Reproducibility of the circadian systolic blood pressure variation in the elderly

OBJECTIVES: To establish the reproducibility of the nocturnal systolic blood pressure (SBP) change in elderly subjects and to examine the use of cumulative sums (cusums) analysis in the assessment of circadian SBP variation. SUBJECTS: Forty-two untreated elderly subjects (35 hypertensive, 7 normotensive) of mean age 75.5 years from the hypertension clinic at a large teaching hospital participated in a reproducibility study. METHODS: Twenty-four-hour ambulatory blood pressure monitoring was performed and repeated at a median interval of 2 months (range 2 weeks to 9 months). OUTCOME MEASURES: Reproducibility of circadian SBP variation from fixed time analysis of day-night SBP difference and from cusums-based parameters. RESULTS: Twenty-four-hour SBP values were highly reproducible with a coefficient of variation of 5.8%. However, the day-night SBP difference for fixed time periods was poorly reproducible, with a coefficient of variation > 130%. A substantial proportion of subjects (36-43%) altered their 'dipping status' between visits. The use of cusums analysis improved the reproducibility of measures of circadian SBP change (cusums plot height and maximum circadian variation) with coefficients of variation falling to 40 and 38%, respectively. CONCLUSIONS: The use of fixed time definitions results in poor reproducibility of the circadian SBP change in the elderly, which will lead to regression dilution bias when studying the relationship of circadian SBP variation to outcome measures in hypertension. The notion of dipping and non-dipping circadian blood pressure patterns should be abandoned in favour of more reproducible cusums-based measures of circadian blood pressure variation.     

The relationship between blood pressure and biochemical risk factors in a general population

The relationship between blood pressure, ponderal index, sex, blood glucose, haemoglobin, serum uric acid, calcium cholesterol and creatinine, and albumin has been examined in 698 subjects aged between 44 and 49 years from the register of a group general practice. Sixty per cent of the variation in systolic pressure could be explained by statistically significant associations with diastolic pressure, sex, blood glucose, serum calcium, and cholesterol. The diastolic blood pressure (not corrected for systolic pressure) was significantly related only to ponderal index, haemoglobin in men, and cholesterol in women. Pulse pressure was also positively related to the risk factors blood glucose, serum cholesterol, and calcium. The possibility is discussed that one or more of these variables reduce aortic compliance and that the serum calcium contributes to this end. Diastolic, but not systolic pressure, had a prime association with relative weight, obesity being only basically associated with an increase in diastolic pressure.     

A field study of the ventilatory response to ambient temperature and pressure in sport diving

We measured alveolar-to-vascular leakage of surfactant protein A (SP-A) in immature newborn rabbits delivered at a gestational age of 27 days. Experimental animals received, via a tracheal cannula, 2 ml/kg of a mixture of modified porcine surfactant (Curosurf, 80 mg/ml) and human recombinant SP-A (4 mg/ml). Littermate controls received the same volume of human SP-A in saline (4 mg/ml). After 30 min of artificial ventilation with a frequency of 40/min and an inspiration time of either 0.75 or 0.45 s, blood was sampled from the right ventricle and the lungs were lavaged. The content of human SP-A in serum and lung lavage fluid was determined with ELISA kits, and the alveolar-to-vascular leak expressed as the quotient of total SP-A in serum and lavage fluid. The leak in control animals amounted to about 2% of SP-A in lung wash and was several times higher in these animals than in those receiving surfactant. The leak was of the same order irrespective of whether the animals were ventilated with long or short inspiration time. We speculate that serum levels of SP-A may reflect the degree of lung injury in various forms of respiratory failure.     

