Shortcomings of Office Blood Pressures in Assessing Antihypertensive Therapy

The antihypertensive effect of different agents was investigated in patients with essential hypertension both at the clinic and in the ambulatory state using the semi-automatic Remler M2000 blood pressure recorder. In 7 patients treated for 4 weeks with a transdermal therapeutic system delivering clonidine, blood pressures measured at the physician's office were not significantly decreased whereas blood pressures recorded during patients’ customary daily activities were markedly reduced. In an additional study performed in double-blind fashion, the blood pressure lowering effect of timolol (10–20 mg/d, n = 14) and of methyldopa (250–500 mg/d, n = 16) were compared. These agents were given for 6 weeks in association with a baseline diuretic therapy of hydrochlorothiazide and amiloride. When assessed at the clinic, the antihypertensive effect of timolol and methyldopa was similar. During ambulatory blood pressure monitoring, however, pressure levels were lower (p < 0.05 for the diastolic) in the patients given timolol. These data indicate that blood pressure monitoring outside the clinic makes it possible to detect important differences in the response to antihypertensive therapy even though, based on office blood pressure readings, no significant change occurs. It appears therefore desirable to include ambulatory blood pressure recordings in the design of drug trials.     

Analysis of ambulatory blood pressure monitoring: the problem of 'white-coat' hypertension, responders and non-responders

OBJECTIVE: To analyse a randomized study undertaken to compare the antihypertensive efficacy of dihydropyridine calcium antagonists in patients with essential hypertension. METHOD: Blood pressure was measured both conventionally by a doctor and by non-invasive ambulatory monitoring. RESULTS: During amlodipine therapy (5 mg once a day for 4 weeks, n = 121), the mean daytime diastolic blood pressure was lowered by 8.2+/-7.1 and 0.9+/-7.4 mmHg (means +/- SD) in patients with a pretreatment daytime diastolic blood pressure >/= 90 (n = 89) and < 90 mmHg (n = 32), respectively. In 60 (67%) among the 89 patients who had an initial daytime diastolic blood pressure >/= 90 mmHg the daytime diastolic blood pressure was lowered by >/= 5 mmHg, with a mean fall of 12.0+/- 5.2 mmHg. The decrease in daytime diastolic blood pressure averaged 0.6+/- 3.5 mmHg in the remaining non-responder patients (n = 29). CONCLUSION:It seems important to evaluate the efficacy of a given antihypertensive drug by analysing patients with white-coat hypertension separately from responders to the medication. This allows one to gain maximum information concerning the effect of therapy in the individual hypertensive patients.     

Twenty-four hour ambulatory blood pressure in the Hypertension Optimal Treatment (HOT) study

BACKGROUND AND AIMS: The Hypertension Optimal Treatment (HOT) study showed that when antihypertensive treatment reduces diastolic blood pressure well below 90 mmHg, there can be a further reduction of cardiovascular events, particularly myocardial infarction, with no evidence of a J-shaped curve at lower pressures. Office measurement, however, gives no information about blood pressure outside the office. This paper describes a HOT substudy in which patients underwent both office measurement and 24 h ambulatory blood pressure monitoring. METHODS: The mean age of the substudy population was 62 +/- 7 years. Substudy patients were treated for a median period of 2 years. All received the dihydropyridine calcium antagonist felodipine, while some also received an ACE-inhibitor, a beta-blocker or a diuretic. Average 24 h, day and night ambulatory blood pressure values were computed at baseline (n = 277) and during treatment (n = 347): 112 patients had been randomized to a target office diastolic blood pressure 相似文献   

Measurements of blood pressure with various techniques in daily practice: uncertainty in diagnosing office hypertension with short-term in-hospital registration of blood pressure.

