Orthostatic hypotension predicts mortality in elderly men: the Honolulu Heart Program

BACKGROUND: Population-based data are unavailable concerning the predictive value of orthostatic hypotension on mortality in ambulatory elderly patients, particularly minority groups. METHODS AND RESULTS: With the use of data from the Honolulu Heart Program's fourth examination (1991 to 1993), orthostatic hypotension was assessed in relation to subsequent 4-year all-cause mortality among a cohort of 3522 Japanese American men 71 to 93 years old. Blood pressure was measured in the supine position and after 3 minutes of standing, with the use of standardized methods. Orthostatic hypotension was defined as a drop in systolic blood pressure (SBP) of >/=20 mm Hg or in diastolic blood pressure of >/=10 mm Hg. Overall prevalence of orthostatic hypotension was 6.9% and increased with age. There was a total of 473 deaths in the cohort over 4 years; of those who died, 52 had orthostatic hypotension. Four-year age-adjusted mortality rates in those with and without orthostatic hypotension were 56.6 and 38.6 per 1000 person-years, respectively. With the use of Cox proportional hazards models, after adjustment for age, smoking, diabetes mellitus, body mass index, physical activity, seated systolic blood pressure, antihypertensive medications, hematocrit, alcohol intake, and prevalent stroke, coronary heart disease and cancer, orthostatic hypotension was a significant independent predictor of 4-year all-cause mortality (relative risk 1.64, 95% CI 1.19 to 2.26). There was a significant linear association between change in systolic blood pressure from supine position to standing and 4-year mortality rates (test for linear trend, P<0.001), suggesting a dose-response relation. CONCLUSIONS: Orthostatic hypotension is relatively uncommon, may be a marker for physical frailty, and is a significant independent predictor of 4-year all-cause mortality in this cohort of elderly ambulatory men.     

Effects of age and isolated systolic hypertension on cardiovascular reflexes

OBJECTIVES: Given the reported relationship between systolic hypertension and orthostatic hypotension in the elderly, to test the hypothesis that systolic hypertension causes impairment of the cardiovascular reflex function additional to the effects of age alone. DESIGN: Responses were compared in normotensive healthy young (n = 12) and elderly (n = 15) participants and elderly participants with disproportionate supine systolic hypertension (n = 11) using a baroreceptor-mediated stress (head-up tilt) and two non-baroreceptor-mediated stimuli (cold pressor test and isometric exercise). METHODS: Blood pressure and heart rate were measured by oscillometry before and during the three stress tests. Forearm blood flow was measured by venous occlusion plethysmography and pulse wave velocity (PWV) by Doppler ultrasound. RESULTS: Percentage changes in systolic/diastolic (SBP/DBP) blood pressure with head-up tilt were 0/+11, -3/0 and -6/+1 mmHg in the young and elderly normotensives and elderly systolic hypertensives, respectively. Both elderly groups had reduced DBP responses to tilt compared with the young (P < 0.01). All three groups had similar percentage changes in blood pressure responses to non-baroreflex-mediated stresses (cold pressor test: +10/+23, +11/+11, +10/+15; sustained isometric exercise: +18/+33, +22/+24, +13/+17 in the young and elderly normotensives and elderly systolic hypertensives, respectively). Aorto-iliac PWV adjusted for blood pressure was significantly higher in both elderly groups compared with the young (P < 0.01) but there was no difference between elderly normotensives and hypertensives. Unadjusted PWV was higher in elderly hypertensives than in elderly normotensives (P < 0.05). CONCLUSIONS: Compared with healthy young participants, both elderly groups had similarly attenuated blood pressure responses to tilt and reduced arterial compliance. Systolic hypertension is not associated with additional impairment of cardiovascular reflex function over and above the effects of age. The reported association between supine systolic hypertension and orthostatic hypotension does not appear to be a causative one.     

