Clinical benefit of angiotensin-converting enzyme inhibitors in chronic heart failure

Mechanisms for the development of heart failure and improvement of cardiac function by angiotensin-converting enzyme inhibitors

Angiotensin-converting enzyme (ACE) inhibitors, which prevent the conversion of angiotensin I to angiotensin II, are well-known for the treatments of cardiovascular diseases, such as heart failure, hypertension and acute coronary syndrome. Several of these inhibitors including captopril, enalapril, ramipril, zofenopril and imidapril attenuate vasoconstriction, cardiac hypertrophy and adverse cardiac remodeling, improve clinical outcomes in patients with cardiac dysfunction and decrease mortality. Extensive experimental and clinical research over the past 35 years has revealed that the beneficial effects of ACE inhibitors in heart failure are associated with full or partial prevention of adverse cardiac remodeling. Since cardiac function is mainly determined by coordinated activities of different subcellular organelles, including sarcolemma, sarcoplasmic reticulum, mitochondria and myofibrils, for regulating the intracellular concentration of Ca2+ and myocardial metabolism, there is ample evidence to suggest that adverse cardiac remodelling and cardiac dysfunction in the failing heart are the consequence of subcellular defects. In fact, the improvement of cardiac function by different ACE inhibitors has been demonstrated to be related to the attenuation of abnormalities in subcellular organelles for Ca2+-handling, metabolic alterations, signal transduction defects and gene expression changes in failing cardiomyocytes. Various ACE inhibitors have also been shown to delay the progression of heart failure by reducing the formation of angiotensin II, the development of oxidative stress, the level of inflammatory cytokines and the occurrence of subcellular defects. These observations support the view that ACE inhibitors improve cardiac function in the failing heart by multiple mechanisms including the reduction of oxidative stress, myocardial inflammation and Ca2+-handling abnormalities in cardiomyocytes.

Role of the acute care nurse in managing patients with heart failure using evidence-based care

Acute heart failure is a major US public health problem, accounting for more than 1 million hospitalizations each year. As part of the health care team, nurses play an important role in the evaluation and management of patients presenting to the emergency department with acute decompensated heart failure. Once acute decompensation is controlled, nurses also play a critical role in preparing patients for hospital discharge and educating patients and caregivers about strategies to improve long-term outcomes and prevent future decompensation and rehospitalization. Nurses' assessment skills and comprehensive knowledge of acute and chronic heart failure are important to optimize patient care and improve outcomes from initial emergency department presentation through discharge and follow-up. This review presents an overview of current heart failure guidelines, with the goal of providing acute care cardiac nurses with information that will allow them to better use their knowledge of heart failure to facilitate diagnosis, management, and education of patients with acute heart failure.

Hawthorn extract for treating chronic heart failure

BACKGROUND

Hawthorn extract is advocated as an oral treatment option for chronic heart failure. Also, the German Commission E approved the use of extracts of hawthorn leaf with flower in patients suffering from heart failure graded stage II according to the New York Heart Association.

OBJECTIVES

To assess the benefits and harms as reported in double-blind randomised clinical trials of hawthorn extract compared with placebo for treating patients with chronic heart failure.

SEARCH STRATEGY

We searched CENTRAL on The Cochrane Library (issue 2, 2006), MEDLINE (1951 to June 2006), EMBASE (1974 to June 2006), CINAHL (1982 to June 2006) and AMED (1985 to June 2006). Experts and manufacturers were contacted. Language restrictions were not imposed.

SELECTION CRITERIA

To be included, studies were required to state that they were randomised, double-blind, and placebo controlled, and used hawthorn leaf and flower extract monopreparations.

DATA COLLECTION AND ANALYSIS

Two reviewers independently performed the selection of studies, data extraction, and assessment of methodological quality. Data were entered into RevMan 4.2 software. Results from continuous data were reported as weighted mean difference (WMD) with 95% confidence interval (CI). Where data were suitable for combining, pooled results were calculated.

MAIN RESULTS

Fourteen trials met all inclusion criteria and were included in this review. In most of the studies, hawthorn was used as an adjunct to conventional treatment. Ten trials including 855 patients with chronic heart failure (New York Heart Association classes I to III) provided data that were suitable for meta-analysis. For the physiologic outcome of maximal workload, treatment with hawthorn extract was more beneficial than placebo (WMD (Watt) 5.35, 95% CI 0.71 to 10.00, P < 0.02, n = 380). Exercise tolerance were significantly increased by hawthorn extract (WMD (Watt x min) 122.76, 95% CI 32.74 to 212.78, n = 98). The pressure-heart rate product, an index of cardiac oxygen consumption, also showed a beneficial decrease with hawthorn treatment (WMD (mmHg/min) -19.22, 95% CI -30.46 to -7.98, n = 264). Symptoms such as shortness of breath and fatigue improved significantly with hawthorn treatment as compared with placebo (WMD -5.47, 95% CI -8.68 to -2.26, n = 239). No data on relevant mortality and morbidity such as cardiac events were reported, apart from one trial, which reported deaths (three in active, one in control) without providing further details. Reported adverse events were infrequent, mild, and transient; they included nausea, dizziness, and cardiac and gastrointestinal complaints.

