Introduction: The West of Scotland has one of the highest incidences of coronary artery disease in Europe due, in part, to poor diet. It was decided to assess the iron status of our patients as part of our blood use audit with a view to perioperative optimization of iron status. It was hoped not only to assess the proportion of our patients presenting for surgery who were iron deficient but also to assess if those patients had increased red cell requirements during their hospital stay or had lower discharge haemoglobin (Hb) or lower Hb at 6 weeks.
Method: All patients presenting for surgery in our unit have data collected for audit including demographic data, preoperative and discharge Hb, blood and blood product use whilst in hospital and Hb 6 weeks post discharge. Ferritin assay was added to our preoperative work-up and to the 6-week post discharge assessment.
Results: While the median ferritin level preoperatively was 117ngmL−1, 22% of patients had low (<30 ng mL−1) or borderline (31-50 ng mL−1) ferritin levels. Those with low ferritin levels preoperatively had significantly lower admission Hb (11.8 g dL−1) than those with normal levels (13.9 g dL−1) using Minitab statistical software; ANOVA where P < 0.05. Those with low or borderline ferritin were transfused more red cells and had lower discharge Hb than those with normal levels. Six weeks post discharge those with normal ferritin levels had significantly higher Hb (12.8 vs. 11.4g dL−1). The median post discharge ferritin had fallen to 48% of the initial value and almost half of patients now had low or borderline ferritin levels. Of those patients who we considered anaemic (<11.0g dL−1) at 6 weeks, 75% had low or borderline ferritin levels preoperatively.
Discussion: Currently less than 2% of our patients are discharged on iron replacement therapy, largely due to anticipated gastrointestinal upset. Previous work has suggested no benefit in postoperative iron therapy  but, in contrast to our findings, ferritin levels in their control group were within the normal range. Our data suggests that it may be worthwhile discharging all patients on iron, or at least those whose ferritin levels are low preoperatively. Where time permits, there may also be a case for preoperative iron therapy given the significant proportion of our patients who are iron deficient. Since these patients have lower admission Hb and higher red cell demands it may be possible to reduce red cell use.
1 Crosby L, Palarski VA, Cottington E, et al. Iron supplementation for acute blood loss anemia after coronary artery bypass surgery: a randomized, placebo-controlled study. Heart Lung