Association between preoperative neutrophil-to-lymphocyte ratio and outcomes after deep hypothermic circulatory arrest: A cohort study of 1300 patients.

Objective: To investigate the association between preoperative neutrophil-to-lymphocyte ratio (NLR) and outcomes following cardiovascular surgery with deep hypothermic circulatory arrest (DHCA). Methods: This was a retrospective analysis. All cardiovascular surgical procedures with DHCA between July 1997 and January 2025 were included. Maximally selected rank statistics identified the optimal NLR cutoff. This NLR cutoff was used for comparisons between high-NLR and low-NLR cohorts. Multivariable regression analysis assessed independent associations with outcomes. NLR was evaluated as a continuous variable to assess associations irrespective of derived cutoff. The primary outcome was the composite of in-hospital major adverse events (MAE), consisting of operative mortality, myocardial infarction, cerebrovascular accident, reexploration for bleeding, tracheostomy, and new postoperative dialysis. The secondary outcome was all-cause mortality. Results: Our analysis included 1335 patients, with 16.7% (223/1335) in the high-NLR cohort (≥6.22). The high-NLR cohort had increased incidence of smoking (62.8% [140/223] vs 52.1% [579/1112]; Conclusions: Preoperative NLR was associated with increased risk of morbidity and all-cause mortality independent of comorbidities following cardiovascular surgery with DHCA.