Choosing among renin-angiotensin system blockers for the management of hypertension: from pharmacology to clinical efficacy

BACKGROUND

Hypertension is an important healthcare challenge, yet despite initiatives to improve detection and advances in therapy, the majority of patients do not achieve recommended blood pressure targets and remain at high cardiovascular risk. Physicians are confronted with an array of antihypertensive agents, accompanied by increasingly complex and often conflicting evidence regarding their efficacy and tolerability.

SCOPE

An extensive PubMed and Cochrane database search was conducted to identify clinical literature (published 1990-2009) on the blood pressure lowering efficacy, tolerability and target organ protection of angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs). While not a systematic review, this article reviews the best available evidence in an attempt to clarify current uncertainty within medical practice regarding treatment options in patients with hypertension.

FINDINGS

ACEIs have been at the forefront of hypertension therapy for several years, especially in hypertensive at-risk patients. However, their use is restricted by burdensome side-effects and their limited ability to reach target blood pressure. Newer ARBs, such as telmisartan, have more sustained blood pressure control throughout the 24-h dosing period compared with ACEIs and other ARBs. For uncomplicated hypertension, ARBs are preferred to ACEIs because of their superior tolerability and adherence. In specific patient populations, namely heart failure patients, ARBs have previously shown equal cardiovascular protection to ACEIs. ONTARGET showed that an ARB, in this case telmisartan, was as effective as ramipril in reducing cardiovascular events in a wide cross-section of at-risk cardiovascular patients, but was better tolerated even though patients were screened for ACEI tolerance.

CONCLUSION

Telmisartan is currently the only ARB to have demonstrated equivalence to ramipril in reducing cardiovascular events in a broad patient population. In practical terms, telmisartan is superior to the reference standard ramipril because of more powerful blood pressure lowering and superior tolerability. However, in many countries, guidance to physicians prioritizes ACEIs. In these countries, telmisartan should be the first choice ARB for hypertensive at-risk patients who do not achieve adequate blood pressure control with an ACEI, or for whom tolerability is a concern.

Magnitude of the early morning blood pressure surge in untreated hypertensive patients: a pooled analysis

OBJECTIVES

A post hoc analysis was performed to assess the magnitude of the early morning blood pressure surge (EMBPS), which is associated with peak cardiovascular risk, in untreated hypertensive patients enrolled in two sister studies (Prospective, Randomised Investigation of the Safety and efficacy of MICARDIS vs. ramipril using ambulatory blood pressure monitoring I and II) with identical design.

METHODS

In adults with a mild-to-moderate primary hypertension and no significant comorbidities, 24-h ambulatory blood pressure monitoring was conducted after a 2- to 4-week placebo run-in period and before treatment initiation. Individual blood pressure measurements at 20-min intervals were analysed.

RESULTS

In 1419 hypertensive patients with normal sleeping times, blood pressure displayed a typical circadian rhythm, with a mean EMBPS of 29/24 mmHg. An EMBPS of >or= 25 mmHg was observed in around 60% of patients. The surge was significantly increased with smoking, alcohol consumption, longer sleep, later waking times, and increased blood pressure variability during waking and sleeping. The magnitude of the EMBPS was significantly reduced in Black vs. White patients. The surge was not affected by gender, body mass index or duration of hypertension. Further analysis showed that ethnicity, alcohol consumption and smoking were all found to have a significant impact on surge around waking and age, sleep duration and sleep blood pressure variability were all found to have an effect on the prewake surge.

CONCLUSIONS

In untreated hypertensive patients, the magnitude of the EMBPS is significant when compared with the 24-h mean and is affected by individual patient characteristics. In light of these findings, physicians should understand the importance of 24-h blood pressure control and the modification of certain lifestyle factors as ways of reducing the EMBPS.

A comparison of the efficacy and safety of irbesartan/HCTZ combination therapy with irbesartan and HCTZ monotherapy in the treatment of moderate hypertension

This prospective, double-blind, parallel-group study randomized patients with moderate hypertension (seated systolic blood pressure (SeSBP) 160-179 mm Hg when seated diastolic blood pressure (SeDBP) <110 mm Hg; or SeDBP 100-109 mm Hg when SeSBP <180 mm Hg) 3:1:1 to treatment with irbesartan 300 mg/hydrochlorothiazide (HCTZ) 25 mg combination therapy (n=328), irbesartan 300 mg monotherapy (n=106) or HCTZ monotherapy 25 mg (n=104). Treatment was initiated at half dose, with forced titration to full dose after two weeks followed by ten further weeks' treatment. The primary efficacy variable was the mean reduction in SeSBP from baseline to week 8. Baseline characteristics were similar between groups, with mean baseline blood pressure approximately 162/98 mm Hg; the mean age was 55 years. At week 8 there was a reduction in SeSBP of 27.1 mm Hg with irbesartan/HCTZ, compared with 22.1 mm Hg with irbesartan monotherapy (P=0.0016) and 15.7 mm Hg with HCTZ (P<0.0001). Both the rate of decline and the total degree of decline achieved were greatest with irbesartan/HCTZ and least with HCTZ. A significantly greater percentage of patients reached a treatment goal of SeSBP <140 mm Hg and SeDBP <90 mm Hg by week 8 with irbesartan/HCTZ (53.4%), compared with irbesartan (40.6%; P=0.0254) and HCTZ (20.2%; P<0.0001) alone. Treatment was well tolerated in all three-treatment groups with a slight increase in adverse events in the combination therapy group. In conclusion, irbesartan/HCTZ (300/25 mg) is well tolerated and achieves rapid and sustained reductions in both systolic blood pressure and diastolic blood pressure in patients with moderate hypertension.

Hypertension and its management: a problem in need of new treatment strategies

Although treatments of hypertension have significantly decreased morbidity and mortality from cerebrovascular disease, the associated reductions in coronary artery disease have been very disappointing. Hypertension is a complex inherited syndrome of cardiovascular risk factors, all of which contribute to the development of heart disease. Angiotensin II receptor blockers (ARBs), such as the highly selective ARB valsartan, provide an alternative treatment strategy to address the multiple issues in coronary artery disease. These agents are well-tolerated and have a once-daily regimen that improves compliance. They bring multiple cardiovascular benefits beyond blood pressure (BP) control, such as renoprotection and cardiovascular growth reduction.

Effect of the renin--angiotensin system on the vessel wall: using ACE inhibition to improve endothelial function

Plasma renin activity and cardiovascular disease (CVD) incidence correlate closely in people with hypertension. The effects of angiotensin II (Ang II) on blood pressure (BP) are important in hypertensive patients; accumulating data suggest that the growth effects of Ang II in the cardiovascular system play a critical role in the development of atherosclerosis. Atherosclerosis development in hypertensive patients requires fundamental changes in endothelial structure and function. Key among the factors that may affect the endothelium is the renin--angiotensin--bradykinin system. Ang II, independent of other environmental and neurohormonal factors, mediates the vessel wall changes critical for the development of atherosclerotic disease. A strong correlation appears to exist between Ang II and CVD. Blockade of the renin-angiotensin system has a major impact on arterial structure and function independent of BP. Certain angiotensin-converting enzyme (ACE) inhibitors produce significant improvements in arterial compliance, which may yield a reduction in cardiovascular events. Blockade of the neurohormonal system may be a critical first-line approach to management of hypertension in an effort to prevent or reverse endothelial dysfunction. Moreover, the effects of ACE inhibition, in addition to its effect on BP, suggest that this therapeutic approach may be appropriate for managing patients at risk of CVD who do not yet have hypertension. The ideal antihypertensive agent should yield smooth, consistent BP control over the entire 24-hour period, both to avoid BP variability that places patients at increased risk of cardiovascular events and to offer protection during the vulnerable early morning hours when patients are well known to be at high risk.

