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Biomedical subjects

E O'Brien

Publications and source records attributed to E O'Brien.

At least 73 records · Page 4Linked to original sources
PubMed1999

Symptoms reported by elderly patients with isolated systolic hypertension: baseline data from the SYST-EUR trial. Systolic Hypertension in Europe.

OBJECTIVES: To determine the symptomatic well-being of elderly persons with isolated systolic hypertension. DESIGN AND SETTING: Well-being determined during the placebo run-in period prior to entry to the Systolic Hypertension in Europe (SYST-EUR) trial. SUBJECTS: 641 People, 60 years or older with an average sitting blood pressure of 173/86 mm Hg. OUTCOME MEASURES: 33 Symptomatic complaints determined by a standard interview. RESULTS: The 437 women complained of 25% of the symptoms and the 204 men 21% (P<0.001). A markedly higher prevalence was observed in women compared with men for: pain in the joints of the hands (35% of women complained of this against 22% of men); 'racing heart' (33% against 17%); dry eyes (16% against 6%); blurring of vision (35% against 23%); cramps in the legs (43% against 31%); and a sore throat (15% against 7%). Nocturia was the most frequent complaint (68% in both sexes). Eight symptoms increased with age and one (rash) tended to decline. With increasing systolic pressure women also reported more headaches, unsteadiness, blurring of vision, irregular heart beat and 'racing heart' but, of these, only headaches increased with diastolic pressure. These observations were made after adjusting for age, blood sugar and body mass index (BMI) and were not observed in men. Higher blood sugars were associated with mouth ulcers, 'racing heart', blurring of vision and cramps in the legs. A higher BMI was associated with six symptoms, and a lower age of leaving education with eight. In men, alcohol consumption was related to 'racing heart', and smoking to wheezing and having a dry cough. CONCLUSIONS: A high level of complaint was associated with female gender, increasing age, blood sugar and BMI and a low age of leaving education.

Aged↗
PubMed1999

Evaluation of the Schiller BR-102 ambulatory blood pressure system according to the protocols of the British Hypertension Society and the Association for the Advancement of Medical Instrumentation.

OBJECTIVE: To evaluate the Schiller BR-102 monitor for ambulatory blood pressure measurement according to the protocols of the British Hypertension Society (BHS) and the Association for the Advancement of Medical Instrumentation (AAMI). DESIGN: The BHS protocol is divided into two parts. Part I, which is the part applicable to this study, comprises the main validation procedure and has five phases: before-use device calibration; in-use (field) phase; after-use device calibration; static device validation; and report of evaluation. METHOD: Three Schiller BR-102 recorders passed the before-use device calibration test, after which they entered the in-use (field) assessment phase during which the three recorders were each worn by 10 subjects for 24 h, after which calibration was again assessed. Because there was no difference in results of calibration testing among the three devices, one was selected randomly and the main validation test was carried out on 85 subjects with a wide range of blood pressures both for the auscultatory mode and for the oscillometric mode using the Sphygmocorder. The results were analysed according to the BHS grading system from A to D. The data were also analysed according to the standard of the Association for the Advancement of Medical Instrumentation (AAMI), which stipulates that the mean difference between the test device and the standard shall be </= 5 mmHg with a standard deviation of </= 8 mmHg. RESULTS: The Schiller BR-102 achieved a BHS grade B rating for systolic and diastolic blood pressures in the auscultatory mode and satisfied the criteria for accuracy of the AAMI protocol for systolic and diastolic blood pressures. In the oscillometric mode, the Schiller BR-102 achieved grade D for systolic blood pressure and grade B for diastolic blood pressure according to the BHS protocol and satisfied the AAMI criteria for diastolic but not systolic blood pressure. Applying the BHS and AAMI criteria to tertiles of blood pressure (low-pressure range < 130/80 mmHg, medium-pressure range 130-160/80-100 mmHg, high-pressure range > 160/100 mmHg) the Schiller BR-102 was less accurate in the high pressure range for diastolic blood pressure but more accurate for systolic blood pressure, achieving A/C grading, while satisfying the AAMI criteria both for systolic and for diastolic blood pressure in the auscultatory mode. In the oscillometric mode the device performed less accurately in the high-pressure range, achieving grade D/C, while failing to satisfy the AAMI criteria both for systolic and for diastolic blood pressure. The means+/-SD of the first mercury sphygmomanometer measurements were 143+/-32 mmHg for systolic blood pressure and 88+/-21 mmHg for diastolic blood pressure. Acceptability to subjects was good and the manufacturer's manual was satisfactory. CONCLUSION: On the basis of these results, the Schiller BR-102 can be recommended for ambulatory blood pressure measurement in clinical practice using the auscultatory mode, but the oscillometric mode, which operates only if the device fails in the auscultatory mode, does not provide accurate measurements.

