Management of Perioperative Iron Deficiency in Cardiac Surgery: A Modified RAND Delphi Study

Nonanemic Iron Deficiency in Cardiac Surgery: A Retrospective Observational Study

OBJECTIVES

Anemia and iron deficiency in patients having cardiac surgery increases their perioperative risk. Nonanemic iron deficiency (NAID) in this group is less well-described. We aimed to investigate the incidence and outcomes of patients with NAID undergoing cardiac surgery.

DESIGN

Retrospective observational study.

SETTING

A single, tertiary referral center.

PARTICIPANTS

Adult patients who were preassessed and underwent cardiac surgery during the study period had data collected. We enrolled 537 patients enrolled and divided them into 4 groups according to hemoglobin and ferritin: NAID, nonanemic iron replete, iron-deficiency anemia (IDA), and non-iron-deficiency anemia.

INTERVENTIONS

This study was not interventional, but assessed the impact of anemia and iron deficiency on patient outcomes.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the incidence of NAID. Secondary outcomes included the number of patients who became anemic awaiting surgery, allogeneic transfusion burden, length of stay, postoperative complications, and death. 179 of 537 patients (33.3%) had NAID. Seventeen patients (9.5%) became anemic in the NAID group compared with 7 (3.3%) in the nonanemic iron replete group while awaiting for surgery (p = 0.02). Patients with NAID were more likely to receive allogeneic transfusions (33% vs 23%; p = 0.04) and had poorer recovery of hemoglobin at follow-up (13.2 ± 1.46 g/dL vs 13.9 ± 1.46 g/dL; p < 0.001).

CONCLUSIONS

NAID is common and can lead to progression to anemia and increased transfusion. Iron replacement should be considered in patients with NAID in the preoperative setting. A prospective interventional trial is required to demonstrate the benefit of being iron replete.

Implementing a Preoperative Anemia Optimization Protocol for Cardiovascular Surgery Patients: A Quality Improvement Project

BACKGROUND

Patients with anemia have poorer outcomes following cardiac surgery than do those without anemia. To improve outcomes, the Enhanced Recovery After Surgery cardiac recommendations include optimizing patients' condition, including treating anemia, before surgery.

LOCAL PROBLEM

Despite implementing Enhanced Recovery After Surgery initiatives, a midwestern cardiothoracic surgery group recognized a care gap in preoperative patients with anemia. No standardized protocol was in use.

METHODS

An anemia optimization protocol was developed for perioperative care of patients with anemia. Data from retrospective medical record review were analyzed to determine relationships between protocol use and secondary outcomes. The protocol was created using best evidence and expert consensus. Cardiac surgery and hematology specialists revised the protocol and agreed on a final version. The protocol was integrated into the consultation process for cardiac surgery patients.

RESULTS

During the implementation period, 23 of 55 patients with anemia (42%) received interventions via the anemia optimization protocol. The mean quantity of packed red blood cells transfused perioperatively per patient was 1.9 U in the protocol group and 3.5 U in the nonprotocol group. In the subgroup of patients experiencing postoperative acute kidney injury, the mean increase in creatinine level was 0.65 mg/dL in the protocol group and 1.52 mg/dL in the nonprotocol group. Four patients in the protocol group (17%) and 6 patients in the nonprotocol group (19%) experienced postoperative acute kidney injury.

CONCLUSION

Preoperative anemia is associated with poorer cardiac surgical outcomes. Incorporating the anemia optimization protocol into practice may mitigate the risk of postoperative complications for patients with anemia. Continued use of the protocol is recommended.

Executive summary of the consensus document on the management of perioperative anemia in Spain

Perioperative anemia is an independent risk factor for postoperative morbidity and mortality. However, conceptual, logistical and administrative barriers persist that hinder the widespread implementation of protocols for their management. The project coordinator convened a multidisciplinary group of 8 experienced professionals to develop perioperative anemia management algorithms, based on a series of key points (KPs) related to its prevalence, consequences, diagnosis and treatment. These KPs were assessed using a 5-point Likert scale, from "strongly disagree [1]" to "strongly agree [5]". For each KP, consensus was reached when receiving a score of 4 or 5 from at least 7 participants (>75%). Based on the 36 KPs agreed upon, diagnostic-therapeutic algorithms were developed that we believe can facilitate the implementation of programs for early identification and adequate management of perioperative anemia, adapted to the characteristics of the different institutions in our country.

Prevention and Management of Iron Deficiency/Iron-Deficiency Anemia in Women: An Asian Expert Consensus

The lack of standardized clinical practice impeding the optimal management of iron deficiency (ID) and iron deficiency anemia (IDA) in women is a global concern, particularly in the Asia-Pacific region. The aim of this study was to determine best practices through a Delphi consensus process. In Round 1, panelists were asked to rate their level of agreement with 99 statements across four domains: identification, diagnosis and assessment, prevention, and treatment of ID/IDA in women. In Round 2, panelists reappraised their ratings in view of the collective feedback and responses to Round 1. After two rounds, consensus (≥85% agreement) was reached for 84% of the Delphi statements. Experts agreed on the role of presenting symptoms and risk factors in prompting assessments of anemia and iron status in women. Experts repeatedly called for prevention, recommending preventive iron supplementation for pregnant women irrespective of anemia prevalence levels, and for non-pregnant adult women, adolescent girls, and perimenopausal women living in areas with a high prevalence of anemia. Experts unanimously agreed to prescribing oral ferrous iron as first-line therapy for uncomplicated ID/IDA. The recommendations and clinical pathway algorithms generated should be used to inform clinical practice and standardize the care of women at risk or presenting with ID/IDA in the Asia-Pacific region.

