Pressure-independent cardiac effects of angiotensin II in pigs.

Broome M, Haney M, Haggmark S, Johansson G, Aneman A, Biber B.

Department of Surgical and Perioperative Science, Anaesthesiology and Intensive Care, Umea University, Umea, Sweden.

BACKGROUND: Angiotensin II (Ang II) is a potent vasoconstrictor with an important role in the development of cardiovascular disease. Earlier results have shown a positive acute inotropic effect of Ang II in anaesthetized pigs together with significant vasoconstriction. This investigation was designed to study cardiac effects of Ang II, when blood pressure was maintained constant by experimental means. METHODS: Ang II (200 microg h(-1)) was infused in anaesthetized pigs (n = 10) at two different arterial blood pressures, the first determined by the effects of Ang II alone, and the second maintained at baseline blood pressure with nitroprusside. Cardiac systolic and diastolic function was evaluated by analysis of left ventricular pressure-volume relationships. RESULTS: Heart rate, end-systolic elastance (Ees) and pre-load adjusted maximal power (PWRmax EDV(-2)) increased at both blood pressure levels, although less when blood pressure was kept constant with nitroprusside. The time constant for isovolumetric relaxation (tau(1/2)) was prolonged with Ang II alone and shortened with Ang II infused together with nitroprusside. CONCLUSION: Ang II infusion in the pig has inotropic and chronotropic properties independent of arterial blood pressure levels, although the effects seem to be blunted by pharmacological actions of the nitric oxide donor nitroprusside. Copyright 2004 Scandinavian Physiological Society

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Undiagnosed hypertension in the ED setting--an unrecognized opportunity by emergency nurses.

Tanabe P, Steinmann R, Kippenhan M, Stehman C, Beach C.

Institute for Health Services Research and Policy Studies & Emergency Medicine, Northwestern University, Chicago, Ill, USA. p-tanabe northwestern.edu

INTRODUCTION: Hypertension is often undiagnosed, untreated, undertreated, and poorly controlled. Many patients use the emergency department as their primary source of health care, and the emergency department represents an opportunity to identify undiagnosed hypertension. We sought to (1) identify the prevalence of elevated blood pressures in low-acuity patients and (2) describe the existing practice of reassessment, treatment, and referral of abnormal vital signs in these patients. METHODS: We conducted a retrospective study of 88 ED patients at an academic medical center. All patients meeting Emergency Severity Index level 4 or 5 criteria (low acuity) were eligible. The following variables were recorded: triage level, medical history and medications, disposition, and all blood pressures. The investigators independently reviewed and reached consensus regarding the following outcome variables: the need for and actual treatment of elevated blood pressure, and the need for and referral for blood pressure recheck after discharge. RESULTS: Thirty-seven patients (45%) had hypertension by definition on arrival. Systolic hypertension was more common. Ten of the patients (27%) with elevated blood pressures had documented rechecks prior to discharge in the emergency department, and only one patient was referred for follow-up. Twenty-seven out of 37 low-acuity patients (73%) who presented with elevated blood pressures had no documentation of the blood pressure being rechecked and no documentation of the patient being referred. CONCLUSION: Our data suggest that important opportunities for education and follow-up of hypertension are being missed.

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Blood pressure measurement in obese patients: comparison between upper arm and forearm measurements.

Pierin AM, Alavarce DC, Gusmao JL, Halpern A, Mion D Jr.

University of Sao Paulo School of Nursing, Brazil.

BACKGROUND: It is well known that blood pressure measurement with a standard 12-13 cm wide cuff is erroneous for large arms. OBJECTIVE: To compare arm blood pressure measurements with an appropriate cuff and forearm blood pressure measurements (BPM) with a standard cuff, and both measurements by the Photopletismography (Finapres) method. METHODS: One hundred and twenty-nine obese patients were studied (body mass index=40+/-7 kg/m2). The patients had three arm BPM taken by an automatic oscillometric device using an appropriate cuff and three forearm BPM with a standard cuff in the sitting position after a five-minute rest. Data were analysed by the analysis of variance. The correction values were obtained by the linear regression test. RESULTS: Systolic and diastolic arm BPM with an appropriate cuff were significantly lower (p<0.05) than forearm BPM with a standard cuff. The measurements obtained by Finapres were significantly lower (p<0.05) than those found for forearm systolic and diastolic blood pressures and upper arm diastolic blood pressure. The equation to correct BPM in forearm in obese patients with arm circumference between 32-44 cm was: systolic BPM=33.2+/-0.68 x systolic forearm BPM, and diastolic BPM=25.2+0.59 x forearm diastolic BPM. CONCLUSION: This study showed that forearm blood pressure measurement overestimates the values of arm blood pressure measurement. In addition, it is possible to correct forearm BPM with an equation.