OBJECTIVE: To predict blood pressure outside the clinic from a short-term in-hospital registration for patients referred for ambulatory blood pressure monitoring (ABPM) with special attention to office hypertension. PATIENTS AND METHODS: A series of measurements of blood pressure was performed by the same technician for 187 patients, 82% of whom were being administered antihypertensive therapy. She performed three mercury measurements of blood pressure (Hg stress 1) and then three manually started measurements with a semi-automatic device (Dinamap 1846SX; Dinamap stress) alternated with three manually started readings with a SpaceLabs 90207 monitor (SpaceLabs stress) on the contralateral non-dominant arm. The in-hospital session was continued with 15 automatic Dinamap registrations at 2 min intervals without the technician being present (Dinamap unstressed, five periods of three measurements averaged) before the patient left the hospital for 24h ABPM. RESULTS: The percentages of patients with hypertension in the office (systolic blood pressure >/= 140 mmHg or diastolic blood pressure >/= 90 mmHg, or both) were 80% with Hg stress 1, 76% with Dinamap stress and 85.0% with SpaceLabs stress. Average diastolic SpaceLabs stress was 6.0+/-5.6 mmHg (significantly) higher than diastolic Dinamap stress, whereas the difference between systolic blood pressures was 0.2+/-10.0 mmHg. No further change in blood pressure occurred after the fourth period of Dinamap unstressed measurements. Office hypertension defined as SpaceLabs stress systolic blood pressure >/= 140 mmHg or diastolic blood pressure >/= 90 mmHg, or both, and SpaceLabs daytime systolic blood pressure < 135 mmHg and diastolic blood pressure < 85 mmHg was found in 21 individuals. Office hypertension defined with similar cut-off points in the comparison of Dinamap stress versus Dinamap unstressed period 5 was found in 29 cases, 10 of which overlapped with the definition SpaceLabs stress versus SpaceLabs daytime. The differences between Dinamap stress and Dinamap unstressed period 5 were significantly correlated to the changes of SpaceLabs stress and SpaceLabs daytime both for systolic (r =0.41) and for diastolic (r =0.32) blood pressures. CONCLUSIONS: Measurements of blood pressure in the office with various techniques (mercury, Dinamap and SpaceLabs) are not equivalent. Office hypertension cannot be reliably predicted from a short-term semi-automatic in-hospital registration of blood pressure with a Dinamap device.     

Ambulatory pressure monitoring in the assessment of antihypertensive therapy

A low-cost, ambulatory blood-pressure monitor has been calibrated and validated against a random zero sphygmomanometer. The repeatability of ambulatory pressure recordings after a placebo month in 44 mild to moderate untreated hypertensives was assessed. Systolic blood pressure showed a mean difference over 1 month of 2.0 mmHg, with a standard deviation of differences of 9.3 mmHg. The diastolic blood pressure mean difference was 0.1 mmHg (SD=6.3 mmHg). This variability was much less than for clinic readings (SD=17.3 mmHg) or for single home pressure readings (SD=19.7 mmHg). Using ambulatory monitoring to detect a drop in pressure of 8/5 mmHg with a power of 0.9, the number of subjects needed in a parallel group trial is reduced from 360 to 68, and in a crossover study from 88 to 16 subjects. The usefulness of ambulatory pressure monitoring is demon-strated in a placebo-controlled comparisom of atenolol, nifedipine retard, or their combination in random order. Eleven subjects, 21–60 years, with initial average blood pressures of 166.5/104.7 mmHg, showed a reduction in pressure with atenolol 50 mg a day of 15.1/10.0 mmHg, with nifedipine retard 20 mg b.i.d. of 21.0/11.6 mmHg, and with atenolol 50 mg and nifedipine retard 20 mg once a day of 26.2/16.8 mmHg. Ambulatory monitoring of pressure improved the accuracy of the trial and demonstrated a reduction in the alerting response with atenolol.     

The effects of missing a dose of enalapril versus amlodipine on ambulatory blood pressure

OBJECTIVE: To compare the antihypertensive actions of amlodipine and enalapril in a double-blind, randomized, parallel-group study during treatment and when missing a dose. METHOD: After a single-blind run-in 4-week placebo period, patients were randomly allocated to receive enalapril (15 patients) or amlodipine (15 patients). Patients received active treatment for 4 weeks (20 mg enalapril or 5 mg amlodipine). For those with sitting diastolic office pressure not below 90 mmHg the dosage was doubled and continued up to week 12. Ambulatory blood pressure monitoring was performed at the end of the placebo run-in period for 24 h and at the end of week 12 for 48 h; in this case, patients took the active tablet at 0700 h of the first day and a placebo tablet on the next day to stimulate a missing dose in a single-blind manner. RESULTS: Of the patients, 60% had office blood pressure controlled by enalapril therapy and 80% had amlodipine therapy. The average dosage was 30.7 mg a day for enalapril and 7.3 mg a day for amlodipine. Reductions in blood pressures were higher for the amlodipine group. Ambulatory blood pressure measurement shows a reduction in systolic and in diastolic blood pressure during the 24 h when patients from both groups were receiving their medication with respect to placebo values. During the second day of ambulatory blood pressure recording, when the patient had taken a placebo tablet instead of an active one, the antihypertensive effect was progressively lost with enalapril, but not with amlodipine. CONCLUSION: Enalapril and amlodipine reduced ambulatory systolic and diastolic blood pressure during treatment; however, when patients missed an enalapril dose, control of blood pressure was progressively lost, whereas patients receiving amlodipine maintained their blood pressure under control up to 48 h after the last dose.     

