Prevalence and Prognostic Significance of Anemia in Patients With Congestive Heart Failure Treated With Standard vs High Doses of Enalapril

The contribution of the AT1 receptor to erythropoiesis

The renin-angiotensin system (RAS) comprises a broad set of functional peptides and receptors that play a role in cardiovascular homeostasis and contribute to cardiovascular pathologies. Angiotensin II (Ang II) is the most potent peptide hormone produced by the RAS due to its high abundance and its strong and pleiotropic impact on the cardiovascular system. Formation of Ang II takes place in the bloodstream and additionally in tissues in the so-called local RAS. Of the two Ang II receptors (AT1 and AT2) that Ang II binds to, AT1 is the most expressed throughout the mammalian body. AT1 expression is not restricted to cells of the cardiovascular system but in fact AT1 protein is found in nearly all organs, hence, Ang II takes part in several modulatory physiological processes one of which is erythropoiesis. In this review, we present multiple evidence supporting that Ang II modulates physiological and pathological erythropoiesis processes trough the AT1 receptor. Cumulative evidence indicates that Ang II by three distinct mechanisms influences erythropoiesis: 1) stimulation of renal erythropoietin synthesis; 2) direct action on bone marrow precursor cells; and 3) modulation of sympathetic nerve activity to the bone marrow. The text highlights clinical and preclinical evidence focusing on mechanistic studies using rodent models.

Role of Iron Deficiency in Heart Failure-Clinical and Treatment Approach: An Overview

BACKGROUND

The association of chronic heart failure (CHF) and iron deficiency (ID) with or without anemia is frequently encountered in current medical practice and has a negative prognostic impact, worsening patients' exercise capacity and increasing hospitalization costs. Moreover, anemia is common in patients with chronic kidney disease (CKD) and CHF, an association known as cardio-renal anemia syndrome (CRAS) possessing a significantly increased risk of death.

AIM

This review aims to provide an illustrative survey on the impact of ID in CHF patients-based on physiopathological traits, clinical features, and the correlation between functional and absolute ID with CHF-and the benefit of iron supplementation in CHF.

METHOD

We selected the most recent publications with important scientific content covering the association of CHF and ID with or without anemia.

DISCUSSIONS

An intricate physiopathological interplay is described in these patients-decrease in erythropoietin levels, activation of the renin-angiotensin-aldosterone system, systemic inflammation, and increases in hepcidin levels. These mechanisms amplify anemia, CHF, and CKD severity and worsen patients' outcomes.

CONCLUSIONS

Anemia is frequently encountered in CHF and represents a negative prognostic factor. Data from randomized controlled trials have underlined the administration of intravenous iron therapy (ferric carboxymaltose) as the only viable treatment option, with beneficial effects on quality of life and exercise capacity in patients with ID and systolic heart failure.

Heart failure with anemia: novel findings on the roles of renal disease, interleukins, and specific left ventricular remodeling processes

BACKGROUND

Anemia is a highly prevalent and strong independent prognostic marker in heart failure (HF), yet this association is not completely understood. Whether anemia is simply a marker of disease severity and concomitant chronic kidney disease or represents the activation of other detrimental pathways remains uncertain. We sought to determine which pathophysiological pathways are exacerbated in patients with HF, reduced ejection fraction (HFrEF) and anemia in comparison with those without anemia.

METHODS AND RESULTS

In a prospective study involving 151 patients, selected biomarkers were analyzed, each representing proposed contributive mechanisms in the pathophysiology of anemia in HF. We compared clinical, echocardiographic, and circulating biomarkers profiles among patients with HFrEF and anemia (group 1), HFrEF without anemia (group 2), and chronic kidney disease with preserved EF, without established HF (chronic kidney disease control group 3). We demonstrate here that many processes other than those related to chronic kidney disease are involved in the anemia-HF relationship. These are linked to the pathophysiological mechanisms pertaining to left ventricular systolic dysfunction and remodeling, systemic inflammation and volume overload. We found that levels of interleukin-6 and interleukin-10, specific markers of cardiac remodeling (procollagen type III N-terminal peptide, matrix metalloproteinase-2, tissue inhibitor of matrix metalloproteinase 1, left atrial volume), myocardial stretch (NT-proBNP [N-terminal probrain natriuretic peptide]), and myocyte death (troponin T) are related to anemia in HFrEF.

CONCLUSIONS

Anemia is strongly associated not only with markers of more advanced and active heart disease but also with the level of renal dysfunction in HFrEF. Increased myocardial remodeling, inflammation, and volume overload are the hallmarks of patients with anemia and HF.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00834691.