Blood Pressure↗
PubMed1999

Task force II: Ambulatory blood pressure monitoring in population studies.

Ambulatory blood pressure (ABP) has only rarely been employed in population studies because of the difficulty posed by the greater complexity of this technique. The cross-sectional studies that have been published, however, have allowed a number of conclusions to be drawn. One, 24h average blood pressure of populations is significantly but not closely related to office blood pressure, which thus can not predict accurately daily-life values of blood pressure. Two, 24h average blood pressure is usually less than office blood pressure, the discrepancy increasing with the increase in office values and being of magnitude several mmHg at the office blood pressure of 140/90 mmHg (systolic/diastolic) Three, ABP in women is somewhat less than that in men and ABP for both sexes increases less with aging than does office blood pressure. Four, a circadian profile of blood pressure consisting in values that are much lower at night than are those during daytime characterizes both sexes and all ages with the possible exception of individuals aged 75 years and more, in whom the nocturnal hypotension appears to be attenuated. A similar attenuation has been found for blacks in comparison with whites. The upper limit of normality of ABP has not yet been defined conclusively, although 24h average values </=125/80 mmHg are almost invariably regarded as normal. Normality of ABP should be defined, however, by longitudinal population studies in which ambulatory values are related to prognosis. One of these studies has already been published and others will be completed in the near future.

Blood Pressure Monitoring, Ambulatory↗
PubMed1999

Hypotension in patients with coronary disease: can profound hypotensive events cause myocardial ischaemic events?

OBJECTIVE: To determine whether anginal episodes might be related to extremes of hypotension in patients with ischaemic heart disease taking drugs to treat angina and heart failure. DESIGN AND SETTING: Observational study of patients with ischaemic heart disease attending an urban tertiary referral cardiology centre. INTERVENTIONS AND OUTCOME MEASURES: A selected patient population was enrolled, having: angina on one or more hypotensive cardiovascular medications; hypotension on clinic or ambulatory measurement; and a resting ECG suitable for ambulatory monitoring. Patients had echocardiography, ambulatory blood pressure monitoring, and Holter monitoring. Hypotension induced ischaemic (HII) events were defined as episodes of ST segment ischaemia occurring at least one minute after an ambulatory blood pressure measurement (systolic/diastolic) below 100/65 mm Hg during the day, or 90/50 mm Hg at night. RESULTS: 25 suitable patients were enrolled, and 107 hypotensive events were documented. 40 ST events occurred in 14 patients, of which a quarter were symptomatic. Fourteen HII events occurred in eight patients, with 13 of the 14 preceded by a fall in diastolic pressure (median diastolic pressure 57.5 mm Hg, interquartile range 11, maximum 72 mm Hg, minimum 45 mm Hg), and six preceded by a fall in systolic pressure (chi(2) = 11.9, p < 0.001). ST events were significantly associated with preceding hypotensive events (chi(2) = 40.2, p < 0.0001). Patients with HII events were more frequently taking multiple hypotensive drug regimens (8/8 v 9/17, chi(2) = 5.54, p = 0.022). CONCLUSIONS: In patients with ischaemic heart disease and hypotension, symptomatic and silent ischaemia occurred in a temporally causal relation with hypotension, particularly for diastolic pressures, suggesting that patients with coronary disease may be susceptible to ischaemic events incurred as a result of low blood pressure caused by excessive hypotensive drug treatment.

Adrenergic beta-Antagonists↗
PubMed1999

Diagnosis of white coat hypertension by ambulatory blood pressure monitoring.