Application of USAF G-suit technology for clinical orthostatic hypotension: a case study

INTRODUCTION: The purpose of this study was to determine the effectiveness of a USAF anti-gravity suit (G-suit) on the stability of a patient with chronic orthostatic hypotension. METHODS: A 37-yr-old female with a history of insulin-dependent diabetes mellitus (IDDM) and symptomatic orthostasis was evaluated and the results were compared with those of non-diabetic controls, matched for age, height, and weight. Cardiac vagal tone was assessed by determination of standard deviation of 100 R-R intervals (R-R SD). We assessed the carotid-cardiac baroreflex response by plotting R-R intervals (ms) at each of eight neck pressure steps with their respective carotid distending pressures (mm Hg). Heart rate and blood pressure were recorded in response to the Valsalva maneuver (VM) performed at an expiratory pressure of 30 mmHg to assess integrated baroreflex responses. Blood pressures and heart rate were measured during three 5-min stand tests to assess orthostatic responses: a) without G-suit; b) with noninflated G-suit; and c) with inflated G-suit (50 mm Hg). RESULTS: The IDDM patient had minimal baseline cardiac vagal tone (R-R SD = 8.5 ms) compared with the average response of a control group of 24 subjects with orthostatic stability (R-R SD = 67.2 +/- 7.1 ms). Carotid-cardiac baroreflex response was virtually non-existent in the IDDM patient (Gain = 0.06 ms.mm Hg-1) compared to the control subjects (4.4 +/- 0.8 ms.mm Hg-1). VM responses corroborated the lack of cardiac baroreflex response in the IDDM patient, while blood pressure changes during the VM were similar to those of the controls. Upon standing, the IDDM patient demonstrated severe orthostatic hypotension (90 mm Hg SBP) and tachycardia without the G-suit. The G-suit, with and without pressure, reduced hypotension and tachycardia during standing. CONCLUSION: These results demonstrate successful application of Air Force technology as a useful alternative to pharmacologic intervention in the treatment of a patient with autonomic dysfunction leading to supine hypertension and orthostatic hypotension.     

Code Stroke: rapid transport, triage and treatment using rt-PA therapy. The NINDS rt-PA Stroke Study Group

In view of the concern regarding the potential risks and benefits of sodium restriction, the effect on biochemical and orthostatic responses from a moderate reduction in sodium intake in elderly persons that is sufficient to lower systolic blood pressure (SBP) was examined. Seventeen hypertensive subjects aged 65-79 years entered a double-blind randomized placebo controlled cross-over trial of a low sodium diet plus placebo tablets vs a low sodium diet plus sodium tablets (80 mmols/day) each for 5 weeks. At the end of high and low sodium periods, two 24-h urine collections and venous blood samples were undertaken and supine and standing BPs were recorded. On the low compared to the high sodium phase (urinary sodium excretion 95 +/- 36 vs 174 +/- 40 mmols/24-h, respectively), clinic supine SBP fell by 8 mm Hg (95% CI: 1-15 mm Hg, P< 0.05) and diastolic BP (DBP) by 1 mm Hg (CI: -3 to 5 mm Hg); there was no change in total LDL- and HDL-cholesterol and triglyceride levels, serum calcium, phosphate, parathyroid hormone, glucose, creatinine clearance or urinary albumin excretion rate. Serum urate was significantly higher during the low compared to high sodium intake (304 +/- 56 vs 277 +/- 44 micromols/l). Orthostatic BP responses during the high and low sodium intakes were unchanged. In summary, after 5 weeks of moderate sodium restriction no adverse effects other than an increase in serum urate was seen in elderly hypertensive persons.     