Ambulatory blood pressure comparison of the anti-hypertensive efficacy of fixed combinations of irbesartan/hydrochlorothiazide and losartan/hydrochlorothiazide in patients with mild-to-moderate hypertension

This study examined whether the greater anti-hypertensive efficacy of irbesartan monotherapy over losartan monotherapy extends to the respective fixed-dose combinations with hydrochlorothiazide (HCTZ) in patients with mild-to-moderate hypertension. Patients were treated with either irbesartan 150 mg/HCTZ 12.5 mg or losartan 50 mg/HCTZ 12.5 mg over a 4-week period. Twenty-four hour daytime and night-time mean blood pressure (BP), BP load and duration of action were assessed using ambulatory BP monitoring. Both treatment regimens significantly reduced BP from baseline for all efficacy variables assessed. A significant difference was noted in adjusted mean changes from baseline in 24-h ambulatory diastolic BP with irbesartan/HCTZ versus losartan/HCTZ. Reduction in diastolic load was significantly greater with irbesartan/HCTZ than with losartan/HCTZ as was mean ambulatory systolic BP during the last 4 h of the dosing interval. Both regimens were well tolerated, with no significant differences in terms of adverse event profile observed. Irbesartan 150 mg/HCTZ 12.5 mg resulted in greater reductions in ambulatory BP than losartan 50 mg/HCTZ 12.5 mg.

Effects of a structured treatment algorithm on blood pressure goal rates in both stage 1 and stage 2 hypertension

This study analysed the efficacy of an angiotensin receptor blocker-based treatment algorithm for achieving goal blood pressure (BP) in patients with stage 1 (systolic BP (SBP) 140-159 mmHg or diastolic BP (DBP) 90-99 mmHg) or stage 2 (SBP > or = 160 mmHg or DBP > or = 100 mmHg) hypertension. In this 24-week, open-label, multicentre study, patients followed a six-step algorithm until goal BP (< or = 130/85 mmHg) was attained. Initially, olmesartan medoxomil 20 mg/day was administered for 4 weeks. The regimen was modified every 4 weeks until goal BP was attained: increase olmesartan medoxomil to 40 mg/day; add hydrochlorothiazide (HCTZ) 12.5 mg/day; increase HCTZ to 25 mg/day; add amlodipine besylate 5 mg/day; increase amlodipine besylate to 10 mg/day. In patients with stage 1 hypertension, 80% (63/79) and 56% (44/79) achieved BP goals of < or = 140/90 mmHg and < or = 130/85 mmHg, respectively, with olmesartan medoxomil monotherapy (94% (74/79) and 89% (70/79) with olmesartan medoxomil/HCTZ double therapy, and 96% (76/79) and 98% (77/79) with addition of amlodipine besylate (triple therapy)). Mean SBP/DBP reductions were 16.7/11.6, 24.8/15.8, and 26.4/16.5 mmHg for mono-, double-, and triple-therapy, respectively. In patients with stage 2 hypertension, 42% (42/100) and 19% (19/100) achieved BP goals of < or = 140/90 mmHg and < or = 130/85 mmHg, respectively, with monotherapy (75% (75/100) and 54% (54/100) with double therapy, and 90% (90/100) and 81% (81/100) with triple-therapy). Mean SBP/DBP reductions in stage 2 patients were 18.4/10.0, 32.7/16.3, and 39.1/19.4 mmHg for mono-, double, and triple therapy, respectively. Overall, most patients with stage 1 or stage 2 hypertension achieved goal BP.

Telmisartan vs losartan plus hydrochlorothiazide in the treatment of mild-to-moderate essential hypertension--a randomised ABPM study

The objective of this prospective, randomised, open-label, blinded-end point parallel-group, multicentre study was to show that telmisartan 80 mg is not inferior to a fixed-dose combination of losartan 50 mg/hydrochlorothiazide (HCTZ) 12.5 mg in patients with mild-to-moderate hypertension. The criterion for noninferiority was a treatment difference of < or =3.0 mmHg in the reduction of 24-h mean ambulatory diastolic blood pressure (DBP) from the end of the 4-week placebo washout period to the end of the 6-week active treatment period. In the intent-to-treat analysis, the mean reduction in 24-h DBP was 8.3+/-6.7 mmHg among telmisartan-treated patients (n=332) and 10.3+/-6.3 mmHg among losartan/HCTZ-treated patients (n=350). The mean adjusted difference in 24-h DBP between the two treatment groups was 1.9 mmHg, allowing rejection of the a priori null hypothesis of a treatment difference of >3 mmHg. The reduction in mean 24-h systolic blood pressure was 13.2+/-10.2 mmHg with telmisartan and 17.1+/-10.3 mmHg with losartan/HCTZ. Both drugs provided effective control over the 24-h dosing interval. Analyses of morning (0600-1159) ambulatory blood pressure monitoring DBP means and trough cuff DBP confirmed the noninferiority hypothesis of the protocol for telmisartan 80 mg vs losartan 50 mg/HCTZ 12.5 mg. The reductions in office blood pressures measured at trough in patients treated with telmisartan were -16.3/-9.6 and -18.5/-11.1 mmHg in the patients treated with losartan/HCTZ (difference -2.4/-1.2 mmHg). There were no differences between the side-effect profiles of the two treatments.

Ambulatory blood pressure monitoring to assess the comparative efficacy and duration of action of a novel new angiotensin II receptor blocker--telmisartan

Although a wide range of antihypertensive agents is available, adequate blood pressure control is achieved in only about 25% of hypertensive patients. Poor control rates are often due to inadequate patient compliance and unacceptable side-effects. The importance of once-daily dosing is now fully acknowledged, but it is crucial that therapy when given once a day must be effective at the end of the dosing interval to order to minimize the likelihood of sudden cardiac death, myocardial infarction and stroke. Ambulatory blood pressure monitoring (ABPM) provides a thorough assessment of the blood pressure-lowering characteristics of an antihypertensive agent throughout the dosing interval and can more accurately evaluate differences in the duration of the antihypertensive effect of different agents. Telmisartan, a new angiotensin II receptor antagonist, has been extensively studied in clinical trials using ABPM. When compared with dihydropyridine calcium antagonists, beta-adrenergic blockers, angiotensin-converting enzyme inhibitors and other angiotensin II receptor antagonists, telmisartan has proved superior in diminishing ambulatory blood pressure throughout the 24-h period between doses. Telmisartan also has excellent tolerability and in clinical trials demonstrates no increase, irrespective of dose level, over placebo in the incidence of adverse events. Thus, telmisartan given once daily provides high efficacy and tolerability, and will hopefully assist in improving both blood pressure control rates and cardiovascular outcomes in the future.

Arterial compliance abnormalities in isolated systolic hypertension

Arterial compliance measurements using intraarterial pulse contour analysis and a modified Windkessel model were carried out in 19 patients with isolated systolic hypertension (> or = 160/< or = 90 mm Hg) and compared to measurements in 29 patients with essential hypertension (diastolic blood pressure [BP] > or = 95 mm Hg) and 47 normotensive control subjects. Arterial capacitive compliance was significantly lower in isolated systolic hypertension than in essential hypertension (P < .0002) and significantly lower in essential hypertension than in normotensive control subjects (P < .0001). Although the isolated systolic hypertension group was older than the essential hypertension group, the reduction of capacitive compliance in isolated systolic hypertension persisted even when comparison was made with a more nearly age-matched group of essential hypertension. In contrast, oscillatory compliance was reduced similarly in isolated systolic hypertension and essential hypertension compared to normotensive control subjects (P < .0001). Although pulse pressure was greater in isolated systolic hypertension than in essential hypertension, only a weak correlation (r = -0.34) existed between pulse pressure and capacitive compliance. These data indicate that both essential hypertension and isolated systolic hypertension patients exhibit comparably abnormal structure or tone of the small vessels that are the site of oscillations or reflections in the arterial vasculature. In isolated systolic hypertension there is a profound reduction in large artery or capacitive compliance that accounts for the increase in systolic BP and decrease in diastolic BP. This abnormality cannot be accurately assessed by pulse pressure alone.

