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Eoin O'Brien

Publications and source records attributed to Eoin O'Brien.

53 records · Page 3Linked to original sources
PubMed2003

Determinants of white-coat syndrome assessed by ambulatory blood pressure or self-measured home blood pressure.

BACKGROUND: Gender, age, smoking, race, and body mass index have been reported to determine the ambulatory white-coat effect (WCE) and white-coat hypertension (WCH). METHODS: Baseline conventional, day-time ambulatory and self-measured home blood pressure measurements from the THOP trial were used to study the effect of gender, age, body mass index, smoking habits and treatment status on the white-coat syndrome as assessed by ambulatory monitoring or self-measurement. RESULTS: The mean systolic/diastolic WCE was 9.1/6.7 mmHg if based on ambulatory blood pressure and 12.2/8.7 mmHg if based on self-measured blood pressure. The ambulatory WCE was significantly higher in women, in older subjects (65+), in obese subjects, in non-smokers and in patients on antihypertensive drug treatment. The self-measured WCE was significantly higher in women and in non-smokers. Ambulatory WCH was present in 6.6% of the untreated patients and 14.2% had self-measured WCH. The proportion of ambulatory WCH was significantly higher in obese subjects; the proportion of self-measured WCH did not differ by gender, age, body mass index, or smoking habits. CONCLUSIONS: The ambulatory white-coat syndrome was determined by gender, age, body mass index, smoking habits, and treatment status. The self-measured white-coat syndrome was greater than the ambulatory white-coat syndrome but depended less on the determinants under study.

Age Factors↗
PubMed2003

Silent myocardial ischaemia in treated hypertensives with and without left ventricular hypertrophy.

BACKGROUND: Silent ischaemia has been reported to be associated with an increased risk of myocardial infarction and sudden death in a wide range of patient groups. The aim of this study was to examine the prevalence of silent ischaemia in hypertensive patients with and without left ventricular hypertrophy (LVH). METHODS: Twenty hypertensive patients participating in the Anglo-Scandinavian Cardiac Outcomes Trial with echocardiographic LVH (11 males, nine females), and 20 age, sex, blood pressure, and drug treatment-matched hypertensive patients without LVH underwent 24-h combined ambulatory blood pressure and electrocardiographic (ECG) monitoring. Ischaemic events were defined by the 'rule of 3 x 1'-asymptomatic ST-depression >/= 1 mm (0.1 mV), lasting at least 1 min, and with a duration of at least 1 min between two events. RESULTS: Thirteen patients with LVH had ischaemic events, whilst only four without LVH demonstrated ischaemia. Median numbers of events (seven versus zero; P < 0.01) and median total ischaemic area (0.25 versus 0 mV*min/day; P < 0.01) were significantly increased amongst hypertensive patients with LVH by comparison to those without LVH. CONCLUSION: Despite similar levels of established risk factors for atherosclerotic coronary artery disease, the prevalence of silent ischaemia was markedly increased amongst hypertensive patients with LVH by comparison to those with normal left ventricular dimensions. Ambulatory ECG monitoring may have a use in the identification of those at greatest risk of cardiovascular complications and sudden death, amongst hypertensive patients with persistent cardiac hypertrophy despite anti-hypertensive therapy.

Adult↗
PubMed2003

Ambulatory blood pressure measurement as a predictor of outcome in an Irish population: methodology for ascertaining mortality outcome.

BACKGROUND: Ambulatory blood pressure monitoring (ABPM) has proven to be a superior predictor of morbid events when compared to clinic or office blood pressure measurement (CBPM). The purpose of this study was to evaluate the predictive value of ABPM in a sample of 14 414 people referred for management of cardiovascular risk. METHODS: In this paper we describe the methodology required to examine mortality outcome in the absence of a national unique identifier. RESULTS: Using a computerized database of deaths we were able to establish that 1348 people had died by the end of the follow-up period (30 September 2002). Sixty-four percent of deaths were cardiovascular and in 207 subjects who had post-mortem examinations, 78% were cardiovascular. CONCLUSIONS: The accurate identification of the cause of death in a large population will allow comparison of the relative predictive power of APBM and CBPM in an Irish population.

