Preoperative anemia in elective cardiac surgery: prevalence, risk factors, and influence on postoperative outcome

Abstract

Keywords• allogeneic blood transfusion • cardiac surgery • postoperative outcome • preoperative anemia S U M M A R YPreoperative anemia in patients undergoing cardiac surgery is associated with a higher transfusion risk and poorer outcomes. This retrospective study was undertaken to assess the prevalence of preoperative anemia and its associated risk factors, as well as its influence on postoperative outcomes, in 576 patients undergoing elective cardiac surgery (52.3% with cardiopulmonary bypass) for myocardial revascularization, valve replacement, coronary + valve, or miscellaneous pathology at a single institution. Perioperative data were reviewed according to the presence or absence of preoperative anemia (hemoglobin < 13 g/dL for men, hemoglobin < 12 g/dL for women). Overall, 210 patients (36.5%) presented with anemia. Logistic regression analysis revealed that age, chronic kidney disease, and consumption of proton pump inhibitors histamine H 2 receptor antagonists and diuretics were independent risk factors for the presence of preoperative anemia. Postoperatively, anemic patients received transfusions and inotropic support and stayed longer than 4 days in the recovery unit more frequently than non-anemic patients, but there were no differences in the composite outcome variable (stroke, myocardial infarction, renal failure or death). In conclusion, our data seem to indicate that preoperative anemia has a high prevalence among elective cardiac surgical patients and increases postoperative morbidity. Therefore, we need to address two specific areas about preoperative anemia in these patients: early recognition and evaluation, and appropriate and timely treatment.

Meta-analysis of the association between preoperative anaemia and mortality after surgery

“…Characteristics of the included studies are summarized in Table . A total of 949 445 patients were included, and all 24 studies reported the primary outcome of 30‐day or in‐hospital mortality.…”

“…However, stroke and myocardial infarction were reported as an outcome only in studies of patients undergoing cardiac surgery ( Table ). A haemoglobin definition was used in 17 studies, a haematocrit definition in six studies, and both definitions were used in one study. Definitions of anaemia ranged from a haemoglobin concentration of 11 to 12 g/dl or a haematocrit of 30–39 per cent for female patients, and from 11 to 14 g/dl or 30–39 per cent respectively for male patients.…”

“…Cladellas et al 22 Munoz et al 31 Boening et al 21 Ranucci et al 34 Zhang et al 41 Total more frequent amongst anaemic patients (15 804 (18⋅5 per cent) in anaemic groups versus 9539 (4⋅7 per cent) in non-anaemic groups; OR 5⋅04, 4⋅12 to 6⋅17; I 2 = 96 per cent; P < 0⋅001) ( Fig. S2, supporting information).…”

“…When restricted to the 13 studies reporting the WHO definition, 21 322 (29⋅9 per cent) of 71 338 patients were anaemic. Thirteen studies reported the incidence of allogeneic red cell transfusion ( 26 Cladellas et al 22 Wu et al 40 Bell et al 20 Beattie et al 19 Melis et al 30 De Santo et al 23 Shirzad et al 37 Munoz et al 31 Musallam et al 32 Boening et al 21 Vochteloo et al 39 Hung et al 28 Dubljanin-Raspopovic et al 24 Greenky et al 25 Ranucci et al 34 Oshin and Torella 33 Saager et al 35 Gupta et al 27 van Straten et al 38 Seicean et al 36 Jung et al 29 Zhang et al 41 Baron et al 5 Total Heterogeneity: τ 2 = 0·24; χ 2 = 768·79, 22 d.f., P < 0·001; I 2 = 97% Test for overall effect: Z = 8·88, P < 0·001 Cladellas et al 22 Bell et al 20 De Santo et al 23 Munoz et al 31 Musallam et al 32 Boening et al 21 Ranucci et al 34 Zhang et al Cladellas et al 22 Bell et al 20 De Santo et al 23 Munoz et al 31 Boening et al 21 Ranucci et al 34 Total Heterogeneity:…”

Tolerance of intraoperative hemoglobin decrease during cardiac surgery

“…Anemia is a recognized risk factor for operative mortality; additionally serious and invalidating postoperative morbidity like stroke, myocardial infarction, and renal failure have been described. [1][2][3][4] Transfusions with red blood cells (RBCs) serve to prevent the occurrence of anemia-related complications, but have also been associated with severe side effects. 5,6 Therefore, it is sometimes unclear whether an anemic patient will benefit from a RBC transfusion or not.…”