Effect of low-dose perindopril/indapamide on albuminuria in diabetes: preterax in albuminuria regression: PREMIER

Microalbuminuria in diabetes is a risk factor for early death and an indicator for aggressive blood pressure (BP) lowering. We compared a combination of 2 mg perindopril/0.625 mg indapamide with enalapril monotherapy on albumin excretion rate (AER) in patients with type 2 diabetes, albuminuria, and hypertension in a 12-month, randomized, double-blind, parallel-group international multicenter study. Four hundred eighty-one patients with type 2 diabetes and hypertension (systolic BP > or =140 mm Hg, <180 mm Hg, diastolic BP <110 mm Hg) were randomly assigned (age 59+/-9 years, 77% previously treated for hypertension). Results from 457 patients (intention-to-treat analysis) were available. After a 4-week placebo period, patients with albuminuria >20 and <500 microg/min were randomly assigned to a combination of 2 mg perindopril/0.625 mg indapamide or to 10 mg daily enalapril. After week 12, doses were adjusted on the basis of BP to a maximum of 8 mg perindopril/2.5 mg indapamide or 40 mg enalapril. The main outcome measures were overnight AER and supine BP. Both treatments reduced BP. Perindopril/indapamide treatment resulted in a statistically significant higher fall in both BP (-3.0 [95% CI -5.6, -0.4], P=0.012; systolic BP -1.5 [95% CI -3.0, -0.1] diastolic BP P=0.019) and AER -42% (95% CI -50%, -33%) versus -27% (95% CI -37%, -16%) with enalapril. The greater AER reduction remained significant after adjustment for mean BP. Adverse events were similar in the 2 groups. Thus, first-line treatment with low-dose combination perindopril/indapamide induces a greater decrease in albuminuria than enalapril, partially independent of BP reduction. A BP-independent effect of the combination may increase renal protection.

Diabetes and hypertension

The incidence of hypertension is increased in individuals with diabetes mellitus. This is especially true in patients with type 2 diabetes. In these patients high blood pressure is common at the time of diagnosis of diabetes, but the development of diabetes is often preceded by a period during which hyperinsulinemia and insulin resistance is already present. Diabetes represents by itself a major risk of cardiovascular morbidity and mortality. This risk is considerably enhanced by the co-existence of hypertension. One of the main complications of type 2 diabetes is nephropathy, which manifests initially by microalbuminuria, then by clinical proteinuria, leading to a progressive chronic renal failure and end-stage renal disease. Microalbuminuria is considered today as an indicator of renal endothelial dysfunction as well as an independent predictor of the cardiovascular risk. During recent years a number of studies have shown that tight blood pressure control is essential in diabetic patients in order to provide maximal protection against cardiovascular events and the deterioration of renal function. Of note, there is recent evidence indicating that blockade of the renin-angiotensin system with angiotensin II antagonists has marked nephroprotective effects in patients with hypertension and type 2 diabetes, both at early and late stages of renal disease.

Eprosartan versus enalapril in elderly patients with hypertension: a double-blind, randomized trial

AIM

To compare the efficacy and safety of eprosartan and enalapril to lower systolic blood pressure in elderly patients with essential hypertension.

METHODS

334 patients >65 years with sitting systolic blood pressure (sitSBP) > or = 160 mmHg and diastolic blood pressure (sitDBP) 90-114 mmHg were randomized to 12 weeks of double-blind treatment with eprosartan, 600-800 mg once daily (o.d.) or enalapril (5-20 mg o.d.), with flexible dose titration to lower systolic blood pressure below 140 mmHg. The primary outcome measure was change in sitSBP at endpoint.

RESULTS

Least-squares mean changes from baseline in sitSBP were -18.0 and -17.4 mmHg in the eprosartan and enalapril groups, respectively (difference eprosartan-enalapril -0.6, 95% confidence interval, CI, -4.1 to 3.0, p = 0.76). The corresponding figures for sitDBP were -9.4 and -9.6 mmHg (difference eprosartan-enalapril 0.2, 95% CI -1.7 to 2.0, p = 0.84). Normalization and response rates were also similar in the two groups. Adverse events were recorded in 61 (35.7%) patients on eprosartan (one with dry cough) and 83 (50.9%) patients on enalapril (10 with dry cough).

