Pathogenesis of oedema in chronic severe anaemia: studies of body water and sodium, renal function, haemodynamic variables and plasma hormones

Hypervolemia suppresses dilutional anaemic injury in a rat model of haemodilution

Background and Objectives

Haemodilution leads to complications in clinical practice. It is exactly unknown whether this damage is caused by the fluid or by the stretching of the vascular bed. We aimed to compare two different haemodilution techniques at the same anaemic level.

Methods

Normovolemic or hypervolemic haemodilution was performed on twelve adult male Wistar rats. In the normovolemic procedure, blood was withdrawn and instantaneously administered with similar amounts of 6% hydroxyethyl starch (HES 130/0.4). Fluid was administered without withdrawing blood in the hypervolemic procedure. In both models, a 25% haematocrit level was targeted and kept at this level for 90 min to deepen the anaemia effect. Besides haemodynamics measurement, renal function (creatinine, blood urea nitrogen) and injury (tissue norepinephrine, malondialdehyde) were evaluated. Also, systemic hypoxia (lactate), oxidative stress (malondialdehyde, ischaemia-modified albumin), inflammation (tumour necrosis factor-alpha [TNF-α]), osmotic stress, adrenal stress (norepinephrine, epinephrine), and vascular stretching (atrial natriuretic peptide [ANP]) were assessed.

Results

Arterial pressure in the normovolemic group was lower than in the hypervolemic group. Serum creatinine, blood urea nitrogen, and lactate levels were higher in the normovolemic group. Tissue norepinephrine and malondialdehyde levels were higher in the normovolemic group. Serum ANP, malondialdehyde, ischaemia-modified albumin, free haemoglobin, syndecan-1, and TNF-α were higher in both groups compared to respective baseline.

Conclusions

Normovolemic haemodilution may lead to hypoxic kidney injury. The hypervolemic state may be advantageous if fluid is to be administered. Thus, the effect of the fluid itself can be relatively masked.

The Prognostic Significance of Anemia in Patients With Heart Failure: A Meta-Analysis of Studies From the Last Decade

Background: Anemia is a commonly occurring comorbidity in patients with heart failure (HF). Although there are a few reports of a higher prevalence of mortality and hospitalization-related outcomes due to accompanying anemia, other studies suggest that anemia does not have an adverse impact on the prognostic outcomes of HF. Two meta-analyses in the past decade had reported the adverse impact of anemia on both mortality and hospitalization- related outcomes. However, only one of these studies had evaluated the outcome while using multivariable adjusted hazard ratios. Moreover, several studies since then reported the prognostic influence of anemia in HF. In this present study, we evaluate the prognostic impact of anemia on mortality and hospitalization outcomes in patients with HF.

Methods: We carried out a systematic search of the academic literature in the scientific databases EMBASE, CENTRAL, Scopus, PubMed, Cochrane, ISI Web of Science, clinicaltrial.gov, and MEDLINE based on the PRISMA guidelines. Meta-analysis was then performed to evaluate the effect (presented as risk ratio) of anemia on the overall mortality and hospitalization outcome in patients with HF.

Results: Out of 1,397 studies, 11 eligible studies were included with a total of 53,502 (20,615 Female, 32,887 Male) HF patients (mean age: 71.6 ± 8.3-years, Hemoglobin: 11.9 ± 1.5 g/dL). Among them, 19,794 patients suffered from anemia (Hb: 10.5 ± 1.6), and 33,708 patients did not have anemia (Hb: 13.2 ± 1.7 g/dL). A meta-analysis revealed a high-odds ratio (OR) for the overall mortality in patients with anemia (OR: 1.43, 95% CI: 1.29–1.84). A high-risk ratio was also reported for hospitalization as the outcome in patients with anemia (1.22, 1.0–1.58).

Conclusion: This systematic review and meta-analysis provide evidence of the high risk of mortality and hospitalization-related outcomes in patients with HF and anemia. The study confirms the findings of previously published meta-analyses suggesting anemia as an important and independent risk factor delineating the prognostic outcome of chronic HF.

Clinical Characteristics of Overhydration in Patients with Idiopathic Edema

BACKGROUND

Idiopathic edema (IE) is a common clinical syndrome. Designing treatment plans for IE is problematic because of the difficulty in assessing volume status. We aimed to evaluate volume status, measured by bioimpedance spectroscopy (BIS), and investigated clinical parameters associated with volume overload (VO) in patients with IE.

METHODS

Patients with IE were defined as those with symptomatic edema and without abnormal renal function or any other apparent cause of edema. A total of 124 patients were included. Overhydration (OH) and extracellular water (ECW) were calculated using BIS. Relative hydration status (x0394;HS) was defined as OH/ECW. Patients were classified into 2 groups: overhydrated group (OG; x0394;HS ≥7%) and non-OG (NOG; x0394;HS <7). Simple and multiple logistic regression analyses were used to assess the influence of several variables on the incidence of VO.

RESULTS

Of 124 patients, 37 (29.8%) were in the OG. The proportion of men in the OG was higher than that in the NOG (p = 0.020). Patients in the OG showed more frequent pretibial pitting edema (PTPE, p < 0.001) and had lower hemoglobin (p = 0.008) and serum albumin levels (p < 0.001). The multivariate analysis showed that the presence of PTPE (OR 10.62, 95% CI 1.98-57.1), low serum albumin level (OR 0.01, 95% CI 0.00-0.25) and lower fat tissue index (OR 0.78, 95% CI 0.63-0.97) were independent risk factors for the presence of VO.

CONCLUSIONS

BIS helps to identify volume status and body composition in patients with IE.