White coat hypertension (WCH) is common in referred hypertensive patients. Ambulatory blood pressure monitoring (ABPM) is not free from the white coat syndrome. We examined the use of the elevation of the first and last measurements of ABPM for diagnosis of WCH in a hypertensive population that had been referred to a hospital-based hypertension unit. Data were obtained on 1350 patients for clinic and ABPM parameters. WCH, as diagnosed by conventional clinic blood pressure (BP) measurement, was compared with a variety of alternative methods determined from ABPM. In all cases, mean daytime pressure was <135 mm Hg/85 mm Hg with an elevation of clinic BP >/=140 mm Hg systolic or 90 mm Hg diastolic. The definitions tested for this elevation were first hour mean pressure, first reading, maximum reading in first hour, last hour mean pressure, last reading, maximum reading in the last hour and maximum reading in first or last hour. Elevation of the maximum pressure in the first hour or last hour above 140 mm Hg systolic or 90 mm Hg diastolic showed a high level of agreement (kappa=0.91) with classical WCH for diagnosis of the white coat syndrome. Termed ambulatory white coat hypertension, patients with this finding were older than classic white coat patients and had higher daytime (127+/-6/78+/-5 mm Hg versus 121+/-5.5/74+/-6 mm Hg, P<0.005 for systolic and diastolic) and nighttime (114+/-11/67+/-8 mm Hg versus 106+/-9/61+/-6 mm Hg, P<0.005 for systolic and diastolic) pressures. They also had a significantly greater Sokolow-Lyon index (leads V(1)+V(5), 21+/-7 mV versus 18+/-6 mV). Elevation of BP above 140 mm Hg systolic or 90 mm Hg diastolic in the first or last hour of monitoring diagnoses patients with a white coat response in whom there is a higher BP profile than in patients with classic white coat response alone. We suggest, therefore, that this is a better measure of the white coat phenomenon.

Adult↗
PubMed1999

Evaluation of dynamic gadolinium-enhanced breath-hold MR angiography in the diagnosis of renal artery stenosis.

OBJECTIVE: The aim of our study was to evaluate a three-dimensional gadolinium-enhanced breath-hold MR angiography sequence using standard MR gradients in detecting renal artery stenosis. SUBJECTS AND METHODS: Forty-two patients referred for angiography for suspected renal artery stenosis underwent both conventional digital subtraction angiography (DSA) and MR angiography. MR angiography was performed on a 1.5-T scanner with standard gradients. A fast multiplanar spoiled gradient-echo sequence was used with the following parameters: TR/TE, 10.3/1.9; flip angle, 45 degrees; field of view, 36 x 32 cm; matrix size, 256 x 128; one excitation; volume thickness, 70 mm; and partitions, 28. Gadolinium was administered IV as a dynamic bolus of 30-40 ml. Conventional and MR angiographic images were interpreted by two radiologists in consensus. RESULTS: DSA revealed 87 renal arteries, of which 79 were in 35 patients with native kidneys and eight arteries were in seven patients with transplanted kidneys. Gadolinium-enhanced MR angiography showed 85 (98%) of 87 renal arteries. Seventeen patients had 20 significant (>50% stenosis) renal artery stenoses and five patients had five occluded renal arteries revealed by DSA. MR angiography revealed 85 renal arteries (98%), 20 stenoses (100%), and five occlusions (100%). Gadolinium-enhanced MR angiography led to one false-positive interpretation for renal artery stenosis and no false-negative interpretations. Thus, the sensitivity, specificity, and accuracy of MR angiography for renal artery stenosis were 100%, 98%, and 99%, respectively. CONCLUSION: The MR angiography pulse sequence we used was an effective and reliable technique for the diagnosis of renal artery stenosis. The sequence can be performed on widely available MR equipment that does not require fast gradient hardware.

Adult↗
PubMed1999

Sternothoracotomy for combined coronary artery bypass grafting and left upper lobectomy in a patient with low-lying tracheostoma.

A 64-year-old man had a low-lying tracheostoma and presented with unstable angina and a mass in the pulmonary left upper lobe. Simultaneous coronary revascularization and resection of the lung neoplasm were completed through a sternothoracotomy (clam-shell) incision. The advantages of this approach include excellent exposure to the mediastinum and the lung fields, and the option of using both internal thoracic arteries for bypass grafting.

Carcinoma, Squamous Cell↗
PubMed1998

Early phagocytosis of glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes parasitized by Plasmodium falciparum may explain malaria protection in G6PD deficiency.