CONCLUSIONS

Eprosartan and enalapril were equally effective in reducing sitSBP and sitDBP in elderly patients with predominantly systolic hypertension. Eprosartan was better tolerated and, in particular, lacked the propensity of enalapril to cause dry cough.

Eprosartan for the treatment of hypertension

Antihypertensive agents are proven to reduce the cardiovascular risk of stroke, coronary heart disease and cardiac failure. The ideal antihypertensive agent should control all grades of hypertension and have a placebo-like side effect profile. Angiotensin II (AII) receptor antagonists are a relatively new class of antihypertensive agent that block AII Type 1 (AT(1)) receptors, and reduce the pressor effects of AII in the vasculature. By this mechanism, they induce similar pharmacological effects compared with angiotensin-converting enzyme (ACE) inhibitors, resulting in a lowering of blood pressure. However, AII receptor blockers differ from ACE inhibitors with respect to side effects, and induce less cough, a side effect which may be related to bradykinin or other mediators such as substance P. Within the class of AII blockers, eprosartan differs from other currently available agents in terms of chemical structure, as it is a non-biphenyl, non-tetrazole, non-peptide antagonist with a dual pharmacological mode of action. Eprosartan acts at vascular AT(1) receptors (postsynaptically) and at presynaptic AT(1) receptors, where it inhibits sympathetically stimulated noradrenaline release. Its lack of metabolism by cytochrome P450 enzymes confers a low potential for metabolic drug interactions and may be of importance when treating elderly patients and those on multiple drugs. In clinical trials, eprosartan has been demonstrated to be at least as effective in reducing blood pressure as the ACE inhibitor enalapril, and has significantly lower side effects. Eprosartan is safe, effective and well-tolerated in long-term treatment, either as a monotherapy or in combination with other antihypertensive drugs such as hydrochlorothiazide.

Low-dose aspirin does not interfere with the blood pressure-lowering effects of antihypertensive therapy

BACKGROUND

It has been reported that aspirin (ASA) may interfere with the blood pressure (BP)-lowering effect of various antihypertensive agents and attenuate the beneficial effects of angiotensin-converting enzyme (ACE) inhibitors in patients with congestive heart failure.

METHODS AND RESULTS

Data from the Hypertension Optimal Treatment (HOT) Study, in which 18 790 intensively treated hypertensive patients were randomized to either ASA 75 mg daily or placebo for 3.8 years (with a 15% reduction in cardiovascular events and a 36% reduction in myocardial infarction in ASA-treated patients), were reanalysed for the whole group of patients and for various subgroups with particular attention to the possible effects of ASA on BP and renal function. In ASA-treated and placebo-treated patients: (1) systolic blood pressure (SBP) and diastolic blood pressure (DBP) values achieved with antihypertensive treatment were superimposable, with clinically irrelevant differences; (2) these superimposable SBP and DBP were achieved with antihypertensive therapies, that were quantitatively and qualitatively similar, and (3) changes in serum creatinine and in estimated creatinine clearance and the number of patients developing renal dysfunction were also similar. Furthermore, the cardiovascular benefits of ASA were of the same magnitude in hypertensive patients receiving or not receiving ACE-inhibitors.

CONCLUSIONS

Even long-term, low-dose ASA does not interfere with the BP-lowering effect of antihypertensive agents, including combinations with ACE inhibitors, or with renal function. No negative interaction occurs between ACE inhibition and the cardiovascular benefits of small dose of ASA. Our conclusions cannot be extended to larger doses of ASA, or to patients with congestive heart failure.

