Does treatment with ACE inhibitors or angiotensin II receptor antagonists prevent atrial fibrillation after dual chamber pacemaker implantation?

AIMS: A retrospective observational study was performed to test the hypothesis that a lower incidence of atrial fibrillation (AF) would be observed in patients treated with either angiotensin converting enzyme (ACE) inhibitors or angiotensin II receptor antagonists (AIIRAs) than those without these drugs, 1-year following implantation of a dual chamber pacemaker for all indications. METHODS: One hundred and sixty consecutive patients who underwent implantation of a dual chamber pacemaker between January and August 2002 were identified and their case notes were retrospectively analysed. The primary endpoint was the presence of persistent AF (confirmed by 12-lead ECG recorded from the visit to the pacemaker clinic) at 12-month follow-up. RESULTS: Overall, 8% patients developed new onset persistent AF at 1-year follow-up. The incidence of AF at 1-year was 4% in patients treated with ACE inhibitors, 8% in patients taking AIIRAs or 5% on either drug. Although a trend towards a higher incidence of AF was observed at 1-year (10%) in patients not receiving either of these drugs, this was not statistically significant (P = 0.21, drug vs. no drug). The incidence of AF in patients with a previous history of paroxysmal AF or cardioversion was significantly higher (23%) than those patients without (5%), P < 0.0001. An odds ratio (95% CI) of 7.9 (2.3-27.8) was obtained. CONCLUSION: To confirm these interesting initial results and to investigate this important relationship further, larger prospective randomised controlled studies are required.     

Effects of aliskiren on blood pressure and humoral factors in hypertensive hemodialysis patients previously on angiotensin II receptor antagonists

Background: A direct renin inhibitor (DRI), aliskiren, may be effective for blood pressure (BP) control in hemodialysis patients. However, it is unclear whether aliskiren has a greater beneficial effect on BP and humoral factors than angiotensin II receptor antagonists (ARBs) in hypertensive patients on hemodialysis.

Methods: Eighteen hemodialysis patients (58?±?14 years) on the recommended dose of an ARB were prospectively randomized into two groups: ARB and DRI groups. Patients in the ARB group continued taking their previous ARB, whereas those in the DRI group switched to aliskiren (150?mg/day) for 12 weeks. Baseline measurements of BP and humoral factors such as plasma renin activity (PRA), plasma aldosterone concentration (PAC) and brain natriuretic peptide (BNP) were performed. Measurements were repeated every 4 weeks.

Results: At baseline, no differences were observed in age, gender or BP between the two groups. Systolic BP was unaffected by treatment in either groups (group effect, p?=?0.26; time effect, p?=?0.38; group?×?time effect, p?=?0.24). PRA decreased in DRI (p?≦?0.02, group effect, p?=?0.65; time effect, p?=?0.13; group?×?time effect, p?=?0.048), but not in ARB (p?≧?0.94). PAC increased only in DRI (p?≦?0.03), whereas BNP was unaffected in either group.

Conclusion: Aliskiren at a dose of 150?mg/day had a similar effect on BP compared with ARBs, but significantly lowered PRA.     

Differential effects of angiotensin II receptor blocker and losartan/hydrochlorothiazide combination on central blood pressure and augmentation index

Abstract

Central systolic blood pressure (CSBP) may be a better predictor of cardiovascular risk than clinic brachial (B)SBP. The effects of dose increment from medium dose of angiotensin II receptor blockers (ARBs) to the maximum dose of ARBs (maximum) and changing from medium dose of ARBs to losartan 50?mg/hydrochlorothiazide 12.5?mg combination (combination) were compared in hypertensive patients in whom monotherapy with a medium ARB dose did not achieve goal home SBP (135?mmHg). Four weeks after treatment with a medium ARB dose monotherapy, those whose home SBP level was above 135?mmHg were randomized to receive the maximum ARB dose (n?=?101) or the combination (n?=?99) once daily for 8 weeks. Both regimens significantly decreased BSBP and CSBP, while a decrease in BSBP and CSBP was greater with combination. The maximum significantly decreased augmentation index (AIx), while the combination did not. The rate of a decrease in reflection to decrease in CSBP was greater in the maximum than in the combination. In the elderly subgroup, the combination more effectively lowered BSBP than the maximum, and only the combination decreased CSBP. However, in the young subgroup, the maximum decreased AIx more than combination, while both regimens lowered CSBP and BSBP to a similar extent. It is explained in part that the maximum may affect pulse wave reflection more predominantly than the combination, especially in young subjects. A weak effect on pulse wave reflection and, thus, on CSBP, of the combination may be overcome by the potent antihypertensive effect of this regimen.     

