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.
Competing Interests: Conflict of Interest Statement N.A. reported AtriCure consultant, Medtronic speaker, LivaNova consultant, VGS advisory board, CardioSight advisory board, and Left Atrial Appendage Occlusion LLC co-founder. N.B.H. reported Octapharma scientific advisory board. All other authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.
(Copyright © 2023 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)