Clinical application of wave intensity for the treatment of essential hypertension.

Fujimoto S, Mizuno R, Saito Y, Nakamura S.

Department of General Medicine and Clinical Investigation, Nara Medical University, 840 Shijo, Kashihara, Nara 634-8522, Japan. sfujimot naramed-u.ac.jp

Wave intensity analysis is a method of studying intravascular flow wave propagation, calculated as the product of the rate of change in pressure (d P/ t) and the rate of change in velocity (d U/d t). The typical pattern of wave intensity seen during the cardiac cycle has two dominant peaks. The larger first peak (FP) occurs during early systole when a forward traveling compression wave is generated by the left ventricle. The second smaller peak (SP) follows a period of relatively little net wave production during mid-systole. Wave reflection is seen as a small backward-traveling compression wave occurring just after the first peak of wave intensity (NP). In this study, we investigated the usefulness of parameters from the wave intensity for estimating the efficacy of the Alpha-1 blocker, doxazosin, to reduce blood pressure, by the reduction of peripheral vascular resistance. We examined 20 patients with essential hypertension. Patients were included if their diastolic blood pressure was >95 mmHg on at least three separate visits to the clinic. The study consisted of a 2-week baseline phase followed by a 2-4-week dose-adjusted phase with doxazosin. Treatment began with 1 mg/day doxazosin, and the dose was doubled fortnightly until the diastolic blood pressure was <90 mmHg. Blood-pressure measurements and side effects were recorded at intervals of 2 weeks. Before and after 4 weeks of stable treatment with doxazosin, a comprehensive clinical evaluation was given. Doxazosin reduced systolic and diastolic blood pressure. Both FP and SP increased and NP decreased. DeltaMBP (change in mean blood pressure) correlated well with NP before and after the antihypertensive therapy. The efficacy of doxazosin was confirmed by the decreased reflection wave of aortic flow from wave intensity analysis. Thus, patients with a significant reflection wave may be good candidates for antihypertensive treatment by a vasodilator, such as doxazosin.

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Automated self-initiated blood pressure or 24-hour ambulatory blood pressure monitoring in pregnancy?

Brown MA, McHugh L, Mangos G, Davis G.

Departments of Renal Medicine and Women's and Children's Health, St George Hospital and University of New South Wales, Kogarah, Sydney, Australia.

OBJECTIVE: To determine whether self-initiated and recorded automated blood pressure measurement can provide an accurate estimate of ambulatory blood pressure in pregnant women suspected of having 'white coat hypertension'. DESIGN: A prospective observational study. SETTING: Women's and Children's Health Unit, St George Hospital, a teaching hospital of the University of New South Wales. POPULATION: Pregnant women being assessed for possible 'white-coat hypertension'. METHODS: Sixty-six pregnant women who were undergoing 24 hour ambulatory blood pressure monitoring (ABPM) in their home or work environment also measured their blood pressure six times during this interval using a self-initiated automated blood pressure recorder (Omron HEM 705CP). Agreement between awake ABPM and Omron recorded blood pressures was tested by Bland-Altman analysis. MAIN OUTCOME MEASURE: Limits of agreement between blood pressures measured by each device. RESULTS: Average blood pressures obtained by the two devices were identical (125/77 mmHg) but limits of agreement were wide, -20 to +23 mmHg for systolic blood pressure and -9 to +15 mmHg for diastolic blood pressure. CONCLUSION: The Omron HEM 705CP is a useful device for measuring group average blood pressures in pregnant women suspected of having white coat hypertension but cannot reliably replace ABPM for clinical management of individual pregnant women.

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The changing distribution of arm circumferences in NHANES III and NHANES 2000 and its impact on the utility of the 'standard adult' blood pressure cuff.

Graves JW, Bailey KR, Sheps SG.

