Blood pressure monitoring begins its fifth year
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
WB White
Publications and source records attributed to WB White.
Foreword: what have we learned from ambulatory blood pressure monitoring during the past five years?
Explore the source record for details and available documents.
Journal Article↗
Chronobiology in cardiovascular disease. Proceedings from the European Society of Cardiology.
Clinical research in the field of cardiovascular chronobiology has been quite productive during the past decade and results have stimulated new areas of investigation in a field of clinical pharmacology known as chronotherapeutics. Chronotherapeutics is a term that has been used when the delivery of a drug is linked to known biologic rhythms in a disease state. This approach is relatively new to practicing phyusicians in that conventional wisdom has been to administer drugs in a homeostatic fashion.
Journal Article↗
Nocturnal blood pressure epidemiology, determinants, and effects of antihypertensive therapy.
It has been established that blood pressure and heart rate have a reproducible circadian pattern characterized by a low period during sleep; an early morning, post-awakening rise; and a high plateau period while a subject is awake. This rhythm is influenced by extrinsic (lpar;environmental) and intrinsic (physiologic and pathophysiologic) factors. When hypertensive patients have the typical circadian pattern of blood pressure described above, they are referred to as 'dippers', whereas, when the normal nocturnal fall of blood pressure is diminished or blunted,s the term 'nondipper' is applied. Cross-sectional and prospective data have shown that nondippers have more target-organ damage than have dippers. Therefore, the prognostic implications of the nondipper status may be important since the overall 24 h blood pressure load is elevated in these individuals. Assessing the effects of antihypertensive therapy on 24 h blood pressure and heart rate using ambulatory monitoring has become routine in clinical trials. However, the methods of analysis and tyipes of trial design may significantly affect evaluation of therapeutic effects on nocturnal blood pressure. This article describes the influence of analysis on 24 h blood pressure measurement especially insofar as it pertains to nocturnal (or sleep) blood pressure values.
Journal Article↗
Guidelines on the clinical utility of ambulatory blood pressure.
Ambulatory blood pressure monitoring has made the transition from a technology used almost exclusively in clinical research to one that has numerous applications for clinical practice and the management of hypertension. During the past 8 years, many national working committees have published consensus documents or clinical guidelines on ambulatory blood pressure monitoring in practice. Most of these guidelines, including those published by the American College of Cardiology (1994), the American Society of Hypertension (1996), and the USA's Joint National Committee (1997) support the use of ambulatory blood pressure monitoring for selected patients. Because of increasing evidence that ambulatory blood pressure is an independent risk factor for cardiovascular events, some of the more recent consensus documents have endorsed the more widespread use of ambulatory blood pressure monitoring in clinical practice. However, the growth of ambulatory blood pressure monitoring in practice has generally been limited by the state of the health economy, including lack of reimbursement for the costs of the procedure in most countries.
Journal Article↗
Evaluation of the efficacy of the Omron HEM-737 IntelliSense device for use on adults according to the recommendations of the Association for the Advancement of Medical Instrumentation.
BACKGROUND: Automatic noninvasive blood pressure measuring devices should be independently validated prior to marketing by using standard guidelines such as those published by the Association for the Advancement of Medical Instrumentation and British Hypertension Society. OBJECTIVE: To assess a new noninvasive oscillometric automatic home blood pressure (Omron HEM-737 IntelliSense; Omron Healthcare Inc., Vernon Hills, Illinois, USA). METHODS: We compared the device's measurements with mercury column measurements for 90 subjects (270 measurements). In addition to calculation of the limits of agreement for the device versus observers, we also dtermined the impacts of age, level of blood pressure, body mass, and arm size on the levels of agreement. RESULTS: Observers showed that close agreement was attained, with mean differences of 0.42 +/- 3.65 mmHg for systolic blood pressure and 0.37 +/- 3.59 mmHg for diastolic blood pressure. The proportions of values agreeing to within 5, 10, and 15 mmHg were 88, 99, and 100% for systolic and 86, 100, and 100% for diastolic blood pressure for the two obsevers. The observer-device disagreement was 0.76 +/- 6.55 mmHg for systolic and 1.0 +/- 5.5 mmHg for diastolic blood pressure. The proportions of values agreeing to within 5, 10, and 15 mmHg were 71, 93, and 97% for systolic and 77, 96, and 98% for diastolic blood pressure for the observers and device. CONCLUSIONS: The Omron HEM-737 IntelliSense satisfied the Association for the Advancement of Medical Instrumentation's criteria for a general adult population across large ranges of age, blood pressure, body mass, and arm circumference. These findings support the use of this recorder for out-of-office self-monitoring of blood pressure.