Women''s anger: relationship of suppression to blood pressure

Myeloablative therapy followed by allogeneic bone marrow transplantation (BMT) has proven to be curative therapy in patients with hematologic malignancies. Relapse, however, remains a major cause of treatment failure for patients with advanced disease. During the past 15 years, we have gained considerable experience with the combination of fractionated total-body irradiation (FTBI) and etoposide followed by allogeneic BMT for hematologic malignancies. In an attempt to decrease post-transplant relapse rates, 67 patients under the age of 50 years with high-risk or advanced-stage hematological malignancies received an intensified regimen of FTBI and etoposide plus cyclophosphamide followed by BMT from a genotypically-matched related donor. The regimen consisted of 1320 cGy of FTBI in 11 fractions, 60 mg/kg of etoposide (VP-16), and 60 mg/kg of cyclophosphamide (CY). Fifty-three patients received cyclosporine and prednisone for graft-vs.-host disease (GVHD) prophylaxis and 14 patients received cyclosporine, methotrexate, and prednisone. Diagnosis at BMT included 45 patients with acute leukemia, 7 patients with chronic leukemia, and 15 patients with high-grade non-Hodgkin's lymphoma (NHL). Actuarial disease-free survival (DFS) at 3 years was 42% +/- 12% for the entire group with a median follow-up of 50 months (range 20-74) for 28 patients who remain alive in continued complete remission (CR). Actuarial 3-year-DFS was 38% +/- 14% in 52 patients with acute or chronic leukemia and 60% +/- 25% in 15 patients with NHL with relapse rates of 45% +/- 16% and 21% +/- 11%, respectively. DFS at 3 years was 40% +/- 18% in 32 patients with acute leukemia in 1st relapse or 2nd CR or chronic myelogenous leukemia in accelerated phase, and was 32% +/- 22% in 20 patients with more advanced disease. Regimen related mortality occurred in 9 patients (4, veno-occlusive disease of the liver; 2, multi-organ failure; 1, diffuse alveolar hemorrhage; 1, central nervous system (CNS) hemorrhage; 1, adult respiratory distress syndrome (ARDS). The combination of FTBI, etoposide, and cyclophosphamide followed by allogeneic BMT is an effective and relatively well-tolerated regimen for patients with advanced hematologic malignancies. The role for this regimen should be further defined by prospective clinical trials.     

The association of blood lead and blood pressure in population surveys

The association of age, body weight, body mass index (BMI) and glycosylated hemoglobin A1c (HbA1c) to blood pressure in the general population of the Ho-long area in Taiwan was examined. A total of 1341 subjects, 746 men and 595 women, aged 40-90 years, were studied. Sex-specific multiple regression analyses were carried out on variables both univariately and significantly associated with blood pressure. Results show HbA1c to be significantly associated with SBP in both males and females before age, weight and/or BMI are adjusted (p < 0.05). After controlling for these confounders, the strength of SBP-HbA1c association was slightly reduced in males, but remained significant. In contrast, there was no significance in females. Moreover, no significant relationship in DBP-HbA1c was found in either sex group. These findings suggest that although a positive correlation was found between HbA1c and SBP, HbA1c or glucose status appeared to be a less important contributing factor in hypertension than age or body weight.     

Seasonal variations in home and ambulatory blood pressure in the PAMELA population. Pressione Arteriose Monitorate E Loro Associazioni

OBJECTIVE: Clinic blood pressure values are known to change according to seasonal influences. We therefore examined home and 24 h ambulatory blood pressure values to determine whether these measurements are also affected by the seasons. DESIGN AND METHODS: In 2051 subjects of the Pressione Arteriose Monitorate E Loro Associazioni (PAMELA) study, we measured clinic (sphygmomanometric measurements), home (semi-automatic device) and ambulatory (Spacelabs 90207) systolic blood pressure, diastolic blood pressure and heart rate. Because the overall sample was evenly distributed over each month (except August), we were able to make a cross-sectional determination of whether the values differed between seasons. The corresponding heart rates were also evaluated. RESULTS: As expected, summer was associated with the lowest clinic blood pressure and winter with the highest, and this was the case also for home and 24 h average blood pressure, although seasonal differences in the latter were less pronounced. Seasonal clinic, home and ambulatory blood pressure patterns were similar for normotensive subjects (n = 1152), untreated hypertensives (n = 540) and treated hypertensives (n = 359). Heart rate values did not differ by season. CONCLUSIONS: Seasonal influences on blood pressure are not limited to conventional measurements but characterize daily values as well. These effects are visible in both normal and elevated blood pressure values, regardless of the effect of antihypertensive drugs. This has implications both for the clinician and for studies aimed at evaluating the effects of antihypertensive treatment.     

