Remnant cholesterol and residual ischemic risk after percutaneous coronary intervention: a 10-year real-world cohort study

Background Remnant cholesterol (RC), reflecting the cholesterol content of triglyceride-rich lipoproteins, has been implicated in residual atherosclerotic risk. However, data regarding its prognostic significance in patients undergoing percutaneous coronary intervention (PCI) remain limited, particularly concerning the differentiation between ischaemic and fatal outcomes over the long term. Purpose This study aimed to evaluate the association between baseline RC and 10-year clinical outcomes in a large Chinese PCI cohort and to assess its incremental predictive value beyond conventional risk factors. Methods This retrospective cohort study analysed 9,095 consecutive patients undergoing PCI at the Hospital in 2013. Individuals with extreme lipid outliers were excluded. The primary endpoint was major adverse cardiac and cerebrovascular events (MACCE), defined as a composite of all-cause death, cardiac death, myocardial infarction (MI), repeat revascularisation, and stroke. Results During a median follow-up of 10.4 years, 3,450 (37.9%) MACCE occurred. Multivariable Cox regression analysis demonstrated that the highest RC quartile was associated with a significantly elevated risk of MACCE compared with the lowest quartile (adjusted hazard ratio [HR] 1.22, 95% confidence interval [CI] 1.10–1.34; P < 0.001). Notably, elevated RC was strongly associated with recurrent ischaemic events, including incident MI (HR 1.37, 95% CI 1.11–1.69) and repeat revascularisation (HR 1.19, 95% CI 1.05–1.36). Conversely, no significant independent association was identified between RC and all-cause mortality (P = 0.060) or cardiac death (P = 0.390) in the fully adjusted model. Subgroup analyses indicated a robust risk association, particularly in patients presenting with acute coronary syndrome. Furthermore, adding RC to the conventional risk model significantly improved risk reclassification (net reclassification improvement: 0.042, P = 0.010). Conclusion(s) In this large cohort of PCI patients with extended follow-up, elevated baseline RC levels were independently associated with long-term ischaemic events, specifically MI and revascularisation, but not with fatal outcomes. These findings highlight the importance of RC as a distinct marker for residual ischaemic risk and suggest that it provides incremental prognostic value beyond established risk factors.