Journal Article↗
Are there differences in the effects of long-acting calcium antagonists on ambulatory blood pressure? Extended-release nisoldipine versus amlodipine as a model.
BACKGROUND: Twenty-four-hour ambulatory blood pressure monitoring (ABPM), which provides important information regarding mean 24 h efficacy, variability of effect during sleeping-awake cycles, and effects on the early morning surge in blood pressure, is a sensitive method for evaluating efficacy of antihypertensive agents. Extended-release nisoldipine and amlodipine are long-acting dihydropyridine calcium antagonists used for the treatment of hypertension. Because these agents have different pharmacokinetic profiles, 24 h ABPM could provide clues regarding their different effects on blood pressure. OBJECTIVE: To assess the effects of extended-release nisoldipine and amlodipine on 24 h ambulatory blood pressure control and heart rate. METHODS: After completion of a 3-4 week placebo run-in period, 100 patients were randomly allocated to double-blind treatment with 10-40 mg extended-release nisoldipine or 2.5-10 mg amlodipine for 8 weeks, starting at the lowest dose. Medications were titrated at 2-week intervals on the basis of office blood pressures in seated patients. Twenty-four-hour ABPM was performed at placebo baseline and at the end of double-blind therapy. RESULTS: Extended-release nisoldipine and amlodipine provided equivalent mean 24 h changes in blood pressure [systolic blood pressure (SBP)/diastolic blood pressure decreases by 9.8/7.1 and 8.0/6.0 mmHg, respectively] and heart rate. These two treatments also provided similar changes in blood pressure at trough (22-24 h after dosing; decreases by 10.4/7.2 and 10.1/7.3 mmHg, respectively). The antihypertensive effects of amlodipine during the awake and sleeping intervals were similar (decreases by 9.6/5.9 and 9.9/5.8 mmHg, respectively, NS); whereas the effect of nisoldipine during the awake interval was significantly greater than its effect during the sleeping interval (decreases by 12.4/8.0 and 8.9/4.3 mmHg, respectively, P = 0.08/0.01). Furthermore, extended-release nisoldipine, but not amlodipine, blunted the rate of rise in early morning SBP. CONCLUSIONS: Extended-release nisoldipine and amlodipine have similar effects on mean 24 h and trough blood pressures. However, different effects during the sleeping and awake intervals and on the rate of rise in early morning SBP were observed with nisoldipine.
Journal Article↗
Blood Pressure Monitoring begins its second year.
This issue of Blood Pressure Monitoring introduces our second year of publishing research papers devoted to original investigation in the discipliners of blood pressure measurement and variability. In this foreword, we would like tio take the opportunity to review some of the achievements from our first year of the Journal and briefly describe our plans for the future.
Journal Article↗
Circadian variation of blood pressure: clinical relevance and implications for cardiovascular chronotherapeutics.