AT1 receptor antagonists: a challenge for ACE inhibitors in diabetic nephropathy

Due to its hemodynamic, metabolic and growth promoting effects, angiotensin II (AII) may play an important role in the pathogenesis of diabetic kidney disease. Consequently, decreasing the production or cellular action of AII is a rational target for therapeutic attempts aimed at slowing the progression of diabetic nephropathy. Based on their superior renoprotective performance in recent landmark studies, currently ACE inhibitors are the drugs of choice in diabetic patients with microalbuminuria or overt proteinuria. A new class of antihypertensive medications, the AT1 receptor antagonists may represent an alternative to ACE inhibitors in the treatment of diabetic nephropathy. They provide a more complete blockade of the renal renin‐angiotensin system and are generally better tolerated than ACE inhibitors. On the other hand, AT1 receptor antagonists do not increase bradykinin levels, an effect that may contribute to the high level of renoprotection achieved by ACE inhibitors. Although human data are not available at this point, ACE inhibitors and AT1 receptor antagonists have similar beneficial effects on proteinuria, renal hypertrophy and glomerulosclerosis in animal models of diabetic kidney disease. Currently several prospective studies are being conducted to compare the efficacy of ACE inhibitors and AT1 receptor antagonists in the treatment of human diabetic nephropathy. Copyright © 1999 John Wiley & Sons, Ltd.     

Comparison of direct renin inhibitor and angiotensin II receptor blocker on clinic and ambulatory blood pressure profiles in hypertension with chronic kidney disease

We compared the therapeutic effects of aliskiren (direct renin inhibitor (DRI) group) with angiotensin II (Ang II) type 1 receptor blockers (ARBs) (ARB group) on clinic blood pressure (BP) and ambulatory BP in 36 hypertensive chronic kidney disease (CKD) patients. The baseline clinic BP levels and the after-treatment/baseline (A/B) ratios of clinic BP levels, estimated after 24-week treatment period, were similar in DRI group (n = 18) and ARB group (n = 18). With respect to the effects on ambulatory BP, the A/B ratios of the daytime and nighttime systolic BP in DRI group were significantly higher than those in ARB group. The A/B ratio of ankle-brachial pressure index after the study was higher in the DRI group compared with the ARB group. The results of the present study suggest that DRI therapy is not superior to ARB therapy in lowering ambulatory BP in hypertensive CKD patients, in spite of comparable clinic BP-lowering effects.     

Increased vasopressor responsiveness to angiotensin II in Type 1 (insulin-dependent) diabetic patients without complications

Summary The blood pressure response to infused angiotensin II (0.3 to 3 ng · kg^–1 · min ^–1) was investigated in six normotensive patients with Type 1 (insulin-dependent) diabetes free of complications and in six healthy subjects matched for age, sex and weight. Basal blood pressures (111/68 and 114/72 mmHg) and basal plasma angiotensin II levels (18.0±5.2 and 14.1±2.4 pmol/l; mean + SD) were similar in the diabetic and control groups as were 24 h urinary excretions of sodium (157±88 and 154±84 mmol/24h). Equal increments in plasma angiotensin II were produced during the infusions in the two groups. Increases in both diastolic and systolic blood pressure were significantly greater in the diabetic patients throughout the infusion. Mean diastolic increments were: 6.7 versus 1.3 mmHg (0.3 ng dose), 11.0 versus 6.9 mmHg (1 ng dose) and 16.7 versus 12.3 mmHg (3 ng dose) (p<0.001). Corresponding figures for systolic pressure were: 8.7 versus 1.3mmHg, 10.3 versus 3.7mmHg and 15.3 versus 8.7mmHg (p<0.001). Vasopressor responsiveness to angiotensin II is thus increased in Type 1 diabetic patients without complications; it may, therefore, be a consequence of the diabetes rather than of the presence of microvascular disease or hypertension.     

