Y Imai

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 (CBP 140/90 mmHg), 719 were borderline hypertensive (systolic CBP 141–159 mmHg or diastolic CBP 91–94 mmHg) and 1773 were definitely hypertensive. Of the subjects in the last of these categories, 1324 had systolic hypertension (systolic CBP 21 60 mmHg) and 131 0 had diastolic hypertension (diastolic CBP 295 mmHg). Combined systolic and diastolic hypertension was present in 861 subjects. Hypertension had been diagnosed from the mean of two to nine (median two) CBP measurements obtained at one to three (median two) visits. Results The 95th centiles of the ABP distributions in the normotensive subjects were (systolic and diastolic, respectively) 133 and 82 mmHg for 24-h ABP, 140 and 88mmHg for daytime ABP and 125 and 76mmHg for night-time ABP, respectively. Of the subjects with systolic hypertension, 24% had 24-h systolic ABP 4 33 mmHg. Similarly, 30% of those with diastolic hypertension had 24-h diastolic ABP 432 mmHg. The probability that hypertensive subjects had 24-h ABP below these thresholds tended to increase with age and was two- to fourfold greater if the CBP of the subject had been measured at only one visit and if fewer than three CBP measurements had been averaged for establishing the diagnosis of hypertension. By contrast, for each 1 O-mmHg increment in systolic CBP, this probability decreased by 54% for 24-h systolic ABP and by 26% for 24-h diastolic ABP, and for each 5-mmHg increment in diastolic CBP it decreased by 6 and 9%, respectively. In comparison with 24-h ABP, the overlap in the daytime and night-time ABP between normotensive and hypertensive subjects was of similar magnitude and was influenced by the same factors. Conclusions 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 hypertensive subjects had an ABP which was below the 95th centile of the ABP of normotensive subjects, but this proportion decreased if the hypertensive subjects had shown a higher CBP upon repeated measurement. The prognostic implications of elevated CBP in the presence of normal ABP remain to be determined.

Short report: Ambulatory blood pressure in normotensive compared with hypertensive subjects

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 (CBP ≥140/90mmHg), 719 were borderline hypertensive (systolic CBP 141–159mmHg or diastolic CBP 91–94mmHg) and 1773 were definitely hypertensive. Of the subjects in the last of these categories, 1324 had systolic hypertension (systolic CBP ≤160 mmHg) and 1310 had diastolic hypertension (diastolic CBP ≤95 mmHg). Hypertension had been diagnosed from the mean of two to nine (median two) CBP measurements obtained at one to three (median two) visits. Results: The 95th centiles of the 24-h ABP distributions in the normotensive subjects were (systolic and diastolic, respectively) 133 and 82 mmHg. Of the subjects with systolic hypertension, 24% had 24-h systolic ABP <133 mmHg. Similarly, 30% of those with diastolic hypertension had 24-h diastolic ABP <82 mmHg. The probability that hypertensive subjects had 24-h ABP below these thresholds tended to increase with age and was two- to fourfold greater if the CBP of the subject had been measured at only one visit and if fewer than three CBP measurements had been averaged for establishing the diagnosis of hypertension. By contrast, for each 10-mmHg increment in systolic CBP, this probability decreased by 54% for 24-h systolic ABP and by 26% for 24-h diastolic ABP, and for each 5-mmHg increment in diastolic CBP it decreased by 6 and 9%, respectively. Conclusions: 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 hypertensive subjects had an ABP which was below the 95th centile of the ABP of normotensive subjects, but this proportion decreased if the hypertensive subjects had shown a higher CBP upon repeated measurement. The prognostic implications of elevated CBP in the presence of normal ABP remain to be determined.

Thirty years of research on diagnostic and therapeutic thresholds for the self-measured blood pressure at home.

ObjectiveThe goal of this review study is to summarize 30 years of research on cut-off limits for the self-measured blood pressure. MethodsWe reviewed two meta-analyses, several prospective outcome studies in populations and hypertensive patients, studies in pregnant women, three clinical trials and the thresholds proposed in earlier and current hypertension guidelines. ResultsIn line with existing guidelines, prospective studies support that levels of the self-measured blood pressure at home of greater than or equal to 135 mmHg systolic or greater than or equal to 85 mmHg diastolic indicate hypertension. Circumstantial data suggest that levels of the self-measured blood pressure below 120/80 and 130/85 mmHg are optimal and normal, respectively. Therapeutic targets of the self-measured blood pressure to be attained on antihypertensive drug treatment are currently unknown, but should logically be lower (<135/85 mmHg) than those used to diagnose hypertension. Currently, there is no proof that therapeutic thresholds for the home blood pressure should be lower in high-risk compared with normal-risk patients. A large body of evidence, however, demonstrated that each millimetre of mercury of blood pressure lowering counts in the prevention of cardiovascular complications and that in high-risk patients even small decreases in blood pressure result in large absolute benefit. ConclusionThe thresholds to diagnose hypertension from self-measured blood pressure readings at home remain unaltered since the 2000 consensus conference, but are currently supported by outcome data. Further studies need to establish what values of the self-measured blood pressure are optimal and normal in terms of cardiovascular outcome.

