Prevalence and prognostic implication of iron deficiency and anaemia in patients with severe aortic stenosis

Associations Between Nonanemic Iron Deficiency and Postoperative Outcomes in Cardiac Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Preoperative screening for iron deficiency is a part of patient blood management protocols. This systematic review, meta-analysis, and meta-regression reviews the association between nonanemic iron deficiency and postoperative outcomes in patients undergoing cardiac surgery. We aimed to determine whether preoperative screening for nonanemic iron deficiency should be recommended in patients undergoing cardiac surgery.

METHODS

Electronic databases MEDLINE (Ovid), Embase (Ovid), and Scopus were searched from inception until December 9, 2022. Studies were considered for inclusion if they (1) used an observational study design; (2) enrolled adult patients undergoing cardiac surgery; and (3) included an iron-deficient and iron-replete group, defined using serum ferritin and/or transferrin saturation. The primary outcome was the length of acute hospital stay. Secondary outcomes included length of intensive care unit stay, requirement for allogeneic red blood cell transfusion, number of red blood cell units transfused, days alive and at home at postoperative days 30 and 90, all-cause postoperative complications, postoperative infection, mortality, and hospital readmission. Meta-regression was performed to assess the effects of study and patient-level factors on the associations between nonanemic iron deficiency and specific outcomes. Individual study quality was assessed using the Risk of Bias in Non-Randomized Studies of Exposures (ROBINS-E) tool. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework was used to determine the quality of evidence for each outcome.

RESULTS

Eight studies (2683 patients) were included. No significant association was observed between nonanemic iron deficiency and any of the primary or secondary outcomes except for an increased requirement for allogeneic red blood cell transfusion (odds ratio [OR], 1.39 [95% confidence interval, CI, 1.16-1.68; P < .001; I2 2.8%]). Meta-regression did not identify any potential sources of heterogeneity to explain variation in individual study results. The quality of evidence was rated as "low" or "very low" for all outcomes.

CONCLUSIONS

Few high-quality studies are available to assess associations between nonanemic iron deficiency and outcomes after cardiac surgery. Acknowledging these limitations, the presence of preoperative nonanemic iron deficiency was not associated with a change in the primary outcome of length of hospital stay, or any patient-centered secondary outcome compared to those without iron deficiency. There was an association with increased requirement for allogeneic red blood cell transfusion, but this did not impact the reported patient-centered outcomes.

Insights into calcific aortic valve stenosis: a comprehensive overview of the disease and advancing treatment strategies

Aortic valve stenosis is a disease characterized by thickening and narrowing of the aortic valve (AV), most commonly due to calcification, which leads to left ventricular outflow obstruction called calcific aortic valve disease (CAVD). CAVD presents as a progressive clinical syndrome with cardiorespiratory symptoms, often with rapid deterioration. The modern-day pathophysiology of CAVD involves a complex interplay of genetic factors, chronic inflammation, lipid deposition, and valve calcification, with early CAVD stages resembling atherosclerosis. Various imaging modalities have been used to evaluate CAVD, with a recent trend of using advanced imaging to measure numerous AV parameters, such as peak jet velocity. Significant improvements in mortality have been achieved with transcatheter AV repair, but numerous therapeutics and modalities are being researched to delay the progression of CAVD. This article aims to provide a comprehensive review of CAVD, explore recent developments, and provide insights into future treatments with various novel modalities.

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.

Iron deficiency and cardiovascular disease

Iron deficiency (ID) is common in patients with cardiovascular disease. Up to 60% of patients with coronary artery disease, and an even higher proportion of those with heart failure (HF) or pulmonary hypertension have ID; the evidence for cerebrovascular disease, aortic stenosis and atrial fibrillation is less robust. The prevalence of ID increases with the severity of cardiac and renal dysfunction and is probably more common amongst women. Insufficient dietary iron, reduced iron absorption due to increases in hepcidin secondary to the low-grade inflammation associated with atherosclerosis and congestion or reduced gastric acidity, and increased blood loss due to anti-thrombotic therapy or gastro-intestinal or renal disease may all cause ID. For older people in the general population and patients with HF with reduced ejection fraction (HFrEF), both anaemia and ID are associated with a poor prognosis; each may confer independent risk. There is growing evidence that ID is an important therapeutic target for patients with HFrEF, even if they do not have anaemia. Whether this is also true for other HF phenotypes or patients with cardiovascular disease in general is currently unknown. Randomized trials showed that intravenous ferric carboxymaltose improved symptoms, health-related quality of life and exercise capacity and reduced hospitalizations for worsening HF in patients with HFrEF and mildly reduced ejection fraction (<50%). Since ID is easy to treat and is effective for patients with HFrEF, such patients should be investigated for possible ID. This recommendation may extend to other populations in the light of evidence from future trials.