Effect on blood pressure of lumiracoxib versus ibuprofen in patients with osteoarthritis and controlled hypertension: a randomized trial

OBJECTIVES: Nonsteroidal anti-inflammatory drugs vary in their impact on blood pressure and the effect of lumiracoxib 100 mg once daily has not been studied previously. To examine whether lumiracoxib 100 mg once daily would result in lower 24-h mean systolic ambulatory blood pressure than ibuprofen 600 mg three times daily in osteoarthritis patients with controlled hypertension, a 4-week, randomized, double-blind, parallel-group study was conducted in 79 centres in nine countries. METHODS: Hypertensive osteoarthritis patients of 50 years at least whose office blood pressure was less than 140/90 mmHg on stable antihypertensive treatment were randomized to lumiracoxib (n = 394) 100 mg once daily or ibuprofen 600 mg three times daily (n = 393) and 24-h ambulatory blood pressure monitoring was performed at baseline and end of study. The primary outcome measure was a comparison of the change in 24-h mean systolic ambulatory blood pressure from baseline to week 4. Secondary analyses included other blood pressure-related endpoints and efficacy (pain) measurements. RESULTS: Compared with baseline, the 24-h mean systolic ambulatory blood pressure (least square mean) decreased in lumiracoxib-treated patients (-2.7 mmHg) and increased in ibuprofen-treated patients (+2.2 mmHg) at 4 weeks, estimated difference -5.0 mmHg (95% confidence interval -6.1 to -3.8) in favour of lumiracoxib. The 24-h mean diastolic ambulatory blood pressure changes were -1.5 mmHg (lumiracoxib), +0.5 mmHg (ibuprofen), difference -2.0 mmHg (95% confidence interval -2.7 to -1.3). Efficacy results were comparable. CONCLUSIONS: Treatment with lumiracoxib 100 mg once daily resulted in clinically significant lower blood pressure compared with ibuprofen 600 mg three times daily in osteoarthritis patients with well controlled hypertension.     

Potassium supplementation reduces clinic and ambulatory blood pressure in elderly hypertensive patients.

OBJECTIVES: To determine the effects of potassium chloride 60 mmol/day supplementation on clinic and 24-h ambulatory blood pressure values in elderly untreated hypertensive patients. DESIGN: A double-blind randomized placebo-controlled crossover study lasting 8 weeks, following a 4-week run-in period. SETTING: Outpatient clinic in a district general hospital. PATIENTS: Eighteen untreated elderly hypertensive patients (mean age 75 years, range 66-79) with a systolic blood pressure of > or = 160 mmHg and/or a diastolic blood pressure of > or = 95 mmHg were recruited from the clinics of local general practitioners and from the current hospital outpatient department. Patients had not received any antihypertensive medication for at least 4 weeks before entry into the study. INTERVENTIONS: Before entry into the study, the daily dietary electrolyte intake of each individual was established and this was maintained during the run-in and intervention periods. Following a 4-week run-in period patients received potassium supplements or matching placebo, each for 4 weeks. MAIN OUTCOME MEASURES: The within-patient changes in clinic and 24-h ambulatory blood pressures at the end of each intervention period. RESULTS: After 4 weeks potassium supplementation compared with placebo there was a significant fall in supine clinic blood pressure, standing and 24-h ambulatory systolic blood pressure. There was no significant change in clinic standing diastolic blood pressure, 24-h ambulatory diastolic blood pressure or pulse rate. Plasma renin activity increased and body weight fell after potassium supplementation. Twenty-four-hour urinary potassium rose significantly, whereas urinary sodium excretion was unchanged. CONCLUSIONS: A 60-mmol daily supplement of potassium chloride reduces clinic and 24-h ambulatory blood pressure in elderly hypertensive patients.     