Postprandial blood pressure changes in the elderly

Postprandial blood pressure reductions have been observed in frail elderly individuals. This study evaluated blood pressure and heart rate changes in 10 healthy elderly subjects at intervals before and after a morning meal. Subjects did not exhibit significant reductions in systolic blood pressure or increases in heart rate over time, rather, such changes were due to variation within subjects. They did not exhibit significant changes in diastolic blood pressure. Age, health, and meal choice may have influenced results. Further research will determine which groups of elderly are most at risk for postprandial blood pressure reductions and consequently at risk for injury from falls due to dizziness and syncope.     

Autonomic nervous system dysfunction in elderly hypertensive patients with abnormal diurnal blood pressure variation: relation to silent cerebrovascular disease

To investigate the relationships among diurnal blood pressure (BP) variations and autonomic nervous system dysfunction, we assessed heart rate variability (HRV) using power spectral analysis of the 24-hour RR interval in 51 asymptomatic elderly hypertensive patients with various patterns of nocturnal BP fall. The extreme-dippers with marked nocturnal BP fall (n=16) had lower asleep low-frequency power (LF)/high-frequency power (HF) ratios (a relative index of sympathetic nervous system activity), while the nondippers without nocturnal BP fall (n=18) had lower awake LF/HF ratios and asleep/awake ratio for HF (an index of parasympathetic nervous activity), when compared with dippers with appropriate nocturnal BP fall (n=17). The incidence of multiple lacunar infarction detected by brain magnetic resonance imaging was 56% in the extreme-dippers and 38% in the nondippers, and both were markedly higher than that (6.3%) in the dippers (both P<.01). There was no significant relationship between the BP level and any HRV parameter for either the daytime or nighttime period. The asleep/awake ratio for systolic BP was significantly correlated with the asleep/awake ratio for HF (r= -.363, P<.01) and with the asleep/awake ratio for the LF/HF ratio (r=.540, P<.001), regardless of whether multiple lacunar infarction was present. In conclusion, the autonomic nervous system activity is not related to high BP level per se, rather its diurnal variation is more important as a determinant of the diurnal BP patterns, regardless of the presence or absence of cerebrovascular disease.     

The relationship of blood lead and dietary calcium to blood pressure in the normative aging study

BACKGROUND: Previous studies have demonstrated a positive relationship between elevated blood lead (BPb) and blood pressure (BP), but few have additionally examined the role of dietary calcium. METHODS: The cross-sectional relationship between BPb and BP and the possible protective influence of increased dietary calcium on that relationship was examined among 798 male participants in the Normative Aging Study (NAS), a cohort of older men with relatively low BPb levels. RESULTS: The age range of these subjects was 43-93 years (mean = 66.1, SD = 7.4 years) and blood lead concentrations ranged form 0.5 to 35 mcg/dl (median = 5.6 mcg/dl). For the cohort overall, neither ln blood lead nor dietary calcium were significantly correlated with BP. In multivariate linear regression analyses that adjusted for age, body mass index, dietary calcium intake (adjusted for total calorie intake), alcohol intake, sitting heart rate, kilocalories/week expended in exercise, haematocrit, and smoking status, a unit increase in ln BPb predicted an increase on 1.2 mmHg diastolic blood pressure (DBP) (95% CI : 0.11, 2.2; P = 0.03). Adjusted calcium intake of 800 mg/day predicted a decrease of 3.2 mmHg systolic blood pressure (SBP) (95% CI : -5.6, -0.24, P = 0.03). There was no evidence of an interaction between dietary calcium intake and blood lead on BP. When the analyses were restricted to those men <=74 years old, a unit increase in ln BPb predicted an increase of 1.6 mmHg DBP (n = 681; 95% CI : 0.42, 2.7; P = 0.007). However, when men on antihypertensive medication (AHM) were excluded from the analyses, ln BPb was not significantly associated with increased DBP nor was adjusted calcium significantly associated with SBP. CONCLUSIONS: The study did support the hypothesis that increased BPb was associated with increased DBP in a cohort of older men with low blood lead, but there was no evidence of interaction between BPb and dietary calcium on BP. However, the relationship between increased BPb and DBP did not hold when those on anti-hypertensive medications were excluded.     