Twenty-four-hour blood pressure profile and blood pressure responses to head-up tilt tests in Parkinson's disease and multiple system atrophy

OBJECTIVE: To investigate the 24 h blood pressure profile in patients with Parkinson's disease with intact autonomic function or with autonomic failure and patients with multiple system atrophy (MSA), and to assess whether these patients exhibit posture-related variations in blood pressure. PATIENTS AND METHODS: We studied 24 patients with Parkinson's disease (11 with autonomic failure) and 13 patients with MSA (all with autonomic failure). Autonomic failure was determined by autonomic tests. An oscillometric recorder was used for ambulatory blood pressure monitoring. Tilt-table tests were performed with a head-up tilt position of 60 degrees. RESULTS: An alteration in the normal 24 h blood pressure profile was observed in 82% of Parkinson's disease patients with autonomic failure and in 85% of those with multiple system atrophy, but not in the patients with intact autonomic function. Head-up tilt tests revealed a significantly higher supine blood pressure in Parkinson's disease patients with autonomic failure and in those with MSA than in Parkinson's disease patients with intact autonomic function. Tilting resulted in a marked fall in blood pressure in patients with MSA; in Parkinson's disease patients with autonomic failure, the fall was comparatively slighter. CONCLUSIONS: We conclude that autonomic failure contributes to the alterations in the day-night blood pressure profile that may possibly be ascribed to postural dysregulation of blood pressure. We hypothesize that nocturnal hypertension is a risk factor in the development of additional cerebrovascular disease in patients with Parkinson's disease or MSA who are affected by autonomic failure.     

Postprandial hypotension in Alzheimer''s disease

The degree of postprandial hypotension in patients with Alzheimer's disease (AD) is not known. We therefore studied ten AD patients and 23 controls before and after a meal. Seven AD patients but only six controls showed a fall in blood pressure (BP) of 20 mmHg or more. Maximum BP fall in AD patients was observed between 20 and 120 min after food ingestion. This differed from the time course in other groups with primary chronic autonomic failure. Postural hypotension occurred in two controls, but not in AD patients. Abnormalities in cardiac vasomotor regulation, gut peptide liberation or both could be responsible for postprandial hypotension in AD.     

Orthostatic hypotension and low blood pressure in organic dementia: a study of prevalence and related clinical characteristics

OBJECTIVE: To determine the prevalence of orthostatic hypotension (OH), low blood pressure and dizziness, falls and fractures in patients with organic dementia. DESIGN: We prospectively studied 151 patients, assessing the prevalence of OH, hypertension, heart disorders, diabetes mellitus and the use of medication possibly associated with OH. SETTING: The patients were admitted to our psychogeriatric clinic as part of routine clinical investigation of their dementia. PATIENTS: Forty-six patients with Alzheimer's disease (AD), 28 patients with frontotemporal dementia (FTD) and 77 patients with vascular dementia (VaD) were investigated. MAIN OUTCOME MEASURE: Due to the paucity of information about the prevalence of OH in organic dementia, this study is mainly explorative in nature, thus preventing explicit hypothesis formulation. However, clinical impressions indicated a higher prevalence of OH in organic dementia than normally seen in healthy elderly. RESULTS: OH/low blood pressure was present in 39-52% of the patients. The majority reached their maximum systolic decrease within 5 minutes of standing, but in 20-30% the maximum blood pressure drop occurred after 5 minutes or later. In 38%, the systolic blood pressure drop was more than 40 mm Hg. Hypertension and heart disease was found only in AD and VaD, with no difference between those with and without OH/low blood pressure. Falls and fractures were common in orthostatic and hypotensive patients, with an incidence of more than 50% in AD and VaD. CONCLUSIONS: The results support our clinical impressions that OH and low blood pressure is common and an important factor in organic dementia.     

Improved orthostatic tolerance in familial amyloidotic polyneuropathy with unnatural noradrenaline precursor L-threo-3,4-dihydroxyphenylserine