Casual versus 24-hour ambulatory blood pressure recording in the evaluation of chronic administration of sustained-release verapamil

Although ambulatory blood pressure monitoring has been used widely for the evaluation of antihypertensive treatment, little information is available regarding the comparison between this method and casual BP measurement during drug trials. In our study, we tested the efficacy of a new formulation of verapamil, 240 mg sustained-release tablets, and compared the degree of BP reduction as detected by casual (standard mercury manometer) and by 24-hour ambulatory recording (Spacelab ICR 5300). A statistically significant fall in casual BP was observed after verapamil with respect to placebo. Moreover, 24-hour, waking and sleeping ambulatory BPs were significantly reduced by verapamil. The mean BP reduction was similar for office (20.1/16.1 +/- 4.3/3.1 mmHg) and for day-time ambulatory monitoring (13.4/10.7 +/- 4.2/1.9 1.9 mmHg), but no correlation was found between BP fall recorded by the two techniques for individual subjects. This study suggests that sustained-release verapamil is an effective antihypertensive drug. Individual mean BP reduction outside the clinic may not be predicted from office readings and therefore ambulatory BP recording seems to provide a better basis for testing the efficacy of drugs.     

An evaluation of self-measured blood pressure in a study with a calcium-channel antagonist versus a beta-blocker.

In recent years self-measurement of blood pressure at home has gained increasing importance but there have been only a few studies comparing casual, ambulatory, and self-measured blood pressure determinations during a single clinical trial. We therefore compared treatment-induced blood pressure-reductions in a double-blind, placebo-controlled, parallel study design with a single morning dose of either 10 mg bisoprolol (n = 26) or 20 mg nitrendipine (n = 27) with casual blood pressure readings in the morning before the dose, ambulatory 24-h monitoring, and self-recorded measurements in the morning before the dose and in the evening. Mean reductions for systolic and diastolic blood pressure after 4 weeks of therapy were significantly greater for bisoprolol than for nitrendipine. The treatment-induced blood pressure reductions were most pronounced as assessed by casual readings but showed good agreement between casual, ambulatory, and self-measured blood pressure for group comparisons. In some patients, however, marked individual differences between the three methods were observed. Correlation coefficients between ambulatory and self-measured blood pressure were 0.4 for systolic blood pressure (P less than .05) and 0.6 for diastolic blood pressure (P less than .0005). Under the conditions of this parallel study design and the usual statistical risks, a difference of 5 mm Hg in diastolic blood pressure can be detected in 118 patients at the clinic, in 70 patients if ambulatory blood pressure is used, or in 56 patients if self-measured blood pressure is used. In conclusion, bisoprolol was more effective over 24 h than nitrendipine at the doses studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of indomethacin on blood pressure lowering by captopril and losartan in hypertensive patients

NSAIDs are known to attenuate the effects of some antihypertensive medications. It is not known whether the new class of angiotensin II receptor antagonists is similarly affected. We conducted a multicenter study assessing the effect of indomethacin on the antihypertensive effects of losartan and captopril. After 4 weeks of placebo washout, hypertensive patients received 6 weeks of active antihypertensive therapy with either 50 mg losartan once daily (n=111) or 25 mg captopril twice daily for 1 week, which was increased to 50 mg twice daily for 5 weeks (n=105). This was followed by 1 week of concomitant therapy with indomethacin (75 mg daily). The primary outcome measure was the change in mean 24-hour ambulatory diastolic blood pressure after the addition of indomethacin. Both captopril and losartan significantly lowered ambulatory diastolic blood pressure (losartan -5.3 mm Hg, P:<0.001; captopril -5.6 mm Hg, P:<0.001) after 6 weeks of therapy. Indomethacin significantly attenuated the 24-hour ambulatory diastolic blood pressure for both losartan (2.2 mm Hg, P:<0.05) and captopril (2.7 mm Hg, P:<0.001) and also attenuated the effect of captopril on trough sitting diastolic blood pressure. Changes in daytime diastolic blood pressure (7:00 AM to 11:00 PM) were similar to the 24-hour response in both groups. Nighttime diastolic blood pressure (11:01 PM to 6:59 AM) was significantly attenuated in captopril-treated patients (2.0 mm Hg, P:<0.05), but losartan was unaffected (0.4 mm Hg). Thus, concurrent treatment with indomethacin similarly attenuates the 24-hour antihypertensive response to losartan and captopril.     

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.     

Evaluation of the antihypertensive effect of once-a-day trandolapril by 24-hour ambulatory blood pressure monitoring. The Italian Trandolapril Study Group.