Beyond the sphygmomanometric numbers: hypertension as a syndrome

Blood pressure is a critical element of hypertension, but evidence shows that many other interrelated risk factors--such as hypercholesterolemia, left ventricular hypertrophy, insulin resistance, and vascular dysfunction--contribute to form a complex syndrome of hypertension. Studies have demonstrated that these other risk factors often precede the onset of elevated blood pressure (BP). Significantly, this has been shown in the normotensive offspring of hypertensive parents. One factor that the elements of the hypertension syndrome have in common is endothelial dysfunction. An upset in the normal balance of angiotensin II and nitric oxide in the endothelial cell is associated with manifestation of the hypertension syndrome-associated risk factors. Recognition of this fact can and should be constructively incorporated into clinical practice in three ways: earlier identification of patients with the hypertension syndrome, earlier treatment to prevent disease onset/progression, and the use of angiotensin converting enzyme inhibitors to correct the critical imbalance in the endothelial cell.

Valsartan alone or with a diuretic or ACE inhibitor as treatment for African American hypertensives: relation to salt intake

Previous clinical trials have demonstrated the important influence of ethnicity and dietary salt on the antihypertensive efficacy of drugs that block the renin angiotensin system. Angiotensin II receptor blockers are a new therapeutic entity that have not been widely studied in African American hypertensives, either alone, or in combination with other therapies such as diuretics or angiotensin converting enzyme inhibitors. We performed a pilot, prospective, open label, randomized design clinical trial to evaluate the effects of the angiotensin II receptor blocker valsartan (160 mg once a day) on systolic and diastolic blood pressure in hypertensive African Americans (n = 88) on a low salt (100 mEq Na+/day) for 2 weeks and the same diet supplemented by 100 mEq Na+ for 4 weeks. After this evaluation, while continuing the Na+ supplementation, patients were randomized to valsartan 320 mg/day (n = 28), or the addition of hydrochlorothiazide (HCTZ) 12.5 mg/day (n = 30), or benazepril 20 mg/day to the valsartan 160 mg/day for an additional 6 weeks. Valsartan (160 mg/day) lowered blood pressure significantly in African American patients on both low salt (-6.4/-4.8 mm Hg: P < .001) and a high salt diet (-4.9/-3.8 mm Hg: P = .01). The high salt diet attenuated the antihypertensive effect slightly (1.6/1.3 mm Hg, P = not significant). When comparing the efficacy of the three randomized therapeutic regimens while on the Na+ supplement, the valsartan 160 mg/HCTZ 12.5 mg was the most effective therapy with an incremental reduction in blood pressure of -10.5/-6.9 mm Hg (P < .01), compared to valsartan 160 mg/day alone. Doubling the dose of valsartan to 320 mg incrementally lowered blood pressure by -3.8/-3.3 mm Hg (P = not significant). The least effective approach was adding benazepril 20 mg/day to valsartan 160 mg/day with no incremental reduction in systolic blood pressure and diastolic blood pressure reduction of only 1.7 mm Hg (P = not significant). We conclude that in our open label pilot study, the antihypertensive activity of valsartan is not significantly attenuated by supplemented salt diet in hypertensive African Americans. Moreover, adding a low dose of HCTZ appears to be the most effective strategy in enhancing the antihypertensive activity of this angiotensin II receptor blocker in contrast to either doubling the dose or adding an angiotensin converting enzyme inhibitor.

Efficacy of candesartan cilexetil as add-on therapy in hypertensive patients uncontrolled on background therapy: a clinical experience trial. ACTION Study Investigators

A large-scale, 8-week, open-label, clinical experience trial evaluated the efficacy of the angiotensin II receptor (AT1 subtype) blocker candesartan cilexetil (16 to 32 mg once daily) either alone or as add-on therapy in 6465 hypertensive patients. The study population was 52% female and 16% African American with a mean age of 58 years. It included 5,446 patients who had essential hypertension (HBP) and 1,014 patients who had isolated systolic hypertension (ISH). These patients had either untreated or uncontrolled hypertension (systolic blood pressure [SBP] 140 to 179 mm Hg or diastolic blood pressure [DBP] 90 to 109 mm Hg inclusive at baseline) despite a variety of antihypertensive medications including diuretics, calcium antagonists, angiotensin converting enzyme (ACE) inhibitors, and alpha- or beta-blockers, either singly or in combination. The mean baseline blood pressure for the HBP group was 156/97 mm Hg. Candesartan cilexetil as monotherapy (in 51% of HBP patients) reduced mean SBP/DBP by 18.7/ 13.1 mm Hg. As add-on therapy (in 49% of HBP patients) to various background therapies, candesartan cilexetil consistently reduced mean SBP/DBP further, irrespective of the background therapy: diuretics (17.8/11.3 mm Hg), calcium antagonists (16.6/11.2 mm Hg), beta-blockers (16.5/ 10.4 mm Hg), ACE inhibitors (15.3/10.0 mm Hg), alpha-blockers (16.4/10.4 mm Hg). The mean baseline blood pressure for the ISH group was 158/81 mm Hg. Candesartan cilexetil, as monotherapy (in 34% of ISH patients), reduced SBP/DBP by 17.0/4.4 mm Hg. As add-on therapy (in 66% of ISH patients) to various background therapies, candesartan cilexetil consistently reduced mean SBP/DBP further, irrespective of the background therapy: diuretics (17.4/5.1 mm Hg), calcium antagonists (15.6/3.6 mm Hg), beta-blockers (14.0/4.8 mm Hg), ACE inhibitors (13.4/4.3 mm Hg), and alpha-blockers (11.6/4.5 mm Hg). The further blood pressure lowering effects of candesartan cilexetil as add-on therapy were seen regardless of age, sex, and race. Overall, 6.8% of the 6465 patients withdrew because of adverse events, most commonly headache (6.3%) and dizziness (5.0%). Orthostatic hypotension was infrequent; 0.2% with candesartan cilexetil alone, and 0.8% with candesartan cilexetil as add-on therapy. Thus, candesartan cilexetil either alone or as add-on therapy was highly effective for the control of systolic or diastolic hypertension regardless of demographic background when used in typical clinical practice settings.

Clinical studies of CS-866, the newest angiotensin II receptor antagonist

Angiotensin II receptor blockers have shown widespread efficacy as antihypertensive medications. These agents bind selectively to angiotensin II type 1 (AT(1)) receptors, specifically blocking the renin-angiotensin system at the last step in its cascade. CS-866 is the most recently introduced drug in this class. This article presents integrated safety and efficacy data from 7 randomized, double-blind, placebo-controlled, parallel group studies in which once-daily CS-866 monotherapy was used in the treatment of patients with essential hypertension (sitting diastolic blood pressure > or =100 mm Hg and < or =115 mm Hg). Data from a total of 2,145 CS-866-treated patients were included in the efficacy analysis. Safety data were available from 2,540 CS-866-treated patients, with a cumulative exposure of 5,888 patient-months. The antihypertensive efficacy of the drug was assessed using both cuff blood pressure measurements and 24-hour ambulatory blood pressure monitoring. The data show that CS-866 is effective and safe for the treatment of hypertension. Dose-dependent reductions in both diastolic and systolic blood pressures occurred within 1 week of initiating treatment, and the response was almost maximal within 2 weeks. There was no difference in efficacy between younger (<65 years) and older (> or =65 years) groups of patients. Trough-to-peak ratios showed that CS-866 retains the majority of its peak effect 24 hours after treatment, and is therefore suitable for once-daily dosing. Dizziness was the only treatment-emergent adverse event with which CS-866 was associated.

The importance of 24-h blood pressure control

The primary goal of antihypertensive therapy is to restore blood pressure to normal levels and to prevent the complications associated with hypertension. In order to maximize these goals by improving patient compliance, clinical researchers have focused on developing antihypertensive agents that can be given once daily. These agents provide many advantages over multiple-dose daily therapies, but it should not be assumed that they are all equivalent in providing adequate blood pressure control over the full 24-h dosing interval. Ambulatory blood pressure monitoring has uncovered important differences in commonly used once-daily therapies and has provided additional insights into the cardiovascular risks associated with high blood pressure loads and blood pressure variability. In addition to ambulatory blood pressure monitoring data, the calculated trough:peak ratio provides useful information on an agent's ability to provide smooth and consistent blood pressure control. Using such assessments, it has been found that agents with a trough:peak ratio > or = 0.50 are better able to control blood pressure over the full 24h while maintaining natural circadian patterns. Ambulatory blood pressure monitoring studies assessing a recently introduced class of antihypertensive drugs, the angiotensin receptor blockers, have demonstrated 24-h efficacy with once-daily dosing, particularly with the newer agents.

