Comparative effects of losartan and enalapril on exercise capacity and clinical status in patients with heart failure. The Losartan Pilot Exercise Study Investigators

Pharmacotherapy in patients with heart failure with reduced ejection fraction: A systematic review and meta-analysis

BACKGROUND

Angiotensin receptor neprilysin inhibitors (ARNIs), angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), β-blockers (BBs), and mineralocorticoid receptor antagonists (MRAs) are the cornerstones in treating heart failure with reduced ejection fraction (HFrEF). Sodium-glucose cotransporter 2 inhibitors (SGLT-2is) are included in HFrEF treatment guidelines. However, the effect of SGLT-2i and the five drugs on HFrEF have not yet been systematically evaluated.

METHODS

PubMed, Embase, and the Cochrane Library were searched for randomized controlled trials (RCTs) from inception dates to September 23, 2022. Additional trials from previous relevant reviews and references were also included. The primary outcomes were changes in left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter/dimension (LVEDD), left ventricular end-systolic diameter/dimension (LVESD), left ventricular end-diastolic volume (LVEDV), and left ventricular end-systolic volume (LVESV), left ventricular end-systolic volume index (LVESVI), and left ventricular end-diastolic volume index (LVEDVI). Secondary outcomes were New York Heart Association (NYHA) class, 6-min walking distance (6MWD), B-type natriuretic peptide (BNP) level, and N-terminal pro-BNP (NT-proBNP) level. The effect sizes were presented as the mean difference (MD) with 95% confidence interval (CI).

RESULTS

We included 68 RCTs involving 16,425 patients. Compared with placebo, ARNI + BB + MRA + SGLT-2i was the most effective combination to improve LVEF (15.63%, 95% CI: 9.91% to 21.68%). ARNI + BB + MRA + SGLT-2i (5.83%, 95% CI: 0.53% to 11.14%) and ARNI + BB + MRA (3.83%, 95% CI: 0.72% to 6.90%) were superior to the traditional golden triangle "ACEI + BB + MRA" in improving LVEF. ACEI + BB + MRA + SGLT-2i was better than ACEI + BB + MRA (-8.05 mL/m2, 95% CI: -14.88 to -1.23 mL/m2) and ACEI + BB + SGLT-2i (-18.94 mL/m2, 95% CI: -36.97 to -0.61 mL/m2) in improving LVEDVI. ACEI + BB + MRA + SGLT-2i (-3254.21 pg/mL, 95% CI: -6242.19 to -560.47 pg/mL) was superior to ARB + BB + MRA in reducing NT-proBNP.

CONCLUSIONS

Adding SGLT-2i to ARNI/ACEI + BB + MRA is beneficial for reversing cardiac remodeling. The new quadruple drug "ARNI + BB + MRA + SGLT-2i" is superior to the golden triangle "ACEI + BB + MRA" in improving LVEF.

REGISTRATION

PROSPERO; No. CRD42022354792.

Network Meta-Analysis Comparing Angiotensin Receptor-Neprilysin Inhibitors, Angiotensin Receptor Blockers, and Angiotensin-Converting Enzyme Inhibitors in Heart Failure With Reduced Ejection Fraction

The superiority of angiotensin receptor-neprilysin inhibitor (ARNI) over angiotensin-converting enzyme inhibitor (ACE-I) and angiotensin receptor blocker (ARB) has not been reassessed after the publication of recent trials that did not find clinical benefits. Therefore, we performed an updated network meta-analysis comparing the efficacy and safety of ARNI, ACE-I, ARB, and placebo in heart failure with reduced ejection fraction. We included randomized clinical trials that compared ARNI, ARB, ACE-I, and placebo in heart failure with reduced ejection fraction. We extracted prespecified efficacy end points and produced network estimates, p scores, and surface under the cumulative ranking curve scores using frequentist and Bayesian network meta-analysis approaches. A total of 28 randomized controlled trials including 47,407 patients were included. ARNI was associated with lower risk of all-cause mortality (relative risk [RR] 0.81, 95% confidence interval [CI] 0.68 to 0.96), cardiac death (RR 0.79, 95% CI 0.64 to 0.99), and major adverse cardiac events (MACEs; RR 0.83, 95% CI 0.72 to 0.97) but higher risk of hypotension (RR 1.46, 95% CI 1.02 to 2.10) than ARB. ARNI was associated with lower risk of MACE (RR 0.85, 95% CI 0.74 to 0.97), but higher risk of hypotension (RR 1.69, 95% CI 1.27 to 2.24) compared with ACE-I. P scores and surface under the cumulative ranking curve scores demonstrated superiority of ARNI over ARB and ACE-I in all-cause mortality, cardiac death, MACE, and hospitalization for heart failure. In conclusion, ARNI was associated with improved clinical outcomes, except for higher risk of hypotension, compared with ARB and ACE-I.

Combination pharmacotherapies for cardiac reverse remodeling in heart failure patients with reduced ejection fraction: A systematic review and network meta-analysis of randomized clinical trials

Pharmacotherapies, including angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor II blockers (ARBs), β-blockers (BBs), mineralocorticoid receptor antagonists (MRAs) and angiotensin receptor blocker-neprilysin inhibitor (ARNI), have played a pivotal role in reducing in-hospital and mortality in heart failure patients with reduced ejection fraction (HFrEF). However, effects of the five drug categories used alone or in combination for cardiac reverse remodeling (CRR) in these patients have not been systematically evaluated. A Bayesian network meta-analysis was conducted based on 55 randomized controlled trials published between 1989 and 2019 involving 12,727 patients from PubMed, EMBASE, Cochrane Library, and Clinicaltrials.gov. The study is registered with PROSPERO (CRD42020170457). Our primary outcomes were CRR indicators, including changes of left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV) and end-systolic volume (LVESV), indexed LVEDV (LVEDVI) and LVESV (LVESVI), and left ventricular end-diastolic dimension (LVEDD) and end-systolic dimension (LVESD); Secondary outcomes were functional capacity comprising New York Heart Association (NYHA) class and 6-min walking distance (6MWD); cardiac biomarkers involving B type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP). The effect sizes were presented as the mean difference with 95% credible intervals. According to the results, all dual-combination therapies except ACEI+ARB were significantly more associated with LVEF or NYHA improvement than placebo, ARB+BB and ARNI+BB were the top two effective dual-combinations in LVEF improvement (+7.59% [+4.27, +11.25] and +7.31% [+3.93, +10.97] respectively); ACEI+BB was shown to be superior to ACEI in reducing LVEDVI and LVESVI (-6.88 mL/m² [-13.18, -1.89] and -10.64 mL/m² [-18.73, -3.54] respectively); ARNI+BB showed superiority over ACEI+BB in decreasing the level of NT-proBNP (-240.11 pg/mL [-456.57, -6.73]). All tri-combinations were significantly more effective than placebo in LVEF improvement, and ARNI+BB+MRA ranked first (+21.13% [+14.34, +28.13]); ACEI+BB+MRA was significantly more associated with a decrease in LVEDD than ACEI (-6.57 mm [-13.10, -0.84]). A sensitivity analysis ignoring concomitant therapies for LVEF illustrated that all the five drug types except ARB were shown to be superior to placebo, and ARNI ranked first (+4.83% [+1.75, +7.99]). In conclusion, combination therapies exert more benefits on CRR for patients with HFrEF. Among them, ARNI+BB, ARB+BB, ARNI+BB+MRA and ARB+BB+MRA were the top two effective dual and triple combinations in LVEF improvement, respectively; The new "Golden Triangle" of ARNI+BB+MRA was shown to be superior to ACEI+BB+MRA or ARB+BB+MRA in LVEF improvement.

OUTSTEP-HF: randomised controlled trial comparing short-term effects of sacubitril/valsartan versus enalapril on daily physical activity in patients with chronic heart failure with reduced ejection fraction

AIMS

OUTSTEP-HF compared the effect of sacubitril/valsartan vs. enalapril on 6-min walk test (6MWT) distance, non-sedentary daytime physical activity and heart failure (HF) symptoms in patients with HF with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

Ambulatory patients (n = 621) with stable symptomatic HFrEF were randomised 1:1 to sacubitril/valsartan (n = 310) or enalapril (n = 311). Changes in physical activity and mean daily non-sedentary daytime activity from baseline to Week 12 were measured using 6MWT and a wrist-worn accelerometer device, respectively. After 12 weeks, 6MWT improved by 35.09 m with sacubitril/valsartan [97.5% confidence interval (CI) 27.85, 42.32] and by 26.11 m with enalapril (97.5% CI 18.78, 33.43); however, there was no significant difference between groups [least squares means treatment difference: 8.98 m (97.5% CI -1.31, 19.27); P = 0.0503]. Mean daily non-sedentary daytime activity decreased by 27 min with sacubitril/valsartan and by 21 min with enalapril [least squares means treatment difference: -6 min (97.5% CI -25.7, 13.4), P = 0.4769] after 12 weeks. 6MWT improved by ≥30 m in 51% of patients in the sacubitril/valsartan group vs. 44% of patients treated with enalapril (odds ratio 1.251, 95% CI 0.895, 1.748). At Week 4, non-sedentary daytime activity increased by ≥10% in 58% of patients treated with sacubitril/valsartan vs. 64% with enalapril; 58% of patients treated with sacubitril/valsartan reported improved HF symptoms as assessed by patient global assessment vs. 43% with enalapril. However, these differences did not persist at Week 12.