Pathophysiologic and therapeutic importance of tissue ACE: a consensus report

Angiotensin-converting enzyme (ACE) activation and the de novo production of angiotensin II contribute to cardiovascular disease through direct pathological tissue effects, including vascular remodeling and inflammation, as well as indirect action on nitric oxide bioavailability and its consequences. The endothelium plays a pivotal role in both vascular function and structure; thus, the predominant localization of ACE to the endothelium has implications for the pathobiology of vascular disease, such as coronary artery disease. Numerous experimental studies and clinical trials support the emerging realization that tissue ACE is a vital therapeutic target, and that its inhibition may restore endothelial function or prevent endothelial dysfunction. These effects exceed those attributable to blood pressure reduction alone; hence, ACE inhibitors may exert an important part of their effects through direct tissue action. Pharmacologic studies show that while ACE inhibitors may differ according to their binding affinity for tissue ACE the clinical significance remains to be determined.

The relevance of tissue angiotensin-converting enzyme: manifestations in mechanistic and endpoint data

Angiotensin-converting enzyme (ACE) is primarily localized (>90%) in various tissues and organs, most notably on the endothelium but also within parenchyma and inflammatory cells. Tissue ACE is now recognized as a key factor in cardiovascular and renal diseases. Endothelial dysfunction, in response to a number of risk factors or injury such as hypertension, diabetes mellitus, hypercholesteremia, and cigarette smoking, disrupts the balance of vasodilation and vasoconstriction, vascular smooth muscle cell growth, the inflammatory and oxidative state of the vessel wall, and is associated with activation of tissue ACE. Pathologic activation of local ACE can have deleterious effects on the heart, vasculature, and the kidneys. The imbalance resulting from increased local formation of angiotensin II and increased bradykinin degradation favors cardiovascular disease. Indeed, ACE inhibitors effectively reduce high blood pressure and exert cardio- and renoprotective actions. Recent evidence suggests that a principal target of ACE inhibitor action is at the tissue sites. Pharmacokinetic properties of various ACE inhibitors indicate that there are differences in their binding characteristics for tissue ACE. Clinical studies comparing the effects of antihypertensives (especially ACE inhibitors) on endothelial function suggest differences. More comparative experimental and clinical studies should address the significance of these drug differences and their impact on clinical events.

Effects of individual risk factors on the incidence of cardiovascular events in the treated hypertensive patients of the Hypertension Optimal Treatment Study. HOT Study Group

BACKGROUND

The Hypertension Optimal Treatment (HOT) Study has provided information about cardiovascular events in 18790 hypertensives, subjected to pronounced blood pressure (BP) lowering for a mean of 3.8 years. The HOT study data have subsequently been analysed after stratification of the patients according to global cardiovascular risk, and it has been found that, despite intensive blood pressure lowering in all risk strata, morbid event rates increased with increasing risk stratum.

OBJECTIVES

Previously analysed global risk strata were based on combinations of risk factors. The analyses presented here were intended to provide information on the relative role that the presence of each individual factor may have in increasing cardiovascular risk, despite good BP control.

METHODS

Risk ratios (RR) for patients with and those without a risk factor were calculated with 95% confidence intervals (CI) using a Cox proportional hazard model, and adjusted for all variables except the one under examination.

RESULTS

For all risk factors considered and for all types of event, RR were always greater than 1, indicating a greater risk in the presence, compared with that in the absence of each factor. The male gender was a statistically significant risk for cardiovascular (CV) events, CV and total mortality and particularly for myocardial infarction (MI); age > or = 65 years for CV events, stroke, CV and particularly total mortality; smoking for all events analysed, but particularly for total mortality (twice higher in smokers than in non-smokers); high serum cholesterol (> 6.8 mmol/l) for CV events, MI and CV mortality; high serum creatinine (> 155 micromol/l) for CV events, stroke, CV and total mortality; diabetes for CV events, stroke, total mortality and particularly CV mortality; and ischaemic heart disease for all events analysed. Adjusted RR were often close to or greater than 2.

CONCLUSIONS

Each of the risk factors considered was found to be an important cause of residual risk, despite good BP control. These findings emphasize the importance of addressing other correctable risk factors, e.g. smoking, hypercholesterolaemia and diabetes, as well as rigorous control of blood pressure, and of initiating antihypertensive therapy before cardiovascular and renal damage becomes manifest.

