Iron Deficiency Is Associated with Adverse Outcomes in Pediatric Heart Failure

Evaluation and Management of Chronic Heart Failure in Children and Adolescents With Congenital Heart Disease: A Scientific Statement From the American Heart Association

With continued medical and surgical advancements, most children and adolescents with congenital heart disease are expected to survive to adulthood. Chronic heart failure is increasingly being recognized as a major contributor to ongoing morbidity and mortality in this population as it ages, and treatment strategies to prevent and treat heart failure in the pediatric population are needed. In addition to primary myocardial dysfunction, anatomical and pathophysiological abnormalities specific to various congenital heart disease lesions contribute to the development of heart failure and affect potential strategies commonly used to treat adult patients with heart failure. This scientific statement highlights the significant knowledge gaps in understanding the epidemiology, pathophysiology, staging, and outcomes of chronic heart failure in children and adolescents with congenital heart disease not amenable to catheter-based or surgical interventions. Efforts to harmonize the definitions, staging, follow-up, and approach to heart failure in children with congenital heart disease are critical to enable the conduct of rigorous scientific studies to advance our understanding of the actual burden of heart failure in this population and to allow the development of evidence-based heart failure therapies that can improve outcomes for this high-risk cohort.

Iron deficiency in children with a focus on inflammatory conditions

Iron deficiency (ID) tends to be overlooked compared with anemia. However, its prevalence is estimated to be twice as high as that of ID anemia, and ID without anemia can be accompanied by clinical and functional impairments. The symptoms of ID are nonspecific, such as fatigue and lethargy, but can lead to neurodevelopmental disorders in children, restless legs syndrome, and recurrent infections due to immune system dysregulation. In particular, the risk of ID is high in the context of chronic inflammatory diseases (CIDs) due to the reaction of various cytokines and the resulting increase in hepcidin levels; ID further exacerbates these diseases and increases mortality. Therefore, the diagnosis of ID should not be overlooked through ID screening especially in high-risk groups. Ferritin and transferrin saturation levels are the primary laboratory parameters used to diagnose ID. However, as ferritin levels respond to inflammation, the diagnostic criteria differ among guidelines. Therefore, new tools and criteria for accurately diagnosing ID should be developed. Treatment can be initiated only with an accurate diagnosis. Oral iron is typically the first-line treatment for ID; however, the efficacy and safety of intravenous iron have recently been recognized. Symptoms improve quickly after treatment, and the prognosis of accompanying diseases can also be improved. This review highlights the need to improve global awareness of ID diagnosis and treatment, even in the absence of anemia, to improve the quality of life of affected children, especially those with CIDs.

Nutritional Strategies for Managing Iron Deficiency in Adolescents: Approaches to a Challenging but Common Problem

Iron deficiency (ID) is a common and challenging problem in adolescence. In order to prevent, recognize, and treat ID in this age range, it is critical to understand the recommended daily intake of iron in relation to an adolescent's activity, dietary habits, and basal iron losses. Adolescents following vegetarian or vegan diets exclusively rely on plant-based, nonheme iron, which has decreased bioavailability compared with heme iron and requires increased total iron intake. Individuals with disordered eating habits, excessive menstrual blood loss, and certain chronic health conditions (including inflammatory bowel disease and heart failure) are at high risk of ID and the development of symptomatic iron deficiency anemia (IDA). Adolescent athletes and those with sleep and movement disorders may also be more sensitive to changes in iron status. Iron deficiency is typically treated with oral iron supplementation. To maximize iron absorption, oral iron should be administered no more than once daily, ideally in the morning, while avoiding foods and drinks that inhibit iron absorption. Oral iron therapy should be provided for ≥3 mo in the setting of ID to reach a ferritin of 20 ng/mL before discontinuation. Intravenous iron is being increasingly used in this population and has demonstrated efficacy and safety in adolescents. It should be considered in those with persistent ID despite a course of oral iron, severe and/or symptomatic IDA, and chronic inflammatory conditions characterized by decreased gastrointestinal iron absorption.

Iron deficiency and anemia in pediatric dilated cardiomyopathy are associated with clinical, biochemical, and hematological markers of severe disease and adverse outcomes

BACKGROUND

There is limited evidence regarding the prevalence and impact of iron deficiency (ID) in children with dilated cardiomyopathy (DCM).

