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Biomedical subjects

W B White

Publications and source records attributed to W B White.

At least 19 recordsLinked to original sources
PubMed2003

Terminal digit bias in a specialty hypertension faculty practice.

Traditional blood pressure (BP) methodology is subject to observer error such as terminal digit preference and single number preference leading to inaccuracies in measurement. A high percentage (60-90%) of terminal BP readings digit being zero has been reported from general medical- and hospital-based clinics. This study examined terminal digit preference in a hypertension specialty practice and assessed clinical factors that may be associated with zero preference in this setting. A retrospective chart review of patients presenting to the hypertension clinic at the University of Connecticut Health Center during the month of September 2001 was performed. Data were extracted on age, gender, height, weight, treatment status, and systolic and diastolic BP measurements taken by nursing staff and attending physicians. Terminal digit preference was apparent in BP readings taken by both nursing staff and physicians. Zero was the terminal systolic BP digit in 40% of readings taken by the nursing staff and 31% of readings taken by physicians. For diastolic BP readings, the percentages were 23 and 36%, respectively. Nurses also recorded 43% of diastolic BP readings with terminal digit 2. Age was significantly higher in those persons in whom the physician diastolic BP terminal digit was zero than in those with nonzero terminal digits (67+/-14 vs 59+/-18 years, P=0.008). Body mass index was lower in the patient group with diastolic terminal digit zero bias compared to those with nonzero terminal digits (28+/-5 vs 32+/-6 kg/m(2), P=0.02). In conclusion, although the frequency of zero digit preference did not reach the 60-80% levels found in previous studies, there was evidence of terminal digit preference in the systolic and diastolic measurements taken by nursing staff and attending physicians in a specialist hypertension clinic. We believe that the lower levels of terminal digit preference observed are an effect of increased training in proper BP measurement and technique. However, the observed bias in measurement even in a hypertension unit argues for regular monitoring and feedback to minimize such errors.

Aged↗
PubMed2001

Impact of smoking cessation on ambulatory blood pressure and heart rate in postmenopausal women.

BACKGROUND: Smoking and hypertension interact to increase the incidence of cardiovascular disease; however, little is known about the effects of smoking cessation on blood pressure (BP) control. We prospectively evaluated the impact of smoking cessation on clinic and ambulatory BP and heart rate (HR) in stage 1 hypertensive and normotensive postmenopausal women. METHODS: A total of 66 women were randomly assigned using a 3:1 randomization scheme to immediate smoking cessation or to a wait list control group. Clinic and ambulatory BP and HR, and 24-h urinary catecholamine concentrations were obtained at baseline and again at 6 weeks. Carbon monoxide levels and self-report were used to assess compliance with smoking cessation. RESULTS: Ambulatory monitoring showed that the awake SBP decreased by 3.6+/-1.9 mm Hg in the treated subjects who quit smoking (n=19), whereas in the control group (n=15) there was an increase of 1.7+/-2.4 mm Hg (P=.045). Awake HR decreased after smoking cessation by 7+/-1 beats/min and did not change (0+/-1 beat/min) in the control group (P=.001). Blood pressure and HR did not significantly change during sleep after smoking cessation. Changes in the awake HR correlated with changes in urinary epinephrine concentrations (r= 0.58, P=.001), and norepinephrine concentrations (r= 0.45, P=.001), There was no significant change in clinic systolic BP, diastolic BP, or HR between groups. CONCLUSIONS: Smoking cessation reduces systolic BP and HR during the daytime, when patients typically smoke. These hemodynamic changes are due in part to reductions in sympathetic nervous system activity.

Aged↗
PubMed2001

Evaluation of the 24-hour blood pressure effects of eprosartan in patients with systemic hypertension.