Disabling orthostatic hypotension, due to insufficiency of the autonomic nervous system, is a common complication of type I familial amyloidotic polyneuropathy (FAP). We investigated whether oral treatment with L-threo-3,4-dihydroxyphenylserine (L-threo-Dops), a noradrenaline precursor, might be of therapeutical benefit. In twenty untreated FAP patients, aged 33 to 44 years, who, because of severe orthostatic hypotension, were bedridden or constrained to a sitting life, supine and erect blood pressure (BP), plasma noradrenaline and tilting time, defined as the interval (s) between the beginning of a 60 degrees head-up tilt and the occurrence of orthostatic symptoms (dizziness, blurred vision or near syncope) were determined before and at repeated intervals during oral treatment with L-threo-Dops, 100 mg bid, for 6 months. Before treatment supine mean BP was 80 (76-85) mmHg (mean and 95% CI), supine plasma noradrenaline was low, 59 (41-77) pg/ml and tilting time ranged from 38 to 118 s. In response to tilt, mean BP immediately fell by 36 (31-41) mmHg, whereas plasma noradrenaline increased by only 11 (0-21) pg/ml (p = 0.05). After 3 to 5 days of treatment with L-threo-Dops all patients experienced marked improvement of their orthostatic tolerance as reflected by their ability to walk freely around. This effect sustained throughout the six months of treatment. Plasma noradrenaline increased moderately by 37 (11-63) pg/ml (p = 0.02) and supine mean BP increased by 8.6 (5.8-12.4) mmHg (p < 0.001) during chronic treatment. Supine or nocturnal hypertension did not develop, the fall in mean BP in response to tilt diminished by 12.5 (6.5-17.3) mmHg (p < 0.001) and tilting time became longer than 600 s in all patients. Because of its efficacy, its sustained duration of action and the lack of side effects, L-threo-Dops is advocated to improve orthostatic tolerance in patients with autonomic insufficiency due to FAP.     

Cerebral hypoperfusion in orthostatic hypotension with globally denervated myocardium

A 57-yr-old woman had frequent syncope when rising from a seated position. Her blood pressure fell from 140/80 mmHg to 60-70/40 mmHg while changing positions. Iodine-123-metaiodobenzylguanidine ([123I]MIBG) did not accumulate in the heart, whereas 201Tl-Cl (201Tl) did. Raise-up 99mTc-hexamethyl-propyleneamine oxime (99mTc-HMPAO) brain SPECT revealed decreased activity in the bilateral frontal areas, and subsequent supine 99mTc-HMPAO brain SPECT revealed filling in these areas, indicating that the cerebral blood flow (CBF) was transiently decreased in the frontal areas more than others in a standing position. The plasma norepinephrine (NE) level of this patient was normal during supine rest, but when she stood up, failure to increase the plasma level of NE uncovered a sympathetic nervous dysfunction. The CBF abnormality in patients with orthostatic hypotension may be due to a "functional" hemodynamic mechanism that induces orthostatic stress. This patient had transient hypoperfusion in the frontal areas when standing, without organic cerebral arterial stenosis. Only CBF in the frontal areas revealed relative hypoperfusion. These regions might be highly susceptible to a change in blood flow. The causes of orthostatic hypotension of this patient were autonomic failure with a disturbance of the sympathetic nerve endings, which was revealed by 99mTc-HMPAO brain SPECT and cardiac [123l]MIBG imaging.     

Role of nitrates in pharmacologic modulation of reflected waves and their significance in the treatment of arterial hypertension in the elderly

