Moderate-to-Severe Preoperative Anemia is Associated with Increased Postoperative Myocardial Infarction and Mortality in Patients Undergoing Transcarotid Artery Revascularization.

Background: While preoperative anemia is prevalent among surgical patients, its impact on patients undergoing transcarotid artery revascularization (TCAR) remains poorly understood. This study aims to assess the relationship between the severity of preoperative anemia and outcomes following TCAR.

Methods: A retrospective analysis of the Vascular Quality Initiative database (2016-2021) was performed to identify patients who underwent TCAR for carotid stenosis. Anemia was defined according to World Health Organization guidelines as a hemoglobin (Hb) level <12 g/dL in females and <13 g/dL in males. The severity of anemia was further classified as mild (Hb: 10-11.9 g/dL in females and 11-12.9 g/dL in males) or moderate to severe (Hb < 10 g/dL in females and <11 g/dL in males). Patients were stratified into three cohorts as follows, based on the presence and severity of preoperative anemia: no anemia, mild anemia, and moderate-to-severe anemia. The primary outcome was 30-day mortality. Secondary outcomes included in-hospital stroke, in-hospital death, myocardial infarction (MI), and prolonged postoperative hospitalization (>1 day). Univariable and multivariable logistic regression analyses were conducted to evaluate the association between the severity of preoperative anemia and clinical outcomes.

Results: Among 21,648 patients who underwent TCAR, 4,240 (19.8%) had mild anemia, and 3,401 (15.8%) had moderate-to-severe anemia preoperatively. After adjusting for relevant clinical factors and confounders, moderate-to-severe preoperative anemia was associated with significantly increased odds of in-hospital MI (adjusted odds ratio [aOR], 2.39; 95% confidence interval [CI]: 1.53-3.74; P < 0.001), in-hospital death (aOR, 2.65; 95% CI: 1.62-4.34; P < 0.001), and 30-day mortality (aOR, 1.89; 95% CI: 1.32-2.72; P < 0.001) compared to nonanemic patients. Among patients with moderate-to-severe anemia, factors such as a history of chronic obstructive pulmonary disease (COPD) or congestive heart failure (CHF), urgent or emergent procedures, and symptomatic carotid stenosis were the strongest predictors of 30-day mortality. In contrast, mild anemia was not associated with increased odds of adverse postoperative outcomes compared to the nonanemic cohort. Preoperative anemia, regardless of severity, was not associated with an increased risk of postoperative stroke following TCAR. However, the severity of preoperative anemia was associated with a stepwise increase in the adjusted odds of prolonged hospitalization (aOR, 1.19 [mild anemia] and 1.57 [moderate-to-severe anemia]).

Conclusion: In this multi-institutional retrospective study of patients undergoing TCAR, moderate-to-severe preoperative anemia was independently associated with higher adjusted odds of in-hospital MI, in-hospital death, and 30-day mortality, without an increased risk of postoperative stroke. These findings highlight moderate-to-severe preoperative anemia as a potential independent prognostic marker for identifying high-risk patients. Furthermore, incorporating the severity of anemia into preoperative risk stratification may aid in tailoring perioperative cardiac assessment and optimization strategies, potentially mitigating the risk of adverse outcomes following TCAR.