Blood Pressure Monitoring, Ambulatory↗
PubMed2003

A website for blood pressure measuring devices: dableducational.com.

Consumers are faced with an ever-increasing array of blood pressure measuring devices, whether for use in clinical areas or for use by individuals anxious to measure their own blood pressure. Validation protocols that allow for independent evaluation of blood pressure measuring devices are available, and some of the devices on the market have been evaluated according to these protocols. The results of such evaluations have been published periodically in medical journals. However, such surveys are not readily available to the public and to health care authorities with responsibility for purchasing blood pressure measuring equipment for use in clinical medicine, and because of the necessarily lengthy publication process they are no longer up-to-date at the time of publication. Moreover, the results of published validation studies are often flawed because of protocol violations and the conclusions may not be valid. These considerations have been the stimulus for the establishment of an independent non-profit website, which will provide quarterly updates on the accuracy and performance of blood pressure measuring devices on the market as well as an expert assessment of the validation procedures on which recommendations are based. The ethos of the website is primarily educational and it is hoped that it will serve as a forum for the provision of much-needed information that will ultimately improve the management of hypertension. The website is due to be launched shortly and this paper outlines the general principles that have governed its establishment and the facilities that it will provide.

Blood Pressure Determination↗
PubMed2003

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

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

Adult↗
PubMed2003

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

BACKGROUND: It is now accepted that blood pressure measuring devices should be subjected to an independent evaluation of their accuracy before they are marketed for clinical use. The results of validation of the ROSSMAX Blood Pressure Measuring Monitor for self-measurement according to the European Society of Hypertension International Protocol for Validation of Blood Pressure Measuring Devices in Adults are presented in this paper. POPULATION: Thirty-three subjects were recruited from among staff and patients at Beaumont Hospital, Dublin, Ireland. METHODS: The ROSSMAX monitor was connected to the Sphygmocorder, an audiovisual system for validation, which records blood pressure on tape and video for later analysis. Nine sequential same-arm measurements between the device and a standard mercury sphygmomanometer were recorded using the Sphygmocorder. RESULTS: In phase 1, the ROSSMAX monitor produced 21 measurements within 5 mmHg, 31 within 10 mmHg and 38 within 15 mmHg for systolic blood pressure (SBP), and 36 within 5 mmHg, 43 within 10 mmHg and 45 within 15 mmHg for diastolic blood pressure (DBP). The mean differences were -5.6 (10.2) [mean (SD)] mmHg for SBP and -0.5 (4.5) mmHg for DBP. The ROSSMAX monitor failed to meet any of the criteria for SBP but comfortably passed all of the criteria for DBP. In phase 2.1, the ROSSMAX monitor had 51 measurements within 5 mmHg, 73 within 10 mmHg and 86 within 15 mmHg for SBP, and 71 measurements within 5 mmHg, 93 within 10 mmHg and 98 within 15 mmHg for DBP. The mean differences were -4.5. (9.5) mmHg for SBP and -1.8 (5.0) mmHg for DBP. The ROSSMAX monitor failed to meet any of the criteria for SBP but comfortably passed all of the criteria for DBP. In phase 2.2, 16 subjects had at least two of the differences lying within 5 mmHg and 10 subjects had no differences within 5 mmHg for SBP; 26 subjects had at least two of the differences falling within 5 mmHg and three subjects no differences within 5 mmHg for DBP. The ROSSMAX monitor failed to meet the criteria for SBP but passed the criteria for DBP. CONCLUSIONS: The ROSSMAX monitor cannot be recommended for clinical use in an adult population because it records SBP inaccurately.

Adult↗
PubMed2003

Demise of the mercury sphygmomanometer and the dawning of a new era in blood pressure measurement.

After a little more than a century of use, the conventional Riva-Rocci/Korotkoff technique of measuring blood pressure with a mercury sphygmomanometer and stethoscope, is now being relegated to the museum shelves. Affectionately attached though we may be to this clinical measurement, we must acknowledge that the technique is fraught with inaccuracy and that the age of technology has brought more accurate alternative methodologies. However, we must ensure that the automated devices that are replacing the conventional technique are validated independently for accuracy. The Working Group on Blood Pressure Monitoring of the European Society of Hypertension has recently published an International Protocol to facilitate the validation of more automated devices than was possible with the earlier more complicated protocols.