OBJECTIVE: To analyse the efficacy of a sustained release form of isosorbide mononitrate in the treatment of isolated systolic hypertension in the elderly. PATIENTS: 24 patients suffering from essential hypertension and with an average age of 68.5 +/- 1.1 years were studied: 20 male and four female patients, all with isolated systolic hypertension (systolic blood pressure (SBP) > 160 mmHg and diastolic blood pressure (DBP) < 90 mmHg). None of the patients had received pharmacological treatment for their hypertension. None were receiving other medication or displayed concomitant pathologies. METHODS: Assessment of all the patients was made with the measurement of their occasional blood pressure, ambulatory measurement of blood pressure and the measurement of pulse wave velocity in two arterial zones (carotid-femural) by mecanography before and after thirty days of monotherapy with a single 50 mg dose of a sustained release form of isosorbide mononitrate. Four patients were withdrawn from tests due to signs of intolerance to the drug. RESULTS: A fall in occasional blood pressure was recorded, with statistical significance in relation to SBP only: SBP-192 +/- 15.5-->164 +/- 10.2 mm Hg (p < 0.001); DBP-85 +/- 4.2-->83 +/- 5.4 mm Hg. Ambulatory blood pressure readings also showed a significant drop in average SBP readings over the 24 hours: SAP 152.6 +/- 13.6-->140.5 +/- 15.4 mm Hg (p < 0.03); DBP 77.2 +/- 8.7-->72.3 +/- 5.47 mm Hg. No significant changes in pulse wave velocity were recorded for the zones studied: carotid-femural -20.8 +/- 6.0-->21.7 +/- 5.1 m/sec; femural-foot -4.5 +/ -1.4-->4.4 +/- 2.6 m/sec; a marked alteration in the morphology of arterial pulse in the aortic zone was observed, however, with a clear levelling off and reduction of the systolic peak. CONCLUSION: Treatment with nitrates may be a new and effective alternative for the treatment of the age group in question. It acts specifically on the pathophysiological mechanisms of isolated systolic arterial hypertension in the elderly. Changes in reflected wave velocity (retrogrades) seem to cause the significant reduction in SBP, observed in this group of patients.     

Age-related differences in simultaneous interarm blood pressure measurements

Simultaneous noninvasive blood pressure measurement were recorded bilaterally in 40 young and 40 elderly subjects. Overall interarm blood pressure (BP) differences for the elderly and young groups were similar, the absolute interarm differences being for systolic blood pressure (SBP) elderly: 4.2 mmHg (95% CI 3.1-5.3 mmHg); young 3.3 mmHg(2.6-4.1 mmHg); diastolic blood pressure (DBP) elderly 3.6 mmHg(2.8-4.4 mmHg), young 2.7 mmHg(2.0-3.3 mmHg). However, the range of interarm BP differences was wide. Four (10%) of the elderly had an interarm SBP difference > 10 mmHg compared to one (3%) of the young group. Interarm DBP differences > 8 mmHg were found in three (8%) of the elderly and in none of the young group. Although age does not affect mean interarm BP differences, clinically important interarm BP differences exist in both young and elderly subjects. Blood pressure should be measured in both arms of all patients at initial assessment to avoid potential problems with misclassification of blood pressure status.     

Hereditary macular dystrophies

BACKGROUND: Orthostatic hypotension is a common phenomenon in the elderly. Hormonal changes during orthostatic stress have been described in elderly normotensive people and in those with essential hypertension. However, the hormonal response in elderly people who have systolic hypertension during orthostasis has not yet been quantified. METHODS: In this study we investigated 14 non-diabetic men, aged 60 to 75 years, with untreated systolic hypertension who were subjected to 45 degrees passive head-up incline on a tilt table for 15 min. Their hormonal profile and hemodynamic changes were analyzed before and after the stress. RESULTS: In the supine position, plasma levels of norepinephrine, atrial natriuretic peptide and aldosterone were in the normal range, while the plasma renin activity was low. Immediately upon tilt the systolic blood pressure fell but it reverted to baseline values after 15 min of orthostasis. At that time the cardiac output decreased while the systemic vascular resistance and the plasma norepinephrine concentration rose. The atrial natriuretic peptide appeared to fall, and the renin-aldosterone level did not change. CONCLUSION: The physiologic response to orthostatic stress in elderly people with systolic hypertension is comparable to that of elderly normotensive people and those with essential hypertension, i.e. a decrease in cardiac output and an increase in plasma norepinephrine levels. The atrial natriuretic peptide appeared to fall appropriately. The response of the renin-aldosterone system mimicked that in elderly patients with low renin essential isolated hypertension. These observations may have a bearing on the management of elderly people with systolic hypertension who also have orthostatic symptoms; they may not require a different approach from that needed for others of the same age group.     

