The Predictive Value of the Systemic Immune-Inflammation Index for Cardiovascular Events in Chronic Total Occlusion Patients Who Prior Coronary Artery Bypass Grafting.

Background: There is limited research on the long-term prognosis of percutaneous coronary intervention (PCI) in coronary chronic total occlusion (CTO) patients who have previously undergone coronary artery bypass grafting (CABG). Additionally, the prognostic value of a novel systemic immune inflammation index (SII) in this specific patient population remains unclear. Methods: To adjust for differences in baseline features and minimize bias, 335 pairs of patients with or without prior CABG undergone PCI were obtained after probability score matching (PSM) in a single-center cohort. The clinical characteristics were collected, and the primary outcomes were major cardiovascular events (MACE), which included all-cause death, nonfatal MI and unplanned revascularization, were recorded during the follow-up period after discharge. The group with prior CABG were divided according to the median level of SII: Lower SII group (SII ≤ 570.10, N = 167) and higher SII group (SII ≥ 570.10, N = 168). Results: The SII values were significantly higher in the prior CABG group than in the without prior CABG group [570.10 (444.60, 814.12) vs 519.65 (446.86, 565.84), P < 0.001, respectively]. The survival Kaplan-Meier analysis showed that patients with prior CABG was significantly associated with a higher risk of MACE than patients without prior CABG (P = 0.016) in the long-term follow-up. As SII levels increased, the cumulative risk of MACE became significantly higher in the patients with prior CABG (P = 0.023) stratified by the median value of SII. The Cox proportional hazards regression model analysis indicated that the level of SII (hazard ratio = 2.035, 95% CI, 1.103-3.753, P = 0.023) emerged as independent predictors of MACE. The restricted cubic spline (RCS) analysis illustrated that the HR for MACE increased with increasing SII. Conclusion: SII is a reliable predictor of long-term cardiovascular events after PCI in CTO patients with prior CABG, suggesting that SII may be helpful in identifying high-risk patients who need more aggressive treatment and follow-up strategies.