BACKGROUND: Eprosartan is a new nonphenyl angiotensin II receptor blocker, which has been approved for the treatment of hypertension. Although the drug has a relatively short plasma half-life of 5 to 9 h, clinical studies have suggested that its antihypertensive effect persists for 24 h. METHODS: We assessed both the changes in 24-h and trough blood pressure (BP) (last 4 h of the ambulatory BP while the patient was awake) of eprosartan at doses of 600 and 1,200 mg once daily in a randomized, double-blind, placebo-controlled trial. Ambulatory BP was monitored at placebo baseline and after 8 weeks of double-blind therapy. RESULTS: Two hundred patients randomized in the study with 177 patients completing the trial. The 24-h change in BP from baseline was 0.2/0.1 +/- 1.4/1.0 mm Hg, -7.9/ -5.4 +/- 1.0 mm Hg (P < .0001), and -7.4/-5.0 +/- 0.9 mm Hg (P < .0001) in the placebo, 600-mg eprosartan, and 1,200-mg eprosartan groups, respectively. Changes in trough ambulatory BP showed significant reductions of -6.3/-4.1 +/- 1.6/1.1 mm Hg and -7.7/-5.5 +/- 1.5/1.0 mm Hg for 600 mg of eprosartan and 1,200 mg of eprosartan, respectively. CONCLUSIONS: These data demonstrate that eprosartan at doses of 600 or 1200 mg significantly reduced BP throughout an entire 24-h dosing period. There were no differences between the 600- and 1,200-mg dose; thus, 600 mg once daily should be the only dose used in the treatment of hypertension with eprosartan.

Acrylates↗
PubMed2001

Gender and age effects on the ambulatory blood pressure and heart rate responses to antihypertensive therapy.

BACKGROUND: The aim of this study was to assess potential differences in the 24-h antihypertensive response to treatment with the controlled-onset, extended-release (COER) calcium antagonist, verapamil in men versus women and older versus younger patients with hypertension. METHODS: Meta-analyses were performed of three prospective randomized, double-blind, placebo-controlled trials with COER-verapamil in patients with mid-stage I to stage III essential hypertension. The trials were conducted at medical clinics in the US and Canada in patients with a mean office diastolic blood pressure (BP) of 95 to 115 mm Hg on 2 consecutive weeks and a mean daytime diastolic BP >90 mm Hg. Patients were randomized to treatment with 180 to 540 mg/day of COER-verapamil (N = 273) or placebo (N = 125). Changes from baseline in ambulatory BP and heart rate after COER-verapamil were compared in men versus women and in older versus younger patients. RESULTS: Treatment with COER-verapamil caused significant reductions in 24-h and early-morning systolic and diastolic BP in all of the subpopulations as compared with placebo (P < .001). COER-verapamil induced a greater reduction in both 24-h systolic (-15.1 v -10.0 mm Hg; P < .001) and diastolic (-10.4 v -8.2 mm Hg; P = .003) BP in women compared with men. Older patients showed a greater mean reduction in 24-h diastolic BP (-10.2 v -8.2 mm Hg; P < .05) and heart rate (-5.7 v -4.4 beats/min; P < .05) compared with younger patients. Side effects were similar in all of the COER-verapamil treatment groups. CONCLUSIONS: Both gender and age were significant determinants of the response to COER-verapamil. The antihypertensive effect of verapamil is greater in women than in men and in older patients compared with younger patients.

Adult↗
PubMed2001

Chronotherapeutic delivery of verapamil in obese versus non-obese patients with essential hypertension.

BACKGROUND: The effect of controlled-onset, extended-release (COER) verapamil on haemodynamic parameters in obese and non-obese patients is evaluated in this analysis. METHODS: Data were pooled from three clinical trials evaluating efficacy and tolerability of COER-verapamil. Hypertensive men and women (stage I to III) were randomised to COER-verapamil (180-540 mg at bedtime) or placebo for 4-8 weeks and stratified according to body mass index (BMI-obese > 28 kg/m2). Efficacy was assessed as change from baseline in blood pressure (BP), heart rate, and rate-pressure product during four time periods throughout the dosing interval. Safety and tolerability were assessed by monitoring all adverse events and changes in metabolic laboratory parameters. RESULTS: Reductions in all haemodynamic parameters were significantly greater following COER-verapamil compared with placebo for all time periods. The haemodynamic effects of COER-verapamil in obese (n = 166, BMI = 32.8 kg/m2) and non-obese patients (n = 115, BMI = 25.0 kg/m2) were similar. COER-verapamil was well tolerated in both subgroups, but the incidence of constipation was significantly less in obese patients (P < 0.001). CONCLUSIONS: COER-verapamil is effective in reducing BP, heart rate, and rate-pressure product independently of BMI.

Aged↗
PubMed2001

A forced titration study of antihypertensive efficacy of candesartan cilexetil in comparison to losartan: CLAIM Study II.