The aim of this study was to evaluate the effects of trandolapril on 24-hour blood pressure in patients with mild-to-moderate essential hypertension. After a washout period of 4 weeks, 42 patients were randomized to receive 2 mg of trandolapril once daily and 20 to receive placebo in a double-blind fashion for 6 weeks. This was followed by a second washout period of 4 weeks. At the end of each period, clinic blood pressure was assessed at 24 hours after the last dose and 24-hour ambulatory blood pressure was measured noninvasively, taking blood pressure readings every 15 minutes during the day and every 20 minutes during the night. Two patients were dropped out before any blood pressure evaluation under treatment. Analysis of ambulatory blood pressure was performed in 48 patients who met the criteria for the minimal number of ambulatory blood pressure data (2 values per hour during the day and 1 value per hour in the night). In the trandolapril-treated group (n = 41) clinic systolic/diastolic blood pressures were 159.8 +/- 2.0/102.4 +/- 0.8, 146.8 +/- 2.3/94.8 +/- 1.1, and 155.7 +/- 2.0/99.2 +/- 0.7 mm Hg in the pretreatment, treatment, and post-treatment periods, respectively. The corresponding values for 24-hour mean blood pressure (n = 31) were 139.5 +/- 1.9/91.2 +/- 1.5, 131.0 +/- 2.0/84.3 +/- 1.2, and 139.7 +/- 1.8/90.9 +/- 1.1 mmHg. The differences between the lower treatment, versus the higher pre- and post-treatment, values were all statistically significant (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Using different methods to evaluate the efficacy of olmesartan medoxomil in Chinese patients with mild to moderate essential hypertension according to ambulatory blood pressure monitoring

OBJECTIVE: To evaluate the efficacy of olmesartan medoxomil in Chinese patients with mild to moderate essential hypertension using different methods according to ambulatory blood pressure monitoring. METHODS: Chinese patients 18-75 years of age with clinic diastolic blood pressure (BP) 90-109 mmHg and systolic BP less than 180 mmHg were treated with olmesartan medoxomil 20-40 mg once daily for 24 weeks to reach the goal BP (<140/90 and <130/80 mmHg in diabetes) in a multicenter study. The trough-to-peak ratio (T/P ratio) and the smoothness index (SI) for systolic/diastolic BP were calculated using different methods according to ambulatory blood pressure monitoring. RESULT: Olmesartan medoxomil 20-40 mg once daily reduced the systolic/diastolic ambulatory BP for 24-h, daytime, and night-time by 13.3±16.3/7.6±9.5, 13.9±17.4/8.0±10.4, and 12.3±18.1/6.8±10.2 mmHg in all eligible patients at week 24 from baseline (n=87, P<0.0001). The global and individual T/P ratios were 0.64/0.62 and 0.32/0.30 (n=87) for systolic/diastolic BP, whereas these were 0.71/0.70 and 0.31/0.39 in fair responders (n=71). Global and individual SI were 6.81/5.37 and 0.92/0.67 (n=87) for systolic/diastolic BP, whereas these were 7.04/5.44 and 1.03/1.03 in fair responders (n=71). Global and individual T/P ratios for systolic/diastolic BP were 0.75/0.82 and 0.45/0.46 in the 20 mg subgroup (n=41), whereas these were 0.44/0.59 and 0.30/0.29 in the 40 mg subgroup (n=30). Global and individual SI were 5.70/5.32 and 1.03/0.87 for systolic/diastolic BP in the 20 mg subgroup (n=41), but these were 3.64/2.46 and1.01/0.60 in the 40 mg subgroup (n=30). CONCLUSION: The duration of the antihypertensive action of olmesartan medoxomil with 20-40 mg once daily can be assessed by the global T/P ratio and SI rather than the individual values, even in different populations and dosages.     