Improving prognosis in hypertension: exploring the benefits of angiotensin II type 1 receptor blockade

Prognosis can be improved in hypertensive patients not only by reducing blood pressure, but probably also by effective suppression of adverse neurohormonal influences. Inhibition of the renin-angiotensin system by angiotensin-converting enzyme inhibitors effectively reduces left ventricular hypertrophy and decreases morbidity and mortality due to heart failure, as well as slowing the progression of renal disease. Initial data from studies of angiotensin II type 1 (AT1) receptor blockers indicate that these agents should also be effective in reducing cardiac and renal damage. In this class, candesartan, by virtue of its tight and long-lasting binding to the AT1-receptor, provides pronounced 24-h blood pressure control with effective blockade of all the major negative cardiovascular effects of angiotensin II. Candesartan cilexetil has also been shown to be effective and well tolerated in combination with hydrochlorothiazide in those hypertensive patients who require more than one agent to reach their target blood pressure.

A randomised, double-blind comparison of the angiotensin II receptor antagonist, irbesartan, with the full dose range of enalapril for the treatment of mild-to-moderate hypertension

OBJECTIVE

To compare the anti-hypertensive efficacy, safety, and tolerability of irbesartan with those of the full dose range of enalapril in patients with mild-to-moderate hypertension.

DESIGN AND METHODS

A total of 200 patients were randomised to irbesartan 75 mg or enalapril 10 mg (once daily). Doses were doubled at Weeks 4 and/or 8 if seated diastolic blood pressure (DBP) was > or = 90 mm Hg. Trough blood pressure was measured after completion of a 4- to 5-week placebo lead-in period and again after 2, 4, 8, and 12 weeks of treatment.

MAIN OUTCOME MEASURES

Efficacy was evaluated by determining the change from baseline in trough seated blood pressure and the proportion of patients normalised (seated DBP <90 mm Hg) at Week 12. Safety and tolerability were assessed by adverse events reported by physicians, by patients in response to a specific-symptoms questionnaire, by open-ended questioning of patients by physicians, and by clinical laboratory evaluations.

RESULTS

Both treatments significantly lowered blood pressure with no significant difference in efficacy between treatment groups. At Week 12, the percentage of patients titrated to either enalapril 40 mg or irbesartan 300 mg was 24% and 28%, respectively. The frequency of overall adverse events was similar in both groups. The incidence of cough in the enalapril and irbesartan groups was 17% and 10%, respectively. In contrast to other AII receptor antagonists, there was no change in uric acid concentrations with irbesartan.

CONCLUSIONS

Irbesartan was as effective as the full dose range of enalapril. Irbesartan also demonstrated an excellent tolerability profile.

Human pharmacokinetic/pharmacodynamic profile of irbesartan: a new potent angiotensin II receptor antagonist

BACKGROUND

Inhibition of the renin-angiotensin system has been the focus of considerable research as the enzymatic pathway resulting in the production of angiotensin II is implicated in the development of hypertension and cardiovascular disease.

ANGIOTENSIN CONVERTING ENZYME INHIBITORS

Blocking the renin-angiotensin system with angiotensin converting enzyme (ACE) inhibitors is an effective blood pressure control measure, but is less than ideal due to incomplete blockade and the effects of concomitant blockade of kinase II.

ANGIOTENSIN II RECEPTOR ANTAGONISTS

Angiotensin II receptor antagonists block the renin-angiotensin system at the receptor level, and thus impede the system regardless of the pathway responsible for the formation of ACE. Irbesartan is a new, unique angiotensin II receptor antagonist with favorable pharmacokinetic/pharmacodynamic properties that are close to ideal for an antihypertensive agent. Irbesartan is a specific AT1 receptor antagonist with rapid oral bioavailability (peak plasma concentrations occurring at 1.5-2 h after administration) and a long half-life (11-15 h) that provides 24-h blood pressure control with a single daily dose. The maximal blood pressure fall occurs between 3 and 6 h after the dose. Unlike other angiotensin II receptor antagonists, irbesartan is relatively unaffected by food or drugs.