An 8-week, multicentre (72 sites in the US), double-blind, randomised, parallel group, forced titration study compared the antihypertensive efficacy of candesartan cilexetil and losartan. A total of 611 patients with essential hypertension (diastolic blood pressure 95 to 114 mm Hg) were randomised initially to candesartan cilexetil 16 mg once daily or losartan 50 mg once daily. After 2 weeks of randomised treatment, the doses of candesartan cilexetil and losartan were doubled to 32 mg and 100 mg once daily and continued respectively for 6 weeks. At week 8, candesartan cilexetil lowered the blood pressure (BP) at 24 h (trough), 6 h (peak) and 48 h post dose to a significantly greater extent (P < 0.05) than losartan: candesartan cilexetil lowered trough BP by 13.4/10.5 mm Hg, peak BP by 15.5/12.9 mm Hg and 48-h BP by 10.5/9.9 mm Hg compared to a reduction of trough BP by 10.1/9.1 mm Hg, peak BP by 12.0/9.5 mm Hg, and 48-h BP by 5.9/7.0 mm Hg by losartan. The responder and control rates were numerically higher in the candesartan cilexetil group, but the differences did not reach statistical significance; the responder rates were 58.8% for the candesartan cilexetil group and 52.1% for the losartan group and control rates were 49.0% for the candesartan cilexetil group and 44.6% for the losartan group. Overall, both treatment regimens were well tolerated. A total of 15 of the 611 (2.5%) patients withdrew from the study due to an adverse event, including nine (2.9%) in the candesartan cilexetil group and six (2.0%) in the losartan group. In conclusion, this forced titration study confirms that candesartan cilexetil is more effective in lowering BP than losartan when compared at once daily maximum doses.

Antihypertensive Agents↗
PubMed2001

Safety of controlled-onset extended-release verapamil in middle-aged and older patients with hypertension and coronary artery disease.

BACKGROUND: Our purpose was to study the safety of controlled-onset, extended-release (COER) verapamil in patients with hypertension or coronary artery disease, with a focus on elderly patients. METHODS: Adverse event data were pooled from 7 double-blind, multicenter, randomized trials including 1999 patients with hypertension or chronic stable angina pectoris. There were 1042 patients who received COER verapamil 180 to 540 mg once daily in the evening for up to 10 weeks, 373 patients who received placebo, and 584 who received an active comparator agent. Data were analyzed according to the following groups: all patients, patients with hypertension, patients with angina, older patients (>/=65 years old), and younger patients (<65 years old). Adverse event rates were compared across the treatment groups by the Fisher exact test. RESULTS: In all patients combined, the incidence of constipation (13% vs 2%), dizziness (6% vs 2%), and back pain (3% vs 1%) was higher in patients treated with COER verapamil than with placebo. Patients with hypertension had more back pain (4% vs 1%) and constipation (12% vs 1%) with COER verapamil than with placebo, whereas patients with angina had more bradycardia (2.6% vs 0%), dizziness (8% vs 2%), and constipation (15% vs 3%). Older patients treated with COER verapamil had more bradycardia, constipation, dizziness, and fatigue and had fewer headaches compared with younger patients treated with COER verapamil. Second- or third-degree atrioventricular block was not observed after administration of COER verapamil in any subgroup. CONCLUSION: These data demonstrate that COER verapamil has an acceptable safety profile that is largely unrelated to age in patients with hypertension or coronary artery disease.

Adult↗
PubMed2001

Cardiovascular risk and therapeutic intervention for the early morning surge in blood pressure and heart rate.

The incidence of most adverse cardiovascular events appears to follow a circadian pattern, reaching a peak in the morning shortly after wakening and arising. The activities of many physiologic parameters, including hemodynamic, hematologic and humoral factors, also fluctuate in a cyclical manner over the 24h. It has been suggested that, during the post-awakening hours, the phases of these cycles synchronize to create an environment that predisposes to atherosclerotic plaque rupture and thrombosis in susceptible individuals, thereby accounting for the heightened cardiovascular risk at this time of day. Blood pressure and heart rate are part of this physiologic process, following a clear circadian rhythm characterized by a fall during sleep and a sharp rise upon awakening. This so-called 'morning surge' in blood pressure may act as a trigger for cardiovascular events, including myocardial infarction and stroke. The clinical implication of these observations is that antihypertensive therapy should provide blood pressure control over the entire interval between doses. For agents taken once daily in the morning, the time of trough plasma drug level (and lowest pharmacodynamic effect) will often coincide with the early morning surge in blood pressure and heart rate. For these reasons, chronotherapeutic formulations of drugs and intrinsically long-acting antihypertensive agents provide the most logical approach to the treatment of hypertensive patients since they provide 24 h blood pressure control from a single daily dose as well as attenuating the early morning rise in blood pressure (and in some instances heart rate).