Blood Pressure Determination↗
PubMed2002

Has conventional sphygmomanometry ended with the banning of mercury?

The banning of mercury from clinical practice will lead to the inevitable demise of traditional clinical sphygmomanometry. There are differences in approach to this important issue between European countries on the one hand, which generally have accepted that the mercury sphygmomanometer must be replaced with alternative devices, and the U.S. on the other, where the view is that the mercury sphygmomanometer should remain as the mainstay of blood pressure measurement. The availability of alternative devices for the mercury sphygmomanometer is improving but the problem of independent validation is a serious issue, which is being addressed by the European Society of Hypertension Working Party on Blood Pressure Monitoring, which has drafted an International Protocol for validating blood pressure measuring devices. The removal of the mercury sphygmomanometer from clinical practice has other implications, which merit careful consideration; the advent of automated devices must lead inevitably to the disappearance of the traditional clinical auscultatory technique of blood pressure measurement, and with the disappearance of mercury it will be argued that the Système International(SI) unit of measurement -- the kilopascal -- should replace the millimetre of mercury.

Auscultation↗
PubMed2002

Quality control of the blood pressure phenotype in the European Project on Genes in Hypertension.

OBJECTIVES: In the European Project on Genes in Hypertension (EPOGH) standardized epidemiological methods were used to determine complex phenotypes consisting of blood pressure (BP) in combination with other traits. In this report, we present the quality control of one of the BP phenotypes. METHODS: In seven European countries eight different research groups recruited random samples of nuclear families. Trained observers measured the BP five times consecutively with the participants in the seated position at each of two separate home visits, 1 to 3 weeks apart, according to the guidelines of the British Hypertension Society. Quality assurance and quality control of this BP phenotype were implemented according to detailed instructions defined in the protocol of the EPOGH study. RESULTS: On 31 August 2001, BP measurements of 2476 subjects were available for analysis. Fewer BP readings than the five planned per visit occurred in one of the eight centres, but only in 0.4% of the home visits. Across centres the relative frequency of identical consecutive readings for systolic or diastolic blood pressure varied from 0 to 6%. The occurrence of odd readings ranged from 0 to 0.1%. Of the 49,488 systolic and diastolic BP readings, 24.0% ended on a zero (expected 20%). In most EPOGH centres there was a progressive decline in the BP from the first to the second home visit. Overall, these decreases averaged 2.36 mmHg [95% confidence interval (CI): 1.98-2.74, P < 0.001] for systolic BP and 1.74 mmHg (95% CI: 1.46-2.02, P < 0.001) for diastolic BP. CONCLUSIONS: Quality assurance and control should be planned at the design stage of a project involving BP measurement and implemented from its very beginnings until the end. The procedures of quality assurance set up in the EPOGH study for the BP measurements resulted in a well-defined BP phenotype, which was consistent across centres.

Adolescent↗
PubMed2002

Limitations of current validation protocols for home blood pressure monitors for individual patients.

BACKGROUND: Automatic blood pressure monitoring conducted at home is increasingly used in the diagnosis and management of hypertension. We assessed the adequacy of existing British Hypertension Society (BHS) and Association for the Advancement of Medical Instrumentation (AAMI) validation standards for automatic blood pressure monitoring devices. SUBJECT AND METHODS: A theoretical study and an empirical test are presented to estimate the proportion of persons for whom a blood pressure monitor validated according to existing BHS and AAMI standards would be inaccurate. RESULTS: The results suggest that a major limitation of both protocols is the lack of attention given to the number of individual patients for whom a monitor may be inaccurate. A blood pressure monitor that meets the AAMI and BHS validation criteria may report blood pressures in error by more than 5 mmHg for more than half of the people. CONCLUSIONS: A validation standard that does not take account of the person-effects on error will lead to a substantial proportion of persons using self-monitors that are systematically inaccurate for that person.

Blood Pressure Determination↗
PubMedDate not supplied

Prevention of cardiovascular events with an antihypertensive regimen of amlodipine adding perindopril as required versus atenolol adding bendroflumethiazide as required, in the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BPLA): a multicentre randomised controlled trial.

