Role of Preoperative Intravenous Iron Therapy to Correct Anemia before Major Surgery

• Author / Creator

  Elhenawy, Abdelsalam

• In patients undergoing elective major surgery, preoperative anemia is a common morbidity that may necessitate allogeneic blood transfusion in a substantial proportion of patients depending on the degree of anemia. Allogeneic blood transfusion has potential adverse outcomes. Preoperative intravenous iron (IV) monotherapy has been recommended as a bloodless therapy to decrease perioperative blood transfusion; however, class 1A evidence is lacking due to the absence of meta-analysis and systematic reviews, and high quality randomized controlled trials. The aim was to evaluate the efficacy and safety of preoperative IV monotherapy injection versus placebo/oral iron (standard of care) as a strategy to increase the hemoglobin concentration to minimize the necessity of blood transfusion. Therefore, this systematic review and meta-analysis of the randomized controlled trials was conducted. The results of the meta-analysis study in this thesis showed that preoperative IV supplementation was found to be effective in decreasing allogeneic blood transfusion by 17% in patients who received IV iron therapy compared to who did not receive it. This reduction in transfusion rate was statistically significant (risk ratio [RR]: 0.83, 95% confidence interval [CI]: 0.70, 0.98, p = 0.03). Concomitantly, pre-operative iron therapy was also associated with increases in the hemoglobin concentrations prior to surgery compared with not receiving pre-operative IV iron therapy (mean difference [MD] between the study groups: 6.65, 95% CI: 0.83, 12.47 g/L, p = 0.03). Because some of the trials started administration of IV iron 3-4 weeks before surgery and some studies started the IV injection 1-2 days before surgery, the hemoglobin rise showed a bi-phasic pattern with the first wave appeared before surgery and the second wave existed 4 weeks after surgery. Moreover, the blood loss perioperatively interrupted this hemoglobin concentration growth throughout the hospital stay. As a follow-up > 4 weeks postoperatively, the second wave existed and the hemoglobin level increased significantly again in favor of the IV group (6.46, 95% CI: 3.11, 9.80 g/L, p = 0.0002) indicating an augmented/new effect of the injected IV iron later by the other trials. Intravenous iron administration was able to restore the depleted iron stores and increased serum ferritin levels significantly pre-surgery, at hospital discharge, and > 4 weeks postoperatively, (MD between groups: 108.03, 95 % CI: 45.58, 170.49 ng/mL, p = 0.0007), (MD between groups: 547.77, 95 % CI: 36.61, 1058.94 ng/mL, p = 0.04), and (MD between groups: 391.00, 95 % CI: 271.44, 510.56 ng/mL, p < 0.00001), respectively. There were no differences in non-serious and serious adverse effects between the two groups (RR: 1.17, 95% CI: 0.80, 1.71, p = 0.42) and (RR: 0.89, 95% CI: 0.40, 1.99, p = 0.77) respectively. Similar results were obtained from the case series of the thesis where is IV iron treatment was capable to increase Hb level significantly from 125.70 ± 11 g/L at baseline to be 132.30 ± 16 g/L at the time of surgery with p = 0.007, with mean difference of 6.6 g/L (95% confidence interval [CI]: 2.00, 11.11 g/L). Moreover, depleted iron stores were restored, and serum ferritin level increased significantly from 25.43 ± 18.47 ng/mL at baseline to be 239.80 ± 18.47 ng/ml at surgery (p = 0.004). Allogeneic perioperative red blood cell transfusion occurred in 9 (29%) patients, which is lower than a recent Canadian report. Preoperative intravenous iron monotherapy is a safe and efficacious intervention. It successfully lowers the transfusion rate and increases hemoglobin concentration pre-surgery and at four weeks postoperatively. However, further randomized controlled trials are required to establish its effectiveness, potential adverse effects, and to show which intravenous iron preparation has better cost-effectiveness than the other preparations to reduce blood transfusion.

• Subjects / Keywords

  • Major surgery
  • Preoperative anemia
  • Intravenous iron therapy

• Graduation date

  Spring 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3MW28W1M

• License

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