Division of Hypertension, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA. graves.john mayo.edu

BACKGROUND: Accurate blood pressure measurement is dependent on using a blood pressure cuff that is appropriate to the patient's arm circumference. OBJECTIVE: This study identifies the change in distribution of arm circumferences in the United States and its impact on usage of the 'standard adult' cuff. METHOD: The most current National Health and Nutritional Examination Survey (NHANES) data, available on the website (http://www.cdc.gov/nchswww/nchshome.htm), covers NHANES III (Cycle 1, 1988-1991; 8381 subjects and Cycle 2, 1991-1994; 8566 subjects) and NHANES 2000 (1999-2000; 4,444 subjects). The weighted change in arm circumference between NHANES III as a whole and NHANES 2000 was calculated. Correlates for increased arm circumference were obtained via multivariate analysis. The predicted change in blood pressure cuff usage based on the changing prevalence of arm circumferences was calculated. RESULTS: The mean arm circumference for the whole population increased significantly from NHANES III to NHANES 2000 (31.83 +/- 0.08 cm versus 32.86 +/- 0.15 cm, p < 0.001) and in the hypertension population without reaching statistical significance (33.07 +/- 0.16 to 33.61 +/- 0.30 cm, p = 0.11). When adjusted regressions were performed, the increases in arm circumference were due to increasing weight in both the whole population and the hypertensives. The numbers of Americans predicted to require the 'standard adult' cuff to accurately measure blood pressure decreased from 76.2% to 66.3% while the number of Americans increased from 42.2% to 45%. CONCLUSIONS: The increasing prevalence of overweight and obese Americans found in NHANES III and NHANES 2000 has led to larger mean arm circumferences in hypertensives and the total population. This increased frequency of larger arm circumferences predicts that the 'large adult' cuff will be increasingly required in clinician's offices for accurate blood pressure measurement.

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Job strain and physiological stress responses in nurses and nurse's aides: predictors of daily blood pressure variability.

Brown DE, James GD, Nordloh L, Jones AA.

Department of Anthropology, University of Hawaii at Hilo, Hilo, Hawaii 96720-4091, USA. dbrown hawaii.edu

BACKGROUND: Job strain has been implicated in risk of cardiovascular disease, and there is evidence for increased blood pressure among men with job strain. It is unclear, however, to what degree job strain affects blood pressure in women. This study examined the relationships between job strain, norepinephrine and epinephrine excretion in the workplace, and ambulatory blood pressure variability during waking hours in women working as nurses or nurse's aides in Hilo, Hawaii. METHODS: Women from two ethnic groups, Filipino-Americans (n = 36) and Euro-Americans (n = 23), were measured on a workday, urinary catecholamine excretion and ambulatory blood pressure being measured over a 4-h period at work and home, and overnight over an 8-h period. The rates of catecholamine excretion were measured in timed urine samples using high-performance liquid chromatography with electrochemical detection, and ambulatory blood pressure was measured at 15-min intervals using a SpaceLabs 90207 monitor. The women filled out the Job Content Questionnaire prior to the physiological measurements. RESULTS: Scores on the Job Content Questionnaire were not significantly associated with the physiological measures, although correlations were higher for Euro-American participants than Filipino-Americans. Catecholamine excretion rates in the workplace were significantly related to blood pressure variability throughout the day and to systolic blood pressure means, but catecholamine excretion rates in other daily settings were not significantly related to blood pressure. CONCLUSIONS: These results support the idea that stress in the workplace has special significance for the prediction of cardiovascular health risk, and that catecholamine excretion at work is significantly associated with increased blood pressure variability during the day. Job strain, as measured by subscales from the Job Content Questionnaire, was not associated with any of the physiological measures. This lack of association may be the result of ethnic and circumstantial bias in the questionnaire, suggesting that job strain should be evaluated in a more critical manner in populations differing from the ones in which the concept was developed.

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Validation of the TONOPORT V ambulatory blood pressure monitor according to the European Society of Hypertension International Protocol for Validation of Blood Pressure Measuring Devices in Adults.

O'Brien E, Atkins N, Murphy A, Lyons S.