The tip-top branching ureter

Abnormal postprandial cardiovascular responses such as postprandial hypotension (PPH) occur in primary autonomic failure and contribute significantly to morbidity. The extent and frequency of PPH and its relationship to the parkinsonian state in idiopathic Parkinson's disease (IPD) is unknown. By studying 20 patients with IPD (without autonomic failure) and 16 age-matched controls after both groups ingested a standard isocaloric balanced liquid meal, we have shown that supine PPH complicates IPD and is related to marked worsening of the parkinsonian state as measured by a cumulative score of tremor, rigidity, bradykinesia, posture, and gait. Furthermore, significant postural hypotension is unmasked that results in postural intolerance due to presyncopal symptoms. Our study indicates that, in patients with IPD, ingestion of a meal may lead to abnormal postprandial cardiovascular responses and aggravation of the parkinsonian stage. The underlying mechanisms are unclear, although vasodilatory gut peptides released in response to food ingestion may be contributory.     

The impact of ibuprofen on the efficacy of antihypertensive treatment with hydrochlorothiazide in elderly persons

BACKGROUND: Nonsteroidal antiinflammatory drugs (NSAIDs) may alter blood pressure through their inhibitory effects on prostaglandin biosynthesis. Such potential hypertensive effects of NSAIDs have not been adequately examined in the elderly, who are the largest group of NSAID users. METHODS: We performed a randomized, double-blind, two-period crossover trial of ibuprofen (1800 mg per day) vs placebo treatment in patients older than 60 years of age with hypertension controlled with hydrochlorothiazide. While continuing their usual thiazide dosage, subjects were randomized to a 4-week treatment period (ibuprofen or placebo) followed by a 2-week placebo wash-out period and a second 4-week treatment period with the alternative therapy. Supine and standing systolic and diastolic blood pressures were measured weekly. RESULTS: Of 25 randomized subjects, 22 completed the study protocol (mean age = 73 +/- 6.7 years). Supine systolic blood pressure and standing systolic blood pressure were increased significantly with ibuprofen treatment, compared with placebo. Mean supine systolic blood pressures were 143.8 +/- 21.0 and 139.6 +/- 15.9 mmHg on ibuprofen and placebo, respectively (p = .004). Mean standing systolic blood pressures were 148.1 +/- 19.9 and 143.4 +/- 17.9 mmHg on ibuprofen and placebo, respectively (p = .002). CONCLUSION: We conclude that 1800 mg per day of ibuprofen does induce a significant increase in systolic blood pressure in older hypertensive patients treated with hydrochlorothiazide. NSAID therapy may negatively impact the control of hypertension in elderly patients.     

Mental and physical stress as moderators of the postural response in insulin-dependent diabetic patients.

In 14 insulin-dependent diabetic patients (mean age 31.3 yrs) and in 15 normal controls (mean age 30.9 yrs), continuous measures were taken of heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and skin conductance (SC) during postural change under baseline and stressor conditions. Diabetic Ss without symptoms of neuropathy and healthy controls showed generally similar responses to postural change and to stressor conditions (mental arithmetic and isometric handgrip). SBP and DBP were more responsive to mental and physical stressors than were HR or SC, especially after standing. Two diabetics with postural hypotension showed significant increases in overall BP levels and less of a fall in BP during postural change under the stressor conditions, despite minimal HR or SC responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Seasonal variation of blood pressure and its relationship to ambient temperature in an elderly population