METHODS

Retrospective single-center review of all children between 2010 and 2020 with a diagnosis of DCM and complete iron studies. ID was defined as ≥2 of ferritin <20 μg/liter, iron <9 μmol/liter, transferrin >3 g/liter, or transferrin saturation (TSat) <15%. Clinical and laboratory indices and freedom from a composite adverse event (CAE) of mechanical circulatory support (MCS), heart transplant, or death were compared between children with and without ID.

RESULTS

Of 138 patients with DCM, 47 had available iron studies. Twenty-nine (62%) were iron deficient. Children with ID were more likely to be receiving inotropes (17, 59%, p = 0.005) or invasive/noninvasive ventilation (13, 45%, p = 0.016) than those who were iron replete. They had a higher incidence of anemia (22, 76%, p = 0.004) and higher NT-proBNP (1,590 pmol/liter, IQR 456-3,447, p = 0.001). Children with ID had significantly less freedom from the CAE at 1-year (54% ± 10%), 2-years (45 ± 10), and 5-years (37% ± 11%) than those without (p = 0.011). ID and anemia were the only significant predictors of the CAE on univariate Cox regression.

CONCLUSIONS

ID is highly prevalent in children with DCM. Iron studies are undermeasured in clinical practice, but ID is associated with severe heart failure (HF) and an increased risk of the CAE. The need for iron replacement therapy should be considered in children who present in HF with DCM.

Association between aluminum and iron exposure in maternal blood and umbilical cord blood and congenital heart defects in children

Background

Congenital heart disease (CHDs) is the major cause of mortality from birth defects, affecting up to 1% of live births worldwide. However, the relationship between aluminum (Al) and iron (Fe) levels and the risk of CHDs has yielded inconsistent results.

Methods

We conducted a pair-matched case-control study that included 97 CHDs and 194 non-CHDs to investigate the association and interaction between Al/Fe exposure and the risk of CHDs in a birth cohort study in Lanzhou, China.

Results

Higher concentrations of cord blood Al were associated with a greater risk of total CHDs (aOR = 2.826, 95% CI [1.009-7.266]) and isolated CHDs (aOR = 10.713, 95% CI [1.017-112.851]) compared to the lowest Al level. Both in maternal blood and cord blood, a significant dose-effect was observed between Al level and total CHDs (Ptrend < 0.05), but a similar pattern was not observed for Fe. High Al in addition to high Fe appeared to elicit a stronger association with CHDs than both lowest tertile of Al and Fe level in umbilical cord blood, particularly for multiple CHDs, septal defects and patent ductus arteriosus.

Conclusions

Our study suggests that exposure to Al during pregnancy (≥2,408 μg/L) is significantly associated with an increased risk of CHDs in offspring, especially septal defects, and that high levels of Al and Fe are strongly correlated with fetal heart development. Further research is needed to understand the underlying mechanisms.

Intravenous iron therapy in pediatrics: who should get it and when is the right time?

Iron-deficiency anemia occurs most commonly in young children due to a low-iron diet and adolescent girls due to menstrual blood loss. However, children with gastrointestinal conditions such as intestinal failure, inflammatory bowel disease, celiac disease, and/or other chronic conditions, including chronic kidney disease and heart failure, also commonly have iron deficiency. Many patients with classic iron-deficiency anemia will improve with oral iron therapy. However, in children who have an incomplete response to oral iron, intravenous iron therapy is increasingly being used. Benefits of intravenous iron therapy include a rapid repletion of iron stores in addition to resolution of anemia, less gastrointestinal side effects, and relief for patients and families struggling with long-term iron supplementation. Indications for first-line therapy with intravenous iron in children with chronic conditions have also increased. Four intravenous iron formulations have approved indications in pediatrics, and many are increasingly used off-label in children as well. Here we discuss the indications and appropriate timing of intravenous iron therapy in children with a wide range of underlying etiologies.

Iron Deficiency in Chronic Pediatric Heart Failure: Overall Assessment and Outcomes in Dilated Cardiomyopathy

OBJECTIVE

To evaluate the frequency of iron status assessment in pediatric heart failure and the prevalence and adverse effects of absolute iron deficiency in dilated cardiomyopathy-induced heart failure.