Contrasting clinical properties and exercise responses in obese and lean hypertensive patients

OBJECTIVES

We sought to test whether the differences in activity of the renin-angiotensin and sympathetic nervous systems at rest or during exercise can explain the differing cardiovascular properties and outcomes of lean and obese hypertensive patients.

BACKGROUND

Although lean hypertensive patients have fewer metabolic abnormalities than obese hypertensive patients, paradoxically they appear to have a poorer cardiovascular prognosis.

METHODS

To evaluate the heightened risks in lean hypertensive patients, this study compared metabolic, neuroendocrine and cardiovascular characteristics at rest and during a standardized treadmill protocol in obese (body mass index [BMI] = 32.5 +/- 0.3 kg/m2, n = 55) and lean (BMI = 24.3 +/- 0.2 kg/m2, n = 66) hypertensive patients. Normotensive obese (n = 21) and lean (n = 55) volunteers served as control subjects.

RESULTS

Compared with the lean normotensive subjects, the lean and obese hypertensive patients had greater left ventricular mass index (LVMI) values, but on multivariate analysis, LVMI correlated with plasma renin activity (p < 0.001) and plasma norepinephrine (PNE) (p < 0.01) in the lean but not the obese hypertensive patients. Arterial compliance (stroke volume/pulse pressure ratio) was reduced in the lean hypertensive patients, in whom it correlated (p = 0.033) with PNE. The PNE rose less (22%) in the obese than in the lean (55%) hypertensive patients in response to standing (p < 0.05). Likewise, during treadmill exercise, there were lesser increases in renin (65% vs. 145%, p < 0.01) and epinephrine (200% vs. 500%, p < 0.05) in the obese hypertensive patients. These changes were also less in obese patients than in lean control subjects, indicating attenuated neurohormonal responses to stress in obesity.

CONCLUSIONS

Compared with obese hypertensive patients, cardiovascular properties in lean hypertensive patients are more dependent on catecholamines and the renin system. The different neuroendocrine responses to dynamic stimuli in lean and obese patients also might help to explain the disparity in their cardiovascular outcomes.

A new chronotherapeutic oral drug absorption system for verapamil optimizes blood pressure control in the morning

A novel verapamil chronotherapeutic oral drug absorption system (CODAS-Verapamil) designed for bedtime dosing and with controlled onset and extended-release properties was evaluated in 257 patients with mild-to-moderate essential hypertension in an 8-week, double-blind, placebo-controlled trial. After bedtime dosing (9 PM to 11 PM, this delivery system delays drug release for 4 to 5 h, and provides the highest concentrations of verapamil between 6 AM and noon. The study results showed that CODAS-verapamil produced its greatest antihypertensive effect during this morning period (6 AM to 12 noon) and also provided effective trough diastolic blood pressure reductions at 200, 300, and 400 mg. Significant trough systolic blood pressure reductions were achieved only with the 300- and 400-mg doses. The nighttime dosing regimen was not associated with excessive blood pressure (BP) reductions during the sleeping hours, when the antihypertensive effect was generally slightly less than that of the 24-h mean reduction. The CODAS-verapamil provides enhanced BP reduction during the morning period when compared with other time intervals of the 24-h dosing period.

Endothelial dysfunction: its pathogenic role in atherosclerosis and its reversal by ACE inhibition

Not so long ago the structure and function of the endothelium were of no concern to physicians intent on preventing atherosclerosis and its life-threatening sequelae in their patients. Unexpectedly, researchers have found that this supposedly inert cell line controls many important processes, including maintenance of blood vessel compliance. During the early stages of atherosclerosis and even before the onset of borderline hypertension, its vasodilative function is impaired because of an increase in its permeability to lipoproteins and other plasma constituents. Oxidized lipoproteins inhibit the release of the vasodilative substance nitric oxide, and angiotensin II degrades bradykinin, a potent stimulator of nitric oxide production in endothelial cells that is known to protect against atherosclerosis. Fortunately, preclinical and clinical study data strongly suggest that therapy with angiotensin-converting enzyme inhibitors can reverse endothelial dysfunction by decreasing angiotensin II levels and increasing bradykinin and, in turn, nitric oxide levels.

Use of ambulatory blood pressure monitoring to evaluate the selective angiotensin II receptor antagonist, telmisartan, and other antihypertensive drugs

Telmisartan (Micardis (R)) is a new, orally active, long-acting angio-tensin (Ang) II receptor antagonist that is effective in the treatment of hypertension. Ambulatory blood pressure monitoring (ABPM) has emerged as an important method for evaluating the consistency of the antihypertensive effects of a drug throughout the dosing interval. ABPM was used to evaluate the antihypertensive efficacy of telmisartan in several placebo-controlled, double-blind, multicenter studies. Patients with mild-to-moderate hypertension were allocated randomly to groups to receive telmisartan 40 or 80 mg, losartan 50 mg, or placebo, once daily in a 6-week, fixed-dose study, or telmisartan 40-120 mg, amlodipine 5-10 mg, or placebo, once daily in a 12-week, dose-titration study. Patients treated with telmisartan 40 and 80 mg or placebo in a separate 4-week, fixed-dose study were included in an additional analysis. Telmisartan 40 and 80 mg significantly decreased mean ambulatory systolic blood pressure (SBP) and diastolic blood pressure (DBP) relative to placebo for the entire 24 h period and in the following intervals: day (6 a.m. to 10 p.m.), morning (6 a.m. to noon), night (10 p.m. to 6 a.m), and the last 4 h of the dosing interval (P<0.01). Notably, telmisartan 40 or 80 mg was more effective than losartan, especially during the last 4-6 h of the dosing interval (P<0.05). Telmisartan 40- 120 mg tended to be more effective than amlodipine 5-10 mg in reducing SBP and DBP in each time interval, with significant differences between treatments noted for DBP in the last 4 h of the dosing interval and in the morning (P < 0.05). ABPM also revealed that the magnitude of the blood pressure decreasing effect with telmisartan was consistent throughout the dosing interval. These results demonstrate that telmisartan maintains a normal circadian blood pressure pattern and provides full 24 h blood pressure control with once-daily dosing.

Why lowering blood pressure is not enough: the hypertension syndrome and the clinical context of cardiovascular risk reduction

Although drug treatment for hypertension has been widely used for many years, overall control of this disease continues to be less than optimal. Hypertension treatment has had a positive impact on stroke rates, but rates of coronary heart disease remain high. One reason for this lack of success in treatment is that physicians have focused too narrowly on lowering blood pressure. Blood pressure is a critical element of hypertension, but many other interrelated risk factors contribute to form a complex syndrome of hypertension. Studies show that young adult subjects who do not yet have high blood pressure but do have a family history of hypertension exhibit increased incidence of other risk factors, such as high cholesterol, left ventricular dysfunction, reduced arterial compliance, and insulin resistance. These patients with "normotensive hypertension" share many characteristics with patients with fully developed hypertension, both uncontrolled and controlled. The link between these many risk factors and high blood pressure seems to lie in endothelial cell balance. If this balance is upset, elements of the hypertension syndrome start to become manifest, often before blood pressure becomes elevated. Angiotensin-converting enzyme inhibitors can restore this critical balance, improving overall arterial health and arterial compliance and thus preventing the progression of the hypertension syndrome to high blood pressure and, ultimately, target organ damage.

Efficacy of valsartan in patients aged > or =65 years with systolic hypertension

OBJECTIVE

This randomized, double-blind, placebo-controlled, parallel-group, multicenter trial investigated the effects of valsartan, an angiotensin II receptor blocker, on systolic blood pressure (SBP) in patients aged > or =65 years with systolic hypertension, with or without diastolic hypertension.