In population-based studies it has been established that inherited deficiency of erythrocyte (E) glucose-6-phosphate dehydrogenase (G6PD) confers protection against severe Plasmodium falciparum (P falciparum) malaria. Impaired growth of parasites in G6PD-deficient E in vitro has been reported in some studies, but not in others. In a systematic analysis, we have found that with five different strains of P falciparum (FCR-3, KI, C10, HB3B, and T9/96), there was no significant difference in either invasion or maturation when the parasites were grown in either normal or G6PD-deficient (Mediterranean variant) E. With all of these strains and at different maturation stages, we were unable to detect any difference in the amount of P falciparum-specific G6PD mRNA in normal versus deficient parasitized E. The rate of 14C-CO2 production from D-[1-14C] glucose (which closely reflects intracellular activity of G6PD) contributed by the parasite was very similar in intact normal and deficient E. By contrast, in studies of phagocytosis of parasitized E by human adherent monocytes, we found that when the parasites were at the ring stage (ring-stage parasitized E [RPE]), deficient RPE were phagocytosed 2.3 times more intensely than normal RPE (P = .001), whereas there was no difference when the parasites were at the more mature trophozoite stage (trophozoite-stage parasitized E [TPE]). Phagocytic removal markers (autologous IgG and complement C3 fragments) were significantly higher in deficient RPE than in normal RPE, while they were very similar in normal and deficient TPE. The level of reduced glutathione was remarkably lower in deficient RPE compared with normal RPE. We conclude that impaired antioxidant defense in deficient RPE may be responsible for membrane damage followed by phagocytosis. Because RPE, unlike TPE, are nontoxic to phagocytes, the increased removal by phagocytosis of RPE would reduce maturation to TPE and to schizonts and may be a highly efficient mechanism of malaria resistance in deficient subjects.

Animals↗
PubMed1998

Can heart rate predict blood pressure response to anti-hypertensive drug therapy?

The use of heart rate in clinical practice is limited by its variability under measurement situations. The mean heart rate on ambulatory monitoring provides a more robust statistic for clinical use. We examined the relationship between mean heart rate on initial referral ambulatory blood pressure monitoring (ABPM) to the BP-lowering efficacy of the four main groups of anti-hypertensive medications, in a referral hypertensive population. Patients were retrospectively identified by review of the BP database, and data collected from the initial referral BP monitor off medication, and the subsequent ABPM after treatment with either beta-blockers, diuretics, calcium antagonists or angiotensin-converting enzyme (ACE) inhibitors. The change in mean arterial BP from the initial to the subsequent ABPM (ie, as a result of treatment) was correlated with the mean heart rate on the initial ABPM. A moderate association was found for initial daytime heart rate and BP response to beta-blockers (r = 0.24, P = 0.02), and ACE inhibitors (r = 0.14, P = 0.05). No such association was found for calcium antagonists or diuretics. When the groups were divided into those with a mean daytime heart rate <75 and > or =75 beats per min, BP reduction from beta-blocker and ACE inhibitor therapy was significantly greater in those patients with a higher daytime heart rate. We conclude that average daytime heart rate on pre-treatment ABPM can be useful as a predictor of BP response to beta-blockade or ACE inhibition.

Adrenergic beta-Antagonists↗
PubMed1998

Quality of life of elderly patients with isolated systolic hypertension: baseline data from the Syst-Eur trial. Syst-Eur Trial Investigators.

OBJECTIVE: To describe measures of quality of life of elderly patients with isolated systolic hypertension at entry to a placebo-controlled randomized trial of antihypertensive treatment and to investigate factors associated with these. DESIGN: Cross-sectional analyses at entry to a randomized controlled trial. SETTING: Patients attending hypertension clinics or general practitioners' surgeries at 30 centres in 10 European countries. PATIENTS: Six hundred and thirty-one patients aged 60 years or more, with a sitting systolic blood pressure during the run-in phase of 160-219 mmHg, a sitting diastolic blood pressure below 95 mmHg and a standing systolic blood pressure of 140 mmHg or more. MAIN OUTCOME MEASURES: Cognitive function tests (Reitan Trail Making A and B), Brief Assessment Index (a measure of depressed mood) and four subscales from the Sickness Impact Profile (Ambulation, Social Interaction, Sleep and Rest and Housework). RESULTS: Poor quality of life was generally associated with increasing age, previous treatment with antihypertensive drugs, presence of cardiovascular complications and, among women, high diastolic blood pressure, higher consumption of alcohol and high body mass index. CONCLUSIONS: At entry to the trial there was considerable heterogeneity of patients in terms of measures of quality of life and cognitive performance. It remains to be determined whether these influence subsequent quality of life during randomized treatment.

Age Factors↗
PubMed1998

Ambulatory blood pressure in the hypertensive population: patterns and prevalence of hypertensive subforms.

