The residual risk of inflammation and remnant cholesterol in acute coronary syndrome patients on statin treatment undergoing percutaneous coronary intervention

Background Residual risk assessment for acute coronary syndrome (ACS) patients after sufficient medical management remains challenging. The usefulness of measuring high-sensitivity C-reactive protein (hsCRP) and remnant cholesterol (RC) in assessing the level of residual inflammation risk (RIR) and residual cholesterol risk (RCR) for risk stratification in these patients needs to be evaluated. Methods Patients admitted for ACS on statin treatment who underwent percutaneous coronary intervention (PCI) between March 2016 and March 2019 were enrolled in the analysis. The included patients were stratified based on the levels of hsCRP and RC during hospitalization. The primary outcome was ischemic events at 12 months, defined as a composite of cardiac death, myocardial infarction, or stroke. The secondary outcomes included 12-month all-cause death and cardiac death. Results Among the 5778 patients, the median hsCRP concentration was 2.60 mg/L and the median RC concentration was 24.98 mg/dL. The RIR was significantly associated with ischemic events (highest hsCRP tertile vs. lowest hsCRP tertile, adjusted hazard ratio [aHR]: 1.52, 95% confidence interval [CI]: 1.01-2.30, P = 0.046), cardiac death (aHR: 1.77, 95% CI:1.02-3.07, P = 0.0418) and all-cause death (aHR: 2.00, 95% CI: 1.24-3.24, P = 0.0048). The RCR was also significantly associated with these outcomes, with corresponding values for the highest tertile of RC were 1.81 (1.21-2.73, P = 0.0043), 2.76 (1.57-4.86, P = 0.0004), and 1.72 (1.09-2.73, P = 0.0208), respectively. The risks of ischemic events (aHR: 2.80, 95% CI: 1.75-4.49, P < 0.0001), cardiac death (aHR: 4.10, 95% CI: 2.18-7.70, P < 0.0001), and all-cause death (aHR: 3.00, 95% CI, 1.73-5.19, P < 0.0001) were significantly greater in patients with both RIR and RCR (highest hsCRP and RC tertile) than in patients with neither RIR nor RCR (lowest hsCRP and RC tertile). Notably, the RIR and RCR was associated with an increased risk of ischemic events especially in patients with adequate low-density lipoprotein cholesterol (LDL-C) control (LDL-C < 70 mg/dl) (P (interaction) =0.04). Furthermore, the RIR and RCR provide more accurate evaluations of risk in addition to the GRACE score in these patients [areas under the curve (AUC) for ischemic events: 0.64 vs. 0.66, P = 0.003]. Conclusion Among ACS patients receiving contemporary statin treatment who underwent PCI, high risks of both residual inflammation and cholesterol, as assessed by hsCRP and RC, were strongly associated with increased risks of ischemic events, cardiac death, and all-cause death.