Intravenous ferric derisomaltose in iron-deficient patients undergoing transcatheter aortic valve implantation due to severe aortic stenosis: study protocol of the randomised controlled IIISAS trial

INTRODUCTION

Iron deficiency is a prevalent comorbidity in patients with severe aortic stenosis and may be associated with procedural and clinical outcomes after transcatheter aortic valve implantation (TAVI). In the Intravenous Iron Supplement for Iron Deficiency in Patients with Severe Aortic Stenosis (IIISAS) trial, we aim to examine whether a single administration of ferric derisomaltose can improve physical capacity after TAVI.

METHODS AND ANALYSIS

This randomised, double-blind, placebo-controlled trial aims to enrol 150 patients with iron deficiency who are scheduled for TAVI due to severe aortic stenosis. The study drug and matching placebo are administered approximately 3 months prior to TAVI, and the patients are followed for 3 months after TAVI. Inclusion criteria are iron deficiency, defined as serum ferritin<100 µg/L or ferritin between 100 and 300 µg/L in combination with a transferrin saturation<20% and written informed consent. Exclusion criteria include haemoglobin<10 g/dL, red blood cell disorders, end-stage kidney failure, intolerance to ferric derisomaltose, and ongoing infections. The primary endpoint is the baseline-adjusted distance walked on a 6 min walk test (6MWT) 3 months after TAVI. Secondary end points include quality of life, New York Heart Association functional class (NYHA functional class), and skeletal muscle strength.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Regional Committee for Medical and Health Research of South-Eastern Norway and The Norwegian Medicines Agency. Enrolment has begun, and results are expected in 2022. The results of the IIISAS trial will be disseminated by presentations at international and national conferences and by publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04206228.

Perioperative Quality Initiative and Enhanced Recovery After Surgery-Cardiac Society Consensus Statement on the Management of Preoperative Anemia and Iron Deficiency in Adult Cardiac Surgery Patients

Preoperative anemia is common in patients presenting for cardiac surgery, with a prevalence of approximately 1 in 4, and has been associated with worse outcomes including increased risk of blood transfusion, kidney injury, stroke, infection, and death. Iron deficiency, a major cause of anemia, has also been shown to have an association with worse outcomes in patients undergoing cardiac surgery, even in the absence of anemia. Although recent guidelines have supported diagnosing and treating anemia and iron deficiency before elective surgery, details on when and how to screen and treat remain unclear. The Eighth Perioperative Quality Initiative (POQI 8) consensus conference, in conjunction with the Enhanced Recovery after Surgery-Cardiac Surgery Society, brought together an international, multidisciplinary team of experts to review and evaluate the literature on screening, diagnosing, and managing preoperative anemia and iron deficiency in patients undergoing cardiac surgery, and to provide evidence-based recommendations in accordance with Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria for evaluating biomedical literature.

Non-anemic iron deficiency predicts prolonged hospitalisation following surgical aortic valve replacement: a single-centre retrospective study

Background

Iron deficiency has deleterious effects in patients with cardiopulmonary disease, independent of anemia. Low ferritin has been associated with increased mortality in patients undergoing cardiac surgery, but modern indices of iron deficiency need to be explored in this population.

Methods

We conducted a retrospective single-centre observational study of 250 adults in a UK academic tertiary hospital undergoing median sternotomy for non-emergent isolated aortic valve replacement. We characterised preoperative iron status using measurement of both plasma ferritin and soluble transferrin receptor (sTfR), and examined associations with clinical outcomes.