Diuretics enhance effects of increased dose of candesartan on ambulatory blood pressure reduction in Japanese patients with uncontrolled hypertension treated with medium-dose angiotensin II receptor blockers

Although blockade of the renin–angiotensin system by increasing the dose of angiotensin II receptor blockers (ARBs) is recommended to achieve clinical benefits in terms of blood pressure (BP) control and cardiovascular and renal outcomes, the effect of this increased dose on ambulatory BP monitoring has not been evaluated completely in Japanese patients with uncontrolled hypertension undergoing medium-dose ARB therapy. The primary objective of this study was to examine the effect of the relatively high dose of the ARB candesartan (12?mg/day) on 24-h systolic BP and the attainment of target BP levels in uncontrolled hypertension treated with a medium dose of ARBs. A total of 146 hypertensive patients (age: 69.9?±?9.3 years; females: 65.8%) completed the study. After switching to candesartan at 12?mg/day, all these BP measurements decreased significantly (p?p?=?0.0014) and 24-h BP levels (p?=?0.0296) also improved significantly. Subgroup analysis indicated that the reduction of 24-h systolic BP was larger in patients treated with diuretics than those without (p?=?0.0206). Multivariate analysis revealed a significant correlation between the combined ARB and diuretic therapy, and the change in 24-h systolic BP irrespective of preceding ARBs. In conclusion, the switching therapy to increased dose of candesartan caused significant reductions in office and ambulatory BP levels, and improved the attainment of target BP levels in patients with uncontrolled hypertension treated with a medium dose of ARBs. Combination with diuretics enhanced this effect.     

Assessment of angiotensin II receptor blockade in humans using a standardized angiotensin II receptor-binding assay

An in vitro angiotensin II (AngII) receptor-binding assay was developed to monitor the degree of receptor blockade in standardized conditions. This in vitro method was validated by comparing its results with those obtained in vivo with the injection of exogenous AngII and the measurement of the AngII-induced changes in systolic blood pressure. For this purpose, 12 normotensive subjects were enrolled in a double-blind, four-way cross-over study comparing the AngII receptor blockade induced by a single oral dose of losartan (50 mg), valsartan (80 mg), irbesartan (150 mg), and placebo. A significant linear relationship between the two methods was found (r = 0.723, n = 191, P < .001). However, there exists a wide scatter of the in vivo data in the absence of active AngII receptor blockade. Thus, the relationship between the two methods is markedly improved (r = 0.87, n = 47, P < .001) when only measurements done 4 h after administration of the drugs are considered (maximal antagonist activity observed in vivo) suggesting that the two methods are equally effective in assessing the degree of AT-1 receptor blockade, but with a greatly reduced variability in the in vitro assay. In addition, the pharmacokinetic/pharmacodynamic analysis performed with the three antagonists suggest that the AT-1 receptor-binding assay works as a bioassay that integrates the antagonistic property of all active drug components of the plasma. This standardized in vitro-binding assay represents a simple, reproducible, and precise tool to characterize the pharmacodynamic profile of AngII receptor antagonists in humans.     

Effect of ACE inhibitors and angiotensin II receptor antagonists in a mouse model of colorectal cancer liver metastases

BACKGROUND AND AIMS: Angiotensin converting enzyme inhibitors (ACE-I) and angiotensin II type I receptor (AT1R) antagonists are commonly used as a treatment for hypertension. Recent experimental and population studies have suggested that these agents may exert an inhibitory effect on malignancy, possibly through anti-angiogenic pathways. The aim of this study was to investigate the effect of an ACE-I (captopril) and an AT1R antagonist (irbesartan) in colorectal cancer liver metastases. METHODS: The effect of captopril and irbesartan on tumor growth was investigated in a mouse model using quantitative stereological and histological analysis. Tumor microcirculation was assessed by microvascular resin casting. A survival study was also carried out. RESULTS: Both captopril and irbesartan markedly decreased tumor growth when compared to control (P = 0.003 and P = 0.004, respectively). However, there was no significant difference in survival or tumor necrosis for either of the drugs. Tumor microvasculature exhibited a reduction in central microvascular density, with constriction and tapering of vessels. CONCLUSION: Captopril and irbesartan caused a marked reduction in volume of colorectal cancer liver metastases and caused changes in tumor microvasculature. However, there was no difference in percentage tumor necrosis or improvements in survival. Further investigation is needed to identify the mode of action of these agents.     

