolic BP variance could be accounted for by a combination of age and norepinephrine, while 20% of the diastolic BP variance was accounted for by SaO₂min alone. In contrast, RDI entered the prediction equation only when minimal oxygen saturation was rejected first. Our results indicate that the degree of nocturnal hypoxia is more closely associated with the level of sympathetic activation and with daytime level of blood pressure than with sleep fragmentation.     

Blood Pressure Monitoring. Task force III: Target-organ damage, morbidity and mortality

OBJECTIVE: To reach a consensus on ambulatory blood pressure (ABP) as a predictor of target-organ damage (TOD), morbidity and mortality. METHOD:The members of task force III wrote this article in preparation for the Seventh International Consensus Conference (23-25 September 1999). This article was amended after the meeting to reflect the consensus reached at the conference. POINTS OF CONSENSUS: In most studies, TOD in essential hypertension was more closely associated with ABP than it was with clinic blood pressure, the mean weighted correlation coefficients for the relationship of left ventricular mass with blood pressure being 0.50/0.44 (24h systolic/diastolic blood pressure) and 0.35/0.32 (clinic systolic/diastolic blood pressure), respectively. The above correlation coefficients vary among studies, possibly because of different standardizations of clinic blood pressure measurements and ways of selecting subjects, among other reasons. The closeness of the association between clinic blood pressure and left ventricular mass increases with the numbers of clinic measurements of blood pressure and visits to a clinic. Thus, the variance of left ventricular mass explained by ABP in addition to that explained by clinic blood pressure diminishes with the number of clinic blood pressure readings. The proportion of variability of left ventricular mass that is directly accounted for by the day-night difference in blood pressure is 15% at the most. Thus, the advantage of ABP over clinic blood pressure appears to be, at least in part, a result of the greater number of measurements over the 24h. It might also depend, however, on the information offered by ambulatory blood pressure monitoring (ABPM) on daily-life variations in blood pressure. TOD appears to be more closely associated with ABP than it is with clinic blood pressure for the subjects with reproducible ABP tracings, but not for those with poorly reproducible tracings. The probability of developing sustained clinic hypertension at follow-up seems to be better predicted by clinic blood pressure on several occasions over a 6-month period than it is by ABP at baseline, although, when also ABPM is repeatedly performed at follow-up, its ability to predict clinical outcomes of hypertensive patients remains superior to that of repeated clinic blood pressure measurements. ABPM of the elderly appears feasible and is tolerated well. A blunted day-night fall in blood pressure ('non-dipping') seems to be harmful, while evidence regarding the potentially harmful effect of extreme dipping is still limited. Authors of the Syst-Eur study recently demonstrated the prognostic value of ambulatory systolic blood pressure and in particular, of night-time blood pressure, in assessing old subjects with isolated systolic hypertension. The assessment of variability of blood pressure has been shown to provide a further prediction of cardiovascular risk and the potentially prognostic value of beat-to-beat variability assessed non-invasively (using a Finapres or Portapres device)needs further study. In the published event-based studies, the prognostic value of ABP recorded during a single session was superior to that of clinic blood pressure. Since the authors of published event-based prognostic studies compared ABP with only a few clinic measurements of blood pressure, it is not known how many visits or measurements of blood pressure (and at what cost) would equate to a single session of ABPM in terms of prediction of cardiovascular events. ABPM might allow one to identify a subset with 'normal' ABP (white-coat or isolated clinic hypertension). Daytime ABP levels <135 mmHg systolic and 85 mmHg diastolic can be defined as normal and values <130/80 mmHg could be defined as optimal. Cardiovascular risk for subjects with normal ABP seems to be lower than that for those with abnormally high ABP. Long-term observational and intervention studies concerning subjects with white-coat hypertension are needed. (ABST     

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.     

Prognostic significance of 24-h ambulatory blood pressure characteristics for cardiovascular morbidity in a population of elderly men

OBJECTIVE: This study aimed to investigate the prognostic significance of 24-h ambulatory systolic (SBP), diastolic (DBP) and pulse pressure (PP), and blood pressure (BP) variability for cardiovascular morbidity in elderly men. DESIGN AND METHODS: Twenty-four hour ABP monitoring was performed in 70-year-old men (n = 872) participating in a longitudinal population-based study. The population was followed for up to 9.5 years, and the relationship between different blood pressure components and cardiovascular (CV) morbidity was assessed by Cox proportional hazard analysis. RESULTS: During follow-up, 172 CV events occurred (2.97 per 100 person-years). SBP and PP, both office and ambulatory, were significant predictors of CV morbidity. Twenty-four hour ambulatory PP [hazard ratio (HR) for 1 SD increase in BP 1.32, 95% confidence interval (CI) 1.15-1.52] and daytime ambulatory PP (HR 1.29, 95% CI 1.13-1.48) predicted CV morbidity independently of office PP and other established CV risk factors. Addition of night-time PP to a regression model with daytime PP and covariates did not increase the predictive value. However, the variability of daytime SBP (adjusted HR 1.24, 95% CI 1.07-1.42) provided additional prognostic power, independently of the 24-h SBP level. CONCLUSIONS: Ambulatory PP was a powerful predictor of CV morbidity in elderly men, independently of office PP and other established cardiovascular risk factors. Moreover, variability of daytime SBP added important prognostic information, suggesting that 24-h ambulatory BP monitoring may contribute to an improved risk assessment in elderly subjects.     

Aging and arterial blood pressure variability during orthostatic challenge

BACKGROUND: It has been demonstrated that a decrease in vagal cardiac function compromises arterial blood pressure (ABP) stability during orthostatic challenge. Augmentations in low-frequency (LF) ABP oscillations are indicative of this change in autonomic hemodynamic control. Aging is associated with diminished arterial baroreflex sensitivity and vagal cardiac dysfunction. However, the effect of aging on the stability of ABP during an orthostatic challenge remains to be elucidated. OBJECTIVE: The purpose of this study was to investigate ABP stability with aging during central hypovolemia induced by lower-body negative pressure (LBNP). METHODS: Graded LBNP up to -40 mm Hg was applied in 16 older (65 +/- 3 years of age) and 16 younger (25 +/- 3 years of age) healthy adults. ABP variability was analyzed by fast Fourier transform. LF spectral density (0.04-0.15 Hz) was extracted to provide an index of vasomotor responsiveness. RESULTS: Both LF systolic blood pressure (SBP) variability and diastolic blood pressure variability were augmented with LBNP. The rate of increase in LF SBP variability was augmented significantly greater in older as compared with younger subjects (p = 0.049). In addition, LF SBP variability was inversely correlated with decreases in pulse pressure in both age groups (r = -0.84, p = 0.01). The magnitude of the decreases in SBP and pulse pressure during LBNP was significantly affected by age, with the largest changes occurring in older subjects. The altered ABP response that manifested in older individuals was associated with a significant diminution in the reflex tachycardiac response elicited by LBNP. CONCLUSIONS: Induction of central hypovolemia via graded LBNP augments LF ABP variability. This increased ABP variability is significantly greater in older individuals. Our data suggest that aging is associated with ABP instability during orthostatic challenge.