1.
Preoperative anemia and outcomes in cardiovascular surgery: systematic review and meta-analysis
Padmanabhan H, Siau K, Curtis J, Ng A, Menon S, Luckraz H, Brookes MJ
The Annals of thoracic surgery. 2019
Abstract
BACKGROUND Pre-operative anemia is common in patients scheduled for cardiac surgery. However, its effect on postoperative outcomes remains controversial. This meta-analysis aimed to clarify the impact of anemia on outcomes following cardiac surgery. METHODS A literature search was conducted on MEDLINE, Embase, Cochrane, and Web of Science databases. The primary outcome was 30-day postoperative or in-hospital mortality. Secondary outcomes included acute kidney injury (AKI), stroke, blood transfusion, and infection. A meta-analytic model was used to determine the differences in the above postoperative outcomes between anemic and non-anemic patients. RESULTS Out of 1103 studies screened, 22 met the inclusion criteria. A total of 23624 (20.6%) out of 114277 patients were anemic. Anemia was associated with increased mortality (odds ratio [OR] 2.74, 95% confidence interval [CI] 2.32-3.24; I(2)=69.6%; p<0001), AKI (OR 3.13, 95% CI 2.37-4.12; I(2)=71.1%; p<0001), stroke (OR 1.46, 95% CI 1.24-1.72; I(2)=21.6%; p<0001), and infection (OR 2.65, 95% CI 1.98-3.55; I(2)=46.7%; p<0001). More anemic patients were transfused than non-anemic (33.3 versus 11.9%). No statistically significant association was found between mortality and blood transfusion (OR 1.35, 95% CI 0.92-1.98; I(2)=83.7%; p=0.12) but we were not able to compare mortality with or without transfusion in those who were or were not anemic. CONCLUSIONS Preoperative anemia is associated with adverse outcomes following cardiac surgery. These findings support the addition of preoperative anemia to future risk prediction models, and as a target for risk modification.
2.
Intravenous iron does not effectively correct preoperative anaemia in cardiac surgery: a pilot randomized controlled trial
Padmanabhan H, Siau K, Nevill AM, Morgan I, Cotton J, Ng A, Brookes MJ, Luckraz H
Interactive Cardiovascular and Thoracic Surgery. 2018
Abstract
OBJECTIVES Preoperative anaemia is a strong predictor of blood transfusion requirements and must be assessed for appropriate optimization before elective surgery. Iron therapy is a transfusion-sparing approach effective for increasing haemoglobin concentrations. However, its role in elective cardiac surgery and the optimal route of administration remain unknown. This single-centre, non-blinded, randomized, controlled trial compared the effectiveness of intravenous ferric carboxymaltose therapy with oral iron for anaemic patients undergoing elective cardiac surgery. METHODS Fifty anaemic patients scheduled for elective cardiac surgery were randomized to receive either oral or intravenous iron therapy 3-8 weeks preoperatively. Changes in haemoglobin concentration were measured. Blood transfusion and postoperative outcome data were collected. RESULTS Preoperative median increases in haemoglobin were 1.0 g/l (interquartile range -3.25 to 7.25 g/l) and 3.0 g/l (interquartile range -1.25 to 6.25 g/l) for patients receiving intravenous and oral iron, respectively (P = 0.42). The median first 12-h blood loss was significantly higher in the intravenous group (655 ml; interquartile range 162-1540 ml) compared to the oral group (313 ml; interquartile range 150-1750 ml; P < 0.007). Median increments in serum ferritin were superior for the intravenous group (median difference 313 microg/l; interquartile range 228-496) compared to the oral group (median difference 5.5 microg/l; interquartile range -1.4 to 19.4; P < 0.001). CONCLUSIONS Increases in ferritin after intravenous iron administration were significantly greater than those after oral iron administration. There was no significant difference in haemoglobin increments between groups. Despite significantly higher intraoperative blood loss in the group receiving intravenous iron, blood transfusion requirements for both groups were not statistically different. Clinical trial registration: ISRCTN22158788.