Changes in hemodynamics, caused by the inherent variability of the activity and awake-sleep cycle, may influence the outcome of various cardiovascular diseases. Recent data suggest that increased variability of blood pressure may promote excessive hypertensive target-organ disease. Several epidemiologic studies have demonstrated that myocardial ischemia, myocardial infarction, and sudden cardiac death have an excess incidence in the first several hours after awakening. In addition, surveys of the incidence of stroke (both ischemic and hemorrhagic) have shown an excess for the hours between 0800 a.m. and noon. The pathophysiologic bases for the increased number of cardiac and cerebrovascular events in the early-morning hours may be both hemodynamic and rheologic in nature. Over the past several years, therapeutic studies have evaluated the effects of antihypertensive and anti-ischemic therapies during the morning surge of blood pressure and heart rate. Generally, the few studies that have evaluated night-time dosing of conventional antihypertensive therapies have been statistically underpowered to demonstrate differences of morning versus evening dosing on early-morning blood pressure. One future direction of antihypertensive and anti-ischemic therapy is the delivery of the agents according to inherent variability that changes with time. The clinical impact of cardiovascular chronotherapy is that drug delivery is greatest when disease activity is enhanced (for example, during the early-morning hours) and least when disease activity is reduced.
Journal Article↗
Evaluation of the Datascope Accutorr Plus according to the recommendations of the Association for the Advancement of Medical Instrumentation.
BACKGROUND: Automatic noninvasive blood pressure measurement devices should be clinically validated prior to marketing using standard criteria such as those published by the Association for the Advancement of Medical Instrumentation and the British Hypertension Society. OBJECTIVE: To assess a new bedside oscillometric device (Accutorr Plus, Datascope Inc., Montvale, New Jersey, USA). METHODS: We compared measurements obtained using the device with mercury column measurements for 90 subjects (448 measurements). In addition to calculation of the limits of agreement for the device versus observers, we determined the impact of age, the blood pressure level, the body mass, and the arm size on the levels of agreement. RESULTS: There was a good agreement between observers, with a mean difference of 0.38 +/- 4.47 mmHg for the systolic and 0.0 +/- 3.7 mmHg for the diastolic blood pressure. The observer-device agreement was -0.04 +/- 7.93 mmHg for the systolic and 0.35 +/- 5.75 mmHg for the diastolic blood pressure. Regression analyses showed that, as the systolic blood pressure and age increased, the level of disagreement for the systolic blood pressure also increased ( P < 0.001 for both). CONCLUSIONS: The Accutorr Plus satisfied the criteria of the Association for the Advancement of Medical Instrumentation for a general adult population with large ranges in age, blood pressure, body mass and arm circumference. Not unlike many oscillometric devices, for systolic blood pressures > 190 mmHg, the device error increased.
Journal Article↗
Comparison of office and ambulatory blood pressure measurements to assess the angiotensin II receptor antagonist eprosartan.
BACKGROUND: To determine the efficacy and dose-response of the new angiotensin II receptor antagonist eprosartan, we conducted a 4-week, double-blind, randomized, multicenter study in 114 men with essential hypertension using trough clinic and ambulatory blood pressure measurements.METHODS: Patients were included if the seated diastolic blood pressure was between 95 and 115 mmHg inclusive and 0-12 h diastolic blood pressure was at least 87 mmHg. The effects of twice daily eprosartan at 50, 100, 150 and 200 mg were compared with those of placebo. RESULTS: At trough, the clinic diastolic blood pressure was reduced significantly only by the 200 mg dose compared with placebo (mean placebo-subtracted change -6.0 mmHg, 95% confidence intervals -10.5, -1.5, P = 0.001). In contrast, the 12 h mean reduction in diastolic blood pressure was significant for both the 150 mg dose (mean change -5.3 mmHg, 95% confidence intervals -10.2, -0.1, P = 0.0075) and the 200 mg dose (mean change -5.5 mmHg, 95% confidence intervals -10.3, -0.6, P = 0.0049). Similar trends were observed for the systolic pressure and mean changes in 24 h pressures. Eprosartan significantly reduced adjusted mean daytime (0-12 h after dose) diastolic ambulatory pressure linearly with dose. CONCLUSION: These data demonstrate increased sensitivity of the ambulatory blood pressure over the research clinic blood pressure in evaluating the efficacy of the new antihypertensive agent eprosartan. Additionally, these findings demonstrate that higher doses of this drug will be necessary in future studies.
Journal Article↗
The usefulness of ambulatory blood pressure monitoring to assess hypertensive therapy.
Explore the source record for details and available documents.
Journal Article↗
Clinical relevance of ambulatory versus clinic blood pressure when evaluating antihypertensive therapy.