OBJECTIVE: To measure the magnitude and timing of seasonal variation of blood pressure and related factors in the elderly living in the community, and to assess their potential impact on cardiovascular risk. DESIGN: Prospective study; from January 1991 to February 1992 blood pressure and other variables were measured at 2-monthly intervals in each subject in their own homes. SUBJECTS: Ninety-six men and women, age range 65-74 years, recruited from a single group general practice in Cambridge. MAIN OUTCOME MEASURES: Seasonal variation of blood pressure, seasonal variation of prevalence of hypertension, seasonal variation of ambient temperature and body mass index. RESULTS: Both systolic (SBP) and diastolic blood pressure (DBP) were greatest during the winter across the whole distribution of blood pressure. There was a fourfold increase in the proportion of subjects with blood pressures > 160/90 mmHg in winter compared with in summer. Regression analysis revealed highly significant seasonal differences in both SBP and DBP. After adjustment for confounding seasonal effects, a 1 degree C decrease in living-room temperature was associated with rises of 1.3 mmHg in SBP and 0.6 mmHg in DBP. CONCLUSIONS: Seasonal variation of blood pressure is heightened in older adults and may partly explain the greater cardiovascular disease mortality of elderly subjects during the winter. The blood pressures of elderly people may be inversely related to the ambient temperature. The public health implications of these findings deserve further investigation.     

Cerebrovascular and cardiovascular responses to graded tilt in patients with autonomic failure

BACKGROUND AND PURPOSE: Patients with autonomic nervous system failure often experience symptoms of orthostatic intolerance while standing. It is not known whether these episodes are caused primarily by a reduced ability to regulate arterial blood pressure or whether changes in cerebral autoregulation may also be implicated. METHODS: Eleven patients and eight healthy age- and sex-matched control subjects were studied during a graded-tilt protocol. Changes in their steady state middle cerebral artery mean flow velocities (MFV), measured by transcranial Doppler, brain-level mean arterial blood pressures (MABPbrain), and the relationship between the two were assessed. RESULTS: Significant differences between patients and control subjects (P < .05) were found in both their MFV and MABPbrain responses to tilt. Patients' MFV dropped from 60 +/- 10.2 cm/s in the supine position to 44 +/- 14.0 cm/s at 60 degrees head-up tilt, whereas MABPbrain fell from 109 +/- 11.7 to 42 +/- 16.9 mm Hg. By comparison, controls' MFV dropped from 54 +/- 7.8 cm/s supine to 51 +/- 8.8 cm/s at 60 degrees, whereas MABPbrain went from 90 +/- 11.2 to 67 +/- 8.2 mm Hg. Linear regression showed no significant difference in the MFV-MABPbrain relationship between patients and control subjects, with slopes of 0.228 +/- 0.09 cm.s-1.mm Hg-1 for patients and 0.136 +/- 0.16 cm.s-1.mm Hg-1 for control subjects. CONCLUSIONS: The present study found significant differences between patients and control subjects in their MFV and MABPbrain responses to tilt but no difference in the autoregulatory MFV-MABPbrain relationship. These results suggest that patients' decreased orthostatic tolerance may primarily be the result of impaired blood pressure regulation rather than a deficiency in cerebral autoregulation.     

Alterations in reflex function contributing to syncope: orthostatic hypotension, carotid sinus hypersensitivity and drug-induced dysfunction

