The role of remnant cholesterol in patients with ST-segment elevation myocardial infarction.

Aims: Remnant cholesterol (RC) is the cholesterol content within triglyceride-rich lipoproteins. It promotes atherosclerotic cardiovascular disease beyond LDL cholesterol (LDL-C). The prognostic role of RC in patients with ST-segment elevation myocardial infarction (STEMI) is unknown. We aimed to estimate RC-related risk beyond LDL-C in patients with STEMI.

Methods and results: A total of 6602 consecutive patients with STEMI treated with primary percutaneous coronary intervention (PCI) from 1999 to 2016 were included. Remnant cholesterol was calculated as total cholesterol minus LDL-C minus HDL cholesterol. Adjusted Cox models were used to estimate the association between continuous RC levels and all-cause mortality, cardiovascular death, ischaemic stroke, and recurrent myocardial infarction (MI) at long-term (median follow-up of 6.0 years). Besides, discordance analyses were applied to examine the risk of the discordantly high RC (RC percentile rank minus LDL-C percentile rank > 10 units) compared with the discordantly low RC (LDL-C percentile rank minus RC percentile rank > 10 units). The concordance was defined as the percentile rank difference between RC and LDL-C ≤ 10 units. The median age of patients was 63 years [interquartile range (IQR) 54-72] and 74.8% were men. There were 2441, 1651, and 2510 patients in the discordantly low RC group, concordant group, and discordantly high RC group, respectively. All outcomes in the discordantly high RC group were higher than the other groups, and the event rate of all-cause mortality in this group was 31.87%. In the unadjusted analysis, the discordantly high RC was associated with increased all-cause mortality [hazard ratio (HR) 1.82, 95% confidence interval (CI) 1.63-2.04] and increased cardiovascular death (HR 1.79, 95% CI 1.55-2.06) compared with the discordantly low RC. In an adjusted model, RC was associated with higher all-cause mortality (HR 1.14, 95% CI 1.07-1.22). The discordantly high RC was associated with increased all-cause mortality (adjusted HR 1.55, 95% CI 1.37-1.75) and increased cardiovascular death (adjusted HR 1.47, 95% CI 1.25-1.72) compared with the discordantly low RC. There were no associations between RC and ischaemic stroke or recurrent MI.

Conclusion: In patients with STEMI treated with primary PCI, elevated RC levels beyond LDL-C and discordantly high RC were independently associated with increased all-cause mortality.