Blood Pressure↗
PubMed2001

Evaluation of the overall efficacy of the Omron office digital blood pressure HEM-907 monitor in adults.

BACKGROUND: Non-invasive self blood pressure monitoring has become increasingly popular. To assure the accuracy of devices used for this purpose, all need to be validated independently prior to marketing. The objective of this study was to assess the accuracy of the HEM-907, a new semi-automatic, non-invasive, oscillometric blood pressure monitoring device specifically designed to be used in the clinic or physician's office setting. METHODS: Blood pressure measurements taken employing this device were compared with the results obtained by two experienced observers using a mercury sphygmomanometer on 100 subjects and patients (384 measurements). The limits of agreement were calculated for the device compared with the results of the two observers according to the standards of the Association for the Advancement of Medical Instrumentation (AAMI). RESULTS: The agreement between the two observers was -0.36+/-2.32mmHg for systolic blood pressure and 0.02+/-2.42mmHg for diastolic blood pressure. The agreement between the device and the observers was 1.56+/-4.42mmHg and 3.49+/-4.61mmHg for systolic and diastolic blood pressure respectively. CONCLUSIONS: The Omron HEM-907 satisfied the AAMI criteria for accuracy for a non-invasive blood pressure monitoring device.

Adult↗
PubMed2000

Management of patients with hypertension and diabetes mellitus: advances in the evidence for intensive treatment.

Diabetes mellitus is common in patients with hypertension, and greatly increases the risk of cardiovascular disease, including myocardial infarction, stroke, and peripheral vascular disease. "The pharmacologic therapy of patients with hypertension and diabetes has been surrounded by controversy because of concerns about the metabolic effects of several antihypertensive agents, as well as concerns about the safety of calcium antagonists. The objective of this review is to re-evaluate the management of diabetic patients with hypertension in light of the latest clinical trials. We also review the importance of intensive blood pressure control in these patients.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Circadian heart rate response to chronotherapy versus conventional therapy in patients with hypertension and myocardial ischemia.

BACKGROUND: Changes in heart rate (HR) may contribute to the higher incidence of cardiovascular events in the morning. HYPOTHESIS: The objectives of this analysis were to assess HR patterns in two populations (patients with chronic stable angina or stage I to III hypertension) and to compare the effects of various antianginal and antihypertensive treatments on HR. METHODS: This was a retrospective analysis of HR data from two clinical trials evaluating the efficacy of controlled-onset, extended-release (COER)-verapamil. The effects of COER-verapamil were compared with placebo, nifedipine gastrointestinal therapeutic system (GITS), amlodipine, and the combination of amlodipine and atenolol. RESULTS: In patients with angina (n = 498), the change from baseline in HR following 4 weeks of treatment was -6.7 +/- 10.5 beats/min in the COER-verapamil group, -10.8 +/- 10.8 beats/min in the amlodipine/atenolol group, + 2.5 +/- 9.1 beats/ min in the amlodipine monotherapy group, and -1.3 +/- 10.5 beats/min in the placebo group (p<0.001). Data were stratified based on whether patients experienced asymptomatic ischemia during baseline ambulatory electrocardiographic monitoring. The circadian HR pattern was morphologically similar in all groups; however, differences in the magnitude of HR response were evident. In the subset of patients with asymptomatic ischemia (n = 101), treatment with amlodipine monotherapy increased HR compared with placebo. In this same subset of patients, HR reductions were achieved with COER-verapamil and amlodipine/atenolol. In patients with hypertension (n = 557), the change in HR following 10 weeks of treatment was -3.3 beats/min for patients treated with COER-verapamil compared with + 2.0 beats/min for patients treated with nifedipine GITS (p < 0.0001, between-group differences). CONCLUSION: This analysis demonstrates that morphologically similar circadian patterns of HR occur in both hypertensive patients and those with angina. In addition, significant variation exists among antianginal and antihypertensive agents regarding HR effects.

Adrenergic beta-Antagonists↗
PubMed2000

The relationship of electronically monitored physical activity to blood pressure, heart rate, and the circadian blood pressure profile.