BACKGROUND

Hypertension in older persons is a public health problem of epidemic proportions. SBP, which increases with age, is a better predictor of cardiovascular morbidity and all-cause mortality than is diastolic blood pressure (DBP). SBP is now thought to be a major modifiable risk factor for cardiovascular disease.

METHODS

The study population consisted of 146 outpatients (74 female and 72 male) with a mean (+/- SD) age of 73.0+/-6.7 years and a trough mean sitting SBP > or =160 mm Hg; 88.4% were white. Patients with clinically relevant cardiac valvular disease, documented or suspected renal artery stenosis, and a serum creatinine level >2.5 mg/dL were excluded from the study. After a 2- to 4-week, single-blind, placebo run-in period, patients were randomly assigned to receive valsartan 80 mg or placebo once daily for 4 weeks and were then force-titrated to valsartan 160 mg or matching placebo once daily for an additional 4 weeks. Median DBP was 90 mm Hg, and >50% of the patients had isolated systolic hypertension.

RESULTS

For the primary efficacy variable, the change from baseline to end point in trough mean sitting SBP, treatment with valsartan was superior to placebo, with reductions of 19.2 mm Hg compared with 8.8 mm Hg, respectively (P < 0.001, 95% CI -15.7, -5.5). Valsartan also produced superior reductions in trough mean sitting DBP (5.2 mm Hg and 1.2 mm Hg for valsartan and placebo, respectively; P < 0.001, 95% CI -6.4, -2.3). The tolerability of valsartan was comparable to that of placebo, with adverse events occurring in 31 (42.5%) valsartan-treated patients compared with 28 (38.4%) patients who received placebo.

CONCLUSIONS

In this patient population of hypertensive patients aged > or =65 years, valsartan was effective and well tolerated and offers a promising new approach to the treatment of systolic hypertension.

What are the approaches for evaluating antihypertensive treatment by 24 h ambulatory blood pressure monitoring?

Measurements of trough blood pressure in a clinic setting have been the traditional method of assessing the efficacy of antihypertensive agents. The duration of action of antihypertensive drugs has been assessed by calculation of a trough-to-peak ratio; drugs with a trough-to-peak ratio greater than 50% are typically given once-a-day indications. However, the use of clinical measurements to assess antihypertensive agents can be misleading. Ambulatory blood pressure monitoring is a simple technique that provides accurate and reproducible data on both the efficacy and duration of action of antihypertensive agents. Although several complicated techniques have been used for the analysis of ambulatory blood pressure data, studies have demonstrated that calculation of simple blood pressure means (24 h mean, day-time mean and night-time mean) will provide all the data required to assess the efficacy of a drug. Calculations of systolic and diastolic load also provide useful information, and the index correlates closely with target-organ damage. Assessing the reduction of blood pressure during the last 2-6 h of the dosing interval provides critical information on the duration of action of agents with once-a-day dosing. Trough-to-peak ratio can also be calculated from an ambulatory blood pressure monitor. Furthermore, a simple line graph constructed from hourly means makes available, at a simple glance, a large amount of information about a drug. The reproducibility of ambulatory monitoring, together with the absence of placebo effect and the ability to exclude patients with white-coat hypertension, make the technique an extremely powerful tool for the assessment of antihypertensive agents that clearly provides more data on the efficacy and duration of action of an antihypertensive agent than do traditional clinical measurements.

Differing roles of body mass and the renin-angiotensin system in mediating the hypertension syndrome

BACKGROUND

Hypertension is characterized not only by a metabolic syndrome that includes obesity and insulin resistance, but also by increases in left-ventricular mass (LVM), reduced arterial compliance and altered renal function. This investigation has examined a possible role for the renin-angiotensin system as well as body mass and insulin values in mediating these cardiovascular and renal aspects of the hypertension syndrome.

METHODS

This was a cross-sectional study of 142 patients identified by community screening. Mean (+/-SE) age was 46 +/- 1 years and patients had stage I-II hypertension (blood pressure: 145 +/- 1/98 +/- 0.5 mm Hg). For analysis, patients were divided into 2 groups: those with body mass index (BMI) <27 kg/m(2) (lean, n = 72) or BMI >27 kg/m(2) (overweight, n = 70).

RESULTS

By univariate analysis, LVM in lean patients correlated significantly with plasma renin activity (PRA), plasma aldosterone, BMI and systolic BP; but with multivariate regression, only PRA (p < 0.01) and BMI (p < 0.04) remained in the model as independent predictors of LVM. For LVM in overweight patients, only BMI (p < 0.02) remained in the model. For total arterial compliance (stroke volume/pulse pressure) only fasting plasma insulin (in the overweight group) was significantly related (p < 0.01). For urinary protein excretion, the only predictor in lean patients was PRA (p < 0.02), whereas in overweight patients it was BMI (p < 0.03). For creatinine clearance, BMI (p < 0.01 in overweight patients) remained in the model, though by univariate regression PRA had an age-dependent dichotomous relationship to clearance: r = +0.25 (p < 0.01) in patients <55 years, but r = -0.54 (p < 0.01) in patients > or =55 years.

CONCLUSION

These findings suggest that in overweight patients cardiovascular and renal values depend chiefly on body weight and insulin, but that in normal weight hypertensives the renin-angiotensin system may play the major role.

Implications of a health lifestyle and medication analysis for improving hypertension control

BACKGROUND

National Health and Nutritional Examination surveys have documented poor rates of hypertension treatment and control, leading to preventable morbidity and mortality.

OBJECTIVES

To examine covariation in the medication and health lifestyle beliefs and behaviors of persons with hypertension to identify and profile distinct subgroups of patients.

METHODS

A sample of 727 patients with hypertension, weighted to match the 1992 National Health Interview Survey age and sex distribution of patients with hypertension, was interviewed by telephone about their beliefs and behaviors regarding hypertension and its management. Cluster analysis of key variables was used to identify 4 patient types.

RESULTS

Subgroups differed significantly. Group A members use an effective mix of medication and health lifestyle regimens to control blood pressure. Group B members are most likely to depend on medication and have high adherence rates. Yet they also have high rates of smoking (29%) and alcohol use (average, 104 times per year) and are less likely to exercise regularly. Group C members are most likely to forget to take medication, are likely to be obese, and find it most difficult to comply with lifestyle changes (except for very low rates of smoking and alcohol use). Group D members are least likely to take medication, most likely to change or stop medication without consulting their physician (20%), most likely to smoke (40%), and least likely to control diet (29%). Group A and B members have better health outcomes than group C and D members.

CONCLUSIONS

Optimal management strategies are likely to differ for the 4 patient types. Further research should be conducted to validate these findings on a separate sample and to devise and test tailored management algorithms for hypertension compliance and control.

Is high blood pressure a late manifestation of the hypertension syndrome?

Because hypertension has generally been defined as a disease of elevated systolic and diastolic blood pressure, the goals of treating hypertension have been simply to normalize the blood pressure. It was believed that if normal blood pressure were achieved, patients with hypertension would experience significant reductions in the incidence of associated cardiovascular events. However, studies to assess cardiovascular events in patients with hypertension have repeatedly demonstrated that reducing blood pressure results in very impressive reductions in cerebrovascular disease but in reductions of only about 16% in coronary artery disease, which is far lower than what was statistically predicted from the reductions in blood pressure. Although there are probably several reasons for the poor rate of reductions in the incidence of coronary artery disease, one of the most compelling appears to be the realization that hypertension is not simply a disease of numbers but rather a complex inherited syndrome of cardiovascular risk factors, all of which contribute to the development of heart disease in these patients. Included in the hypertension syndrome are abnormalities of lipid profile and insulin resistance, changes in renal function, endocrine changes, obesity, abnormalities of coagulation factors, and changes in the structure and function of the left ventricle and of vascular smooth muscle in the vasculature. In many patients, high blood pressure is a late manifestation of this disease process and is preceded by some or all of the associated cardiovascular risk factors. This paradigm suggests that therapeutic strategies for hypertension should be interventions that target both the hemodynamic and nonhemodynamic mechanisms of this syndrome to more completely reduce cardiovascular morbidity and mortality in patients with hypertension.