CONCLUSION

After 12 weeks of treatment, there was no significant benefit of sacubitril/valsartan on either 6MWT or daytime physical activity measured by actigraphy compared with enalapril.

Effect of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers on cardiovascular events in patients with heart failure: a meta-analysis of randomized controlled trials

Background

Heart failure (HF) remains a significant cause of morbidity and mortality. Multiple trials over the past several years have examined the effects of both angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) in the treatment of left ventricular dysfunction, both acutely after myocardial infarction and in chronic heart failure. Yet, there is still confusion regarding the relative efficacy of rennin-angiotensin-aldosterone system (RAAS) inhibition. Our study was conducted to assess efficacy of ACEIs and ARBs in reducing all-cause and cardiovascular mortality in heart failure patients.

Methods

We included randomized clinical trials compared ACEIs and ARBs treatment (any dose or type) with placebo treatment, no treatment, or other anti-HF drugs treatment, reporting cardiovascular or total mortality with an observation period of at least 12 months. Data sources included Pubmed, EMBASE, the Cochrane Central Register of Controlled Trials. Dichotomous outcome data from individual trials were analyzed using the risk ratio measure and its 95%CI with random-effects/ fixed-effects models. We performed meta-regression analyses to identify sources of heterogeneity. All-cause mortality and CV mortality were thought to be the main outcomes.

Results

A total of 47,662 subjects were included with a mean/median follow-up ranged from 12 weeks to 4.5 years. Of all 38 studies, 32 compared ACEIs with control therapy (included 13 arms that compared ACEIs with placebo, 10 arms in which the comparator was active treatment and 9 arms that compared ACEIs with ARBs), and six studies compared ARBs with placebo. ACEIs treatment in patients with HF reduced all-cause mortality to 11% (risk ratio (RR): 0.89, 95% confidence interval (CI): 0.83–0.96, p = 0.001) and the corresponding value for cardiovascular mortality was 14% (RR: 0.86, 95% CI: 0.78–0.94, p = 0.001). However, ARBs had no beneficial effect on reducing all-cause and cardiovascular mortality. In head-to-head analysis, ACEIs was not superior to ARBs for all-cause mortality and cardiovascular deaths.

Conclusions

In HF patients, ACEIs, but not ARBs reduced all-cause mortality and cardiovascular deaths. Thus, ACEIs should be considered as first-line therapy to limit excess mortality and morbidity in this population.

Electronic supplementary material

The online version of this article (10.1186/s12872-017-0686-z) contains supplementary material, which is available to authorized users.

Thirty Years of Evidence on the Efficacy of Drug Treatments for Chronic Heart Failure With Reduced Ejection Fraction: A Network Meta-Analysis

BACKGROUND

Treatments that reduce mortality and morbidity in patients with heart failure with reduced ejection fraction, including angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), β-blockers (BB), mineralocorticoid receptor antagonists (MRA), and angiotensin receptor-neprilysin inhibitors (ARNI), have not been studied in a head-to-head fashion. This network meta-analysis aimed to compare the efficacy of these drugs and their combinations regarding all-cause mortality in patients with heart failure with reduced ejection fraction.

METHODS AND RESULTS

A systematic literature review identified 57 randomized controlled trials published between 1987 and 2015, which were compared in terms of study and patient characteristics, baseline risk, outcome definitions, and the observed treatment effects. Despite differences identified in terms of study duration, New York Heart Association class, ejection fraction, and use of background digoxin, a network meta-analysis was considered feasible and all trials were analyzed simultaneously. The random-effects network meta-analysis suggested that the combination of ACEI+BB+MRA was associated with a 56% reduction in mortality versus placebo (hazard ratio 0.44, 95% credible interval 0.26-0.66); ARNI+BB+MRA was associated with the greatest reduction in all-cause mortality versus placebo (hazard ratio 0.37, 95% credible interval 0.19-0.65). A sensitivity analysis that did not account for background therapy suggested that ARNI monotherapy is more efficacious than ACEI or ARB monotherapy.

CONCLUSIONS

The network meta-analysis showed that treatment with ACEI, ARB, BB, MRA, and ARNI and their combinations were better than the treatment with placebo in reducing all-cause mortality, with the exception of ARB monotherapy and ARB plus ACEI. The combination of ARNI+BB+MRA resulted in the greatest mortality reduction.

ACE Inhibition versus Angiotensin-II Antagonism in Heart Failure

Heart failure is becoming increasingly frequent. Once diagnosed, 5-year survival is less than 50% and a substantial percentage of patients (25% to 50%) die suddenly. Angiotensin-converting enzyme inhibitors are the only agents shown to reduce mortality in heart failure. All angiotensin-converting enzyme inhibitors appear to have similar clinical benefits in heart failure. Therapy should be started with a low dose and titrated up to the target dosage in major trials. Although angiotensin-I receptor antagonists provide more complete inhibition of angiotensin-II effects, they have not been found to be superior to long-acting angiotensin-converting enzyme inhibitors in reducing morbidity and mortality in heart failure. Therefore, in current clinical practice, angiotensin-II antagonists should be used as an alternative to angiotensin-converting enzyme inhibitors when the latter are not tolerated. The combined use of angiotensin-converting enzyme inhibitors and angiotensin-II antagonists is not currently recommended in the treatment of heart failure.

Old and new tools to assess dyspnea in the hospitalized patient

In the assessment of dyspnea one has to take into account both the patient's own experience of the symptom and the clinicians observations of breathing rates, sounds and effort to get a complete picture. In addition, to choose appropriate treatment, the underlying cause of dyspnea needs to be assessed. While tools for clinical evaluation of heart failure have gained great interest in research and found a place in guidelines and clinical practice, the same cannot be said for instruments to assess patient self-reported dyspnea. To date, no specific dyspnea rating tool has been recommend over another. Reports from clinical practice are lacking and large; international studies in this field are warranted.

Inhibition of brain angiotensin III attenuates sympathetic hyperactivity and cardiac dysfunction in rats post-myocardial infarction

AIMS

In rats post-myocardial infarction (MI), activation of angiotensinergic pathways in the brain contributes to sympathetic hyperactivity and progressive left ventricle (LV) dysfunction. The present study examined whether angiotensin III (Ang III) is one of the main effector peptides of the brain renin-angiotensin system controlling these effects.

METHODS AND RESULTS

After coronary artery ligation, Wistar rats were infused intracerebroventricularly for 4 weeks via minipumps with vehicle, the aminopeptidase A (APA) inhibitor RB150 (0.3 mg/day), which blocks the formation of brain Ang III, or losartan (0.25 mg/day). Blood pressure (BP), heart rate, and renal sympathetic nerve activity in response to air stress and acute changes in BP were measured, and LV function was evaluated by echocardiography and Millar catheter. At 4 weeks post-MI, brain APA activity was increased, sympatho-excitatory and pressor responses to air stress enhanced, and arterial baroreflex function impaired. LV end-diastolic pressure (LVEDP) was increased and ejection fraction (EF) and maximal first derivative of change in pressure over time (dP/dt(max)) were decreased. Central infusion of RB150 during 4 weeks post-MI normalized brain APA activity and responses to stress and baroreflex function, and improved LVEDP, EF, and dP/dt(max). Central infusion of losartan had similar effects but was somewhat less effective, and had no effect on brain APA activity.

CONCLUSION

These results indicate that brain APA and Ang III appear to play a pivotal role in the sympathetic hyperactivity and LV dysfunction in rats post-MI. RB150 may be a potential candidate for central nervous system-targeted therapy post-MI.

Cardiovascular outcomes in high-risk patients without heart failure treated with ARBs: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Angiotensin II type 1 receptor antagonists (ARBs) are widely used as a substitute for angiotensin-converting enzyme inhibitors (ACEIs) to treat patients without heart failure, but their effect on cardiovascular morbidity and mortality has not been clearly determined. A systematic review and meta-analysis was undertaken to determine the impact of ARBs on cardiovascular outcomes in high-risk patients without heart failure.

METHODS

A computerized literature search was carried out using PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, and EMBASE, from January 1990 to April 2008. The following search terms were used: 'hypertension', 'clinical trial', 'sartan', 'ARB', 'angiotensin receptor antagonist', 'losartan', 'candesartan', 'valsartan', 'irbesartan', 'eprosartan', 'telmisartan', 'olmesartan', 'coronary disease', 'coronary heart disease', 'myocardial infarction', 'cardiovascular disease', 'cerebrovascular disease', and 'stroke'. Criteria for inclusion of clinical trials in our meta-analysis were the use of a randomized control group not receiving an ARB and the availability of outcome data for any one of four endpoints: myocardial infarction (MI), stroke, cardiovascular death, and all-cause death (these were not always pre-specified endpoints in all trials). Out of 45 potentially relevant studies, 37 trials met the inclusion criteria. We tabulated all occurrences of these four adverse outcomes.