BACKGROUND: The apparent shortfall in prevention of coronary heart disease (CHD) noted in early hypertension trials has been attributed to disadvantages of the diuretics and beta blockers used. For a given reduction in blood pressure, some suggested that newer agents would confer advantages over diuretics and beta blockers. Our aim, therefore, was to compare the effect on non-fatal myocardial infarction and fatal CHD of combinations of atenolol with a thiazide versus amlodipine with perindopril. METHODS: We did a multicentre, prospective, randomised controlled trial in 19 257 patients with hypertension who were aged 40-79 years and had at least three other cardiovascular risk factors. Patients were assigned either amlodipine 5-10 mg adding perindopril 4-8 mg as required (amlodipine-based regimen; n=9639) or atenolol 50-100 mg adding bendroflumethiazide 1.25-2.5 mg and potassium as required (atenolol-based regimen; n=9618). Our primary endpoint was non-fatal myocardial infarction (including silent myocardial infarction) and fatal CHD. Analysis was by intention to treat. FINDINGS: The study was stopped prematurely after 5.5 years' median follow-up and accumulated in total 106 153 patient-years of observation. Though not significant, compared with the atenolol-based regimen, fewer individuals on the amlodipine-based regimen had a primary endpoint (429 vs 474; unadjusted HR 0.90, 95% CI 0.79-1.02, p=0.1052), fatal and non-fatal stroke (327 vs 422; 0.77, 0.66-0.89, p=0.0003), total cardiovascular events and procedures (1362 vs 1602; 0.84, 0.78-0.90, p<0.0001), and all-cause mortality (738 vs 820; 0.89, 0.81-0.99, p=0.025). The incidence of developing diabetes was less on the amlodipine-based regimen (567 vs 799; 0.70, 0.63-0.78, p<0.0001). INTERPRETATION: The amlodipine-based regimen prevented more major cardiovascular events and induced less diabetes than the atenolol-based regimen. On the basis of previous trial evidence, these effects might not be entirely explained by better control of blood pressure, and this issue is addressed in the accompanying article. Nevertheless, the results have implications with respect to optimum combinations of antihypertensive agents.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Role of blood pressure and other variables in the differential cardiovascular event rates noted in the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BPLA).

BACKGROUND: Results of the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BPLA) show significantly lower rates of coronary and stroke events in individuals allocated an amlodipine-based combination drug regimen than in those allocated an atenolol-based combination drug regimen (HR 0.86 and 0.77, respectively). Our aim was to assess to what extent these differences were due to significant differences in blood pressures and in other variables noted after randomisation. METHODS: We used data from ASCOT-BPLA (n=19 257) and compared differences in accumulated mean blood pressure levels at sequential times in the trial with sequential differences in coronary and stroke events. Serial mean matching for differences in systolic blood pressure was used to adjust HRs for differences in these events. We used an updated Cox-regression model to assess the effects of differences in accumulated mean levels of various measures of blood pressure, serum HDL-cholesterol, triglycerides and potassium, fasting blood glucose, heart rate, and bodyweight on differences in event rates. FINDINGS: We noted no temporal link between size of differences in blood pressure and different event rates. Serial mean matching for differences in systolic blood-pressure attenuated HRs for coronary and stroke events to a similar extent as did adjustments for systolic blood-pressure differences in Cox-regression analyses. HRs for coronary events and stroke adjusted for blood pressure rose from 0.86 (0.77-0.96) to 0.88 (0.79-0.98) and from 0.77 (0.66-0.89) to 0.83 (0.72-0.96), respectively. Multivariate adjustment gave HRs of 0.94 (0.81-1.08) for coronary events (HDL cholesterol being the largest contributor) and 0.87 (0.73-1.05) for stroke events. INTERPRETATION: Multivariate adjustment accounted for about half of the differences in coronary events and for about 40% of the differences in stroke events between the treatment regimens tested in ASCOT-BPLA, but residual differences were no longer significant. These residual differences could indicate inadequate statistical adjustment, but it remains possible that differential effects of the two treatment regimens on other variables also contributed to the different rates noted, particularly for stroke.

Adult↗