Renin-Angiotensin System Inhibitors Prognostic Benefit in Older Patients with Atrial Fibrillation

OBJECTIVES

Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin-receptor blockers (ARB) have shown antiarrhythmic effects that are useful as part of the upstream therapy for atrial fibrillation (AF), both for primary and secondary prevention. Nevertheless, the potential prognosis value of these drugs in terms of mortality and major cardiovascular events is unclear, especially in older population with AF. Scientific evidence is scarce in this population and shows contradictory results. The aim of this study was to assess the potential benefit of ACEi and ARB in terms of mortality and major cardiovascular outcomes (hospitalization for heart failure, acute myocardial infarction and stroke) in older patients with AF, based on a real-world data analysis.

DESIGN

Observational: analysis of a retrospective registry.

SETTINGS AND PARTICIPANTS

The study included 9365 patients of 75 years or older diagnosed with AF, from CardioCHUVI-AF_75 registry: ClinicalTrials.gov Identifier: NCT04364516. Date of registration: November 26, 2018.

METHODS

We performed propensity score matching techniques to obtain 2 comparable groups of 3601 patients with and without ACEi or ARB treatment. We compared survival and cardiovascular outcomes in both groups of patients using Cox proportional hazards models.

RESULTS

We did not find significant differences in terms of survival between using or not using ACEi or ARB for the older population (hazard ratio for mortality: 0.959, 95% confidence interval 0.872-1.054). There were no significant differences regarding cardiovascular major events between the 2 groups.

CONCLUSIONS AND IMPLICATIONS

Treatment with ACEi or ARB did not improve outcomes in terms of survival and cardiovascular events in older patients with AF. These results should prompt the conduct of randomized clinical trials specifically in the older AF patient population to robustly address this issue.

Effect of calcium channels blockers and inhibitors of the renin-angiotensin system on renal outcomes and mortality in patients suffering from chronic kidney disease: systematic review and meta-analysis

BACKGROUND

The renoprotective effect of inhibitors of renin-angiotensin system (RAS) has been identified through placebo-controlled trials. However, the effect of calcium-channel blockers (CCBs) on renal system is still controversial. Our current meta-analysis includes available evidences to compare the effect of dihydropyridine CCBs and ACEIs or ARBs on renal outcomes and mortality. We also further investigate whether CCBs can be used in combination with inhibitors of RAS to improve the prognosis of patients with chronic kidney disease (CKD).

METHODS AND RESULTS

Electronic databases were searched up to July 2012, for clinical randomized controlled trials, assessing the effect of dihydropyridine CCBs on the incidence of end-stage renal disease (ESRD) and all-cause mortality in contrast to ACEIs or ARBs. Eight clinical trials were included containing 25,647 participants. ESRD showed significantly higher frequency with CCBs therapy compared with ACEIs or ARBs therapy, though blood pressure was decreased similarly in both groups in every trial (OR, 1.25; 95% CI, 1.05-1.48; p = 0.01). In contrast, there was no significant difference in the incidence of all-cause mortality between these two groups, though ACEIs or ARBs exhibited better renoprotective effect compared to CCBs (OR, 0.96; 95% CI, 0.89-1.03; p = 0.24).

CONCLUSIONS

CCBs did not increase all-cause mortality incidence in patients with CKD though they displayed weaker renoprotective, compared to ACEIs or ARBs therapy. Our results suggest the combination of a CCB and an ACEI or ARB should be a preferable antihypertensive therapy in patients with CKD, considering their higher effect in decreasing blood pressure and fewer adverse metabolic problems caused.

Beneficial effects of an angiotensin-II receptor blocker on structural atrial reverse-remodeling in a rat model of ischemic heart failure

The remodeling of gap junctions may affect their conduction properties and contribute to the maintenance of atrial fibrillation. The significance of the role of angiotensin-II receptor blockers (ARBs) in upstream therapy is not clear. This study was performed to investigate the effects of ARBs on atrial remodeling in a heart failure model. A model of heart failure was established or sham surgery performed in 24 Sprague-Dawley male rats. The rats were divided into sham, heart failure and heart failure-ARB groups. In the ARB group, 30 mg/kg of losartan was administered each day for 4 weeks. Echocardiography was performed at the baseline and 4 weeks following the surgery. An atrial fibrillation induction study and histological and immunohistochemical evaluation were performed 4 weeks after surgery. The increase in the left atrial diameter of the heart failure-ARB group was smaller than that of the heart failure group (P=0.028). The atrial fibrillation inducibility and duration of induced atrial fibrillation were not different between the heart failure and heart failure-ARB groups. Masson’s trichrome staining revealed less fibrosis in the heart failure-ARB group compared with the heart failure group. Immunohistochemical staining and western blot analysis for connexin 43 showed a lower expression level in the heart failure-ARB group compared with that in the heart failure group. In a rat model of ischemic heart failure the ARB losartan had structural and histological atrial reverse-remodeling effects. However, its role as an electrical stabilizer requires further study.

Angiotensin II-inhibiting drugs have no effect on intraneuronal Aβ or oligomeric Aβ levels in a triple transgenic mouse model of Alzheimer's disease

BACKGROUND

Reducing the excessive accumulation of amyloid β-protein (Aβ) in Alzheimer's disease (AD) is a key objective of most AD therapies. Several studies suggest that pharmacological inhibition of angiotensin-converting enzyme (ACE) or its by-product angiotensin II may delay onset or progression of dementia and it has been suggested that this occurs via regulation of Aβ. Intraneuronal oligomeric accumulation of Aβ is postulated to be one of the earliest pathological events. Thus this study investigated the effect of an ACE-inhibitor, captopril, and two angiotensin II receptor blockers (ARBs), eprosartan and valsartan, on intraneuronal Aβ pathology and oligomeric Aβ levels in a triple transgenic (3xTGAD) mouse model of AD.

METHODS

Male, adult (3-4 month old) 3xTgAD mice (n=39) were randomly assigned to 4 treatment groups: valsartan (0.17g/l), eprosartan (0.8g/l), captopril (5g/l) or normal drinking water and the drugs given ad libitum for 2 months. Mean arterial blood pressure (MABP) was measured at baseline, at 2 weeks and at 2 months when the mice were sacrificed and the brains hemisected for analysis. One hemisphere was processed for Aβ and amyloid precursor protein (APP) immunohistochemistry and the other for biochemical measurement of oligomeric Aβ and APP. ACE activity was measured in the brain and kidney.

RESULTS

MABP was significantly reduced at 2 weeks and 2 months in the ACE-I group (p=0.0006) but was unaltered in the ARB groups compared to vehicle. Neither ACE-I nor ARB treatment altered Aβ and APP immunolabelling or the level of Aβ or APP in brain tissue homogenates. Similarly neither ACE-I nor ARB treatment altered ACE activity in either brain or kidney compared to control tissue.

CONCLUSIONS

ACE-I or ARB administration over 2 months did not affect APP levels or either intraneuronal Aβ or oligomeric Aβ levels in 3xTGAD mice. While ARBs did not alter MABP, captopril did mediate reductions in MABP in the 3xTGAD mice which appeared to be independent of ACE activity. Further studies are needed to examine the effects of these drugs over a longer term and in older mice (i.e. when AD-like changes are more pronounced).