Assessment of the anti-hypertensive effect of diltiazem in delayed-action capsules by ambulatory monitoring of arterial pressure]

The aim of this parallel controlled-placebo study was to assess the antihypertensive effect of diltiazem in a slow release formulation in monotherapy by the ambulatory blood pressure monitoring (ABPM). Twenty patients with moderate essential hypertension entered the trial. Whole day ambulatory blood pressure (BP) monitoring, with a COLIN ABPM 630, was done after a wash-out period, after placebo administration and 60 days of therapy with diltiazem in a 120 or 180 mg once or twice daily administration. We verified by ABPM that placebo administration did not have an antihypertensive effect (146 +/- 10 mmHg/87 +/- 7 mmHg at base line to 145 +/- 8 mmHg/84 +/- 6 mmHg with placebo p = ns). Eithy four percent of the patients showed a significant systolic and diastolic BP decrease after 60 days of therapy (from 146 +/- 10 mmHg/87 +/- 7 mmHg at base line to 132 +/- 7/77 +/- 6 mmHg - p less than 0.025). In 56% of the patients this was achieved with 180 mg/day and this effect was sustained throughout the 24 hours. We did not find a significant decrease on heart rate. The ABPM is a valuable technique to assess the effect of antihypertensive drugs and demonstrated that diltiazem in a slow release formulation was effective in decreasing systolic and diastolic BP, throughout the day even in patients with low doses, once daily.     

Use of 24-h ambulatory blood pressure monitoring to assess blood pressure control: a comparison of olmesartan medoxomil and amlodipine besylate

OBJECTIVE: Olmesartan medoxomil is an angiotensin II receptor blocker with similar antihypertensive efficacy as the calcium channel blocker amlodipine besylate in patients with mild-to-moderate hypertension. In addition to a drug's ability to lower blood pressure, the effectiveness of the agent in enabling patients to achieve specific blood pressure targets is an important clinical consideration. This secondary analysis of a randomized, double-blind study compared the efficacy of olmesartan medoxomil with that of amlodipine besylate in achieving ambulatory blood pressure goals among patients with mild-to-moderate hypertension. METHODS: Following a 4-week placebo run-in, 440 study participants aged >or=18 years were randomized to olmesartan medoxomil (20 mg/day), amlodipine besylate (5 mg/day), or placebo for 8 weeks. The proportion of participants achieving specific systolic and diastolic ambulatory blood pressure goal levels was calculated by dividing the number of participants who had achieved a particular blood pressure goal by the total number of patients in the intent-to-treat population. RESULTS: After 8 weeks of treatment, a mean 24-h ambulatory blood pressure of <130/80 or <130/85 mmHg was achieved by significantly more participants in the olmesartan medoxomil group (18.1 and 30.4%, respectively) than in the amlodipine besylate (7.0 and 14.0%, respectively) or placebo (1.9% for both) groups. The target daytime ambulatory blood pressure of <135/85 mmHg was achieved by more participants in the olmesartan medoxomil group than in the amlodipine besylate group (15.8 vs. 5.8%, respectively; P<0.01). CONCLUSION: In a previous publication of the same study, we demonstrated that starting doses of olmesartan medoxomil and amlodipine besylate produced similar mean reductions in blood pressure. In this subanalysis of the blood pressure data from that primary publication, however, olmesartan medoxomil therapy was shown to result in a greater proportion of patients achieving specific ambulatory blood pressure goals than therapy with amlodipine besylate. As blood pressure goal attainment may be of more direct clinical relevance than numerical blood pressure lowering, the achievement of blood pressure goals should be a key efficacy parameter assessed in clinical trials of antihypertensive medications.     

Clinical significance of ambulatory blood pressure monitoring. Evaluation of severity of hypertension, efficacy of treatment and effects on nighttime blood pressure

Blood pressure (BP) obtained by the physician in his office and ambulatory BP recorded every hour throughout 24 hours with a noninvasive automated BP monitoring device were compared in 10 normotensives and 162 hypertensives. Casual BPs significantly correlated with averages in ambulatory BPs (ABPs) throughout the whole day, day (7 am - 10 pm) and night (0-5 am). However, it was noted that 6 of 10 normotensives and all of the moderate to severe hypertensives had ABPs of more than 150/90 mmHg at least once during the 24-hour period. The incidence of ABPs greater than 150/90 mmHg among all readings was higher in untreated and treated hypertensives with diastolic BPs in the office of more than 105 mmHg, and, when checked along with the clock time, higher not only in the morning but also in the evening. On the other hand, one-third or one-fifth of treated hypertensives with diastolic office BPs less than 90 mmHg or between 90 and 105 mmHg respectively had ABPs less than 150/90 mmHg throughout the whole day. When the effect of nicardipine (60 mg, t.i.d.) or slow-release nifedipine (27.3 +/- 3.0 mg, b.i.d.) on minimum BP during the night was analyzed, long-acting nifedipine decreased BP throughout the night to levels not significantly different from normotensive controls, whereas short-acting nicardipine did not affect nighttime BPs. These results suggest that simple ABP monitoring throughout the day gives us useful information to evaluate the severity of hypertension and the efficacy of antihypertensive medication as well as to avoid overtreatment with long-acting hypotensive agents resulting in a great fall in BP during sleep.     