RESULTS

Homogenous subgroups were combined by means of a fixed-effects model, while heterogenous subgroups were not combined. In the subgroup without heart failure, ARBs, when compared with the control group, had an odds ratio of 1.09 (95% CI 1.00, 1.18; p = 0.05) for MI. Other endpoints, namely, cardiovascular death and all-cause death, did not reach statistical significance. There was a clear trend for fewer strokes in the ARB group, but these studies were clearly heterogenous, and therefore a pooled risk estimate was not computed.

CONCLUSION

After pooling more than 89 000 patients, there is no evidence to suggest that ARBs confer cardiovascular protection akin to ACEIs, and the results that emerged are not in favor of ARB therapy in terms of its use as a substitute for ACEIs in non-heart failure patients. ARBs may have a small benefit in terms of stroke risk, but the studies are heterogenous, making it very difficult to quantify this effect. Given that ACEIs protect against both stroke and MI, caution is advised in the use of ARBs as a substitute for ACEIs in patients without a heart failure indication, who are tolerant of an ACEI.

Angiotensin receptor blockers for heart failure

BACKGROUND

Chronic heart failure (HF) is a prevalent world-wide. Angiotensin receptor blockers (ARBs) are widely prescribed for chronic HF although their role is controversial.

OBJECTIVES

To assess the benefit and harm of ARBs compared with ACE inhibitors (ACEIs) or placebo on mortality, morbidity and withdrawals due to adverse effects in patients with symptomatic HF and left ventricular systolic dysfunction or preserved systolic function.

SEARCH METHODS

Clinical trials were identified by searching CENTRAL, HTA, and DARE , (The Cochrane Library 2010 Issue 3), as well as MEDLINE (2002 to July 2010), and EMBASE (2002 to July 2010). Reference lists of retrieved articles and systematic reviews were checked for additional studies not identified by the electronic searches.

SELECTION CRITERIA

Double blind randomised controlled trials in men and women of all ages who have symptomatic (NYHA Class II to IV) HF and: 1) left ventricular systolic dysfunction, defined as left ventricular ejection fraction (LVEF) ≤40%; or 2) preserved ejection fraction, defined as LVEF >40%.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed risk of bias and extracted data from included studies.

MAIN RESULTS

Twenty two studies evaluated the effects of ARBs in 17,900 patients with a LVEF ≤40% (mean 2.2 years). ARBs did not reduce total mortality (RR 0.87 [95% CI 0.76, 1.00]) or total morbidity as measured by total hospitalisations (RR 0.94 [95% CI 0.88, 1.01]) compared with placebo.Total mortality (RR 1.05 [95% CI 0.91, 1.22]), total hospitalisations (RR 1.00 [95% CI 0.92, 1.08]), MI (RR 1.00 [95% CI 0.62, 1.63]), and stroke (RR 1.63 [0.77, 3.44]) did not differ between ARBs and ACEIs but withdrawals due to adverse effects were lower with ARBs (RR 0.63 [95% CI 0.52, 0.76]). Combinations of ARBs plus ACEIs increased the risk of withdrawals due to adverse effects (RR 1.34 [95% CI 1.19, 1.51]) but did not reduce total mortality or total hospital admissions versus ACEI alone.Two placebo-controlled studies evaluated ARBs in 7151 patients with a LVEF >40% (mean 3.7 years). ARBs did not reduce total mortality (RR 1.02 [95% CI 0.93, 1.12]) or total morbidity as measured by total hospitalisations (RR 1.00 [95% CI 0.97, 1.05]) compared with placebo. Withdrawals due to adverse effects were higher with ARBs versus placebo when all patients were pooled irrespective of LVEF (RR 1.06 [95% CI 1.01, 1.12]).

AUTHORS' CONCLUSIONS

In patients with symptomatic HF and systolic dysfunction or with preserved ejection fraction, ARBs compared to placebo or ACEIs do not reduce total mortality or morbidity. ARBs are better tolerated than ACEIs but do not appear to be as safe and well tolerated as placebo in terms of withdrawals due to adverse effects. Adding an ARB in combination with an ACEI does not reduce total mortality or total hospital admission but increases withdrawals due to adverse effects compared with ACEI alone.

A randomized double-blind trial of enalapril in older patients with heart failure and preserved ejection fraction: effects on exercise tolerance and arterial distensibility

BACKGROUND

Exercise intolerance is the primary symptom in older patients with heart failure and preserved ejection fraction (HFPEF); however, little is known regarding its mechanisms and therapy.

METHODS AND RESULTS

Seventy-one stable elderly (70+/-1 years) patients (80% women) with compensated HFPEF and controlled blood pressure were randomized into a 12-month follow-up double-blind trial of enalapril 20 mg/d versus placebo. Assessments were peak exercise oxygen consumption; 6-minute walk test; Minnesota Living with HF Questionnaire; MRI; Doppler echocardiography; and vascular ultrasound. Compliance by pill count was excellent (94%). Twenty-five patients in the enalapril group versus 34 in the placebo group completed the 12-month follow-up. During follow-up, there was no difference in the primary outcome of peak exercise oxygen consumption (enalapril, 14.5+/-3.2 mL/kg/min; placebo, 14.3+/-3.4 mL/kg/min; P=0.99), or in 6-minute walk distance, aortic distensibility (the primary mechanistic outcome), left ventricle mass, or neurohormonal profile. The effect size of enalapril on peak exercise oxygen consumption was small (0.7%; 95% CI, 4.2% to 5.6%). There was a trend toward improved Minnesota Living with HF Questionnaire total score (P=0.07), a modest reduction in systolic blood pressure at peak exercise (P=0.02), and a marginal improvement in carotid arterial distensibility (P=0.04).

CONCLUSIONS

In stable, older patients with compensated HFPEF and controlled blood pressure, 12 months of enalapril did not improve exercise capacity or aortic distensibility. These data, combined with those from large clinical event trials, suggest that angiotensin inhibition does not substantially improve key long-term clinical outcomes in this group of patients. This finding contrasts sharply with observations in HF with reduced EF and highlights our incomplete understanding of this important and common disorder.

Effects of angiotensin-converting enzyme inhibitor versus valsartan on cellular signaling events in heart transplant

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) provide similar biologic effects in model systems and similar clinical impacts in humans. The changes in the cardiac angiotensin system signaling pathways in the human heart in response to ACE inhibitors versus ARBs have been incompletely studied.

OBJECTIVE

To investigate the effects of ACE inhibitors versus valsartan on the angiotensin II signal transduction pathways in the transplanted human heart.

METHODS

Twenty-seven stable cardiac transplant recipients were randomized to remain on ACE inhibitor therapy (n = 8) or to receive valsartan (n = 19). Two additional endomyocardial biopsy samples were obtained at baseline and after 9 months of therapy. The expression of cardiac angiotensin type I and II receptors and atrial natriuretic factor (ANF) was measured by quantitative polymerase chain reaction. The expression and phosphorylation levels of selected signal transduction pathways were analyzed by immunoblotting.

RESULTS

The mean dose of valsartan was 114 +/- 41 mg/day. The use of valsartan resulted in a similar impact on blood pressure and biochemistry profile. There were no significant changes in the expression of angiotensin type I and II receptors and ANF with valsartan. Similarly, no significant changes in the expression and phosphorylation of Jun N-terminal kinase, extracellular signal-regulated kinase 1 and 2, and p38 mitogen-activated protein kinases or AKT, and mammalian target of rapamycin was observed in the valsartan-treated group.

CONCLUSIONS

Valsartan use is associated with similar clinical and molecular cardiac effects as ACE inhibitor therapy in stable long-term cardiac transplant recipients.

Effects of enalapril, candesartan or both on neurohumoral activation and LV volumes and function in patients with heart failure not treated with a beta-blocker

Background: The long-term effects of the angiotensin-receptor blocker candesartan, the angiotensin-converting enzyme inhibitor enalapril or their combination have been incompletely studied in a large cohort of patients with heart failure not treated with beta-blockers. The objective of this study was to investigate the changes in neurohormones and LV volumes and ejection fraction in patients treated with enalapril, candesartan, or enalapril plus candesartan without concomitant beta-blocker therapy.

Methods: Three hundred and ninety-two patients from the RESOLVD pilot study not treated with a beta-blocker at baseline or at any time during the trial were analyzed. Norepinephrine, endothelin-1, big endothelin-1, angiotensin-II, aldosterone, N-terminal proANP, BNP, and radionuclide angiography were measured before and after 43 weeks of treatment with candesartan alone ( n = 162), or enalapril alone ( n = 45), or candesartan plus enalapril ( n = 185). Endpoints were assessed at baseline and after 43 weeks of therapy.