Single shot of intravenous iron in cardiac surgery: The ICARUS study

BACKGROUND

Iron deficiency (ID), with or without anemia, is commonly observed among patients scheduled for cardiac surgery. We investigated if screening ID in the immediate preoperative period and treating ID patients regardless of anemia could reduce perioperative transfusion requirements.

METHODS

This is an observational single-center propensity score-matched study including candidates to elective cardiac surgery prospectively and retrospectively enrolled. Prospectively enrolled patients were screened for ID at hospital admission: if ferritin was ≤100 μg/L or ≤ 300 μg/L with transferrin saturation index ≤20% they received intravenous ferric carboxymaltose, B12-vitamin, and folic acid. A retrospective series of patients not screened for ID and matched for gender, type of surgery, BMI, Goudie transfusion risk score, hemoglobin level, and red blood cell (RBC) indices, served as controls. The primary outcome was the proportion of patients requiring ≤1 packed RBC (pRBC) unit within day 7 or discharge The main secondary outcomes were intraoperative and postoperative pRBC transfusions, duration of hospitalization, and cost-effectiveness of ID screening and treatment.

RESULTS

We included 479 prospective and 833 retrospective cases: 442 patients screened for ID and 442 matched controls with unknown iron status were analyzed. ID was observed in 196 patients (44.3%) and iron was administered 1 day (IQR 1-2) before surgery. Overall, 76.9% of patients in the prospective group and 69.7% of controls received ≤1 pRBC transfusion (p = 0.014). The risk for multiple transfusions was lower in patients screened for ID (OR 0.689, 95% CI 0.510-0.930). Despite similar Hb levels at day 7, patients in the prospective group received fewer postoperative pRBC transfusions (p < 0.001) and had a shorter hospital length of stay (p < 0.001). Globally, hospitalization costs were lower in patients screened and treated for ID.

CONCLUSIONS

Short-term pre-operative iron therapy is associated with a reduction in postoperative transfusions in anemic and non-anemic ID cardiac surgery patients and has a favorable impact on hospitalization costs.

CLINICAL TRIAL REGISTRATION

NCT04744181.

The efficacy of intravenous iron for treatment of anemia before cardiac surgery: An updated systematic review and meta-analysis with trial sequential analysis

BACKGROUND

Preoperative anemia is common in patients undergoing cardiac surgery with various etiologies, among which iron deficiency is the leading cause. However, the benefit of intravenous (IV) iron for the treatment of anemia before cardiac surgery is uncertain. This updated meta-analysis aimed to evaluate the efficacy of IV iron in adult cardiac surgery patients with preoperative anemia.

METHODS

This review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched Embase, PubMed and the Cochrane Central Register of Controlled Trials to identify eligible randomized controlled trials (RCTs) and observational studies. Quality was assessed using the Cochrane Collaboration risk of bias tool and Newcastle-Ottawa scale, and the strength of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) criteria. Trial sequential analysis was performed on the primary outcome (transfusion rate) to confirm whether firm evidence was reached.

RESULTS

Six RCTs (936 patients) and 5 observational studies (1350 patients) were included in this meta-analysis. The IV iron group and the control group were comparable in terms of transfusion rate [55.1% vs 60.9%, risk ratio (RR) = 0.91, 95% confidence interval (CI) 0.81-1.03, P = 0.13, low quality]. There were no significant differences in units transfused per patient, ICU stay and hospital length of stay between the two groups. And pooled data showed a benefit of IV iron compared to the control group on mortality (2.76% vs 3.75%, RR = 0.58, 95% CI 0.36-0.95, P = 0.03, moderate quality) and no mortality reduction existed when including only RCTs.

CONCLUSIONS

This meta-analysis suggested that IV iron treatment for patients with anemia before cardiac surgery did not reduce the transfusion requirement (low quality), but it was associated with decreased mortality (moderate quality). More large-scale, high-quality randomized clinical trials are warranted to confirm or refute our findings. PROSPERO registry reference: CRD42022331875.

Iron deficiency in cardiac surgical patients

Iron is an essential element and involved in a variety of metabolic processes including oxygen transport, cellular energy production, energy metabolism of heart muscles, brain function, cell growth and cell differentiation. Preoperative anaemia is an independent risk factor for poor outcome. Recently, iron deficiency was considered only in the context of anaemia. However, negative consequences of iron deficiency in the absence of anaemia have been described for patients undergoing cardiac surgery. To date, the benefit of intravenous iron supplementation in these patients has been controversially debated. In this review, we discuss the latest progress in studies of intravenous iron supplementation in iron deficient cardiac surgical patients.

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.

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.

Effect of iron deficiency without anaemia on days alive and out of hospital in patients undergoing valvular heart surgery

Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml^-1 or < 300 ng.ml^-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127-141 [120-172]) g.l^-1 , 143 (133-150 [120-179]) g.l^-1 , p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77-82 [9-85]) days vs. 81 (79-83 [0-85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.