Showing up for cardiac surgery with enough red blood cells

Unexpected impact of preoperative anemia in low-risk isolated coronary artery bypass grafting or single-valve surgical patients: Do not overlook these patients in anemia management!

OBJECTIVE

Preoperative anemia is prevalent in cardiac surgery and independently associated with increased risk for short-term and long-term mortality. The purpose of this study was to examine the effect of preoperative hematocrit (Hct) on outcomes in cardiac surgical patients and whether the effect is comparable across levels of Society of Thoracic Surgeons Predicted Risk of Mortality (STS PROM).

METHODS

The study consisted of adult, isolated coronary artery bypass grafting (CABG) or single-valve surgical patients in a statewide registry from 2011 to 2022 (N = 29,828). Regressions were used to assess effect of preoperative Hct on STS-defined major morbidity/mortality including the interaction of Hct and STS PROM as continuous variables.

RESULTS

Median age was 66 years (58-73 years), STS PROM was 1.02% (0.58%-1.99%), and preoperative Hct was 39.5% (35.8%-42.8%). The sample consisted of 78% isolated CABG (n = 23,261), 10% isolated mitral valve repair/replacement (n = 3119), 12% isolated aortic valve replacement (n = 3448), and 29% were female (n = 8646). Multivariable analyses found that greater Hct was associated with reduced risk of STS-defined morbidity/mortality (odds ratio, 0.96; P < .001). These effects for Hct persisted even after adjustment for intraoperative blood transfusion. The interaction of Hct and STS PROM was significant for morbidity/mortality (odds ratio, 1.01; P < .001). There was a stronger association between Hct levels and morbidity/mortality risk in the patients with the lowest STS risk compared with patients with the greatest STS risk.

CONCLUSIONS

Patients with lower risk had a greater association between preoperative Hct and major morbidity and mortality compared with patients with greater risk. Preoperative anemia management is essential across all risk groups for improved outcomes.

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.