Results

Measurement of plasma sTfR gave a prevalence of iron deficiency of 22%. Patients with non-anemic iron deficiency had clinically significant prolongation of total hospital stay (mean increase 2.2 days; 95% CI: 0.5–3.9; P = 0.011) and stay within the cardiac intensive care unit (mean increase 1.3 days; 95% CI: 0.1–2.5; P = 0.039). There were no deaths. Defining iron deficiency as a plasma ferritin < 100 µg/L identified 60% of patients as iron deficient and did not predict length of stay. No significant associations with transfusion requirements were evident using either definition of iron deficiency.

Conclusions

These findings indicate that when defined using sTfR rather than ferritin, non-anemic iron deficiency predicts prolonged hospitalisation following surgical aortic valve replacement. Further studies are required to clarify the role of contemporary laboratory indices in the identification of preoperative iron deficiency in patients undergoing cardiac surgery. An interventional study of intravenous iron targeted at preoperative non-anemic iron deficiency is warranted.

Intravenous iron supplement for iron deficiency in patients with severe aortic stenosis scheduled for TAVI Results of the IIISAS randomised trial

Aims

The aim of this trial was to evaluate whether intravenous iron could provide benefit beyond transcatheter aortic valve implantation (TAVI) in iron‐deficient patients with severe aortic stenosis.

Methods and results

In this randomised, placebo‐controlled, double‐blind, single‐centre trial, we enrolled patients with severe aortic stenosis and iron deficiency (defined as ferritin <100 µg/L, or 100–299 µg/L with a transferrin saturation <20%) who were evaluated for TAVI. Patients were randomly assigned (1:1) to receive intravenous ferric derisomaltose or placebo ∼3 months before TAVI. The primary endpoint was the between‐group, baseline‐adjusted 6‐min walk distance measured 3 months after TAVI. Secondary outcomes included quality of life, iron stores, hand grip strength, New York Heart Association (NYHA) class, and safety. Between January 2020 and September 2021, we randomised 74 patients to ferric derisomaltose and 75 patients to placebo. The modified intention‐to‐treat population comprised the 104 patients who completed the 6‐min walk test at baseline and 3 months after successful TAVI. Iron stores were restored in 76% of the patients allocated to iron and 13% of the patients allocated to placebo (p < 0.001). There was no difference in the baseline‐adjusted 6‐min walk distance between the two treatment arms (p = 0.82). The number of serious adverse events, quality of life, hand grip strength, and NYHA class did not differ between the treatment arms.

Conclusion

Treatment with intravenous iron did not provide clinical benefit beyond TAVI in iron‐deficient patients with severe aortic stenosis.

Clinical Trial Registration: ClinicalTrials.gov NCT04206228.

Influence of the degree of anaemia on the prognosis of older adults with heart failure (SPAN-HF study)

OBJECTIVE

To assess whether a sustained optimal haemoglobin value in the 3 months after admission for heart failure (HF) decompensation reduces morbidity and mortality during the 12 months after admission for acute HF.

PATIENTS AND METHOD

Retrospective study of the 1408 patients older than 65 years included in the RICA registry divided into 3 groups: no anaemia (group A), recovered anaemia (group B), and persistent anaemia (group C), according to haemoglobin levels on admission, and 3 months after discharge. Kaplan-Meier curves were constructed, comparing the groups using the log-rank test and a Cox regression model was performed to analyse survival.

RESULTS

578 (41.1%), 299 (21.2%) and 531 (37.7%) were included in groups A, B and C, respectively. We recorded a total of 768 deaths and readmissions. There were 23 (4%), 12 (4%) and 49 (9.2%), (p=.001) individuals who died due to HF and 154 (27%), 73 (24%) and 193 (36%) (P<.001) admissions for this pathology, respectively. Patients with persistent anaemia had a higher risk of death (RR 1.29, 95% CI 1.04-1.61, P=.024) or readmission (1.92, 95% CI 1.16-3, 19; P=.012) due to HF.

CONCLUSIONS

Persistent anaemia in the months after admission for HF increases morbidity and mortality in the subsequent year.