Results: LV end-diastolic and end-systolic volumes increased significantly at 43 weeks in all groups except for patients treated with enalapril plus candesartan. BNP decreased at 43 weeks only in patients receiving dual angiotensin-II suppression (-6.1 ± 37.8 pmol/l). Angiotensin-II levels were significantly increased in patients treated with candesartan (+23.6 ± 47.1 pg/ml; p<0.05).

Conclusion: We conclude that angiotensin-II modulation, with enalapril and candesartan, without concomitant utilization of beta-blocker lead to a decrease in BNP and an attenuation of the increase in LV end-diastolic and end-systolic volumes without a reversal of this process in the long term.

Both enalapril and losartan attenuate sarcolemmal Na+-K+-ATPase remodeling in failing rat heart due to myocardial infarctionThis article is one of a selection of papers published in the special issue Bridging the Gap: Where Progress in Cardiovascular and Neurophysiologic Research Meet

To investigate the mechanisms underlying the depressed sarcolemmal (SL) Na+-K+-ATPase activity in congestive heart failure (CHF), different isoforms and gene expression of Na+-K+-ATPase were examined in the failing left ventricle (LV) at 8 weeks after myocardial infarction (MI). In view of the increased activity of renin–angiotensin system (RAS) in CHF, these parameters were also studied after 5 weeks of treatment with enalapril (10 mg·kg–1·day–1), an angiotensin-converting enzyme inhibitor, and losartan (20 mg·kg–1·day–1), an angiotensin II type 1 receptor antagonist, starting at 3 weeks after the coronary ligation in rats. The infarcted animals showed LV dysfunction and depressed SL Na+-K+-ATPase activity. Protein content and mRNA levels for Na+-K+-ATPase α2isoform were decreased whereas those for Na+-K+-ATPase α3isoform were increased in the failing LV. On the other hand, no significant changes were observed in protein content or mRNA levels for Na+-K+-ATPase α1and β1isoforms. The treatment of infarcted animals with enalapril or losartan improved LV function and attenuated the depression in Na+-K+-ATPase α2isoform as well as the increase in α3isoform, at both the protein and mRNA levels; however, combination therapy with enalapril and losartan did not produce any additive effects. These results provide further evidence that CHF due to MI is associated with remodeling of SL membrane and suggest that the blockade of RAS plays an important role in preventing these alterations in the failing heart.

Subcellular remodeling as a viable target for the treatment of congestive heart failure

It is now well known that congestive heart failure (CHF) is invariably associated with cardiac hypertrophy, and changes in the shape and size of cardiomyocytes (cardiac remodeling) are considered to explain cardiac dysfunction in CHF. However, the mechanisms responsible for the transition of cardiac hypertrophy to heart failure are poorly understood. Several lines of evidence both from various experimental models of CHF and from patients with different types of CHF have indicated that the functions of different subcellular organelles such as extracellular matrix, sarcolemma, sarcoplasmic reticulum, myofibrils, mitochondria, and nucleus are defective. Subcellular abnormalities for protein contents, gene expression, and enzyme activities in the failing heart become evident as a consequence of prolonged hormonal imbalance, metabolic derangements, and cation maldistribution. In particular, the occurrence of oxidative stress, development of intracellular Ca2+ overload, activation of proteases and phospholipases, and alterations in cardiac gene expression result in changes in the biochemical composition, molecular structure, and function of different subcellular organelles (subcellular remodeling). Not only does subcellular remodeling appear to be intimately involved in the transition of cardiac hypertrophy to heart failure, the mismatching of the function of different subcellular organelles leads to the development of cardiac dysfunction. Although blockade of the renin-angiotensin system, sympathetic nervous system, and various other hormonal actions have been reported to produce beneficial effects on cardiac remodeling and heart dysfunction in CHF, the actions of various cardiac drugs on subcellular remodeling have not been examined extensively. Some recent studies have indicated that both the angiotensin-converting enzyme inhibitors and angiotensin receptor antagonists attenuate changes in sarcolemma, sarcoplasmic reticulum, and myofibril enzyme activities, protein contents, and gene expression, and partly improve cardiac function in the failing hearts. It is suggested that subcellular remodeling is an excellent target for the development of improved drug therapy for CHF. Furthermore, extensive studies should investigate the effects of different agents individually or in combination on reverse subcellular remodeling, cardiac remodeling, and cardiac dysfunction in various experimental models of CHF.

Angiotensin II receptor blockers in congestive heart failure

The benefits of angiotensin-converting enzyme (ACE) inhibitors for the treatment of congestive heart failure (CHF) are well-established. A newer class of medications, angiotensin II receptor blockers (ARBs), may be a suitable replacement for ACE inhibitors as a result of a more complete inhibition of angiotensin II and better tolerability among patients. To examine the current literature on the efficacy and safety of ARBs in the setting of CHF, a Medline search was conducted of the English language literature for the years 1987 to 2005. Clinical trials that reported data on cardiac outcomes were reviewed. The earlier trials were direct ARB to ACE inhibitor comparisons (ELITE I and ELITE II). These studies indicated that ARBs do not confer an improvement in cardiac outcomes over ACE inhibitors. RESOLVD, Val-HeFT, and the 3 separate trials of the CHARM program investigated the addition of an ARB to standard therapy. The RESOLVD trial showed no significant differences in clinical events among ACE inhibitor, ARB, and their combination. Although no mortality benefit was evident in the Val-HeFT trial, a substantial reduction in CHF rehospitalizations was reported among patients who were not receiving ACE inhibitor therapy. The CHARM-Overall program demonstrated a significant benefit in cardiovascular death and hospital admissions for CHF with the addition of ARB to standard therapy, a benefit that was more pronounced in patients with depressed left ventricular ejection fraction. In the setting of CHF, rates of cardiac outcomes do not differ substantially between ARBs and ACE inhibitors. However, their combination may improve outcomes for patients with CHF.

Angiotensin Receptor Blockers in Congestive Heart Failure

Heart failure results in neurohormonal activation of which the renin-angiotensin-aldosterone system (RAS) is the main mediator. Activation of this system leads to the production of angiotensin II (ATII), which leads to multiple adverse short-term and long-term effects, including hemodynamic dysfunction, renal dysfunction, inflammation, and cardiac remodeling. Angiotensin-converting enzyme inhibitors (ACEIs) exert favorable effects in congestive heart failure (CHF) by inhibiting the production of ATII. It has been shown that ACEIs may not be able to suppress the production of ATII completely because there are RAS-independent mechanisms of ATII production. Hence, it was thought that angiotensin receptor blockers (ARBs) might be more useful in CHF because they directly block the ATII receptors. Many studies have been done to evaluate the role of ARBs in CHF. We reviewed these studies and have attempted to define the place and ARBs in the therapy for CHF.

Angiotensin Receptor Blockade and Exercise Capacity in Adults With Systemic Right Ventricles

Background— Pharmacological blockade of the renin-angiotensin system improves exercise tolerance in patients with left ventricular dysfunction, yet its impact on patients with systemic right ventricles (RVs) remains unknown.

Methods and Results— A multicenter, randomized, double-blind, placebo-controlled, crossover clinical trial was performed to assess the effects of losartan on exercise capacity and neurohormonal levels in patients with systemic RVs. Of 29 patients studied (age, 30.3±10.9 years), 21 had transposition of the great arteries with a Mustard baffle, and 8 had congenitally corrected transposition of the great arteries. Baseline values were as follows: V̇ o 2 max, 29.8±5.6 mL · kg −1 · min −1 (73.5±12.9% predicted value); RV ejection fraction, 41.6±9.3%; N-terminal pro brain natriuretic peptide (NT-proBNP), 257.7±243.4 pg/mL (normal <125 pg/mL); and angiotensin II, 5.7±4.9 pg/mL (normal <5.0 pg/mL). Comparing losartan to placebo showed no differences in V̇ o 2 max (29.9±5.4 versus 29.4±6.2 mL · kg −1 · min −1 ; P =0.43), exercise duration (632.3±123.0 versus 629.9±140.7 seconds; P =0.76), and NT-proBNP levels (201.2±267.8 versus 229.7±291.5 pg/mL; P =0.10), despite a trend toward increased angiotensin II levels (15.2±13.8 versus 8.8±12.5 pg/mL; P =0.08).

Conclusions— In adults with systemic RVs, losartan did not improve exercise capacity or reduce NT-proBNP levels. Minimal baseline activation of the renin-angiotensin system may explain this lack of benefit and imply an alternative pathophysiological mechanism for the progressive ventricular dysfunction and impaired exercise capacity observed in such patients.