Home ambulatory blood pressure readings do not differ from clinic readings taken at the same time of day

In most hypertensives clinic blood pressure (BP) is variably higher than home BP, but the underlying mechanisms are uncertain. We investigated whether the 24-hour ambulatory home BP profile as well as the office-home BP discrepancy could vary with the time of day of application of the recording system (from 08.00 h to 19.00 h) in 135 untreated hypertensives who underwent non-invasive home BP monitoring (ICR 5200). Neither systolic nor diastolic 24-hour home BP (average of daily readings, area-under-the-curve) varied significantly with the time of day of application of the system. Clinic BP was about 12% higher than 24-hour home BP in the whole population, mean values being 161.4/102.9 mmHg (office BP) vs 141.2/90.8 mmHg (average 24-hour home readings), as well as in each of the subcohorts based on the time of day of application of the system (all P less than 0.01). However, in none of the subcohorts were there any statistically significant differences between clinic BP and home BP readings taken at the same time of day as the clinic readings. No correlation was found between clinic heart rate and clinic-home discrepancy. We conclude that in essential hypertension 24-hr non-invasive ambulatory BP monitoring can begin indifferently from 08.00 h to 19.00 h with no expected influence of time of application on results and that clinic BP is not dissimilar from home BP at the same time of day.     

Twenty-Four hour ambulatory blood pressure profile of a new slow-release formulation of diltiazem in mild to moderate hypertension

Twelve patients with a mild to moderate essential hypertension were included in a double-blind, balanced, randomized placebo-controlled cross-over study to assess the efficacy and duration of action of a new slow-release formulation of diltiazem (300 mg) given once daily for 3 weeks. All office blood pressure measurements were done 24 hours after drug intake. In order to improve the accuracy of the trial, 24-hours non-invasive ambulatory blood pressure monitoring (Spacelabs 90207 system) were performed as well. Diltiazem significantly lowered supine and standing systolic and diastolic office blood pressure (by 16.9/12.7 mmHg and by 17.3/13.8 mmHg, respectively), without changing office heart rate. Diltiazem also significantly lowered ambulatory blood pressure measured over 24 hours, as well as ambulatory heart rate. The blood pressure lowering effect was most pronounced during the daytime period and did not reach statistical significance during the sleeping hours. The treatment was well tolerated, and there were no significant side effects. The results confirm the antihypertensive efficacy of diltiazem LP 300 mg once daily during the daytime and during the early morning blood pressure rise, without inducing nocturnal hypotension.     

White-coat effect in normotension and hypertension

OBJECTIVES: The difference between clinic and daytime ambulatory blood pressure is referred to as the white-coat effect. In this study, we investigated (i) the magnitude of the white-coat effect in subjects with different daytime ambulatory blood pressure levels, and (ii) the association of the white-coat effect with left ventricular mass. METHODS: A total of 1581 subjects underwent clinic blood pressure readings, 24-h ambulatory blood pressure monitoring and left ventricular echocardiographic assessment. Their mean daytime systolic blood pressure varied from 88.0 to 208.9 mmHg and their mean daytime diastolic blood pressure from 40.3 to 133.0 mmHg. RESULTS: A negative correlation was found between the systolic or diastolic white-coat effect and the systolic or diastolic daytime ambulatory blood pressure (r = -0.22, P < 0.000 and r = -0.50, P < 0.000, respectively). Left ventricular mass significantly correlated with ambulatory blood pressure (P < 0.001), but there was no association between left ventricular mass and clinic blood pressure or white-coat effect. Furthermore, the white-coat effect was reversed at the highest level of systolic or diastolic daytime ambulatory blood pressure (systolic over 170 mmHg or diastolic over 100 mmHg) when systolic or diastolic daytime ambulatory blood pressure was higher than systolic or diastolic clinic blood pressure (ambulatory blood pressure hypertension). CONCLUSIONS: The white-coat effect shows an inverse association with daytime ambulatory blood pressure level (systolic or diastolic), being significantly more prominent for levels below 140/80 mmHg for systolic/diastolic daytime ambulatory blood pressure and reversed with daytime ambulatory blood pressure levels above 170/100 mmHg.