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]; P = .004), chronic obstructive pulmonary disease (26.9% [60/223] vs 14.1% [157/1112]; P < .001), peripheral vascular disease (11.7% [26/223] vs 7.3% [81/1112]; P = .04), and renal disease (37.2% [83/223] vs 12.3% [137/1112]; P < .001). The incidence of MAE was higher in the high-NLR cohort (11.7% [26/223] vs 5.8% [64/1112]; P = .002). Median follow-up was 10.6 years (95% confidence interval [CI], 9.9-11.6 years). Ten-year survival was lower in high-NLR cohort (52.7% [95% CI, 46%-60.5%] vs 71.3% [95% CI, 68.2%-74.5%]). On multivariate analysis, NLR was associated with increased risk of MAE (odds ratio, 1.04; 95% CI, 1.00-1.07; P = .02) and all-cause mortality (hazrd ratio, 1.03; 95% CI, 1.02-1.05; P < .001).

CONCLUSIONS

Preoperative NLR was associated with increased risk of morbidity and all-cause mortality independent of comorbidities following cardiovascular surgery with DHCA.