Association of systolic blood pressure with mortality in patients with heart failure with reduced ejection fraction: a complex relationship

BACKGROUND

In ambulatory patients with heart failure with reduced ejection fraction (HFrEF), high systolic blood pressure (SBP) is associated with better outcomes. However, it is not known whether there is a ceiling beyond which high SBP has a detrimental effect. Thus, our aim was to assess the linearity of association between SBP and mortality.

METHODS

We used the External Peer Review Program (EPRP) and Digitalis Investigation Group (DIG) trial databases of HFrEF patients. Linearity of association of SBP with mortality was assessed by plotting Martingale residuals against SBP. To assess the patterns of relationship of SBP with mortality, we used restricted cubic spline analysis with Cox proportional hazards model.

RESULTS

In patients with mild-to-moderate left ventricular systolic dysfunction (LVSD) (30% ≤ LVEF < 50%), SBP had a nonlinear association with mortality in both EPRP (n = 3,693) and DIG (n = 3,263) databases. In these patients, SBP had a significant U-shaped association with mortality in EPRP and a trend toward U-shaped relationship in DIG database. In patients with severe LVSD (LVEF <30%), SBP had a linear association with mortality in both EPRP (n = 2,906) and DIG (n = 3,537) databases, with lower SBP being associated with increased mortality.

CONCLUSIONS

Systolic blood pressure has a complex nonlinear association with mortality in patients with heart failure. Whereas it has a U-shaped association in patients with mild-to-moderate LVSD, it has a linear association with mortality in patients with severe LVSD. Recognition of this pattern of association of blood pressure profile may help clinicians in providing better care for their patients and help improve existing prediction models.

The economic burden of anemia in heart failure

Anemia is a complex issue in patients with heart failure (HF). In past years, clinicians accepted anemia as a given or an "accessory" diagnosis in HF patients. This attitude has changed since understanding of the causes and morbidity of anemia in HF has improved and with the introduction of targeted treatments. Increasing health care costs have stimulated vigorous debate about the cost-effectiveness of such treatments. It behooves clinicians to understand the effectiveness of specific treatments, risks and benefits, and costs. This review addresses the impact of anemia's prevalence, etiology, associated outcomes, and treatments on the economic burden of HF patients.

Anemia in heart failure: pathophysiologic insights and treatment options

Anemia has been recognized as a very common and serious comorbidity in heart failure, with a prevalence ranging from 10 to 79%, depending on diagnostic definition, disease severity and patient characteristics. A clear association of anemia with worse prognosis has been confirmed in multiple heart failure trials. This finding has recently triggered intense scrutiny in order to identify the underlying pathophysiology and the best treatment options. Etiology is multifactorial, with iron deficiency and cytokine activation (anemia of chronic disease) playing the most important roles. Treatment is aimed at not only restoring hemoglobin values back to normal, but also at improving the patient's symptoms, functional capacity and hopefully the outcome. Iron supplementation and erythropoietin-stimulating agents have been used for this purpose, either alone or in combination. In this review, the recent advances in elucidating the mechanisms leading to anemia in the setting of heart failure are presented and the evidence supporting the use of different treatment approaches are discussed.

[Etiology and clinical management of anemia in heart failure. GESAIC Study]

BACKGROUND AND OBJECTIVE

Studies about anemia in heart failure (HF) tend to link the anemia to a cardio-renal dysfunction, and its syndromic value is seldom evaluated. Our objective was to assess the etiology and clinical management of anemia in HF patients in a hospital setting.

PATIENTS AND METHOD

Initial cross-sectional analysis of a multi-center and prospective cohort of patients with HF and anemia. Anemia was defined according to the WHO criteria; the Modification of Diet in Renal Disease equation was used to assess glomerular filtration and the etiology of anemia was defined according to common criteria.

RESULTS

We evaluated 228 patients, with a median age of 79.1 years and 59.65% women. Iron deficiency anemia was present in 36,8% of patients and anemia of chronic disease in 30.3%. Of note, 12.7% cases did not meet any etiological criteria. The main factor associated with iron deficiency was anti-platelet therapy (OR=1.99; 95% CI, 1.16-1.68) and the main factors associated with anemia of chronic disease were the use of angiotensin converting enzyme inhibitors (ACEI) or angiotensin II receptor antagonists (ARA-II) (OR=3.29; 95% CI, 1.36-7.94). The main factor associated with undefined anemia was initial heart failure (OR=5.41; 95% CI, 1.65-17.65). On the other hand, 8.1% of patients required transfusion, 6% were treated with erythropoietin and 25.3% were treated with iron. Both age (OR=1.04; 95% CI, 1-1.08) and hemoglobin level at admission (OR=1.81; 95% CI, 1.46-2.25) were associated with active treatment for anemia.