Methodology and technology for peripheral and central blood pressure and blood pressure variability measurement: Current status and future directions - Position statement of the European Society of Hypertension Working Group on blood pressure monitoring and cardiovascular variability

Office blood pressure measurement has been the basis for hypertension evaluation for almost a century. However, the evaluation of blood pressure out of the office using ambulatory or self-home monitoring is now strongly recommended for the accurate diagnosis in many, if not all, cases with suspected hypertension. Moreover, there is evidence that the variability of blood pressure might offer prognostic information that is independent of the average blood pressure level. Recently, advancement in technology has provided noninvasive evaluation of central (aortic) blood pressure, which might have attributes that are additive to the conventional brachial blood pressure measurement. This position statement, developed by international experts, deals with key research and practical issues in regard to peripheral blood pressure measurement (office, home, and ambulatory), blood pressure variability, and central blood pressure measurement. The objective is to present current achievements, identify gaps in knowledge and issues concerning clinical application, and present relevant research questions and directions to investigators and manufacturers for future research and development (primary goal).

Is blood pressure during the night more predictive of cardiovascular outcome than during the day

The objective of this study was to investigate the prognostic significance of the ambulatory blood pressure (BP) during night and day and of the night-to-day BP ratio (NDR). We studied 7458 participants (mean age 56.8 years; 45.8% women) enrolled in the International Database on Ambulatory BP in relation to Cardiovascular Outcome. Using Cox models, we calculated hazard ratios (HR) adjusted for cohort and cardiovascular risk factors. Over 9.6 years (median), 983 deaths and 943 cardiovascular events occurred. Nighttime BP predicted mortality outcomes (HR, 1.18–1.24; P<0.01) independent of daytime BP. Conversely, daytime systolic (HR, 0.84; P<0.01) and diastolic BP (HR, 0.88; P<0.05) predicted only noncardiovascular mortality after adjustment for nighttime BP. Both daytime BP and nighttime BP consistently predicted all cardiovascular events (HR, 1.11–1.33; P<0.05) and stroke (HR, 1.21–1.47; P<0.01). Daytime BP lost its prognostic significance for cardiovascular events in patients on antihypertensive treatment. Adjusted for the 24-h BP, NDR predicted mortality (P<0.05), but not fatal combined with nonfatal events. Participants with systolic NDR of at least 1 compared with participants with normal NDR (≥0.80 to <0.90) were older, at higher risk of death, but died at higher age. The predictive accuracy of the daytime and nighttime BP and the NDR depended on the disease outcome under study. The increased mortality in patients with higher NDR probably indicates reverse causality. Our findings support recording the ambulatory BP during the whole day.

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 < or = 140 mmHg and diastolic CBP < or = 90 mmHg) and 1773 were hypertensive (systolic CBP > or = 160 mmHg and/or diastolic CBP > or = 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.

[PP.21.11] NOVEL IDENTIFICATION OF NOCTURNAL HYPERTENSION IMPROVES PREDICTION OF CARDIOVASCULAR DEATH IN A GENERAL POPULATION

Objective: Subjects with nocturnal hypertension often show a non-dipping pattern and have higher risk of cardiovascular mortality. Usually, time-based classification of nocturnal dipping is used to define risks but this is limited by a variability of dipping pattern amongst subjects (e.g. early risers and late risers). Design and method: We applied new method to classify non-dipper using a 6 parameter logistic equation to determine the exact magnitude of the dip irrespective of time, and defined as the range of mean blood pressure (BP) between the upper and lower plateaus. We examined the prognostic value of a < 10% reduction in range versus the conventional day-night difference of <10% using the data from the Ohasama 15-year outcome study. Results: Among 1522 subjects, 7.4% (n = 112) was categorized non-dipper by our new range classification (R-ND), they had higher nocturnal mean BP (89 ± 10 vs 84 ± 9 mmHg, p < 0.01), lower day-time mean BP (88 ± 10 vs 93 ± 10 mmHg, p < 0.01), similar 24 h averaged mean BP (88 ± 10 vs 89 ± 9 mmHg), and were older (67.1 ± 11 vs 61.3 ± 11, p < 0.01), compared with dippers. On the other hand, using convention classification by times, 56% (n = 847) defined as non-dippers (C-ND), had higher nocturnal mean BP (87 ± 10 vs 81 ± 7 mmHg, p < 0.01), lower day-time mean BP (90.1 ± 9.6 vs 95.0 ± 9.2 mmHg, p < 0.01), similar 24 h averaged mean BP (88.6 ± 9.4 vs 88.8 ± 8.2 mmHg), and were older (63.5 ± 0.4 vs 59.5 ± 0.4, p < 0.01), compared with dippers. Both R-ND and C-ND were correlated with the severe adverse cardiovascular events but R-ND predicted all caused deaths (odds ratio 2.72, p < 0.01) and cardiovascular deaths (odds ratio 2.33, p < 0.01) stronger than C-ND (odds ratio 2.2, p < 0.01; odds ratio 1.91, p < 0.01, respectively). Conclusions: In conclusion, our novel methods of analysis avoid the uncertainty of choosing the best time to predict nocturnal dipping and better identify the high risk patients with nocturnal hypertension. This leads to an overall improvement in the risk stratification for predicting cardiovascular deaths.