REVIEW IN DEPTH: The evaluation of the effect of antihypertensive drugs over time has led to the increasing popularity of noninvasive ambulatory monitoring of blood pressure in the drug development process. Although not mandated by the Food and Drug Administration of the USA, from a practical standpoint new drug applications for antihypertensive agents typically include one or more studies that have used ambulatory blood pressure recordings. Ambulatory blood pressure monitoring is now used in several phases of drug development, including phase II dose-ranging studies, phase III efficacy studies, and phase IV comparative trials. The perceived benefit of the ambulatory blood pressure methodology during drug development is that it avoids observer bias, markedly reduces the effect of placebo, and may economize on sample size, especially in cross-over-designed trials. Furthermore, there is a clinical benefit of ambulatory blood pressure monitoring in the assessment of antihypertensive drugs because it allows evaluation of the effect and duration of effect of a drug during activities of daily living, including sleep.
Journal Article↗
Ambulatory monitoring of the blood pressure in multicenter clinical trials.
By reducing measurement error associated with clinic (or casual) blood pressure, ambulatory blood pressure measurement (ABPM) potentially enhances the precision of blood pressure estimation. Enhanced precision leads to lower sample size requirements or increased statistical power, or both, in clinical trials. Thus, by virtue of its increased numbers of measurements and improved reproducibility, ABPM can differentiate among active antihypertensive therapies when clinic blood pressure measurements do not. Additional benefits of ABPM can include identification of white-coat hypertensives, removal of observer bias, a marked reduction in placebo effects and evaluation of the circadian blood pressure pattern. By identifying circadian patterns, ABPM aids in the evaluation of the diurnal and nocturnal effects of a therapeutic regimen. ABPM has found more frequent application in the assessment of antihypertensive therapies in multicenter trials in recent years. However, using ABPM in multicenter trials might increase the complexities of the conduct of the trial relevant to the maintenance of homogeneity in study methods. Special concerns for multicenter trials involving ABPM include device use and validation, experience of study coordinators or research technicians and patient compliance. In recent years in the USA, ambulatory blood pressure values have been used to serve as secondary 'cut-off' criteria before random allocation in a trial (after primary entry criteria based on clinical blood pressure values have been satisfied). Sponsors of trials have become highly selective in recruiting study sites with substantial experience in ABPM. These practices may create a more homogeneous cohort in the trial and make the population less representative of the general hypertensive population.
Journal Article↗
Effects of three methods of analysis on ambulatory blood pressure indices and the early morning rise in blood pressure.
OBJECTIVE: To study the effects of actigraphic, diary and fixed-time methods of analysis on ambulatory blood pressure, the day (awake)-night (asleep) difference and early morning blood pressure. METHODS: We analyzed 50 ambulatory blood pressure studies of patients who also underwent actigraphic activity studies. We divided each study into awake and sleeping intervals by three methods: a patient diary of sleep hours, actigraphically determined sleep hours and a fixed schedule of estimated sleep (2200-0700 h). We then calculated the overall ambulatory blood pressure averages, the awake-asleep differences and the average blood pressure for 4 h after awakening. RESULTS: We found that actigraphic division of the data and patient-kept diaries provided similar ambulatory blood pressure averages whereas fixed-time analysis (2200-0700 h as the sleeping period) was less similar to that using the diary method. The nocturnal decline in diastolic blood pressure calculated by the diary method tended to be higher than that obtained by the fixed time method (16+/-6 versus 14+/-7%, P = 0.037). The limits of agreement for the early morning blood pressure rise for diary and fixed-time analyses were wider than those for diary and actigraphic analyses (-9.5 to +10.0/-6.6 to +7.0) versus (-4.4 to +4.7/-4.1 to +4.0 mmHg). CONCLUSION: Actigraphic division of the ambulatory blood pressure data is more similar to the diary than it is to the fixed-time method studied here. Researchers studying the early morning rise in blood pressure should consider using either actigraphy or diary rather than fixed-time methods of analysis to identify times of awakening.
Journal Article↗