Hypertension control: multifactorial contributions

Treatment of hypertension reduces the risk of several associated deleterious conditions, although it does not lower risk for all cardiovascular diseases. A new theory suggests that high blood pressure is but one piece in the puzzle of a complex syndrome of inherited risk factors called the hypertension syndrome. Several new findings have emerged theorizing that patients may have coronary artery disease before the actual onset of elevated blood pressure. Epidemiologic studies have found that normotensive patients with a family history of hypertension often have a disease process and prognosis similar to that of hypertensives. It seems that some patients may "inherit" abnormalities that make them prone to the development of hypertension, as well as a complex series of cardiovascular disease risk factors. These include elevated lipids, increased left ventricular hypertrophy, arterial stiffening, insulin resistance, renal function abnormalities, and neuroendocrine changes. It is conceivable that the hypertension syndrome may be reversible if the disease process is diagnosed early, which appears to be well before the actual onset of high blood pressure. High blood pressure may be a risk marker for irreversible vascular disease and early detection of the many components of hypertension syndrome may delay or prevent cardiovascular disease from developing in high-risk patients.

Comparisons of the effects of different long-acting delivery systems on the pharmacokinetics and pharmacodynamics of diltiazem

The benzothiazepine calcium channel antagonist diltiazem is a short-acting drug. To achieve effective 24-h blood pressure control with once-daily dosing, it relies on various extended drug-delivery systems that have grown in importance as a result of the recent reports relating the use of short-acting calcium channel antagonists to increased cardiovascular morbidity. This study examines the pharmacokinetics and resulting pharmacodynamics of two different delivery systems, each loaded with 240 mg of diltiazem and administered to 40 moderately hypertensive patients in a randomized, double-blind crossover trial. After a 4-week, single-blind placebo lead-in, patients with a clinical diastolic blood pressure of > or =100 mm Hg were randomized to either the single or dual microbead diltiazem delivery system for a 4-week period. At the end of this period, each subject was evaluated with 24-h ambulatory blood pressure monitoring and subjected to 24-h inpatient pharmacokinetic analysis on separate days. This was followed by a similar 4-week period in which each subject was treated with the alternative delivery system. For diltiazem, the area under the curve for plasma concentration versus time and the maximum plasma concentration attained by the single microbead system exceeded the values achieved by the dual bead system by 15% and 25%, respectively. These differences were greatest from the 3rd through the 13th h after dosing. During this period, both systolic and diastolic ambulatory blood pressure was significantly lower when the single microbead system was used. When compared with baseline blood pressure, blood pressure reductions achieved with the single microbead system exceeded reductions achieved with the dual microbead system by at least 2 mm Hg for 10 of the 24 postdose hours. Heart rates were slightly reduced but not significantly different. This improved blood pressure control at higher plasma levels of diltiazem suggests that a more efficient delivery system could provide better blood pressure control for identical doses of diltiazem.

Low-dose antihypertensive combination therapy: its rationale and role in cardiovascular risk management

Antihypertensive monotherapy, although commonly used, does not address the multifactorial nature of hypertension as a disease with many pathways. Using more than one drug makes more therapeutic sense because combination agents cover more than one pathway, yet the use of drugs in tandem is typically relegated to more problematic patients later in therapy. Many patients with hypertension are not controlled, because the monotherapeutic agent is used at its highest dose, resulting in side effects that lead to noncompliance. As opposed to fixed-dose combinations that merge two drugs at their highest doses, low-dose combination therapy provides more novel coverage of two or more metabolic pathways that contribute to hypertension. Their once-daily dosing encourages compliance. In addition, because the two drugs are combined at low doses, the probability of side effects is decreased and efficacy is often enhanced. The use of low-dose combination antihypertensive agents is a good contemporary strategy for first-line therapy in that patients can take advantage of their cardiovascular benefits and the control these agents offer early in therapy.

Safety and efficacy of angiotensin II receptor antagonists

A disturbing pattern in the management of hypertension is emerging worldwide. More patients are being treated for hypertension, but blood pressures are not decreasing to target levels. Inadequate reduction in blood pressure is a risk factor for coronary artery disease. Poor drug efficacy, side effects, and lack of compliance are important factors leading to inadequate control of blood pressure. Angiotensin II receptor antagonists provide adequate 24-hour blood pressure control, as measured by ambulatory blood pressure monitoring, and have a side-effect profile similar to placebo. They also provide better patient compliance through once-daily dosing. This article compares the safety and efficacy of angiotensin II receptor antagonists with other antihypertensive agents.

Comparison of telmisartan with lisinopril in patients with mild-to-moderate hypertension

In this study, telmisartan, a new angiotensin AT ( 1 ) receptor antagonist given as monotherapy and in combination with hydrochlorothiazide (HCTZ), was compared with lisinopril as monotherapy and in combination with HCTZ. This 52-week, randomized, multicenter, double-blind, double-dummy, parallel-group, dose-titration study of 578 patients with mild-to-moderate essential hypertension (mean diastolic blood pressure [DBP], >/=95 mm Hg), compared the efficacy and safety of telmisartan (n = 385) with lisinopril (n = 193). Dosage could be increased for both telmisartan (40 --> 80 --> 160 mg) and lisinopril (10 --> 20 --> 40 mg) at each of the first 2 monthly visits if DBP control (<90 mm Hg) had not been established. Once DBP control was established, patients entered the 48-week maintenance period. During this period, the dose of the study drug was fixed, although open-label HCTZ at 12.5 mg or 25 mg was added, when needed, to regain DBP control. At the end of the titration period, DBP control was achieved on monotherapy by 67% and 63% of the telmisartan and lisinopril patients, respectively. At the end of the maintenance period, supine DBP was controlled in 83% and 87% of the telmisartan and lisinopril patients, respectively, with systolic blood pressure over DBP reductions of 23.8/16.6 mm Hg for telmisartan and 19.9/15.6 mm Hg for lisinopril. Treatment-related side effects occurred in fewer telmisartan-treated patients (28%) than in lisinopril-treated patients (40%; P =.001). Significantly fewer patients (P =.018) receiving telmisartan experienced treatment-related cough (3% v 7%), and cough led to discontinuation significantly less often (P =.007) with telmisartan treatment than with lisinopril treatment (0.3% v 3.1%). In addition, two cases of angioedema were observed, both in the lisinopril group. The selective AT (1) receptor antagonist, telmisartan, is extremely effective in the treatment of mild-to-moderate hypertension both as monotherapy and in combination with HCTZ and is at least comparable in efficacy to lisinopril, with a tolerability profile that may offer advantages in terms of a reduced incidence of adverse events.

The efficacy and safety of telmisartan compared to enalapril in patients with severe hypertension

This 8-week, open-label study compared the efficacy and safety of once-daily telmisartan, either alone or in combination with hydrochlorothiazide (HCTZ) and amlodipine, with a similar enalapril regimen in patients with severe hypertension. Clinically relevant reductions in supine systolic blood pressure/DBP were observed with telmisartan (14.6/13.2 mmHg) and enalapril (13.0/12.9 mmHg) monotherapy. Incremental reductions were seen with up-titration of monotherapy (telmisartan 8.1/7.4 and enalapril 9.2/7.7 mmHg), and the addition of HCTZ (telmisartan 14.9/8.7 and enalapril 8.0/6.7 mmHg), and amlodipine (telmisartan 8.0/6.5 and enalapril 10.5/6.4). After 8 weeks of treatment, supine DBP control was achieved in 55% and 35% of the patients on the telmisartan and enalapril regimens, respectively. Both treatment regimens were well tolerated. Telmisartan, a new angiotensin receptor blocker, is a safe and effective drug to use in combination for the treatment of patients with severe hypertension and proved at least as effective as the enalapril combination.