Blood Pressure Unit, Beaumont Hospital and Department of Clinical Pharmacology, Royal College of Surgeons, Dublin, Ireland. eobrien iol.ie

BACKGROUND: It is now accepted that blood pressure measuring devices should be subjected to an independent evaluation of their accuracy before they are marketed for clinical use. The results of validation of the TONOPORT V blood pressure monitor for the measurement of ambulatory blood pressure according to the European Society of Hypertension International Protocol for Validation of Blood Pressure Measuring Devices in Adults are presented in this paper. POPULATION: Thirty-three subjects were recruited from among staff and patients at Beaumont Hospital, Dublin, Ireland. METHODS: The TONOPORT V monitor was connected to the Sphygmocorder, an audiovisual system for validation, which records blood pressure on tape and video for later analysis. Nine sequential same-arm measurements between the device and a standard mercury sphygmomanometer were recorded using the Sphygmocorder. RESULTS: In phase 1, the TONOPORT V monitor produced 28 measurements within 5 mmHg, 37 within 10 mmHg and 40 within 15 mmHg for systolic blood pressure (SBP), and 26 within 5 mmHg, 38 within 10 mmHg and 44 within 15 mmHg for diastolic blood pressure (DBP). The mean differences were -2.2 (8.6) [mean (SD)] mmHg for SBP and +0.5 (7.2) mmHg for DBP. The TONOPORT V monitor passed all the criteria for both SBP and DBP. In phase 2.1, the TONOPORT V monitor had 56 measurements within 5 mmHg, 78 within 10 mmHg and 88 within 15 mmHg for SBP, and 60 measurements within 5 mmHg, 83 within 10 mmHg and 97 within 15 mmHg for DBP. The mean differences were -1.4 (8.7) mmHg for SBP and -0.2 (6.8) mmHg for DBP. The TONOPORT V monitor passed the criteria for DBP but failed to meet any of the criteria for SBP. In phase 2.2, 19 subjects had at least two of the differences within 5 mmHg and six subjects had no differences within 5 mmHg for SBP, and 22 subjects had at least two of the differences within 5 mmHg and six subjects no differences within 5 mmHg for DBP. The TONOPORT V monitor failed to meet the criteria for SBP and for DBP. CONCLUSIONS: The TONOPORT V monitor cannot be recommended for clinical use in an adult population because it records SBP inaccurately and because it records DBP inaccurately in an unacceptably high proportion of people.

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Ambulatory blood pressure monitoring: is the daytime period enough for making clinical decisions?

Suarez C, del Arco C, Garcia-Polo I.

Hypertension Unit, Internal Medicine, Hospital de la Princesa, Madrid, Spain. csuarez.hlpr salud.madrid.org

AIM: To assess the agreement between the clinical information provided by the ambulatory daytime average and 24 h average blood pressure value for diagnosing hypertension and assessing the effects of antihypertensive treatment. METHODS: We analysed 261 24 h ambulatory monitoring records (SpaceLabs 90207, SpaceLabs, Redmond, Washington, USA) obtained from hypertensives over 18 years of age (mean age 55.8 years) in order to make a diagnosis of hypertension or assess its control in response to treatment. Recording was programmed to occur every 20 min during waking periods and every 30 min during sleep, daily activity also being registered. The criteria compared in the diagnosis of hypertension were: (1) the evaluation criterion: an average blood pressure for the activity period of less than 135/85 mmHg (Joint National Committee VI); (2) the gold standard: an average blood pressure over 24 h of less than 125/80 mmHg (World Health Organization-International Society of Hypertension, 1999). RESULTS: In 90% of the records, there was agreement between both criteria. In 7.2%, the awake blood pressure average was normal and the 24 h average high. Values obtained were: sensitivity, 89% (95% confidence interval 84-89%); specificity, 92% (95% CI 88-95%); positive predictive value, 95.6% (95% CI 93-98%); negative predictive value, 81% (95% CI 75-85%); pretest probability, 66% (95% CI 60-72%); positive likelihood ratio, 11; and negative likelihood ratio, 0.3. There were no significant differences in age, gender or percentage of treated subjects between the groups with and without agreement. CONCLUSIONS: Daytime and 24 h average blood pressure may indeed carry similar information for diagnosing hypertension and assessing the effects of antihypertensive treatment in clinical practice. Ambulatory blood pressure monitoring used only during the daytime period could be better tolerated and agreed to by patients than 24 h monitoring.