We studied how closely changes in electronically monitored physical activity are reflected in changes in blood pressure and heart rate in a group of untreated hypertensive subjects. Thirty-nine hypertensive patients (office blood pressure > 140/ 90 mm Hg) of mean age 57 +/- 10 years (mean +/-SD) wore an ambulatory blood pressure monitor and a wrist actigraph simultaneously. Both average and peak activity for 5 min before each valid blood pressure reading were determined, as was average activity for awake and sleep periods, determined by patient kept diaries. For the overall group, awake and 24-h activities were inversely correlated to age (n = 39, r = -0.42; P = 0.01 and n = 39, r = -0.38; P = 0.01, respectively). No correlation was found between group awake activity and group-average blood pressure or heart rate. For individual patients, there was marked variation in the degree of correlation between awake activity measures (both peak and average) and blood pressure and heart rate. The strongest positive correlation was between activity levels and the heart rate-pressure product. Nondipper profile hypertensives had higher sleep activity than dipper hypertensives (44 +/- 28 units/min v 25 +/- 20 units/min, df = 37, t = 2.12; P = 0.04), but awake activity levels were similar. The higher sleep activity remained after adjustment for age. These findings indicate that the relationship between actigraphic activity and hemodynamic parameters is highly variable and that the rate-pressure product is the strongest correlate of short-term activity. Furthermore, hypertensives with the nondipper profile have higher sleep activity than dipper hypertensives. These findings stress the need for further study into the role of day-to-day activity in determining ambulatory blood pressure and heart rate variability.

Activities of Daily Living↗
PubMed2000

Coexistence of atherosclerotic renal artery stenosis with primary hyperaldosteronism.

The discovery of two forms of secondary hypertension in the same patient is unusual and suggests similar pathophysiological mechanisms, a predisposition to one type in the presence of the other or a chance occurrence. We describe two patients with renal artery stenosis who after successful correction of the stenotic lesions were discovered to have primary hyperaldosteronism associated with bilateral adrenal hyperplasia. Initially prior to revascularisation of the renal artery stenosis, the diagnosis of primary hyperaldosteronism was not evident. Both patients were subjected to further diagnostic evaluation after the appearance of hypokalaemia in one patient and continued resistant hypertension in both patients. The addition of spironolactone therapy reduced blood pressure impressively in both patients. Clinicians should be aware of the possibility that these two forms of secondary hypertension may be present in the same patient and that optimal blood pressure control requires diagnostic assessment and intervention for both disorders.

Aged↗
PubMed2000

Reproducibility of ambulatory blood pressure monitoring in hemodialysis patients.

Ambulatory blood pressure monitoring (ABPM) has been increasingly used in hemodialysis (HD) practice and research; however, no study has evaluated the reproducibility of ABPM in this population. To address this question, we performed 48-hour interdialytic ABPM on 21 HD patients (mean age, 53 +/- 16 years; 7 women) on two different occasions 68 +/- 34 days (range, 30 to 154 days) apart. To qualify for the protocol, patients had to be at the same dry weight and on the same vasoactive drug regimen at both monitoring periods. BP was analyzed according to three different methods: isolated pre-HD and post-HD values, average pre-HD and post-HD values for the five HD sessions surrounding each monitoring period, and 48-hour interdialytic ABPM. Reproducibility was determined by analysis of the SD of the differences (SDD) between the two monitoring periods and the coefficient of variation of each method of BP determination. Our results show better reproducibility of ABPM (SDD, 10.6/6.6 mm Hg; coefficient of variation, 7.5%/8.1%) compared with isolated pre-HD BP (SDD, 24.4/11.3 mm Hg; coefficient of variation, 16.7%/14.1%) or post-HD BP (SDD, 16.8/14.5 mm Hg; coefficient of variation, 11.7%/17.8%), and averaged pre-HD BP (SDD, 14.7/7.2 mm Hg; coefficient of variation, 10.1%/9.1%) or post-HD BP (SDD, 12.4/8.7 mm Hg; coefficient of variation, 8.9%/11.1%). The reproducibility of the decrease in BP during sleep was poor, with up to 43% of the subjects changing dipping category within or between interdialytic periods. We conclude that ABPM is the most accurate method to study BP in HD patients over time. However, variability is significant, and there is poor reproducibility of the nocturnal decline in BP.

Blood Pressure↗