AUTHORS' CONCLUSIONS

These results suggest that there is a significant benefit in symptom control and physiologic outcomes from hawthorn extract as an adjunctive treatment for chronic heart failure.

A meta-analysis of the effect of angiotensin-converting enzyme inhibitors on functional capacity in patients with symptomatic left ventricular systolic dysfunction

AIM

To determine by meta-analysis whether angiotensin-converting enzyme (ACE) inhibitors improve exercise tolerance in patients with symptomatic left ventricular systolic dysfunction (LVSD).

METHODS AND RESULTS

After literature search 13 multi-centre double blind parallel group trials that evaluated the effect of ACE inhibitors vs. placebo on exercise duration were selected. Ninety-four percent of patients were in New York Heart Association class II-IV. The studies were combined using the Cochrane meta-analysis program (Review manager version 4.1). Analyses according to treatment period, exercise protocols and publication periods were performed. Treatment with ACE inhibitor over 4-12 weeks resulted in a beneficial effect on exercise duration (P=0.003 and P=0.0008 for 4- and 12-weeks treatment, respectively), but the magnitude of improvements did not exceed 30 s corresponding to only 5% compared with placebo.

CONCLUSION

In addition to the pronounced effect on mortality and morbidity in patients with symptomatic LVSD, ACE inhibitors have improving effect on functional capacity measured as exercise tolerance time.

Hawthorn extract for treating chronic heart failure: meta-analysis of randomized trials

The aim of this meta-analysis was to assess the evidence from rigorous clinical trials of the use of hawthorn extract to treat patients with chronic heart failure. We searched the literature using MEDLINE, EMBASE, the Cochrane Library, CINAHL, CISCOM, and AMED. Experts on and manufacturers of commercial preparations containing hawthorn extract were asked to contribute published and unpublished studies. There were no restrictions about the language of publication. Two reviewers independently performed the screening of studies, selection, validation, data extraction, and the assessment of methodological quality. To be included, studies were required to state that they were randomized, double-blind, and placebo controlled, and used hawthorn extract monopreparations. Thirteen trials met all inclusion criteria. In most of the studies, hawthorn was used as an adjunct to conventional treatment. Eight trials including 632 patients with chronic heart failure (New York Heart Association classes I to III) provided data that were suitable for meta-analysis. For the physiologic outcome of maximal workload, treatment with hawthorn extract was more beneficial than placebo (weighted mean difference, 7 Watt; 95% confidence interval [CI]: 3 to 11 Watt; P < 0.01; n = 310 patients). The pressure-heart rate product also showed a beneficial decrease (weighted mean difference, -20; 95% CI: -32 to -8; n = 264 patients) with hawthorn treatment. Symptoms such as dyspnea and fatigue improved significantly with hawthorn treatment as compared with placebo. Reported adverse events were infrequent, mild, and transient; they included nausea, dizziness, and cardiac and gastrointestinal complaints. In conclusion, these results suggest that there is a significant benefit from hawthorn extract as an adjunctive treatment for chronic heart failure.

Combined effects of enalapril and spironolactone in hamsters with dilated cardiomyopathy

Chronic angiotensin I-converting enzyme inhibition can be associated with aldosterone escape. We investigated the effects of enalapril, spironolactone, and their combination on hemodynamics and cardiac remodeling in cardiomyopathic hamsters to determine whether these drugs could exert additive effects. Cardiomyopathic hamsters, Bio TO-2 dilated strain, were orally treated with enalapril (20 mg. kg. day ) and/or spironolactone (20 mg. kg. day ) according to a 2 x 2 factorial design from 120 days of age. Animals were investigated at 180 (10 animals per group) and 240 (16 animals per group) days of age. Compared with corresponding untreated groups, enalapril significantly decreased mean blood pressure (-18%); enalapril and spironolactone significantly increased cardiac output (+28%, +11%) and femoral blood flow (+10%, +12%) and significantly decreased systemic (-38%, -17%) and femoral (-26%, -13%) vascular resistances. Enalapril and spironolactone significantly decreased left ventricle cavity area (-21%, -26%) and left (-34%, -47%) and right (-37%, -48%) ventricle collagen density. Spironolactone significantly increased left ventricle wall thickness (+4%). There were significant enalapril x spironolactone interactions for most variables (compared with control group, +52%, +36%, +45% for cardiac output; +26%, +28%, +26% for femoral blood flow; -50%, -30%, -45% for systemic vascular resistance; -33%, -20%, -35% for femoral vascular resistance; -27%, -31%, -40% for left ventricle cavity area; and -46%, -58%, -60% for left and -39%, -50%, -66% for right ventricle collagen density in enalapril, spironolactone, and enalapril + spironolactone groups, respectively). In cardiomyopathic hamsters, enalapril and spironolactone in combination did not improve hemodynamics more than enalapril alone but induced stronger effects than each drug alone on cardiac remodeling.