A review of the current evidence for the use of angiotensin-receptor blockers in chronic heart failure

Angiotensin-converting enzyme (ACE) inhibitors have a central role in the management of heart failure, reflecting the contribution of the renin-angiotensin-aldosterone system to the pathophysiology of the condition. Angiotensin-receptor blockers (ARBs) bind specifically to the angiotensin type 1 receptor and may offer further benefits compared with ACE inhibitors. Candesartan, losartan and valsartan have all been evaluated in large clinical outcome trials in heart failure. They display marked differences in pharmacokinetics and receptor-binding properties that may contribute to observed differences in outcome. ELITE II found no significant difference in outcome with losartan as compared with captopril. In the Val-Heft trial, valsartan reduced heart failure hospitalisations when added to conventional therapy including an ACE inhibitor in most patients, but had no effect on mortality. The CHARM programme showed that candesartan reduced morbidity and mortality in heart failure with reduced systolic function, both when added to ACE inhibitor therapy or when used as an alternative in patients who are intolerant to ACE inhibitors. Moreover, the CHARM-preserved study suggested that candesartan is beneficial in patients with heart failure and preserved left-ventricular systolic function. A growing body of evidence show that ARBs are an important contribution to the pharmaceutical management of patients with heart failure.

Six minute corridor walk test as an outcome measure for the assessment of treatment in randomized, blinded intervention trials of chronic heart failure: a systematic review

AIMS

The 6 min walk test (6MWT) is commonly used in clinical trials to assess treatments for heart failure, but its ability to distinguish between effective and ineffective treatments is questionable. The aim of this study is to investigate, using a systematic literature review, the utility of the 6MWT as a measure of the effectiveness of treatment in randomized controlled trials of heart failure.

METHODS AND RESULTS

A literature search was performed using Medline, EMBASE, CINAHL, and Biological abstracts for randomized controlled trials that measured 6MWT between 1988 and 31 May 2004. A significant increase in 6MWT distance was observed in only 9 of 47 randomized controlled trials of pharmacological therapy; 2 of 6 trials of ACE-inhibitors; 3 of 17 trials of beta-blockers; 1 of 4 trials of digoxin; one trial of ibopamine; one trial of l-arginine; one trial of beriberine; and one trial showed superiority of captopril over flosequinan. A significant increase in 6MWT was observed in four out of six placebo-controlled trials of cardiac resynchronization. Smaller pharmacological trials with fewer centres were more likely to be positive; six out of nine positive pharmacological trials had four or less participating centres, raising the possibility of publication bias. Pharmacological trials including patients with more severe heart failure were more likely to show a significant improvement with therapy than trials of milder heart failure. Five out of seven pharmacological trials that reported an improvement in symptoms also reported an improvement in 6MWT distance. Of 30 pharmacological trials, 29 that reported no improvement in symptoms also reported no improvement in 6MWT. Using mean values in these trials, the age of patients appeared a more important determinant of 6MWT distance than New York Heart Association classification.

CONCLUSION

The 6MWT has not yet been proven to be a robust test for the identification of effective pharmacological interventions although it appears useful for the assessment of cardiac resynchronization therapy. The results of the 6MWT were concordant with changes in symptoms, suggesting that it may be used as supportive evidence for symptom benefit. The test may be of greater value in patients with more advanced heart failure, where it may function as a maximal exercise test.

The therapeutic potential of angiotensin II receptor blockers in the treatment of heart failure

In clinical heart failure (HF) the renin-angiotensin-aldosterone system is an important component of neurohormonal activation. Angiotensin-converting enzyme inhibitors have been shown to be of great clinical benefit in reducing the production of angiotensin II. However, they do not fully suppress angiotensin II production in HF because there are other pathways through which angiotensin II can be produced. Theoretically, angiotensin II receptor blockers (ARBs) have great potential because of their ability to directly block angiotensin II produced through any pathway. A large body of literature has accumulated examining the effects of ARBs in HF. The earlier, smaller studies examined outcomes such as symptoms, neurohormonal concentrations and cardiac function. More recent, larger studies have examined the effects of ARBs on mortality and morbidity. This paper reviews the data defining the role of ARBs in the treatment of HF patients, focusing more on the large randomised clinical outcome trials.

Losartan: a selective angiotensin II type 1 (AT1) receptor antagonist for the treatment of heart failure

Losartan (COZAAR) is the prototype of a new class of potent and selective angiotensin II (AII) type 1 (AT(1)) receptor antagonists with the largest published preclinical and clinical data base. Since all of the AII antagonists are selective for the AT(1) receptor, these drugs should exhibit similar cardiovascular effects. However, since the pharmacokinetic/pharmacodynamic profiles of these agents and their degree of affinity for the AT(1) receptor differ, it is likely that differences in clinical profiles between these drugs exist and will require investigation. Losartan (parent compound), has moderate affinity for the AT(1) receptor (competitive inhibition). Losartan is well-absorbed orally as an active drug and is rapidly converted via oxidation in the human liver to a more potent metabolite (designated E3174) with an affinity 20- to 30-times greater for the AT(1) receptor (non-competitive inhibition). E3174 has a half-life of 6 - 9 h; elimination is via renal and hepatic routes. Antihypertensive and, in heart failure patients, haemodynamic activity is observed over a 24 h period with once daily dosing. Over 6 million patients have been treated for hypertension with continued excellent tolerability. Clinical experience in heart failure is growing, and recent data suggest an improved survival with losartan versus captopril, a drug from the angiotensin-converting-enzyme inhibitor class with proven benefit in this population. The current comprehensive losartan clinical end-point programme (4 large scale morbidity/mortality trials) should provide evidence regarding the efficacy of direct blockade of the AT(1) receptor with losartan compared to standard therapy: 1) The Losartan Heart Failure Survival Study - ELITE II, 2) The Losartan Post-Myocardial Infarction Survival Study - OPTIMAAL, 3) The Losartan Hypertension Survival Study - LIFE and 4) The Losartan Renal Protection Study - RENAAL.

ACE inhibitors in heart failure: what more do we need to know?

ACE inhibitors have significantly decreased cardiovascular mortality, myocardial infarction (MI), and hospitalizations for heart failure (HF) in patients with asymptomatic or symptomatic left ventricular (LV) systolic dysfunction. Furthermore, the extended 12-year study of the SOLVD (Studies Of Left Ventricular Dysfunction) Prevention and Treatment trials (X-SOLVD) demonstrated a significant benefit with a reduction of cumulative all-cause death compared with placebo (50.9% vs 56.4%) [hazard ratio (HR) 0.86; 95% CI 0.79, 0.93; p < 0.001]. The survival benefits and significant reductions in cardiovascular morbidity related to treatment with ACE inhibitors are likely achieved by titrating the dose of ACE inhibitors to the target dose achieved in clinical trials. Although the ATLAS (Assessment of Treatment with Lisinopril And Survival) study, which randomly allocated HF patients to low- or high-dose lisinopril, showed no significant difference between groups for the primary outcome of all-cause mortality (HR 0.92; 95% CI 0.82, 1.03), the predetermined secondary combined outcome of all-cause mortality and HF hospitalization was reduced by 15% for the patients receiving high-dose lisinopril compared with low-dose (p < 0.001) with a 24% reduction in HF hospitalization (p = 0.002). Despite the use of ACE inhibitors, blockade of the renin angiotensin aldosterone system (RAAS) remains incomplete, with evidence of continued production of angiotensin II by non-ACE-dependent pathways. The safety and potential benefits of angiotensin receptor antagonists (angiotensin receptor blockers [ARBs]) in patients with impaired systolic function have been assessed in moderate to large clinical trials. In patients with impaired LV systolic function and HF, combination therapy with ARBs with recommended HF therapy including ACE inhibitors in patients who remain symptomatic may be considered for its morbidity benefit. Based on the CHARM (Candesartan in Heart failure: Assessment of Reduction in Mortality and morbidity)-Added data, candesartan cilexetil in addition to standard HF therapy results in a further reduction of cardiovascular mortality. Close monitoring of renal function and serum potassium levels is needed in this setting. The VALIANT (VALsartan In Acute myocardial iNfarction Trial) results suggest that valsartan is as effective as captopril in patients following an acute MI with HF and/or LV systolic dysfunction and may be used as an alternative treatment in ACE inhibitor-intolerant patients. There was no survival benefit with valsartan-captopril combination compared with captopril alone in this trial. Despite these results, ACE inhibitors remain the first-choice therapeutic agent in post-MI patients, and ARBs can be used in patients with clear intolerance. Although the use of ACE inhibitors may be appealing in patients with HF and preserved LV systolic function, there is currently no evidence from large clinical trials to support this.

Drug therapy in chronic heart failure

Chronic heart failure is widely recognised as a common and escalating problem that causes major disability and often shortens life. Diuretics and digoxin have formed the mainstay of treatment for many years. Clinical trials have demonstrated that angiotensin converting enzymes and beta-blockers, in selected patients, improve symptoms and reduce mortality. Angiotensin-II antagonists and spironolactone may also have a role in certain individuals. Newer pharmacological approaches to the management of this complex disease are being developed, but await full evaluation.

Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers: what we know and current controversies

A little more than a decade ago, management of heart failure was changed forever when a number of randomized clinical trials confirmed that a class of drugs, angiotensin-converting enzyme (ACE) inhibitors, could improve survival in patients with heart failure. The recognition that blockade of one of the neurohumoral systems activated in heart failure could improve outcomes prompted widespread testing of other neurohumoral blockers, such as beta-adrenergic blocking agents, aldosterone antagonists, and most recently, angiotensin II type 1 receptor blockers (ARBs) for the treatment of heart failure. This article describes what is known about the use of ACE inhibitors and ARBs in the management of heart failure and presents the current controversies surrounding the use of these agents.

Gene Expression Profile Revealed Different Effects of Angiotensin II Receptor Blockade and Angiotensin-Converting Enzyme Inhibitor on Heart Failure

Although recent clinical studies have indicated that angiotensin II receptor blocker is as effective in treating heart failure as an angiotensin-converting enzyme inhibitor, it is unknown whether their effects are different. Dahl salt-sensitive rats were treated with an angiotensin-converting enzyme inhibitor benazepril, and an angiotensin II receptor blocker candesartan from 11 weeks old. We examined cardiac geometry and function by echocardiography, and histology and gene expression by high-density oligonucleotide arrays using Affymetrix U34 (Affymetrix, Santa Clara, CA, U.S.A.). Dahl salt-sensitive rats fed a high salt diet showed a marked increase in blood pressure and developed concentric hypertrophy at 11 weeks, followed by left ventricle dilation and congestive heart failure by 20 weeks after birth. Although both medications had only a mild antihypertensive effect, they strongly suppressed the development of cardiac hypertrophy, fibrosis and heart failure to the same extent. Gene expression pattern examined by Affymetrix GeneChip (Affymetrix) is quite different between the two drug groups, indicating that angiotensin II receptor blocker and angiotensin-converting enzyme inhibitor prevent heart failure by different mechanisms.

Drugs that interrupt the renin-angiotensin system should be among the preferred initial drugs to treat hypertension

The goal of antihypertensive therapy is to provide effective treatment that can be sustained lifelong, while lowering elevated blood pressure and preventing hypertensive end-organ damage and mortality. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II antagonists (AIIAs) control blood pressure as well as other available classes of antihypertensive drugs. The ACE inhibitors have been demonstrated to reduce the incidence of stroke, reverse left ventricular hypertrophy, and improve congestive heart failure symptomatology and mortality to a similar degree as diuretics and beta-adrenergic blockers. ACE inhibitors reduce postmyocardial infarction recurrence, improve congestive heart failure symptomatology and mortality, and slow the progression of glomerular renal disease. The AIIAs reverse left ventricular hypertrophy. Several of these agents have been shown to improve congestive heart failure symptomology and mortality, to reduce the occurrence of early atherosclerotic vascular disease, and to slow the progression of renal failure in type 2 diabetes mellitus nephropathy. One AIIA has reduced the incidence of end-stage renal disease in non-insulin-dependence diabetes mellitus nephropathy over 3 years. Ideally, antihypertensive therapy should maintain or improve the patients quality of life without creating side effects or adverse laboratory effects. Among the available nine classes of antihypertensive drugs, ACE inhibitors and the AIIAs come close to meeting the description of an ideal drug. AIIAs and ACE inhibitors, two classes of antihypertensive drugs that reduce the activity of the renin-angiotensin II system, should be among the preferred first-step drugs for the treatment of hypertension.

The role of angiotensin II receptor blockers in the treatment of heart failure patients

Evidence from large, randomized, controlled clinical trials supports the use of angiotensin-converting enzyme (ACE) inhibitors, beta blockers, and spironolactone to reduce mortality and morbidity. Despite these effective therapies, event rates related to heart failure remain high. Although ACE inhibitors reduce angiotensin II production, they do not fully suppress the increased angiotensin II production in heart failure. Angiotensin II receptor blockers (ARBs) directly block the effect of angiotensin II, derived from any source, at the receptor level and have the potential to be as effective or even more effective than ACE inhibitors. The results of a number of clinical studies have demonstrated ARBs are effective and well tolerated. However, no studies have demonstrated a convincing decrease in mortality with ARB use, although a decrease has been observed for heart failure hospitalization. The results from further studies are awaited to clarify the role of ARBs in the treatment of heart failure.

Angiotensin II receptor blockers in the treatment of heart failure

Heart failure treatment centers on antagonism of the renin-angiotensin-aldosterone system and adrenergic nervous system. Angiotensin-converting enzyme (ACE) inhibitors have been shown to benefit patients with left ventricular systolic dysfunction irrespective of symptoms. Despite ACE inhibitor use, left ventricular dysfunction continues to progress in most patients. In addition, ACE inhibitors are substantially underused in patients who would benefit, in large part due to physician concern over potential adverse effects. Angiotensin receptor blockers (ARBs) have been proposed as either potential substitutes for ACE inhibitors or as additive therapy for heart failure patients. The authors will review the importance of the renin-angiotensin-aldosterone system in the progression of heart failure, as well as the mechanisms by which ACE inhibitors and ARBs counteract this effect. The clinical evidence to date supporting the use of ARBs in heart failure also will be reviewed. Based on current trials, ARBs are suitable substitutes for ACE inhibitors in patients who have true ACE inhibitor intolerance, but ACE inhibitors should still be considered first-line therapy in the treatment of left ventricular systolic dysfunction and heart failure. ARBs are a reasonable additive therapy in patients on maximal ACE inhibitor therapy who remain symptomatic, especially in patients unable to tolerate beta blockade.

Angiotensin II receptor antagonists in chronic heart failure: where do they fit?

Heart failure is a common and disabling condition with a dismal prognosis. Inhibition of the renin-angiotensin-aldosterone system (RAAS) with angiotensin converting enzyme (ACE) inhibitors has proven to be a valuable therapeutic strategy in this condition, with well-proven morbidity and mortality benefits. Nonetheless, ACE inhibitors provide incomplete blockade of the RAAS and also inhibit the degradation of bradykinin. Although increased levels of bradykinin may have haemodynamic advantages by contributing to vasodilatation, they may also be largely responsible for some of the adverse effects of ACE inhibitors. Angiotensin II (Ang II) receptor antagonists offer more complete blockade of the RAAS without the potentiation of bradykinin, and it was therefore hoped that they would provide even greater benefits for patients with heart failure. So far, much of the initial promise of the Ang II receptor antagonists in heart failure has not been realised. There has been no conclusive demonstration of their superiority to ACE inhibitors in their effects on morbidity and mortality, and their equivalence to ACE inhibitors has not been proven. The Ang II receptor antagonists have, however, proven to be better tolerated than ACE inhibitors and they are therefore likely to be a reasonable alternative for those patients with heart failure who cannot tolerate ACE inhibition. Recent evidence has indicated that the Ang II type 1 receptor antagonist valsartan is of value when used in patients already receiving either an ACE inhibitor or a beta-blocker, but has also suggested that giving all three drugs together is deleterious. Further evidence about the value of Ang II receptor antagonists in heart failure may be provided by further studies, of which several are currently ongoing.

The Use of Angiotensin-II Receptor Blockers in Heart Failure

Angiotensin-II receptor blockers (ARBs) have recently been evaluated in large trials to determine their role in the treatment of heart failure. It is clear that angiotensin-converting enzyme inhibitors (ACE-Is) prevent the effects of an overactive renin-angiotensin aldosterone system and therefore prevent disease progression. Despite this evidence, intolerance (eg, cough) limits the use of ACE-Is in heart failure patients. Improved tolerability makes ARBs attractive alternatives in patients intolerant to ACE-Is. ARBs are also hypothesized to have additional benefits when used in combination with ACE-Is through more complete inhibition of angiotensin-II. However, studies of ARBs in patients with heart failure have not confirmed this hypothesis. This article describes the rationale and evaluates the literature for the use of ARBs in heart failure.

Risk-benefit assessment of angiotensin II receptor antagonists

Inhibiting the renin-angiotensin-aldosterone system through the use of angiotensin-converting enzyme (ACE) inhibitors has proven very useful in the treatment of hypertension, congestive heart failure (CHF) and progressive renal failure. More recently, agents that directly block the angiotensin II Type 1 (AT(1)) receptor--angiotensin II receptor antagonists (AIIRAs)--have been developed. These agents are thought to have a more specific mechanism of action since they do not affect other hormone systems as do the ACE inhibitors. Whether such specificity results in a different efficacy profile is still being determined. However, these drugs are extremely well-tolerated and very safe. AIIRAs are effective in the reduction of both systolic and diastolic blood pressure and compare favourably to other classes of agents. Recent results indicate that at least one AIIRA has a favourable effect on stroke in hypertensive patients with left ventricular hypertrophy. Additional studies with other members of the class will provide further information on similar outcomes. In CHF patients, ACE inhibitors remain the drug of choice and AIIRAs are best utilised in patients who cannot tolerate an ACE inhibitor or in those receiving an ACE inhibitor who cannot tolerate a beta-blocker and need additional therapy. AIIRAs are effective in slowing the progression of renal failure in patients with Type II diabetes and may be effective in other proteinuric conditions. Whether they are more or less effective than ACE inhibitors is unknown. Overall, AIIRAs represent an important addition to the armamentarium of cardiovascular therapies with an excellent safety record and an emerging profile of utility in multiple cardiovascular conditions.

