Systemic Immune-Inflammation Index Predicts Prolonged Mechanical Ventilation and Intensive Care Unit Stay After off-Pump Coronary Artery Bypass Graft Surgery: A Single-Center Retrospective Study

Abstract

Purpose: Coronary artery disease (CAD) is the primary cause of mortality in developing countries. Off-pump coronary artery bypass grafting (OPCAB) offers more upside in revascularization by preventing cardiopulmonary bypass trauma and minimizing aortic manipulation. Even though cardiopulmonary bypass is not involved, OPCAB still causes a significant systemic inflammatory response. This study determines the prognostic values of the systemic immune-inflammation index (SII) towards perioperative outcomes in patients who underwent OPCAB surgery.

Patients and methods: This was a single-center retrospective study at the National Cardiovascular Center Harapan Kita, Jakarta, using secondary data from electronic medical records and medical record archives of all patients who underwent OPCAB from January 2019 through December 2021. A total of 418 medical records were obtained, and 47 patients were excluded based on the exclusion criteria. The values of SII were calculated from preoperative laboratory data of segmental neutrophil count, lymphocyte count, and platelet count. Patients were divided into two groups based on the SII cutoff value of 878.056 x 10³/mm³.

Results: The baseline SII values of 371 patients were calculated, among which 63 (17%) patients had preoperative SII values of ≥878.057 x 10³/mm³. High SII values were a significant predictor of prolonged ventilation (RR 1.141, 95% CI 1.001-1.301) and prolonged ICU stay (RR 1.218, 95% CI 1.021-1.452) after OPCAB surgery. A positive correlation was observed between SII and hospital length of stay after OPCAB surgery. From the receiver operating characteristic curve analysis, SII predicted prolonged ventilation duration, with an area under the curve of 0.658 (95% CI 0.575-0.741, p = 0.001).

Conclusion: High preoperative SII values are capable of predicting prolonged mechanical ventilation and intensive care unit stay after OPCAB surgery.

Keywords: intensive care unit stay; mechanical ventilation; off-pump coronary artery bypass graft; systemic immune-inflammation index; systemic inflammation.