STUDY DESIGN

We retrospectively reviewed records of children with chronic heart failure at our center between 2010 and 2020. In children with dilated cardiomyopathy, we analyzed baseline cardiac function, hemoglobin level, and subsequent risk of composite adverse events (CAE), including death, heart transplant, ventricular assist device (VAD) placement, and transplant registry listing. Absolute iron deficiency and iron sufficiency were defined as transferrin saturations <20% and ≥30%, respectively; and indeterminant iron status as 20%-29%.

RESULTS

Of 799 patients with chronic heart failure, 471 (59%) had no iron-related laboratory measurements. Of 68 children with dilated cardiomyopathy, baseline transferrin saturation, and quantitative left ventricular ejection fraction (LVEF), 33 (49%) and 14 (21%) were iron deficient and sufficient, respectively, and 21 (31%) indeterminant. LVEF was reduced to 23.6 ± 12.1% from 32.9 ± 16.8% in iron deficiency and sufficiency, respectively (P = .04), without a significant difference in hemoglobin. After stratification by New York Heart Association classification, in advanced class IV, hemoglobin was reduced to 10.9 ± 1.3 g/dL vs 12.7 ± 2.0 g/dL in iron deficiency and sufficiency, respectively (P = .01), without a significant difference in LVEF.

CONCLUSIONS

In this single-center study, iron deficiency was not monitored in most children with chronic heart failure. In pediatric dilated cardiomyopathy-induced heart failure, absolute iron deficiency was prevalent and associated with clinically consequential and possibly correctable decreases in cardiac function and hemoglobin concentration.

Nutrition for critically ill children with congenital heart disease

Children with congenital heart disease often require admission to the cardiac intensive care unit at some point in their lives, either after elective surgical or catheter-based procedures or during times of acute critical illness. Meeting both the macronutrient and micronutrient needs of children in the cardiac intensive care unit requires complex decision-making when considering gastrointestinal perfusion, vasoactive support, and fluid balance goals. Although nutrition guidelines exist for critically ill children, these cannot always be extrapolated to children with congenital heart disease. Children with congenital heart disease may also suffer unique circumstances, such as chylothoraces, heart failure, and the need for mechanical circulatory support, which greatly impact nutrition delivery. Guidelines for neonates and children with heart disease continue to be developed. We provide a synthesized narrative review of current literature and considerations for nutrition evaluation and management of critically ill children with congenital heart disease.

Poor efficacy of oral iron replacement therapy in pediatric patients with heart failure

INTRODUCTION

Iron deficiency is associated with worse outcomes in children and adults with systolic heart failure. While oral iron replacement has been shown to be ineffective in adults with heart failure, its efficacy in children with heart failure is unknown. We hypothesised that oral iron would be ineffective in replenishing iron stores in ≥50% of children with heart failure.

METHODS

We performed a single-centre retrospective cohort study of patients aged ≤21 years with systolic heart failure and iron deficiency who received oral iron between 01/2013 and 04/2019. Iron deficiency was defined as ≥2 of the following: serum iron <50 mcg/dL, serum ferritin <20 ng/mL, transferrin >300 ng/mL, transferrin saturation <15%. Iron studies and haematologic indices pre- and post-iron therapy were compared using paired-samples Wilcoxon test.

RESULTS

Fifty-one children with systolic heart failure and iron deficiency (median age 11 years, 49% female) met inclusion criteria. Heart failure aetiologies included cardiomyopathy (51%), congenital heart disease (37%), and history of heart transplantation with graft dysfunction (12%). Median dose of oral iron therapy was 2.9 mg/kg/day of elemental iron, prescribed for a median duration of 96 days. Follow-up iron testing was available for 20 patients, of whom 55% (11/20) remained iron deficient despite oral iron therapy.

CONCLUSIONS

This is the first report on the efficacy of oral iron therapy in children with heart failure. Over half of the children with heart failure did not respond to oral iron and remained iron deficient.

Pre-operative nutritional status and its association with short-term post-operative outcomes in Iranian children with CHD

BACKGROUND

Nutritional assessment appears to be an essential component of the evaluation of children with CHD undergoing surgery because nutritional status may impact corrective surgery-associated morbidity.