Clinical update: the role of angiotensin II receptor blockers in patients with left ventricular dysfunction (Part II of II)

Almost 5 million individuals in the United States have chronic heart failure (HF), which is increasing in prevalence. Angiotensin-converting enzyme (ACE) inhibitors are standard therapies for HF, although more than 10% of patients with HF are unable to tolerate these agents. Furthermore, ACE inhibitors may not provide complete blockade of the renin-angiotensin system (RAS) in the long term. Because angiotensin II receptor blockers (ARBs) may block the RAS more completely than ACE inhibitors and are better tolerated, several large-scale ARB trials have been performed exploring their potential role in treating patients with symptomatic HF and left ventricular systolic dysfunction. The Losartan Heart Failure Survival Study (ELITE II) demonstrated no significant differences in morbidity and mortality between the ARB losartan and the ACE inhibitor captopril among elderly patients with HF. The Valsartan Heart Failure Trial (Val-HeFT) demonstrated reductions in hospitalizations for HF with the ARB valsartan when added to standard HF therapy, with no effect on mortality. Both trials suggested a potential negative interaction between ARB and beta-blocker therapy. The Candesartan in Heart failure-Assessment of Reduction in Mortality and morbidity (CHARM) program demonstrated significant reductions in morbidity and mortality with the ARB candesartan in patients with HF due to systolic dysfunction, with or without ACE inhibitors and with or without beta blockers. Thus, the addition of ARBs to the treatment regimen of patients with symptomatic HF should be strongly considered.     

Functional antagonism of different angiotensin II type I receptor blockers in human arteries

Objectives. To evaluate and compare the functional type and the degree of antagonism of the selective angiotensin II type 1 receptor blockers (ARB) losartan, EXP 3174 (the active metabolite of losartan), valsartan and candesartan in human internal mammary arteries. Methods. Human internal mammary arteries were obtained as excess graft material during coronary bypass surgery. Vessels were prepared as rings and mounted in an organ bath in which vasoconstriction and -dilation can be measured. Concentration-response curves of angiotensin II-mediated vasoconstriction were measured in absence or presence of different concentrations of one of the ARBs. Results. Losartan showed a rightward shift of the angiotensin II-mediated vasoconstriction, whereas addition of its metabolite EXP 3174 caused a decrease of the maximal effect of angiotensin II. Incubation with valsartan and candesartan also resulted in a decrease of the maximal effect. The inhibiting effects on the angiotensin II-mediated vasoconstriction by the highest concentration of EXP 3174, valsartan and candesartan did not differ significantly. Conclusion. In human internal mammary arteries, losartan acts as a surmountable antagonist. On the other hand, EXP 3174, valsartan and candesartan demonstrate an insurmountable type of antagonism. Furthermore, the inhibiting effects of EXP 3174, valsartan and candesartan in our study are equal in the highest concentrations.     

Rationale for the use of angiotensin II receptor blockers in patients with left ventricular dysfunction (part I of II)

Almost 5 million individuals in the United States are diagnosed with chronic heart failure (HF), and the prevalence is increasing. Angiotensin-converting enzyme (ACE) inhibitors and beta blockers, neurohormonal antagonists that block the renin-angiotensin system (RAS) and the sympathetic nervous system, respectively, have been shown in clinical trials to reduce morbidity and mortality in patients with HF, and these therapies are now integral components of standard HF treatment. Yet, morbidity and mortality rates in HF remain unacceptably high, and the limitations of current standard therapies are becoming increasingly apparent. About 10% of patients with HF are unable to tolerate ACE inhibitors, often because of cough. In addition, ACE inhibition may not completely block the RAS because angiotensin II, the main end product of the RAS, can be generated via non-ACE enzymatic pathways. Angiotensin II receptor blockers (ARBs) may exert more complete RAS blockade than ACE inhibitors by interfering with the binding of angiotensin II at the receptor level, regardless of the enzymatic pathway of production. They are also better tolerated than ACE inhibitors and have been shown to improve symptoms and function in clinical trials in patients with HF. These factors provide a strong rationale for the study of the clinical effects of ARBs in patients with HF.     