Pharmacokinetics of irbesartan are not altered in special populations

Studies were conducted to determine whether pharmacokinetics of irbesartan (IRBE), a potent, long-acting angiotensin (AT)-II receptor antagonist selective for AT-II type 1 receptor subtype, are altered in patients with renal impairment (RI), hepatic impairment (HI), or heart failure (HF) or by patient gender, age, or race. IRBE pharmacokinetics and blood pressure (BP) response in hypertensive (HT) children and adolescents were also studied. HI or RI (including end-stage renal disease requiring hemodialysis) had no effect on IRBE pharmacokinetics after single or repeated dosing. IRBE was not removed by hemodialysis. In patients with New York Heart Association class II or III HF, IRBE single-dose pharmacokinetics were not altered following either oral or IV administration. There were no clinically significant differences in IRBE pharmacokinetics between men and women, elderly and young, or black and white patients. No accumulation of IRBE occurred with repeated dosing in RI or HI patients or in HT men or women. In a pediatric study, IRBE pharmacokinetics were comparable between 6- to 12-year and 13- to 16-year age groups and to that previously determined for adult subjects receiving the same dose; accumulation of IRBE was minimal during multiple dosing. IRBE lowered BP in the pediatric population. Adverse event profile with IRBE was similar in all patient groups. Based on these pharmacokinetic and safety data, no dosage adjustments of IRBE are necessary for patients with RI, HI, or HF, or based on patient age, gender, or race. IRBE may be a treatment option for pediatric HT patients. The pharmacokinetic profile of IRBE and lack of necessary dosage adjustments in special populations suggest that IRBE is an excellent choice for management of hypertension across all patient groups.

Treatment of heart failure in patients with diabetes mellitus

Patients with diabetes mellitus have an increased morbidity and mortality from cardiovascular disease. Both coronary artery disease and congestive heart failure (CHF) are largely responsible for the increased cardiovascular adverse events in patients with diabetes. This review discusses the pathophysiology of CHF, the mechanisms of left ventricular (LV) dysfunction and the neurohormonal mechanisms involved in both LV dysfunction and CHF. Diabetes with and without hypertension is an important cause of LV dysfunction and CHF. Diabetes may be responsible for the metabolic and ultrastructural causes of LV dysfunction, while hypertension may be responsible for the marked fibrotic changes that are found. Experimental induction of diabetes in animals has shed light on the biochemical and ultrastructural changes seen. The role of insulin to reverse both metabolic and structural changes is reviewed both from experimental data and with the limited amount of clinical data available. The therapy of CHF in patients with diabetes is similar to that of patients without diabetes, with therapy directed toward the use of beta-blockers and angiotensin converting enzyme (ACE) inhibitors. As the morbidity and mortality are higher in patients with diabetes, several studies have pointed out the importance of this subgroup where the opportunity to make a significant clinical impact exists. A significant opportunity exists to reduce morbidity and mortality with beta-blockers and ACE inhibitors when ischaemia and CHF are both present. However, studies in patients diabetes have been limited to post hoc subgroup analyses and rarely as predefined subgroups. Clinical trials involving patients with diabetes with and without hypertension and LV dysfunction are clearly needed in the future to adequately address the needs of this high risk subgroup.

Angiotensin receptor blockers in heart failure: meta-analysis of randomized controlled trials

OBJECTIVES

We sought to determine the effect of angiotensin receptor blockers (ARBs) on mortality and hospitalization in patients with heart failure (HF).

BACKGROUND

There is uncertainty regarding the efficacy of ARBs as substitute or adjunctive therapy to angiotensin-converting enzyme inhibitors (ACEIs) in the treatment of HF.

METHODS

We conducted a meta-analysis of all randomized controlled trials that compared ARBs with either placebo or ACEIs in patients with symptomatic HF. The pooled outcomes were all-cause mortality and hospitalization for HF.

RESULTS

Seventeen trials involving 12,469 patients were included. Overall, ARBs were not superior to controls in the pooled rates of death (odds ratio: 0.96; 95% confidence interval: 0.75 to 1.23) or hospitalization (0.86; 0.69 to 1.06). Stratified analysis, however, showed a non-significant trend in benefit of ARBs over placebo in reducing mortality (0.68; 0.38 to 1.22) and hospitalization (0.67; 0.29 to 1.51) when given in the absence of background ACEI therapy. When compared directly with ACEIs, ARBs were not superior in reducing either mortality (1.09; 0.92 to 1.29) or hospitalization (0.95; 0.80 to 1.13). In contrast, the combination therapy of ARBs and ACEIs was superior to ACEIs alone in reducing hospitalization (0.74; 0.64 to 0.86) but not mortality (1.04; 0.91 to 1.20).

CONCLUSIONS

This meta-analysis cannot confirm that ARBs are superior in reducing all-cause mortality or HF hospitalization in patients with symptomatic HF, particularly when compared with ACEIs. However, the use of ARBs as monotherapy in the absence of ACEIs or as combination therapy with ACEIs appears promising.

Improving the managed care of hypertension with angiotensin II antagonists

Among the modifiable risk factors for cardiovascular disease, hypertension is the most powerful and treatable. For an asymptomatic patient to remain on a lifetime of antihypertensive treatment that might cause adverse effects is difficult for most patients. Managed care plans should treat hypertensive patients in ways that the patient can remain on therapy to prevent complications and thereby reduce the long-term costs associated with untreated hypertension. The recent disappointing outcomes achieved with antihypertensive drugs suggest there is room for improvement in the management of hypertension. Since the introduction of the first orally active angiotensin II receptor blocking drug, losartan, attention has been focused on the central role of angiotensin II in hypertension and cardiovascular disease. Studies of angiotensin II antagonists (AIIAs), which block the tissue receptor for angiotensin II, show that these agents effectively control hypertension when given once daily and cause no significant adverse effects or laboratory abnormalities. Losartan is unique among the AIIAs in that it offers 1-step titration dosing and has a uricosuric effect. Losartan, candesartan, and valsartan have been shown to improve the symptoms of congestive heart failure; losartan has been similar to an angiotensin-converting enzyme inhibitor in reducing systolic dysfunction congestive heart failure mortality. At 1 year, the refill rate for losartan in a managed care setting has been more than that for any other class of antihypertensive agents. Although there is not yet a clinical trial determining the long term mortality of AIIA treatment in hypertension compared with other antihypertensive agents, the use of AIIAs in conjunction with lifestyle modification and patient education can provide more efficient hypertension control and a provide a treatment with which patients can live.

Angiotensin type-1 receptor blockers in heart failure

Chronic heart failure is a common condition with a poor prognosis, usually associated with poor exercise tolerance and debilitating symptoms despite optimal modern therapy. Standard therapy includes diuretics, digoxin, angiotensin-converting enzyme inhibitors (ACEIs) and beta-blockers. Despite this, many patients remain symptomatic, and interest is high as to whether the angiotensin receptor blockers (ARBs) would offer further advantage to a patient already receiving quadruple therapy. In addition, some patients are intolerant of ACEIs, and for this group the ARBs seem a logical choice. This article reviews the evidence for the use of ARBs as a class in heart failure concentrating on clinical recommendations and clinical needs and evidence rather than purely on statistical issues of significance in trials. The trials to date have demonstrated clearly similar hemodynamic effects to those seen with ACEIs and variety of ancillary benefits such as improvements in endothelial function, anti-thrombotic effects, and effects on neurohormonal inhibition. There is consistent evidence of a preservation of exercise tolerance when patients with heart failure are crossed over from stable ACEI therapy, and when added to ACEIs exercise tolerance appears to increase with ARBs. In terms of major outcomes, the two largest trials, Elite-II and Val-Heft, demonstrate that angiotensin receptor blockers probably have a clinical role in improving mortality and morbidity as an alternative to ACEIs in those patients unable to tolerate these agents, which remain, however, the first choice in unselected patients with heart failure. There is a worrying suggestion of a negative interaction when ARBs are added to beta-blockers, which is a reason for caution in using the ARBs, not a reason not to use beta-blockers.

Reliability, validity, and responsiveness of the six-minute walk test in patients with heart failure

BACKGROUND

Our purpose was to evaluate the reliability, validity, and responsiveness of the 6-minute walk test (6MWT) in patients with heart failure (HF) enrolled in the Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) pilot study.

METHODS

A total of 768 patients was enrolled in a multicenter randomized clinical trial evaluating the effect of candesartan, enalapril, and metoprolol on left ventricular ejection fraction (LVEF), 6MWT distance, neurohormones, and quality of life. The 6MWT was performed once at screening and twice at baseline, 18 weeks, and 43 weeks by a standardized method.