METHODS

A prospective single-centre cohort study with children between 6 and 24 months of age. Patients who had genetic syndromes or those who were premature or low birthweight at birth were excluded. Pre-operative nutritional parameters included anthropometric measurements and serum concentrations of total protein, vitamin D, iron, and ferritin. Outcome measures included ICU length of stay, mechanical ventilation, vasoactive-inotropic score, and duration of inotropes. Linear regression analysis was performed to determine whether pre-operative variables were associated with outcomes.

RESULTS

Analysis was performed on 120 patients (median age of 8 months), of whom 67 were male. Prior to surgery, 50.8% of patients had reduced (z ≤ -2.0) weight-for-age z score, 23.3% had reduced length-for-age z score, and 59.2% had reduced mid-upper arm circumference z score. Pre-operative serum total protein levels were 59.36 ± 9.16 g/L. Multiple regression analysis showed that low serum protein was associated with longer ICU length of stay and length of mechanical ventilation, while mid-upper arm circumference z score ≤ -2 was associated with longer ICU length of stay and mechanical ventilation and inotropes duration.

CONCLUSIONS

Pre-operative assessment of nutritional status by performing anthropometric and biochemical measurements including mid-upper arm circumference z score and serum protein concentrations in children undergoing CHD surgery appears to be predictors of some post-operative short-term outcomes and could be used as a guide to highlight patients needing appropriate perioperative nutritional interventions.

Preoperative Iron Deficiency Is Associated With Increased Blood Transfusion in Infants Undergoing Cardiac Surgery

Background

Iron deficiency (ID) is common in patients undergoing cardiac surgery, which is associated with adverse outcomes. However, the relevance of ID in congenital heart disease is still unclear. This study aimed to investigate the characteristics of preoperative ID and its association with clinical outcomes in infants undergoing cardiac surgery with cardiopulmonary bypass.

Methods

In this retrospective study, 314 patients undergoing cardiac surgery were assigned into three groups according to their preoperative ID status. Absolute ID was defined by serum ferritin <12 μg/L, and functional ID was defined by serum ferritin level at 12–30 μg/L and transferrin saturation <20%. Baseline characteristics were compared between groups and multiple logistic regression was used to identify predictors for ID. The association between ID and clinical outcomes, including allogenic blood transfusion requirements, was also evaluated.

Results

Among the 314 patients included, 32.5% were absolute ID and 28.7% were functional ID. Patients with absolute ID were more often of higher weight, cyanotic heart disease, and anemia. The presence of absolute ID was associated with an increase in postoperative blood transfusion (OR 1.837, 95% CI 1.016–3.321, p = 0.044). There was no significant difference in postoperative morbidity, mortality, and the length of hospital stay.

Conclusions

Absolute ID was associated with preoperative anemia and cyanotic heart disease, and was an independent risk factor for postoperative blood transfusion. Further research should better explore the definition of ID and its impact on outcomes in pediatric cardiac surgery.

Preoperative Iron Supplementation in Pediatric Cardiac Surgical Patients: A Preliminary Single-Center Experience

OBJECTIVE

To assess preoperative hemoglobin and perioperative red blood cell transfusion in children undergoing cardiac surgery after the implementation of a preoperative patient blood management (PBM) clinic with oral iron supplementation.

DESIGN

A retrospective analysis.

SETTING

A single tertiary hospital.

PARTICIPANTS

Patients who underwent cardiac surgery with cardiopulmonary bypass at the Hospital for Sick Children (Toronto, Canada) during a 12-month period before and following the implementation of a preoperative PBM clinic. Patients younger than 3 months of age, or who were admitted to the cardiac intensive care unit preoperatively, were excluded because they were not systematically assessed by the PBM clinic.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 296 patients were included in the authors' analysis. After adjustment for confounding factors (age at surgery, preoperative oxygen saturation, type of congenital heart disease, surgery type), they found that preoperative hemoglobin levels were significantly higher in children treated with iron supplementation (n = 201) compared to historic controls (n = 95) (13.9 [12.8-15.1] g/dL v 12.9 [11.7-15.0] g/dL, adjusted p = 0.001). The exposure rate to red blood cell transfusion (50% v 61%, adjusted p = 0.930) was not significantly different between groups. However, the volumes of allogeneic red blood cells (1.4 (0.0-14.0) mL/kg v 12.5 (0.0-23.0) mL/kg, adjusted p = 0.004) and autologous blood (11.0 (6.8-17.0) v 17.0 (11.0-31.0), adjusted p < 0.001) transfused were significantly reduced in children treated with iron supplementation.