CONCLUSIONS

A clinical study of anemia in patients with HF can establish an etiological diagnosis in 70% of cases, resulting in a more effective treatment.

Iron and anemia in human biology: a review of mechanisms

The biology of iron in relation to anemia is best understood by a review of the iron cycle, since the majority of iron for erythropoiesis is provided by iron recovered from senescent erythrocytes. In iron-deficiency anemia, storage iron declines until iron delivery to the bone marrow is insufficient for erythropoiesis. This can be monitored with clinical indicators, beginning with low plasma ferritin, followed by decreased plasma iron and transferrin saturation, and culminating in red blood cells with low-Hb content. When adequate dietary iron is provided, these markers show return to normal, indicating a response to the dietary supplement. Anemia of inflammation (also known as anemia of chronic disease, or ACD) follows a different course, because in this form of anemia storage iron is often abundant but not available for erythropoiesis. The diagnosis of ACD is more difficult than the diagnosis of iron-deficiency anemia, and often the first identified symptom is the failure to show a response to a dietary iron supplement. Confirmation of ACD is best obtained from elevated markers of inflammation. The treatment of ACD, which typically employs erythropoietin (EPO) supplements and intravenous iron (i.v.-iron), is empirical and often falls shorts of therapeutic goals. Dialysis patients show a complex pattern of anemia, which results from inadequate EPO production by the kidney, inflammation, changes in nutrition, and blood losses during treatment. EPO and i.v.-iron are the mainstays of treatment. Patients with heart failure can be anemic, with incidence as high as 50%. The causes are multifactorial; inflammation now appears to be the primary cause of this form of anemia, with contributions from increased plasma volume, effects of drug therapy, and other complications of heart disease. Discerning the mechanisms of anemia for the heart failure patient may aid rational therapy in each case.

Antihypertensive Medications and Anemia

Antihypertensive medication use can be associated with a reduction in hemoglobin concentration. The magnitude of such a change is generally small, but in certain instances it can be extreme enough to produce a clinically significant degree of anemia. The mechanistic basis for antihypertensive medication-related changes in hemoglobin concentration include hemodilution, hemolytic anemia, and suppression of red blood cell production, as this occurs most commonly with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. A reduction in hemoglobin concentration in a patient who is receiving treatment for hypertension and does not have an obvious source of blood loss should account for potential antihypertensive therapy involvement.

Etiology of anemia in patients with advanced heart failure

OBJECTIVES

We prospectively investigated the causes of anemia in patients with advanced congestive heart failure (CHF).

BACKGROUND

Anemia is common in patients with advanced CHF, and its etiology is generally considered to be multifactorial. However, despite its importance, precise information is lacking regarding the prevalence of putative etiologic factors.

METHODS

Patients who were hospitalized for decompensated advanced CHF and who were stabilized after their initial treatment underwent evaluation of "clinically significant" anemia, defined as a hemoglobin content <12 g/dl for men and <11.5 g/dl for women. Patients with a serum creatinine concentration >3 mg/dl or patients with concurrent diseases that are known to cause anemia were not included. The initial evaluation included measurements of vitamin B(12), folic acid, thyroid-stimulating hormone, erythropoietin, lactate dehydrogenase, Coombs test, multiple fecal occult tests, and bone marrow aspiration. Patients without diagnosis by these methods underwent red cell mass measurement with (51)Cr assay.

RESULTS

The mean age of the 37 patients was 57.9 +/- 10.9 years and mean left ventricular ejection fraction 22.5 +/- 5.9%. Iron deficiency anemia was confirmed by bone marrow aspiration in 27 patients (73%), 2 patients (5.4%) had dilutional anemia, and 1 patient (2.7%) had drug-induced anemia. No specific cause was identified in 7 patients (18.9%) who were considered to have "anemia of chronic disease." Serum ferritin for the iron-deficient patients was not a reliable marker of iron deficiency in this population.

CONCLUSIONS

In this group of patients, iron deficiency was the most common cause of anemia. The iron status of patients with end-stage chronic CHF should be thoroughly evaluated and corrected before considering other therapeutic interventions.