RESULTS

Test-retest reliability at baseline (intraclass correlation coefficient [ICC] = 0.90), 18 weeks (ICC = 0.88), and 43 weeks (ICC = 0.91) was very good. Baseline 6MWT distance was weakly inversely correlated to the quality-of-life cumulative score (r = -0.26, P =.0001) and moderately inversely correlated to the New York Heart Association functional classification (NYHA-FC) (r = -0.43, P =.001). In the RESOLVD study, the 6MWT was not responsive to change when effect sizes and standardized response means were used. Disease-specific quality of life was responsive to change in patients treated with candesartan and enalapril and NYHA-FC was responsive to change in the candesartan and enalapril combination and for enalapril alone with small effect sizes. The 6MWT, NYHA-FC, and quality of life were not responsive to change during the metoprolol or placebo phase.

CONCLUSIONS

The 6MWT is highly reproducible in patients with symptoms of HF. It is somewhat correlated to NYHA-FC and quality of life. Overall, quality of life was most responsive to change, whereas 6MWT and NYHA-FC were comparable but less responsive to change in the RESOLVD study.

Therapeutic potential of angiotensin II receptor antagonists

The circulating renin-angiotensin system plays an important role in cardiovascular homeostasis. More importantly, the local tissue renin angiotensin plays a pivotal role in cell growth and remodelling of cardiomyocytes and on the peripheral arterial vasculature. In addition, the renin angiotensin system is related to apoptosis, control of baroreflex and autonomic responses, vascular remodelling and regulation of coagulation, inflammation and oxidation. The cardioprotective and vascular protective effects of the angiotensin receptive blockade appears to be related to selective blockade of the angiotensin II (A-II) Type I (AT(1)) receptors. However, there is now growing evidence showing that some of the effects of AT-II receptor blockers (ARBs) are related to the activation of the kinin pathways. This paper will review some of the recent mechanisms related to the cardiovascular effects of angiotensin and more specifically of ARBs. This paper will present the novel data on the role of ARB in the development of atherosclerosis, vascular remodelling, coagulation balance and autonomic regulation. Finally, the role of ARBs, used alone or in combination with ACE inhibitor in patients with heart failure, will be discussed.

Cardiac rehabilitation and survival in patients with left ventricular systolic dysfunction

BACKGROUND

Exercise training, the major component of cardiac rehabilitation (CR), has been shown in previous trials to improve many pathophysiologic changes found in patients with left ventricular systolic dysfunction. It remains unproven whether exercise training improves survival.

METHODS

By using the Duke Databank for Cardiovascular Disease, we identified patients with an ejection fraction < or = 40% and no recent myocardial infarction, congenital heart disease, or primary valvular disease who survived > or = 30 days after a cardiac catheterization (n = 1902). Participation in CR (n = 70) was identified through computer billing records. We developed a multivariable Cox proportional hazards regression model to estimate survival by using variables known to be independent predictors of survival in patients with systolic dysfunction.

RESULTS

Patients participating in CR were less likely to be female or black and more likely to have a history consistent with ischemic cardiomyopathy. Participation in CR was associated with significantly improved survival after adjustment for baseline characteristics (hazard ratio, 0.39; 95% confidence interval, 0.15 to 0.62, P < .0001). Survival increased when patients participated in > 6 CR sessions (hazard ratio, 0.10; 95% confidence interval, 0.03 to 0.39; P < .0001).

CONCLUSIONS

Participation in CR was associated with improved survival for patients with cardiomyopathy. There appears to be a dose response with improved survival benefit for patients with left ventricular systolic dysfunction participating in cardiac rehabilitation.

[Evidence based medical treatment of heart failure]

INTRODUCTION AND OBJECTIVES

Recommendations for the treatment of heart failure were carried out by a systematic review of the available evidence of the different pharmacologic treatments.

MATERIAL AND METHODS

The review focused on the treatment of chronic and systolic heart failure. All the studies published in english about the pharmacologic treatment of heart failure where identified. The evidence of every pharmacologic treatment was classified according to: a) efficacy variables (reduction of mortality and hospitalizations, improvement of functional class, ejection fraction and exercise tolerance), and b) the level of quality of the evidence according to an evaluation scale. The evidence was also reviewed for the comparisons and the combinations of the pharmacologic treatments, as well as for the toxicity and costs of treatments.

RESULTS

The recommendations were defined according to the NYHA functional class and were classified in the A, B and C categories according to the level of quality of the available evidence. The evidence on mortality was considered the most important. First line drugs, the alternatives and other possible treatments were take into account.

CONCLUSIONS

There is enough evidence based on information about some variables such as reduction of mortality or hospitalizations to carry out treatment recommendations in all stages of heart failure. This point out the interest ant the priority of used them in the evaluation and improvement of the results of heart failure.

Pharmacotherapy in congestive heart failure: Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in congestive heart failure: do they differ in their renal effects in man?

Angiotensin-converting enzyme (ACE) inhibitors are used in the management of a wide range of cardiovascular conditions, including congestive heart failure (CHF). Although the experimental evidence in support of their use in CHF is incontrovertible, their pattern of usage has failed to keep pace with the research findings. One factor that has fueled the hesitancy to use ACE inhibitors in CHF has been the concern that renal function might worsen upon their receipt. Although the glomerular filtration rate may decline when ACE inhibitor or angiotension receptor blocker therapy is started in CHF, in most cases it is not a reason to discontinue therapy other than temporarily. Although ACE inhibitors and angiotensin receptor blockers may differ theoretically in their renal effects, published information to date has not shown such a difference. (c)2001 by CHF, Inc.

Formulating clinical strategies for angiotensin antagonism: a review of preclinical and clinical studies

Extensive animal studies and a growing number of human clinical trials have now definitively demonstrated the central role of the renin-angiotensin-aldosterone system in the expression and modulation of cardiovascular disease. In contrast to the original hypothesis, the benefits of angiotensin antagonism do not emanate from the antihypertensive effect alone. Subsequent extensive investigations of angiotensin blockade suggest that the benefits of this approach may also result from the pharmacologic alteration of endothelial cell function and the ensuing changes in the biology of the vasculature. The more recent availability of direct antagonists of the AT(1) angiotensin receptor has introduced an element of doubt into this realm of clinical decision making. The receptor antagonists and the more widely studied converting-enzyme inhibitors share many endpoint attributes. Nevertheless, the partially overlapping mechanisms of action for the two classes of angiotensin antagonists confer distinct pharmacologic properties, including side effect profiles, mechanisms of action, and theoretic salutary effects upon the expression of cardiovascular disease. The current review will attempt to contrast the biology of angiotensin converting-enzyme inhibition with angiotensin II receptor antagonism. A discussion of the differential effects of these drug classes on endothelial cell function and on the modulation of vascular disease will be utilized to provide a theoretic framework for clinical decision making and therapeutics.

Effects of the replacement of the angiotensin converting enzyme inhibitor enalapril by the angiotensin II receptor blocker telmisartan in patients with congestive heart failure. The replacement of angiotensin converting enzyme inhibition (REPLACE) investigators

AIM

To compare the effects on maximal exercise tolerance of 12 weeks of four dosages of telmisartan (10/20/40/80 mg once daily), an AT(1) specific angiotensin II receptor antagonist, or continuation on the angiotensin converting enzyme inhibitor enalapril, in patients with stable, mild-to-moderate congestive heart failure (NYHA Class II and III and left ventricular ejection fraction < or =40%).

DESIGN

Multicenter, double-blind, parallel-group trial in 378 patients, randomized to once-daily treatment with telmisartan 10, 20, 40 mg, 80 mg, or continuation of enalapril 10 mg twice daily for 12 weeks.

METHODS

Primary efficacy parameter: change from baseline to final visit in bicycle exercise duration. Secondary efficacy parameters included left ventricular ejection fraction, quality-of-life parameters, arterial blood pressures, neurohormonal changes and NYHA classification.

PATIENTS

The mean age of the patients was 64+/-9 years, 89% male, history of myocardial infarction in 68%, NYHA-II: 63%, NYHA-III: 37%, ejection fraction 26.4(7)%, and a reproducible impaired exercise capacity. All patients were on diuretics and enalapril 10 mg twice daily, and 39% were taking digitalis at study entry.

RESULTS

No clinically relevant or statistically significant (P<0.05) differences were observed in the primary efficacy parameter: mean changes (s) in exercise tolerance were +8.6, +8.2, +2.2, and +7.1 for the telmisartan 10-, 20-, 40-, and 80-mg groups, respectively, and +1.4 for enalapril. There was a small but significant increase in blood pressure in all but the 80 mg telmisartan groups, compared to enalapril. Telmisartan and enalapril had comparable adverse event profiles. Cough occurred in 5.6% of the enalapril patients and in 3% of the telmisartan patients (NS).

CONCLUSIONS

(1) In patients with stable, mild-to-moderate congestive heart failure, enalapril could be replaced by telmisartan for a period of 12 weeks without deterioration in exercise capacity or clinical status. (2) No differences were observed in exercise capacity between the four dosages of telmisartan.