Low-dose combination therapy as first-line hypertension treatment for blacks and nonblacks

To assess the efficacy and safety of bisoprolol/6.25-mg hydrochlorothiazide (HCTZ), amlodipine, and enalapril in black and nonblack patients, data from two comparative studies were pooled and subgroup analyses performed. Both studies had similar designs and included all three active treatments. The second study also included a placebo group. Subjects (n = 541) with a sitting diastolic blood pressure of 95-114 mmHg were titrated to achieve a diastolic blood pressure < or = 90 mmHg. The studies included 114 blacks and 427 nonblacks. Results of an intention-to-treat analysis of mean change from baseline after 12 weeks of treatment showed the following: 1) blood pressure was significantly lowered by all three active drugs compared with baseline or placebo; 2) in blacks, bisoprolol/6.25-mg HCTZ resulted in significantly greater reductions of systolic and diastolic blood pressure than enalapril or placebo, but was not significantly different from amlodipine; 3) in nonblacks, bisoprolol/6.25-mg HCTZ resulted in significantly greater reduction of diastolic blood pressure than amlodipine, enalapril, or placebo. The placebo-corrected change in blood pressure was greater for blacks than whites on the bisoprolol/6.25-mg HCTZ combination, but this was not statistically significant. Bisoprolol/6.25-mg HCTZ controlled diastolic blood pressure to < or = 90 mmHg in significantly more patients than enalapril or placebo in blacks and nonblacks. The difference in control rates was not significant versus amlodipine. The incidence of drug-related adverse events was similar between treatments; however, bisoprolol/6.25-mg HCTZ had a lower discontinuation rate due to lack of blood pressure control or adverse experiences in both blacks and nonblacks.

Efficacy and tolerability of tasosartan, a novel angiotensin II receptor blocker: results from a 10-week, double-blind, placebo-controlled, dose-titration study. Tasosartan Investigators Group

BACKGROUND

Angiotensin II receptor antagonists are selective blockers of the renin-angiotensin system and represent an alternative to angiotensin-converting enzyme inhibitors in the treatment of hypertension. Tasosartan is a newly developed nonpeptide AT1 receptor blocker.

METHODS AND RESULTS

In this double-blind, randomized, dose-titration, multicenter trial, tasosartan and placebo were compared in patients with stage I and stage II hypertension. A prequalification washout period (antihypertensive medications withdrawn) and a 2-week qualification period (patients received single-blind placebo) preceded a 10-week, double-blind treatment period. The patients received either 50 mg tasosartan (n = 132) or placebo (n = 130) once per day and were evaluated once per week. The dose of tasosartan was increased at 3-week intervals to 100 mg and then to 200 mg if the mean sitting diastolic blood pressure (SiDBP) exceeded 90 mm Hg. Compared with placebo, tasosartan produced significantly (P <.05) greater reductions in both SiDBP (-9.4 +/- 0.7 vs -2.0 +/- 0.7 mm Hg) and sitting systolic blood pressure (SBP) (-12.2 +/- 1.2 vs +0.4 +/- 1.2 mm Hg). The rate of response (SiDBP </=90 mm Hg or a decrease from baseline of >/=10 mm Hg) was significantly (P <.05) greater in the tasosartan group than in the placebo group (55% vs 19%). The mean 24-hour blood pressure reduction with tasosartan was -12.6 +/- 0. 9/-8.1 +/- 0.6, significantly greater (P <.05) than the reduction with placebo (+0.6 +/- 0.9/+0.5 +/- 0.6 mm Hg). The trough-to-peak ratio (determined from the ambulatory data) was 0.66 for DBP and 0. 72 for SBP for the tasosartan treatment group, demonstrating 24-hour efficacy with once-a-day administration. The safety profile of tasosartan was similar to placebo.

CONCLUSIONS

These results demonstrate that tasosartan at 50 to 200 mg given once a day over a titration period of 10 weeks was effective and safe in the treatment of essential hypertension.

Hypertension: where have we gone wrong and how can we fix it?

Hypertension is defined as a disease of elevated systolic and diastolic blood pressure and consequently the goals of treating hypertension have been simply to normalize the blood pressure. However, effective blood pressure control has not resulted in the expected decreases in coronary artery disease. These findings have forced researchers to reexamine the importance of blood pressure in causing coronary artery disease, and to pose the question "Is there more to hypertension than high blood pressure?" Although there are probably several reasons for the poor reduction in the incidence of coronary artery disease in hypertensive patients, one of the most compelling appears to be the realization that hypertension is not simply a disease of numbers, but is a complex inherited syndrome of cardiovascular risk factors, all of which contribute to heart disease in these patients. Included in the hypertension syndrome are abnormalities of lipid profile, insulin resistance, changes in renal function, endocrine changes, obesity, abnormalities of coagulation factors, left ventricular hypertrophy and diastolic dysfunction, and abnormalities of vascular structure and compliance. In many patients, high blood pressure is a late manifestation of this disease process and is preceded by some or all of the associated cardiovascular risk factors. Perhaps where we have gone wrong in the management of hypertension is in the belief that this is simply a disease of numbers. To improve our management, we need to find methods to diagnose these patients early in the course of this disease process, and to treat it as a syndrome rather than as a number.

Low-dose combination treatment for hypertension versus single-drug treatment-bisoprolol/hydrochlorothiazide versus amlodipine, enalapril, and placebo: combined analysis of comparative studies

To assess the efficacy and safety of 2.5, 5, and 10 mg bisoprolol/6. 25 mg hydrochlorothiazide (HCTZ), 2.5, 5, and 10 mg amlodipine; and 5, 10, 20, and 40 mg enalapril in subjects (n = 541) with a sitting diastolic blood pressure of 95 to 114 mm Hg, data from two comparative studies were pooled. All drugs were titrated to a diastolic blood pressure 90 mm Hg or less. Both studies were double-blind, randomized, parallel dose escalation trials with similar designs and included three active treatments. The second study also had a placebo group. The mean change from baseline of systolic and diastolic blood pressure for placebo (n = 79) was -0. 1/-2.2 mm Hg; amlodipine (n = 154), -12.4/-10.3 mm Hg; enalapril (n = 155), -9.4/-8.2 mm Hg; and bisoprolol/HCTZ (n = 155), -14.0/-12.0. Overall efficacy analyses documented a statistically significant decrease in sitting diastolic blood pressure for bisoprolol/6.25 mg HCTZ compared with placebo, amlodipine, and enalapril. There was a significant reduction in sitting systolic blood pressure for bisoprolol/6.25 mg HCTZ compared with placebo and enalapril but not amlodipine. Also, there was a significant decrease in sitting heart rate for bisoprolol/6.25 mg HCTZ (-6.2 beats/min) compared with placebo (+0.1 beats/min), amlodipine (+1.2 beats/min), and enalapril (+0.5 beats/min). The control rate (diastolic blood pressure < or = 90 mm Hg) for bisoprolol/6.25 mg HCTZ (66.5%) was significantly better than for placebo (21.8%) and enalapril (47.1%) but not amlodipine (58.4%). Of those patients achieving and maintaining control, 49% of the bisoprolol/6.25 mg HCTZ subjects were on the lowest two doses compared with 30% of the amlodipine and 26% of the enalapril subjects. Percentages of patients reporting at least one drug-related adverse event through week 12 were 27%, 24%, 28%, and 25% for placebo, bisoprolol/6.25 mg HCTZ, amlodipine, and enalapril (not significant). Lower doses of two drugs in fixed combination can provide as good or better blood pressure control compared with higher doses of a single drug with similar tolerability and safety.

Efficacy of low-dose combination of bisoprolol/hydrochlorothiazide compared with amlodipine and enalapril in men and women with essential hypertension

The efficacy of the low-dose combination of bisoprolol/hydrochlorothiazide was compared with amlodipine and enalapril. The low-dose combination was found to be at least as effective as amlodipine and more effective than enalapril in both men and women.