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Dietary phytoestrogens and vascular function in postmenopausal women: a cross-sectional study.

Kreijkamp-Kaspers S, Kok L, Bots ML, Grobbee DE, van der Schouw YT.

Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, The Netherlands.

OBJECTIVE: To investigate the effects of low levels of intake of phytoestrogens in Western habitual diet on vascular function. DESIGN: A cross-sectional study. SETTING: A population-based study. PARTICIPANTS: A total of 301 postmenopausal women aged 60-75 years living in The Netherlands. DETERMINANT: Dietary phytoestrogen intake as assessed using a food frequency questionnaire covering the year prior to enrollment. MAIN OUTCOME MEASURES: Blood pressure, hypertension, endothelial function and ankle brachial index. RESULTS: The median isoflavone intake was 0.2 mg in the lowest tertile and 11.4 mg in the highest tertile. Median lignan intake was 0.8 and 2.2 mg, respectively. No associations were found for higher intake of isoflavones, systolic and diastolic blood pressures, ankle-arm blood pressure index, endothelial function or hypertension. For lignans no association was found for ankle-arm blood pressure index or endothelial function, but we did observe lower systolic and diastolic blood pressures and a lower prevalence of hypertension (systolic blood pressure difference T3-T1, -11.2 mmHg, 95% confidence interval = -17.8 to -4.5, P for trend = 0.001; diastolic blood pressure difference T3-T1, -3.6 mmHg, 95% confidence interval = -7.8 to 0.6, P for trend = 0,08; and prevalence of hypertension, odds ratio T3 versus T1 = 0.41, 95% confidence interval = 0.22-0.76, P for trend over tertiles = 0.004). CONCLUSION: The results of this study suggest a protective effect of dietary lignan intake on blood pressure and hypertension, even at low levels.

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Maternal calcium intake and offspring blood pressure.

Gillman MW, Rifas-Shiman SL, Kleinman KP, Rich-Edwards JW, Lipshultz SE.

Department of Ambulatory Care and Prevention, Harvard Medical School/Harvard Pilgrim Health Care, Boston, Mass 02215, USA. matthew_gillman hms.harvard.edu.

BACKGROUND: Few data exist on the intergenerational influence of calcium intake during pregnancy on offspring blood pressure. METHODS AND RESULTS: As part of the ongoing US prospective cohort study Project Viva, we analyzed 4091 Dinamap blood pressure measurements from 936 six-month-old infants whose mothers had completed food frequency questionnaires during the second trimester of pregnancy. We used mixed models to estimate effects of maternal calcium intake on offspring systolic blood pressure. Mean+/-SD daily total maternal calcium intake was 1494+/-523 mg, consisting of 1230+/-486 mg from foods and 264+/-191 mg from supplements. Mean+/-SD 6-month blood pressure was 89.9+/-12.9 mm Hg. From bottom to top quartile of dietary calcium from foods adjusted for energy intake and measurement conditions, mean infant systolic blood pressures were 91.0, 90.2, 90.9, and 90.2 mm Hg (trend P=0.62). From calcium supplements only, the values were 91.5, 90.2, 90.4, and 88.4 mm Hg (trend P=0.006). After further adjustment for demographic, anthropometric, dietary, social, and economic variables, the decrease in 6-month systolic blood pressure was -3.0 mm Hg (95% CI, -4.9 to -1.1) for each 500-mg increment of maternal supplemental calcium intake during pregnancy. We did not find evidence of effect modification by maternal vitamin D or potassium intake or by infant body mass index. First-trimester calcium intake was not associated with offspring blood pressure. CONCLUSIONS: These observational data suggest that supplementing maternal midgestational calcium intake may lower offspring blood pressure, thus helping to prevent hypertension in the next generation.

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Poor glycemic control is associated with increased diastolic blood pressure and heart rate in children with Type 1 diabetes.

Torchinsky MY, Gomez R, Rao J, Vargas A, Mercante DE, Chalew SA.

Pediatric Endocrinology/Diabetes, Department of Pediatrics, Louisiana State University Health Sciences Center and Children's Hospital of New Orleans, New Orleans, LA 70118, USA.