BACKGROUND: A number of clinically identifiable patterns of blood pressure elevation are apparent using ambulatory measurement Their prevalence and age and sex distribution have not been described. The purpose of this study was to describe the epidemiology of patterns of high blood pressure in a large population. DESIGN: Retrospective database analysis of referral hypertensive population. PATIENTS: Clinic and ambulatory blood pressure measurements were performed in 2092 patients with essential hypertension while they were not taking antihypertensive medication. METHODS: The patients were classified into six groups on the basis of their ambulatory blood pressure monitoring profiles: white-coat hypertensives, borderline hypertensives, isolated systolic hypertensives, isolated diastolic hypertensives, combined systolic and diastolic hypertensives and nocturnal hypertensives. The categories were examined for age and sex differences. RESULTS: All patients were categorized into one of the six groups. The majority (56.2%) were systolodiastolic hypertensives, 12.9% were borderline and 10.8% were white-coat hypertensives. Isolated systolic hypertensives comprised 6.2% of the population, isolated diastolic hypertensives 6.9% and nocturnal hypertensives 7.1%. The isolated systolic hypertensives showed the greatest change with age, with a prevalence of < 5% in patients below 40 years of age, rising to almost 20% in the 70 plus age group. White-coat, isolated diastolic and borderline hypertensives showed the opposite change in prevalence, falling from younger to older age groups. Apart from a greater prevalence of white-coat hypertension in females, the patterns were largely similar between sexes. CONCLUSIONS: Ambulatory blood pressure monitoring allows the blood pressure pattern to be defined in hypertensive patients. The patterns identified here in a referral hypertensive cohort show changes in prevalence with age, and further study is required to determine the prognostic significance of hypertensive sub-forms.

Adolescent↗
PubMed1998

What are the normal levels for ambulatory blood pressure measurement?

With acceptance of ambulatory blood pressure measurement as a useful technique in the management of hypertension, the question of what constitutes the upper limit of normality for 24 h blood pressures has been the subject of a number of reviews [1,2]. In fact, there has been remarkable similarity in a number of large population studies [3-10]. For example, taking the 95th percentile as the upper limit of the distribution of daytime blood pressure in various studies in different countries (Internation Database 141/88 mmHg [3,4], Ireland 138/89 mmHg [5], Belgium 137/88 mmHg [6], Japan 138/83 mmHg [7], Denmark 139/88 mmHg [8] and Italy 134/88 mmHg [9,10] gave variations of less than 7/6 mmHg for systolic and diastolic blood pressures, respectively, the average for all studies being 138/87 mmHg (for review, [6]). A review of the literature carried out independently by the American Society of Hypertension [11] and our group [1,2,6] produced an identical recommendation for the levels of daytime blood pressure that may be regarded as normal and abnormal, namely, that blood pressures above 140/90 mmHg are probably abnormal and that blood pressures below 135/85 mmHg are probably normal. Moreover, the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure in its recent communication takes blood pressures of awake subjects below 135/85 mmHg to be normal [12].

Journal Article↗
PubMed1998

Conventional and ambulatory measurements of blood pressure in old patients with isolated systolic hypertension: baseline observations in the Syst-Eur trial.

OBJECTIVES: To compare clinic and am measurements of blood pressure in old patients with isolated systolic hypertension and their reproducibilities. PATIENTS: In total 610 patients aged >/= 60 years with isolated systolic hypertension detected by clinic measurement were monitored during the placebo run-in phase of the Syst-Eur trial. METHODS: The time-weighted 24 h blood pressure, clock-time day and night blood pressures, the cumulative-sum-derived crest and trough blood pressures and the high and low blood pressure levels according to the square-wave model were computed. The daily alteration between the high and low spans of blood pressure was quantified using the day-night difference, the cumulative-sum-derived magnitude of circadian alteration, the Fourier amplitude and the difference between the high and low blood pressure levels of the square-wave model. RESULTS: The daytime am systolic blood pressure was, on average, 21 mmHg lower than the clinic systolic blood pressure, whereas diastolic pressure was, on average, similar with both techniques of measurement. Clinic levels of blood pressure in the 141 patients who underwent repeat measurements and the parameters describing the difference between the daily high and low spans of blood pressure were equally reproducible. However, both were less reproducible than the ambulatory blood pressure levels. The reproducibility coefficients, expressed as percentages of near maximum variation, were 49 and 50% for the clinic systolic and diastolic blood pressures, 30 and 32% for the mean 24 h systolic and diastolic blood pressures and 45-55% for the parameters describing the daily alteration between the high and low spans of blood pressure. CONCLUSION: Values of blood pressure in old patients with isolated systolic hypertension were more reproducible for ambulatory than they were for clinic measurements. Levels in patients selected because they have a high clinic blood pressure may be substantially higher with conventional than they are with daytime ambulatory measurement. The prognostic significance of this difference for the present patients is currently under investigation.

Journal Article↗