Optimization of antihypertensive therapy with a novel, extended-release formulation of diltiazem: results of a practice-based clinical study

Although the effectiveness of diltiazem for the treatment of patients with hypertension has been well demonstrated in numerous placebo-controlled and comparative clinical trials, most physicians have had some concern about its efficacy and have used it predominantly in patients with mild hypertension. Few large-scale studies have evaluated the efficacy and safety of higher dosages of diltiazem for the treatment of patients with hypertension, and few have evaluated the use of diltiazem in patients with more severe hypertension. Tiazac (Forest Pharmaceuticals, Inc., St. Louis, Missouri), a new, extended-release formulation of diltiazem, provides 24-hour blood pressure control with a single daily dose of up to 360 mg. The Study of Titration and Response to Tiazac (START) is an ongoing practice-based, open-label, multicenter study designed to evaluate the efficacy and safety profiles of Tiazac at greater-than-traditional doses in hypertensive patients and to assess the ability of Tiazac to decrease the rate-pressure product, a surrogate marker for cardiac workload. Patients were eligible for study entry whether their hypertension was newly diagnosed or previously treated with a different formulation of diltiazem or any other antihypertensive agent. Normotensive (sitting diastolic blood pressure [SDBP] < 90 mm Hg) subjects and those with mild (SDBP 90 to 99 mm Hg), moderate (SDBP 100 to 109 mm Hg), severe (SDBP 110 to 119 mm Hg), and very severe (SDBP > or = 120 mm Hg) hypertension were assessed at baseline (visit 1), visit 2 (10 to 14 days after visit 1), and visit 3 (25 to 28 days after visit 1). A total of 3082 patients were enrolled, and data from 2802 assessable patients (i.e., those who completed visits 1, 2, and 3) were analyzed. No subjects were lost to follow-up as a result of adverse effects. All subjects received a starting dose of Tiazac 180 mg or 240 mg once daily, and doses were titrated upward to 360 mg once daily as clinically indicated. Blood pressure reduction matched the severity of hypertension in all patients. Subjects who were switched from another diltiazem formulation demonstrated further decreases in SDBP. Antihypertensive monotherapy with Tiazac was well tolerated. This interim START report demonstrates that a daily dose of up to 360 mg of diltiazem is optimal in terms of both control of hypertension and patient compliance. It also provides the practice-based physician with useful clinical information on dose titration and response to a new formulation of an approved drug and supports the efficacy and safety profiles of diltiazem documented in previous well-controlled clinical trials.

The circadian pattern of blood pressure: cardiovascular risk and therapeutic opportunities

It has been known for many years that humans possess internal time clocks that regulate multiple physiologic factors (chronobiology). Epidemiologic studies have demonstrated that the peak incidence of many diseases, including respiratory disease (asthma, allergy), cardiovascular disease (hypotension, angina, myocardial infarction, stroke), as well as several others, tends to occur in a circadian pattern. In particular, studies utilizing ambulatory blood pressure monitoring have demonstrated that blood pressure has a very definite and reproducible circadian pattern over a 24-h period. Blood pressure is highest during the day; lowest during sleep, and then rapidly increases during the period 0400 h to 1200 h. Because recent data have demonstrated a possible cause-effect relationship between increases in blood pressure and angina, effective antihypertensive control in the early morning is desirable. Some once-a-day drugs taken in the morning may lose efficacy in the last few hours of the dosing interval, resulting in increases in blood pressure during the early morning period. In an attempt to ensure peak plasma levels during the early morning period, novel, controlled-onset, extended release-delivery systems have been developed. Studies using these delivery systems have demonstrated that, when dosed at night, these formulations provide maximal plasma levels during the period 0600 h to 1200 h, when blood pressure is physiologically rising at its greatest rate. The use of drugs designed to have peak efficacy at certain desirable times in the circadian pattern is referred to as chronotherapeutics.

Novel delivery system for verapamil designed to achieve maximal blood pressure control during the early morning

Because the risk of cardiovascular events appears to be greatest in the early morning, this period is a time during which adequate blood pressure (BP) control appears to be most desirable. In this study, a controlled-onset extended-release system (COER-24) that delivers verapamil in a manner designed to achieve maximal levels of drug during the early morning surge in BP was compared with placebo. Ninety-five patients with mild to moderate hypertension were studied. Of this group, 49 patients (mean age 57.6 +/- 1.4 years; 35 men and 14 women) were randomized to take verapamil COER-24 240 mg at 10 PM, and 46 subjects (mean age 55.8 +/- 1.5 years; 29 men and 17 women) were randomized to take placebo. Ambulatory BP monitoring was performed after a 4-week initial placebo period and was repeated after 4 weeks of treatment with verapamil or placebo. Verapamil COER-24 resulted in significant (p < 0.001) decreases in mean whole-day systolic and diastolic BP (-8.2/-6.3 mm Hg; baseline 152/93.0 mm Hg) when compared with placebo (+0.3/-0.9 mm Hg; baseline 150.3/93.2 mm Hg). From 6 AM to noon, verapamil COER-24 resulted in a change in systolic and diastolic BP of -11.6/-9.0 mm Hg, which was significantly (p < 0.001) greater than the change that occurred with placebo (-0.5/-1.0 mm Hg) during the same period. In the last 4 hours of the dosing interval (6 PM to 10 PM), verapamil COER-24 caused significantly greater (p < 0.001) decreases in BP (-7.4/-4.8 mm Hg) than did placebo (+2.7/+1.0 mm Hg). These data demonstrate that the COER-24 system, when administered in the late evening, achieves maximal BP reduction during the early morning hours. Moreover, BP reductions were sustained throughout the 24-hour period.

Combination therapy with diuretics: an evolution of understanding

One of the current recommendations for the treatment of hypertension is a stepped-care approach in which a second drug is added to a first-line agent when adequate blood pressure control has not been achieved. It has been well demonstrated in multiple studies that the response rate to any single class of antihypertensive agent, given as monotherapy, is approximately 45-55%. Thus, in approximately half of the hypertensive population, a second drug will be required. This is not surprising, since it is now well recognized that hypertension is a multifaceted disease process. The use of combination therapy with low-dose diuretics (< 25mg hydrochlorothiazide [HCTZ] or its equivalent) has become a very attractive alternative choice to first-line therapy. The data from clinical trials clearly demonstrate that 6.25 mg or 12.5 mg HCTZ has an additive or synergistic effect on blood-pressure reduction when used in combination with most drugs. At low doses, the side-effect profile with diuretics is similar to placebo. Furthermore, metabolic side effects are significantly reduced when diuretics are used in low doses. The use of low-dose diuretics in combination with other first-line agents significantly enhances blood-pressure control and reduces the likelihood of adverse events and alteration in carbohydrate, lipid, and electrolyte metabolism. Thus, combination therapy with low-dose diuretics provides an attractive alternative approach to first-line treatment of essential hypertension.

Metabolic manifestations of low-dose diuretics

Hypertension has been defined and treated as a disease of abnormal systolic and diastolic blood pressure. Recent data have, however, demonstrated that effective blood-pressure control has not resulted in the expected decrease in coronary artery disease. These findings are probably a result of hypertension being a complex inherited syndrome of cardiovascular risk factors, all of which are genetically linked and all of which contribute to the development of cardiovascular disease in these patients. Included in the hypertension syndrome are abnormalities of lipid profile, insulin resistance, changes in renal function, left ventricular hypertrophy and reduced arterial compliance. In many patients, high blood pressure is a late manifestation of this disease process. Since all cardiovascular risk factors contribute to heart disease in these patients, they should all be considered in the management of this disease process. Diuretics and beta blockers, when used at high doses, negatively impact lipid metabolism and insulin sensitivity, while angiotensin converting enzyme (ACE) inhibitors and calcium antagonists tend to have a neutral effect on these metabolic risk factors. These findings have resulted in decreased use of diuretics and beta blockers in favor of newer agents such as ACE inhibitors and calcium antagonists. However, recent data have demonstrated that when used at low doses (6.25 or 12.5 mg of hydrochlorothiazide), diuretics lack significant metabolic side effects while bringing about significant reductions in blood pressure. Thus, at these doses, hydrochlorothiazide is a useful drug in the treatment of hypertension, both as monotherapy and in combination therapy.