Efficacy and safety of two single-pill fixed-dose combinations of angiotensin II receptor blockers/calcium channel blockers in hypertensive patients (EXAMINER study)

Background: There is some controversy regarding which single-pill fixed-dose combinations of angiotensin II type 1 receptor blockers (ARBs) and calcium channel blockers (CCBs) are effective at reducing blood pressure (BP). Methods: Sixty hypertensive patients who received a single-pill fixed-dose combination of valsartan 80?mg/day and amlodipine 5?mg/day were enrolled (UMIN Registration 000013460). They were randomly divided into two treatment groups [single-pill fixed-dose combination therapy with valsartan 80?mg/day and amlodipine 5?mg/day (Val/Am group), or irbesartan 100?mg/day and amlodipine 5?mg/day (Irb/Am group)] and treated for 16 weeks. If the patient did not reach the target office BP at 8 weeks, they received double doses of amlodipine (10?mg/day). Results: In the Irb/Am group, systolic BP (SBP) and diastolic BP (DBP) were significantly decreased at 16 weeks. There were no significant changes in SBP or DBP in the Val/Am group. In the Irb/Am group, serum uric acid (UA) was significantly decreased at 8 weeks and patients who had hyperuricemia showed significantly decreased serum UA at 16 weeks. In addition, the levels of triglycerides (TG) were significantly decreased at 16 weeks in the Irb/Am group. Conclusion: A single-pill fixed-dose combination therapy with irbesartan 100?mg/day and amlodipine 5?mg/day was superior to the combination of valsartan 80?mg/day and amlodipine 5?mg/day with respect to significant decreases in BP, serum UA and TG in patients with hypertension.     

Prolonged treatment with the AT1 receptor blocker,valsartan, increases small and large artery compliance in uncomplicated essential hypertension

BACKGROUND: Decreased arterial compliance (AC) is considered an early marker of vascular wall damage. Hypertension gradually decreases arterial compliance. We studied whether treatment with the angiotensin type 1 (AT(1)) antagonist valsartan will affect AC in patients with essential hypertension (EH). METHODS: Twenty-two patients with EH, 6 men and 16 women, mean age 58.7 +/- 4.1 years, without overt target organ damage were included. Antihypertensive medications were withdrawn for 3 weeks, Valsartan was given at 80- and 160-mg doses. The AC, blood pressure (BP), blood, and urine were measured monthly. Large (C1) and small (C2) AC were derived from radial artery waveforms, obtained using a calibrated tonometer (model CR-2000, HDI Inc., Eagan, MN). RESULTS: After 3 months, systolic BP decreased from 172 +/- 17 to 142 +/- 13 mm Hg (P <.0001) and diastolic BP from 95 +/- 9 to 82 +/- 8 mm Hg (P <.0001). The decrease in BP was significant within 1 month and improved further on. The C1 increased by 22%, from 8.0 +/- 3.1 to 9.7 +/- 2.3 mL/mm Hg x 10 (P <.01). The C2 increased by 35%, from 2.9 +/- 1.3 to 3.9 +/- 1.9 mL/mm Hg x 100 (P <.01). Both C1 and C2 reached statistical significance only after 3 months. Systemic vascular resistance (SVR) decreased by 15% from 2,140 +/- 376 to 1,817 +/- 262 dynes/sec/cm(-5) (P <.0001). CONCLUSIONS: Treatment with valsartan in patients with EH improves small and large AC. The improvement in AC was significant only after 3 months of treatment, whereas systolic BP, diastolic BP, and SVR decreased earlier. The AT(1) receptor blockade with valsartan seems to be an effective means of not only lowering BP but of reversal of vascular wall damage, which predisposes to cardiovascular events.     