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Specific alcoholic beverage and blood pressure in a middle-aged Japanese population: the High-risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) Study.

Okamura T, Tanaka T, Yoshita K, Chiba N, Takebayashi T, Kikuchi Y, Tamaki J, Tamura U, Minai J, Kadowaki T, Miura K, Nakagawa H, Tanihara S, Okayama A, Ueshima H; HIPOP-OHP research group.

Department of Health Science, Shiga University of Medical Science, Japan. tokamura belle.shiga-med.ac.jp

The purpose of this study was to clarify the effects of popular Japanese alcoholic beverages on blood pressure. We performed a cross-sectional study on 4335 Japanese male workers using baseline data from an intervention study. We defined six groups according to the type of alcoholic beverage that provided two-thirds of the subject's total alcohol consumption: beer, sake (rice wine), shochu (traditional Japanese spirits), whiskey, wine and others. The partial regression coefficients of daily alcohol intake (1 drink=11.5 g of ethanol) to systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 0.87(P<0.001, standard error (s.e.)=0.09) and 0.77(P<0.001, s.e.=0.06), respectively. A comparison among the types of alcoholic beverages mainly consumed revealed significant differences in SBP and DBP. Both SBP and DBP were highest in the shochu group. However, an analysis of covariance adjusting for total alcohol consumption resulted in the disappearance of these differences. Although after adjustment for total alcohol consumption, the shochu group exhibited a significant positive association with 'high-normal blood pressure or greater' (odds ratio 1.43, 95% confidence interval 1.06-1.95) compared with the beer group, this significant relation disappeared after adjusting for the body mass index (BMI), urinary sodium and potassium excretion. The pressor effect, per se, of popular Japanese alcoholic beverages on blood pressure may not be different among the types of alcoholic beverages after adjusting for other lifestyle factors. Journal of Human Hypertension (2004) 18, 9-16. doi:10.1038/sj.jhh.1001627

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Longevity-associated mitochondrial DNA 5178 A/C polymorphism and blood pressure in the Japanese population.

Kokaze A, Ishikawa M, Matsunaga N, Yoshida M, Sekine Y, Sekiguchi K, Harada M, Satoh M, Teruya K, Takeda N, Fukazawa S, Uchida Y, Takashima Y.

Department of Public Health, Kyorin University School of Medicine, Shinkawa Mitaka-shi, Tokyo, Japan. dawn kyorin-u.ac.jp

It has been reported that the mitochondrial DNA 5178 adenine/cytosine (mt5178 A/C) polymorphism, also called NADH dehydrogenase subunit 2-237 methionine/leucine (ND2-237 Met/Leu) polymorphism, may be associated with longevity in Japanese individuals, and that the mt5178A genotype may have an antiatherogenic influence. To determine whether mt5178 A/C polymorphism influences blood pressure, we genotyped 412 healthy Japanese individuals and performed a cross-sectional study investigating the relationship between genotype and blood pressure. In women with mt5178A, the mean diastolic blood pressure was higher than in those with mt5178C by 3.2 mmHg (P=0.040). In men, no statistically significant difference in systolic or diastolic blood pressure was observed between mt5178 A/C genotypes. However, a significant correlation between mt5178 A/C genotypes and the effects of habitual drinking on blood pressure was found. After adjustment for several factors, in men carrying mt5178C, both systolic and diastolic blood pressure were significantly higher in daily drinkers than in occasional (P=0.002 and 0.002, respectively) as well as nondrinkers (P<0.001 and 0.001, respectively), whereas in men carrying mt5178A, no significant differences in blood pressure were detected, irrespective of alcohol consumption. These results suggest that mt5178 A/C (=ND2-237 Met/Leu) polymorphism may influence both diastolic blood pressure in Japanese women and the blood-pressure-increasing effect of drinking in Japanese men. Journal of Human Hypertension (2004) 18, 41-45. doi:10.1038/sj.jhh.1001632

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