Orthostatic hypotension and related neurologic symptoms are frequently encountered in clinical practice. The maintenance of appropriate blood pressure and heart rate responses upon assuming the upright posture are dependent upon: 1. intact mechanical (venous valves) mechanisms, 2. functioning arterial and cardiopulmonary baroreceptors, 3. normal peripheral neural pathways, 4. normal central neural integration, and 5. appropriate neurohormonal secretion. Dysfunction at one or more of these loci may facilitate the occurrence of orthostatic hypotension and syncope. In general, the mechanisms of orthostatic hypotension may be divided into three categories. In the first category, processes interfere with normal compensatory responses to upright posture. Examples of this mechanism include age related autonomic changes, diabetic neuropathy and central nervous system disease such as Shy-Drager syndrome. The second principal mechanism involves overwhelming otherwise normal reflexes by an intense orthostatic stimulus. An obvious example of this mechanism is syncope related to hemorrhage. A final category of orthostatic hypotension relates to interference with reflex responses by drugs that may limit vasoconstriction, heart rate or cardiac output adjustments or exaggerate venous pooling. These are commonly used medications such as vasodilators, beta-adrenergic blockers and nitrates. The treatment of orthostatic hypotension revolves around the recognition of underlying causes or contributing factors amenable to correction or avoidance. Other helpful treatment options include nocturnal head-up tilting and mineralocorticoids, both of which help to expand blood volume. Many other therapeutic agents have been tried in small and selected patient populations, often with disappointing results. While many of the drugs available (phenylephrine, ephedrine, tyramine, dihydroergotamine) can improve upright blood pressure, side effects are common, and supine hypertension is problematic in many patients. Interventions of this type should be carefully initiated in a monitored setting. The carotid sinus is an important component of a neural control system responsible for heart rate and blood pressure homeostasis. Excessive heart rate and blood pressure responses to distortion of the carotid sinus are the basis for the carotid sinus syndrome (CSS). Patients with CSS tend to be elderly males and local pathology in the neck is frequently involved. Atherosclerotic coronary artery disease and hypertension are important clinical correlates. Two major categories of carotid sinus hypersensitivity (CSH) are recognized: cardioinhibitory and vasodepressor. Cardioinhibitory CSH is the most common, and in its purest form consists of sinus bradycardia or arrest, asystole or AV block during carotid sinus massage. This vagally-mediated response is eliminated by atropine. Cardiac pacing is nearly universally successful in preventing severe symptoms.(ABSTRACT TRUNCATED AT 400 WORDS)     

A psychobiocultural model of orthostatic panic among Cambodian refugees: Flashbacks, catastrophic cognitions, and reduced orthostatic blood-pressure response.

This paper investigates cognitive and physiological precursors of orthostatic panic (OP), that is, panic upon standing, which is a key complaint among traumatized Cambodian refugees. Prior research links OP to hypotension (lower blood pressure) and catastrophic cognitions. A clinical sample of 102 Cambodian refugees were assessed for posttraumatic stress disorder (PTSD), recent OP attacks, and anticipatory anxiety before engaging in an orthostatic challenge (OC) task during which they were monitored for blood pressure. After the task, they were assessed for OC-induced culture-related catastrophic cognitions, flashbacks, and panic attacks. We found that participants with recent OP (n = 60) had more PTSD, greater anticipatory anxiety before the OC, a larger drop in systolic blood pressure during the OC, more OC-induced catastrophic cognitions and flashbacks, and more severe OC-induced panic attack symptoms. Regression models showed that the severity of OC-induced panic symptoms was predicted by the magnitude of SBP drop and mediated by more severe catastrophic cognitions and flashbacks. Implications of the findings for cross-cultural psychopathology research and the treatment of both panic and PTSD in Cambodian refugees are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of the therapeutic efficacy of delayed-action diltiazem in the treatment of mild and moderate hypertension, with ambulatory of blood pressure monitoring

PURPOSE: To evaluate the behaviour of 24 hour blood pressure and the therapeutic efficacy of diltiazem 240mg (slow release) in mild and moderate hypertension. METHODS: In an open noncomparative study 20 hypertensive patients were evaluated after two weeks of wash out and eight weeks of therapy. Diltiazem 240mg, slow-release, was used in once a day basis. The blood pressure was evaluated through casual measures and by ambulatorial (ABPM) blood pressure monitorization. RESULTS: Sixteen patients (80%) reached therapeutic success (PAD nomalization or at least a reduction of 10mmHg), after six weeks of therapy. There were no changes in heart rate nor orthostatic hypotension. The mean reduction for the systolic blood pressure (PAS) was the 19.25mmHg and for PAD 11.60mmHg. The variables identified in ABPM (systolic and dyastolic load, SBP and DBP) showed significant reduction with maintenance of the circadian rhythm. CONCLUSION: Diltiazem 240mg, slow release, showed significant reduction (therapeutic success = 80%) in blood pressure of mild and moderate hypertensive patients associated with excellent tolerability. The circadian rhythm has been kept. The variables measured by ABPM were significantly reduced. Diltiazem demonstrated to be an important alternative for the treatment of mild to moderate hypertension due to its beneficial therapeutic effects associated to the once daily dosage.