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.

Endothelin in heart failure

Congestive heart failure is a complex disease that results from pumping failure of the cardiac muscle and adaptational processes of the cardiovascular system to correct for the reduced blood supply to the organism. It is associated with increased vasoconstriction and impaired vasodilation in response to physical activity. The elevated vasoconstrictor tone is caused by the activation of compensatory mechanisms including the sympathetic nervous system and stimulation of the release of neurohormones like angiotensin II, catecholamines, and vasopressin. Furthermore, the vascular endothelium is importantly involved in the regulation of vascular tone as it releases a variety of vasoactive substances that act locally and systemically. In congestive heart failure, there is a marked imbalance between the diminished release or the increased inactivation of vasodilators on the one hand, ie, nitric oxide, and the elevated production, release, or reduced inactivation of vasoconstrictors such as endothelin-1 on the other hand. In addition to its very potent vasoconstrictor effects, endothelin-1 possesses antinatriuretic and mitogenic properties that are a common feature of substances that are involved in development of the deleterious consequences that render congestive heart failure a lethal disease. The spectrum of action of the endothelin system and the advent of specific antagonists for its receptors have made this system a very interesting target for clinical research and possibly for future therapeutic approaches.

Prescribing of ACE inhibitors for cardiovascular disorders in general practice

OBJECTIVE

To investigate the prescribing patterns for angiotensin converting enzyme (ACE) inhibitors in the management of patients with heart failure and other cardiovascular disorders as part of a local project on heart failure using information collected from a Primary Care Information Initiative.

METHOD

Patients from a large city-centre practice, who were receiving an ACE inhibitor or with a diagnosis of heart failure at the time of the study, were identified from medical records. Details of concomitant medical conditions and drug treatment were also recorded.

RESULTS

There was extensive prescribing of ACE inhibitors alone, in the treatment of patients with hypertension, where no contraindications for the use of thiazide diuretics or beta-blockers could be identified. ACE inhibitors were being prescribed for post-myocardial infarction patients, but the time for the initiation of treatment was rarely within that recommended in the literature. For those patients diagnosed with heart failure, 60% were not being treated with ACE inhibitors even where there were no contraindications.

CONCLUSION

It is clear from the results of this study that overall prescribing patterns for ACE inhibitors are not always in accord with evidence from the literature. These findings provide valuable information for the initiation and development of clinical guidelines for prescribers.

Renal effects of the calcium channel blocker aranidipine and its active metabolite in anesthetized dogs and conscious spontaneously hypertensive rats

The purpose of this study was to investigate the renal effects of aranidipine, a novel calcium channel blocker of the dihydropyridine type, and its active metabolite in anesthetized dogs and conscious spontaneously hypertensive rats (SHRs). When infused into the renal artery in anesthetized dogs, aranidipine (0.03 microg/kg/min) induced sustained increases in urine volume and urinary excretion of sodium and of potassium. This effect was greater than that elicited by nifedipine (0.1 microg/kg/min). The aranidipine metabolite, M-1 (0.1 microg/kg/min), also caused diuresis and natriuresis almost equal to those of nifedipine. The stop-flow experiment using the anesthetized dog showed that intrarenal infusion of aranidipine (0.03 microg/kg/min), as well as nifedipine (0.1 microg/kg/min), produced natriuresis at the distal tubular site rather than at the proximal site. Aranidipine (0.3, 1, and 3 mg/kg), when administered orally, dose-dependently increased urine volume and urinary excretion of electrolytes in conscious saline-loaded SHRs. M-1 (10 mg/kg, p.o.) also showed diuretic and natriuretic effects comparable to those of nifedipine (10 mg/kg) in SHRs. In addition, after repeated oral administration of aranidipine for 7 days, short-term tolerance was not found for its diuretic and natriuretic effects in SHRs. These results suggest that, apart from antihypertensive efficiency, aranidipine may offer a therapeutic advantage by producing diuresis and natriuresis in hypertensive patients. The metabolite of aranidipine may contribute, in part, to the diuretic, natriuretic, and antihypertensive effects of aranidipine.