Efficacy of combined angiotensin II receptor blocker with tripterygium glycosides on diabetic nephropathy: A protocol for meta-analysis

Background:Several studies have reported good results for angiotensin II receptor blockers (ARB) combined with tripterygium glycosides (TGs) in the treatment of diabetic nephropathy (DN). However, because a small number of cases were included in each study, the statistical power was limited. Therefore, we performed a protocol for meta-analysis to further evaluate the clinical efficacy and safety of combined ARB and TGs in treatment of DN.Methods:The protocol was written following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) statement guidelines. We searched PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang Data, Science Direct up to April 2021. Outcome measures were 24-h urinary total protein, urinary albumin excretion rate, serum creatinine, blood urea nitrogen, albumin, hemoglobin A1c, β2-microglobulin and serum glutamic pyruvic transaminase. The risk of bias assessment of the included studies was performed by two authors independently using the tool recommended in the Cochrane Handbook for Systematic Reviews of Interventions (version 5.1.0). We performed meta-analysis using STATA 11.0.Results:The review will add to the existing literature by showing compelling evidence and improved guidance in clinic settings.Conclusion:The findings will provide helpful evidence for the application of combined ARB and TGs in the treatment of DN.OSF registration number:10.17605/OSF.IO/ARGE3     

Evaluation of angiotensin II type‐1 receptor antibodies in primary aldosteronism and further considerations about their possible pathogenetic role

Angiotensin II type‐1 receptor autoantibodies (AT1RAb) have been involved in the genesis of primary aldosteronism (PA), both in aldosterone‐producing adenoma (APA) and in idiopathic hyperaldosteronism (IHA). In this study, we evaluated the titer of AT1RAb in 44 PA patients (15 with APA and 29 with IHA) compared with 18 normotensive healthy controls who were matched for gender and age. In 17 PA patients (6 APA and 11 IHA) the titer was evaluated under mineralocorticoid receptor (MR) antagonist treatment. We found that PA patients had a significantly higher titer of AT1RAb compared with controls (median values 33 [IQR 15.6] IU/mL vs 17.5 [IQR 10.8] IU/mL, respectively; P < 0.0001). No significant difference of the AT1RAb titer was reported among PA patients, subdivided according to the subtypes and the concomitant MR antagonist therapy. No significant correlation was detected between age, gender, BMI, blood pressure values, baseline aldosterone, ARR, and the AT1RAb titer of all patients enrolled. Our data confirm an increased titer of AT1RAb in both subtypes of PA, independently from the concomitant use of MR antagonists and clinical/biochemical characteristics of PA patients. The small sample of patients and the relatively short time of treatment could have influenced these results. Moreover, the ELISA assay fails to evaluate the bioactivity of AT1RAb. Further studies should evaluate if the subtype, the clinical/biochemical recovery of PA, or both, influence the pathogenetic role of AT1RAb. The possible autoimmune pathogenesis and reversal effect with AT1R blocker treatment in PA patients with AT1RAb positivity is intriguing and requires further study.     

New angiotensin II type 1 receptor blocker olmesartan improves portal hypertension in patients with cirrhosis

Aim: To evaluate the effect of the new oral angiotensin II type 1 receptor blocker olmesartan on portal hemodynamics in patients with cirrhosis. Methods: From January 2005 to March 2006, 18 cirrhosis patients treated with endoscopic band ligation for primary esophageal variceal bleeding were included in the present study. Hepatic venous pressure gradient (HVPG) of the patients was >/=12 mmHg at baseline measurement. The patients were given 10 mg olmesartan orally once daily for 2 weeks. Eighteen cirrhosis patients with esophageal variceal bleeding who did not receive any antihypertensive agents were included in the study as control. On day 14, HVPG, blood pressure, heart rate, and parameters of hepatic and renal function were examined after the treatment. Responders were defined as those with HVPG reduction of >20% versus baseline. Results: Olmesartan significantly reduced HVPG by -16.8 +/- 22.0% (P = 0.031) and mean arterial pressure by -13.1 +/- 10.8% (P = 0.0041). Six of 18 (33.3%) patients in the olmesartan group showed >20% reduction of HVPG from baseline values. None of the patients treated with olmesartan had any complications. Conclusion: Olmesartan reduces portal pressure and may be safe and highly effective in the treatment of portal hypertension.