CONCLUSIONS

The pharmacokinetic/pharmacodynamic properties of irbesartan have been demonstrated to provide superior blood pressure control and tolerability in all classes of hypertension and patient populations.

Renal effects of amino acid infusions in patients with panhypopituitarism

Strong evidence indicates that a high protein diet accelerates end-stage renal disease by increasing glomerular capillary pressure subsequent to renal vasodilatation. The mechanisms underlying this vasodilatation remain undefined, but they have been suspected to be mediated by a pituitary factor. To test this possibility, we measured changes in renal plasma flow and glomerular filtration rate induced by an intravenous infusion of a solution of amino acids in two patients with panhypopituitarism. These patients exhibited changes in renal hemodynamics comparable to those recorded in nine healthy volunteers. The results do not support involvement of the pituitary gland in the acute renal response to amino acids.

Ureolytic Citrobacter freundii infection of the urine as a cause of dissolution of cystine renal calculi

We report a case of cystinuria with staghorn renal lithiasis in a solitary right kidney and chronic renal failure. Right nephropyelolithotomy was performed and although 29 renal calculi were extracted many stones remained in situ. A permanent nephrostomy was left in the kidney. Several months later the urine was infected chronically with a ureolytic Citrobacter freundii bacteria and urinary pH oscillated between 8.0 and 9.2. Spontaneous dissolution of the cystine calculi was observed and many tiny fragments of cystine were expulsed through the nephrostomy, following which renal function improved. Despite the conditions favoring struvite calculi, formation did not occur.

Influence of lisuride, a dopaminergic agonist, on the sexual function of male patients with chronic renal failure

The effects of Lisuride, a dopaminergic agonist, on the levels of plasma prolactin (PRL), testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and on the variations of libido and coital frequency of patients with chronic renal failure (CRF) have been investigated in a group of 20 male patients (ten normoprolactinemic and ten hyperprolactinemic). Ten patients were included in a hemodialysis program and another ten received conservation therapy (all had creatinine clearance rates below 15 mL/min). The response of PRL to TRH administration and that of LH and FSH to LH-RH administration have also been studied. Low levels of plasma testosterone found initially in all the patients, increased in both normoprolactinemic (P less than 0.05) and hyperprolactinemic patients (P less than 0.01) during Lisuride administration. PRL decreased (P less than 0.01) in both groups during therapy. The increase of plasma testosterone was greater in hyperprolactinemic patients (86% v 15% in normoprolactinemic) and was accompanied by a clear improvement in the studied parameters of sexual behaviors. The response of PRL to TRH was modified in hyperprolactinemic patients while that of LH and FSH to LH-RH was not modified, although Lisuride induced an increase of the basal value of LH (P less than 0.01) in the hyperprolactinemic group. The drug was fairly well tolerated, did not induce hypotension, and the overall incidence of side effects decreased along the study. These results stress the need for further studies with this agent in patients with chronic renal failure and sexual dysfunction.

Failure of angiotensin II to reduce plasma renin activity in hypertensive pregnant women

The hypothesis that pregnancy induced hypertension (PIH) is associated with abnormal physiological control of plasma renin activity (PRA) was tested by studying the effects of graded infusion of angiotensin II (ANG II) on PRA, plasma aldosterone (PA), and blood pressure in normal pregnancy, PIH, non-pregnant women in luteal and follicular phase of the menstrual cycle, and males. PIH occurring in the second trimester was associated with elevated PRA, PA and blood pressure compared with all other groups, and reduced urinary thromboxane excretion compared with normal pregnancy. Exogenous ANG II infusion failed to suppress existing PRA in patients with PIH, in contrast to all other groups, but increased PA in all groups. It is concluded that PIH occurring in the second trimester is associated with elevated PRA, PA and blood pressure. The inability of circulating ANG II to reduce PRA in PIH may constitute a major alteration underlying the pathophysiology of PIH.

