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Time-Dependent Changes in NLR, PLR, SII, and SIRI During Intraoperative Cardiopulmonary Bypass in CABG Patients and
Burak Toprak1, Abdulkadir Bilgiç2, Rahime Akın2
1Department of Cardiovascular Surgery, Mersin City Education and Research Hospital, 33240 Mersin, Turkey.
Insights
Early intraoperative inflammatory indices, particularly the systemic immune-inflammation index (SII) and systemic inflammatory response index (SIRI), predict mortality in coronary artery bypass grafting patients. These composite markers show promise for risk stratification during cardiopulmonary bypass.
Area of Science:
- Cardiovascular Surgery
- Inflammation Research
- Medical Diagnostics
Background:
- Systemic inflammation impacts outcomes in coronary artery bypass grafting (CABG) patients.
- Traditional inflammatory markers (neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio) have prognostic value but their intraoperative dynamics are unclear.
- Comprehensive indices like systemic immune-inflammation index (SII) and systemic inflammatory response index (SIRI) may offer better early characterization of inflammation.
Purpose of the Study:
- To evaluate the prognostic relevance of intraoperative inflammatory indices during cardiopulmonary bypass in CABG patients.
- To compare the predictive performance of traditional and composite inflammatory indices for in-hospital mortality.
- To assess the potential of early intraoperative inflammatory markers for perioperative risk stratification.
Main Methods:
- Retrospective nested case-control study of 245 isolated CABG patients.
- Calculation of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), SII, and SIRI at multiple intraoperative time points.
- Univariate and multivariable logistic regression, and ROC curve analysis to assess associations with in-hospital mortality.
Main Results:
- Inflammatory indices, especially at the 5th minute of cardiopulmonary bypass, were significantly higher in non-survivors (p < 0.001).
- SII (AUC=0.790) and SIRI (AUC=0.765) at 5 minutes demonstrated superior predictive performance compared to NLR and PLR.
- SII and SIRI at 5 minutes were independent predictors of mortality; SII improved a clinical model's predictive discrimination.
Conclusions:
- Early intraoperative inflammatory indices during cardiopulmonary bypass offer valuable prognostic information in CABG patients.
- Composite indices (SII, SIRI) show stronger exploratory predictive discrimination for mortality than traditional markers.
- Findings are hypothesis-generating and require prospective validation for clinical application in risk stratification.
Abstract:
Background: Systemic inflammation plays a central role in determining postoperative outcomes in patients undergoing isolated coronary artery bypass grafting with cardiopulmonary bypass. Traditional inflammatory indices such as the neutrophil-to-lymphocyte ratio and the platelet-to-lymphocyte ratio have prognostic value; however, their dynamic behavior during cardiopulmonary bypass remains insufficiently characterized. More comprehensive indices, including the systemic immune-inflammation index and the systemic inflammatory response index, may help characterize early intraoperative inflammatory activity; however, their prognostic relevance should be regarded as exploratory and requires prospective validation. Methods: This retrospective nested case-control study included 245 patients who underwent isolated coronary artery bypass grafting, and intraoperative inflammatory indices during cardiopulmonary bypass were evaluated. Because of the nested case-control design, mortality cases were intentionally overrepresented to improve statistical power; therefore, the observed mortality rate does not reflect the true institutional mortality rate. Inflammatory indices (NLR, PLR, SII, and SIRI) were calculated at induction, at the 5th, 45th, and 90th minutes during cardiopulmonary bypass, and in the early postoperative period. Associations between these indices and in-hospital mortality were evaluated using univariate and multivariable logistic regression analyses. Predictive performance was assessed using receiver operating characteristic (ROC) curve analysis and the area under the curve (AUC). Results: The final enriched analytical sample consisted of 51 mortality cases and 194 randomly sampled surviving controls. During cardiopulmonary bypass, inflammatory indices, particularly at the 5th minute, were significantly higher in patients who experienced mortality (p < 0.001 for all major indices). SII demonstrated the strongest predictive performance at the 5th minute (AUC = 0.790), followed by SIRI (AUC = 0.765), PLR (AUC = 0.687), and NLR (AUC = 0.681). In multivariable analysis, SII and SIRI measured at the 5th minute remained independent predictors of mortality. The addition of 5th-minute SII to the limited study-specific clinical model, which included age, ejection fraction, and preoperative creatinine, improved exploratory discrimination for in-hospital mortality (with AUC increasing from 0.698 to 0.797). Conclusions: Early intraoperative assessment of inflammatory indices during cardiopulmonary bypass may provide additional prognostic information in patients undergoing coronary artery bypass grafting. Composite indices, particularly SII and SIRI, showed stronger exploratory discrimination than traditional inflammatory markers in this enriched analytical sample. However, these findings should be considered hypothesis-generating and require prospective external validation before use in perioperative risk stratification or clinical decision-making can be recommended.