CONCLUSIONS

Preoperative iron supplementation led to an increase in preoperative hemoglobin levels. The exact prevalence of iron deficiency and the effect of iron supplementation on perioperative allogeneic blood transfusion and long-term outcomes should be studied in a prospective randomized study.

Dilated Cardiomyopathy in Pediatric Crohn's Patient: Is It a Manifestation or Consequence of Therapy?

Inflammatory bowel disease (IBD) is a debilitating chronic disorder that is classified into Crohn's disease, ulcerative colitis, and unspecified which are marked by recurrent gastrointestinal inflammatory episodes. Anti-tumor necrosis agents, especially infliximab, are considered the cornerstone in disease management. However, rare but serious adverse effects related to infliximab have been reported. Limited studies reported cardiac adverse effects as a result of using infliximab in IBD especially in the pediatric age group. Here, we report a case of an 11-year-old boy known to have Crohn's disease, who was on a regular infusion of infliximab at a monthly basis which developed dilated cardiomyopathy with severe depression of myocardial function.

Abnormal iron status is independently associated with reduced oscillometric lung function in schoolchildren

BACKGROUND

Associations between anemia and allergic diseases have been reported, but the relationship of iron deficiency with airway dysfunction in children remains unclear. We aimed to investigate the relationship between abnormal iron parameters and lung function in schoolchildren.

METHODS

Four hundred and forty-five children (10-12 years-old) from 11 elementary schools in were enrolled. The relationships of different iron parameters (hemoglobin, serum iron, transferrin saturation, and serum ferritin) with lung function evaluated by impulse oscillometry (airways resistance at 5 Hz [Rrs5], 10 Hz [Rrs10], and the difference of Rrs5 and Rrs20 Hz [Rrs5-20]), and with exhaled nitric oxide (FeNO) were evaluated after adjustment for confounders including height, sex, and body mass index z-score, and for additional covariates that could affect airway function.

RESULTS

Total airway dysfunction represented by Rrs5 was reduced in participants with low serum iron level (aβ: -0.13, 95% CI: -0.23 to -0.03, p = 0.040) after adjustment for key confounders, but did not correlate with other iron profiles. Reduced oscillometric lung function recorded as Rrs5-20 was related with low serum iron and high serum ferritin, but the results were inconsistent after multiple comparisons. Associations were not observed with serum hemoglobin.

CONCLUSIONS

Decreased serum iron level was related with airway dysfunction represented as oscillomteric Rrs5. Our results suggest a relationship of reduced lung function with abnormal iron status in children.

Timing of umbilical cord clamping among infants with congenital heart disease

The optimal timing of clamping and cutting the umbilical cord at birth among infants with congenital heart disease (CHD) remains a subject of controversy and debate. The benefits of delayed umbilical cord clamping (DCC) among term infants without CHD are well described, but the evidence base for DCC among infants with CHD has not been characterized adequately. The goals of the present review are to: 1) compare outcomes of DCC versus early cord clamping (ECC) in term (≥37 weeks of gestation) infants; 2) discuss potential risk/benefit profiles in applying DCC among term infants with CHD; 3) use rigorous systematic review methodology to assess the quality and quantity of published reports on cord clamping practices among term infants with CHD; 4) identify needs and opportunities for future research and interdisciplinary collaboration. Our systematic review shows that previous trials have largely excluded infants with CHD. Therefore, the supposition that DCC is advantageous because it is associated with improved neurologic and hematologic outcome is untested in the CHD population. Given that CHD is markedly heterogeneous, to minimize unnecessary and potentially harmful cord clamping practices, identification of subgroups (single-ventricle, cyanotic lesions) most likely to benefit from optimal cord clamping practices is necessary to optimize risk/benefit profiles. The available evidence base suggests that contemporary, pragmatic, randomized controlled trials comparing DCC with ECC among infants with CHD are needed.