Ambulatory systolic blood pressure patterns in elderly hypertensives

In a recent study we found that patients with isolated systolic hypertension (ISH) had two patterns of systolic blood pressure (SBP) elevations by ambulatory BP monitoring (ABPM), sustained (S) and intermittent (I), the prognostic significance of which seems to be different. In the present study we tried to determine whether such patterns of SBP elevations may be detected among other hypertensives as well. Twenty-eight elderly patients (mean age 65.5+/-5.1 years), nine with ISH, 10 with systolodiastolic hypertension (SDH), and nine with white coat hypertension (WCH), underwent ABPM. Average clinic BP in the ISH group was 184/83 mm Hg, in the SDH group 172/101 mm Hg, and in the WCH group 166/91 mm Hg, where as the ABPM averages were 169/80, 167/95 and 132/73 mm Hg, respectively, and differences held true for both daytime and night-time. Five ISH and four SDH patients had S patterns on ABPM, while the other four ISH and six SDH patients exhibited I patterns; none of the nine WCH subjects had either S or I patterns. ECG revealed left ventricular hypertropy (LVH) and/or ischaemic changes in eight patients with S patterns (ISH and SDH groups combined), as opposed to two patients with I patterns and only one patient of the WCH group. This seems to further suggest that an S pattern of SBP elevation on ABPM may have worse prognostic implications than either an I pattern or no SBP elevation.     

Behavioral predictors of blood pressure variation in hypertensives and normotensives.

Examined the relative impact of activity, posture, location, social involvement, and tension on the 24-hr blood pressure (BP) variability of 21 normotensives, 18 borderline hypertensives, and 18 sustained essential hypertensives. Within each diagnostic group, activity accounted for more variance in BP variability than any other behavioral dimension. For each behavioral dimension, the magnitude of the relationship with BP was greater for the normotensives than for both hypertensive groups. Variation due to individuals was a better predictor of BP variability for the 2 hypertensive groups than for the normotensive group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inadequate management of blood pressure in a hypertensive population

BACKGROUND: Many patients with hypertension have inadequate control of their blood pressure. Improving the treatment of hypertension requires an understanding of the ways in which physicians manage this condition and a means of assessing the efficacy of this care. METHODS: We examined the care of 800 hypertensive men at five Department of Veterans Affairs sites in New England over a two-year period. Their mean (+/-SD) age was 65.5+/-9.1 years, and the average duration of hypertension was 12.6+/-5.3 years. We used recursive partitioning to assess the probability that antihypertensive therapy would be increased at a given clinic visit using several variables. We then used these predictions to define the intensity of treatment for each patient during the study period, and we examined the associations between the intensity of treatment and the degree of control of blood pressure. RESULTS: Approximately 40 percent of the patients had a blood pressure of > or =160/90 mm Hg despite an average of more than six hypertension-related visits per year. Increases in therapy occurred during 6.7 percent of visits. Characteristics associated with an increase in antihypertensive therapy included increased levels of both systolic and diastolic blood pressure at that visit (but not previous visits), a previous change in therapy, the presence of coronary artery disease, and a scheduled visit. Patients who had more intensive therapy had significantly (P<0.01) better control of blood pressure. During the two-year period, systolic blood pressure declined by 6.3 mm Hg among patients with the most intensive treatment, but increased by 4.8 mm Hg among the patients with the least intensive treatment. CONCLUSIONS: In a selected population of older men, blood pressure was poorly controlled in many. Those who received more intensive medical therapy had better control. Many physicians are not aggressive enough in their approach to hypertension.     

Prevalence of high blood pressure and associated coronary risk factors in an adult population of Mexico City

The application of managed care to dialysis raises concerns that dialysis will be rationed in the United States. Rationing means the implicit or explicit denial of beneficial or marginally beneficial medical treatment as a result of insufficient resources to provide treatment to all. In this era of cost containment and budget cutting, rationing appears inevitable in the end-stage renal disease program because of its continued growth in numbers and cost and because many are questioning the benefit of dialysis to certain groups of patients. Rationing according to social worth, ability to pay, or age is not ethically justifiable, but it is justified to ration according to medical benefit. There is an important role for guidelines developed with broad input from patients, families, health care professionals, ethicists, health policy experts, and payers. Consensus statements exist in the literature, and the nephrology community is in the process of developing practice guidelines that will be available for future use. In the meantime, managed care companies should look to broader community input in the form of consensus statements and community dialogue. Managed care companies will need ethics committees to ensure that their policies and procedures for rationing are fair, principled, and subject to review and appeal.     

