Association of IL-8 With Infarct Size and Clinical Outcomes in Patients With STEMI.

Background: Little is known about the role of interleukin (IL)-8 in patients with acute ST-segment elevation myocardial infarction (STEMI).

Objectives: The aims of this study were to evaluate, in STEMI patients, the temporal profile of IL-8 and possible associations with left ventricular (LV) function and remodeling, infarct size, microvascular obstruction, myocardial salvage, and future clinical events.

Methods: A total of 258 patients with STEMI were included. Blood samples were drawn before and immediately after percutaneous coronary intervention (PCI), at day 1, and after 4 months. Cardiac magnetic resonance imaging was performed in the acute phase and after 4 months. Clinical events were registered during 12 months' follow-up and all-cause mortality after median 70 months' follow-up.

Results: Patients with IL-8 levels greater than the median measured both immediately after PCI and at day 1 had larger final infarct size, lower LV ejection fraction, larger increase in LV end-diastolic volume, and higher frequency of microvascular obstruction. After multivariate adjustment, high IL-8 levels at day 1 were associated with an increased risk of developing a large MI and having reduced LV ejection fraction at 4 months, also after adjustment for peak troponin value. Patients with IL-8 levels in the highest quartile measured at all sampling points were more likely to have a clinical event during the first 12 months after the MI and had lower overall survival during long-term follow-up.

Conclusions: High levels of circulating IL-8 were associated with large infarct size, impaired recovery of LV function, and adverse clinical outcome in patients with STEMI, suggesting IL-8 as a future therapeutic target based on its important role in post-infarction inflammation.