Although higher levels of hemoglobin A1c (HbA1c) and blood pressure precede the development of nephropathy in Type 1 diabetes (T1DM), the relationship between glycemic control and cardiovascular factors early in the course of diabetes is not clear. We conducted a retrospective study from clinic data for a 1-year period in 148 children with T1DM aged 12.5+/-4.4 years who had average diabetes duration of 4.5+/-3.3 years. The influence of HbA1c and reported insulin dose on blood pressure and heart rate were analyzed in multivariate linear regression models, statistically adjusted for the effect of race, sex, age, body mass index, and duration of diabetes. There was a significant positive correlation of mean HbA1c with mean diastolic blood pressure (P<.025) and mean heart rate (P<.0004). Higher diastolic blood pressure and heart rate were associated with higher HbA1c. Increased insulin doses were also associated with increased diastolic blood pressure (P<.009) and heart rate (P<.013). Insulin dose and HbA1c were also significantly correlated (P<.001). There was no correlation between mean HbA1c and mean systolic blood pressure. Increased levels of HbA1c and insulin dose are associated with increased diastolic blood pressure and heart rate. Although within the normal range, early increases of diastolic blood pressure and heart may indicate early cardiovascular changes in response to diabetes and potentially contribute to a greater proclivity for later development of nephropathy.

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Blood pressure dependent and independent effects of antihypertensive treatment on clinical events in the VALUE Trial.

Weber MA, Julius S, Kjeldsen SE, Brunner HR, Ekman S, Hansson L, Hua T, Laragh JH, McInnes GT, Mitchell L, Plat F, Schork MA, Smith B, Zanchetti A.

State University of New York, Brooklyn, NY, USA.

The Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial was designed to test whether, for the same achieved blood pressures, regimens based on valsartan or amlodipine would have differing effects on cardiovascular endpoints in high risk hypertension. But inequalities in blood pressure, favouring amlodipine, throughout the multiyear trial precluded comparison of outcomes. A technique of serial median matching, applied at 6 months when treatment adjustments intended to achieve control of blood pressure were complete, created 5006 valsartan-amlodipine patient pairs matched exactly for systolic blood pressure, age, sex, and the presence or absence of previous coronary disease, stroke, or diabetes. Subsequent combined cardiac events, myocardial infarction, stroke, and mortality were almost identical in the two cohorts, but admission to hospital for heart failure was significantly lower with valsartan. Reaching blood pressure control (systolic <140 mm Hg) by 6 months, independent of drug type, was associated with significant benefits for subsequent major outcomes; the blood pressure response after just 1 month of treatment predicted events and survival.

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Exaggerated blood pressure responses during mental stress are prospectively related to enhanced carotid atherosclerosis in middle-aged Finnish men.

Jennings JR, Kamarck TW, Everson-Rose SA, Kaplan GA, Manuck SB, Salonen JT.

Department of Psychiatry, University of Pittsburgh, E1329 WPIC, 3811 O'Hara St, Pittsburgh, PA 15213, USA. JenningsJR upmc.edu

BACKGROUND: Hemodynamic reactions to mental stress may contribute to atherosclerosis. We previously observed cross-sectional relationships between blood pressure reactions to a standardized stress battery and carotid intima-media thickness (IMT) in the Kuopio Ischemic Heart Disease (KIHD) study. These are the first prospective results on this relationship. METHODS AND RESULTS: Men from 4 age cohorts (42 to 60 years old at study onset) were challenged with a standardized mental stress battery, and heart rate and blood pressure reactions were assessed. Ultrasound measures of common carotid IMT were collected at this time and 7 years later as noninvasive markers of atherosclerosis. Data were collected from a sample of 756 men at both times. Systolic blood pressure reactions to mental stress at study onset were positively related to mean carotid IMT 7 years later (beta=0.035, P=0.001, by blood pressure quartile, IMT=0.91, 0.93, 0.96, 1.00 mm) and to the progression of IMT (beta=0.020, P=0.006, by blood pressure quartile, DeltaIMT=0.08, 0.09, 0.11, 0.11 mm). Similar significant relations were shown for maximal IMT and plaque height. Diastolic blood pressure responses were less strongly related to carotid IMT than were systolic responses. Heart-rate responses were unrelated. Adjustment for standard risk factors did not substantially reduce the relation between systolic blood pressure reactivity and the progression of mean carotid IMT (standardized beta=0.059, P=0.026), maximal carotid IMT (standardized beta=0.084, P=0.006), or plaque height (standardized beta=0.093, P=0.008). CONCLUSIONS: The degree of systolic blood pressure reactivity to mental challenge is prospectively related to carotid IMT in middle-aged and older men, independent of known risk factors.

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