Dopaminergic modulation of aldosterone secretion: effect of sodium balance and postural changes

The influence of an increased endogenous production of angiotensin II and of sodium homeostasis upon the response of plasma aldosterone to metoclopramide administration has been investigated in 5 normal volunteers. Our results show that the increase of plasma aldosterone after metoclopramide administration is independent of angiotensin II, ACTH and potassium, and that it increases even further due to the endogenous production of angiotensin II induced by postural changes. The state of sodium balance seems to influence the response of plasma aldosterone to metoclopramide administration as it occurs with other stimuli of aldosterone secretion.

Interference by ranitidine with aldosterone secretion in vivo

The effect of a 3-day oral course of ranitidine on plasma aldosterone level has been studied in 6 normotensive volunteers maintained in a state of sodium depletion. A significant fall in plasma aldosterone (p less than 0.05-0.02), in both the overnight recumbency levels and in the levels obtained during a two hour period of ambulation was observed. The change took place in the absence of variation in plasma renin activity and potassium. Plasma cortisol and prolactin levels were lower after ranitidine at the beginning of the test but their values were not significantly different after ambulation during ranitidine therapy. Ranitidine appears to interfere with aldosterone secretion in vivo.

Effect of furosemide on renal function in the stenotic and contralateral kidneys of patients with renovascular hypertension

In a group of six patients diagnosed as having unilateral renovascular hypertension due to fibromuscular dysplasia, inulin glomerular filtration rate, (GFR) and PAH renal plasma flow, (RPF) clearances, urine flow (V), urine sodium (UVNa), potassium (UVK), urinary excretion of prostaglandin E2 (UVPGE2), thromboxane B2 (UVTxB2), and 6-keto prostaglandin F1 alpha (UVPGF1 alpha) were measured in each kidney before and after the i.v. administration of furosemide (20 mg). The basal values of GFR, RPF, UVNa, UVPGE2, UVTxB2, and UV6-keto-PGF1 alpha were lower (p less than 0.01) in the stenotic kidney. Furosemide increased RPF 11% and 50%, GFR 25% and 62%, and V 142% and 280% in the contralateral and stenotic kidney respectively. The increase of UVNa was similar in the two kidneys. In the stenotic kidney, both UVPGE2 and UV6-keto-PGF1 alpha increased significantly (p less than 0.01) with furosemide while UVTxB2 remained unchanged. Furosemide did not alter the rate of excretion of the three prostaglandins measured in the contralateral kidney. We conclude that furosemide significantly improves renal circulatory and excretory function of the stenotic kidney. Since prostaglandin excretions also increased, the vasodilatation in the stenotic kidney may be prostaglandin mediated.

The role of urinary PGE2 and renin-angiotensin-aldosterone system in the pathogenesis of essential hypertension

In a group of 26 patients diagnosed as essential hypertensive (EH) and in a control group (CG) of 27 normotensive volunteers the urinary excretion of PGE2, plasma renin activity (PRA) and plasma aldosterone were measured. EH patients were classified into normoreninemic (NREH) (n = 21) and hyporeninemic (LREH) (n = 5) by the response of PRA to the combined stimuli of ambulation and furosemide. Urinary PGE2 excretion was higher in NREH than in CG (p less than 0.05) while LREH showed values lower than in CG (p less than 0.001). Plasma aldosterone levels were similar in the three groups. In CG and EH patients PRA and urinary PGE2 were closely related (CG r = 0.516, p less than 0.05, EH patients r = 0.674, p less than 0.001). Indomethacin administration induced a decrease of PGE2 in both CG (n = 8) and NREH (n = 8) (p less than 0.01). In contrast, indomethacin induced no changes in PGE2 excretion of LREH (n = 5). Furthermore in the group of patients with NREH indomethacin induced a significant increase in blood pressure (p less than 0.01) and body weight (p less than 0.01) while glomerular filtration rate, 24 hour natriuresis PRA and plasma aldosterone decreased (p less than 0.01). On the contrary, in LREH indomethacin did not alter any of the parameters measured. These results indicate that LREH and NREH may be regarded as two different populations distinguishable not only by different secretion of PRA but also by different excretion of PGE2 in urine and by their characteristic response to indomethacin.