Increased Interleukin-1β Levels Are Associated with Left Ventricular Hypertrophy and Remodelling Following Acute ST Segment Elevation Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention

Objectives: To assess the relationship between interleukin (IL)-1-related molecules, infarct size and left ventricular (LV) remodelling following acute myocardial infarction (MI).

Methods: Forty-two patients with first-time diagnosis of ST segment elevation MI (STEMI), with a single occluded vessel successfully revascularized by primary percutaneous coronary intervention (PCI), were recruited to this observational study conducted at a university teaching hospital and followed for 1 year.

Main Outcome Measures: Plasma levels of IL-1β, IL-1 receptor antagonist (IL-1Ra), IL-18 and caspase-1 were analysed before and 2 days, 1 week and 2 months after PCI. Serial cardiac magnetic resonance imaging (CMR) was used for the assessment of infarct size and LV remodelling. CMR findings at 1 year was the primary outcome variable.

Results: Univariate analysis showed that IL-1-related mediators were strongly (IL-1 β), moderately (caspase-1) and weakly (IL-1Ra) associated with impaired myocardial function and noninfarct mass, but not infarct size, 1 year after reperfused STEMI. In multivariate analyses, troponin T predicted LV ejection fraction (LVEF), infarct size and LV end-diastolic (LVEDVi) and end-systolic volume index (LVESVi). However, significant additional variance was explained by IL-1β, IL-18 and caspase-1. IL-1β levels at 2 months, IL-18 at 2 days and pre-PCI caspase-1 were predictors of LVEF. Caspase-1 and in particular IL-1β at 2 days were the only predictors of noninfarct mass. IL-1β and IL-18 at 2 days were predictors of LVEDVi, whilst pre-PCI levels of IL-1β contributed to prediction of LVESVi. By contrast, pro-B-type natriuretic peptide, C-reactive protein, IL-6 and transforming growth factor-β1 (TGF-β1) had no or only a weak (TGF-β1) association with these CMR parameters in multivariate analyses.

Conclusions: IL-1β levels after STEMI were strongly associated with impaired myocardial function and noninfarct LV mass after 1 year, suggesting a potential role for IL-1β as a predictor of maladaptive myocardial remodelling following reperfused MI.