Use of antihypertensive drugs and trends in blood pressure in the elderly

BACKGROUND: During the 1980s data became available from randomized trials concerning the clear benefits of treating hypertension in the elderly. In three large communities, we examined the impact of these findings on rates of treatment, use of specific antihypertensive drugs, and rates of elevated blood pressure as well as distributions of levels. METHODS: In 1981 the National Institute on Aging initiated population-based cohort studies in the residents of three communities who were 65 years and older. East Boston, Mass; Washington and Iowa counties, Iowa; and New Haven, Conn. Participation rates ranged from 80% to 85% across sites with 10,294 community-dwelling participants in the combined cohorts. Baseline evaluation included inhome blood pressure assessment and medication inventory. Repeated in-home evaluations occurred 3 and 6 years after baseline and follow-up rates ranged from 71% to 88%. RESULTS: Use of antihypertensive drugs increased over time in all three communities: the age- and sex-adjusted rates of use were between 14% and 32% higher in 1988 and 1989 relative to 1982 and 1983. Parallel declines in the use of thiazide diuretics occurred in all three populations along with large increases in the use of angiotensin-converting enzyme inhibitors and calcium channel blockers. In East Boston and New Haven mean systolic blood pressure decreased substantially over time and the prevalence of elevated systolic pressure (> or = 160 mmHg) decreased overall as well as by age and sex. In Iowa the mean levels of systolic blood pressure were lowest at baseline and increased slightly. CONCLUSIONS: The reported evidence about the benefits of treatment for hypertension in the elderly was followed by substantial increases in treatment rates. The use of drugs with proven efficacy declined while the use of newer agents with theoretical advantages, not yet tested in clinical trials of mortality, increased. In the United States, the ongoing therapeutic efforts to lower elevated blood pressure in elderly populations may be contributing to the continuing decline in cardiovascular and stroke mortality.     

Occurrence of dementia and depression in an elderly Danish population

A community survey of all Danish speaking residents above the age of 64 in a geographically delimited area was performed. The aim of the survey was to establish the prevalence of dementia disorders and depression by the use of international screening tools: the Mini Mental State Examination for dementia and the Beck's Depression Inventory for depression. The screening was performed during the period of one year in the municipality of Karlebo and the interviews took place in the homes of the participants. Six hundred and sixty-four (66%) of the 1,008 eligible persons entered the study. Six percent were residents in nursing homes. Thirteen point seven percent were found to be suffering from dementia. Nine point six percent had symptoms of depression. These prevalences would indicate that more than 6,000 persons in Frederiksborg county suffer from dementia while more than 4,000 might be suffering from depression. The study confirms knowledge obtained in other studies, indicating that one out of seven of the elderly suffers from dementia. We do not conclude, however, that nine point six percent suffer from depression, but rather that they need further examination to make it possible to decide whether they are indeed depressed.     

Phase response curves to ambient temperature pulses in rats

The effect of pulses of warm ambient temperature on the phase of activity onset in Long-Evans hooded rats, Rattus norvegicus, free-running in constant light was examined. In two experiments, rats were exposed to pulses reaching a maximum of 34 degrees C or 32 degrees C. Phase response curves were obtained with advances occurring mainly in the subjective day, and delays mainly, but not entirely, in the subjective night. Significant negative correlations between rhythm period and phase-shifts were found. There were no consistent relationships between changes in activity levels due to the temperature pulses and phase-shifts. Cycles of higher and lower ambient temperature may entrain circadian activity rhythms in mammals by daily advance or delay phase-shifts.     

Normal values for ambulatory blood pressure and differences between casual blood pressure and ambulatory blood pressure: results from a Danish population survey

Oncogenic forms of the Abl and Src tyrosine kinases trigger the destruction of the Abi proteins, a family of Abl-interacting proteins that antagonize the oncogenic potential of Abl after overexpression in fibroblasts. The destruction of the Abi proteins requires tyrosine kinase activity and is dependent on the ubiquitin-proteasome pathway. We show that degradation of the Abi proteins occurs through a Ras-independent pathway. Significantly, expression of the Abi proteins is lost in cell lines and bone marrow cells isolated from patients with aggressive Bcr-Abl-positive leukemias. These findings suggest that loss of Abi proteins may be a component in the progression of Bcr-Abl-positive leukemias and identify a novel pathway linking activated nonreceptor protein tyrosine kinases to the destruction of specific target proteins through the ubiquitin-proteasome pathway.