Interleukin-6 is the strongest predictor of 30-day mortality in patients with cardiogenic shock due to myocardial infarction

Abstract

Introduction: Cardiogenic shock (CS) remains the leading cause of death in patients hospitalized for myocardial infarction (MI). Systemic inflammation with inappropriate vasodilatation is observed in many patients with CS and may contribute to an excess mortality rate. The purpose of this study was to determine the predictive role of serial measurements of Nt-proBNP, interleukin-6 (IL-6), and procalcitonin (PCT) for 30-day mortality in patients with CS due to MI.

Methods: The present study is a prospective single-center study including 87 patients with MI complicated by CS treated with acute revascularization and intraaortic balloon counterpulsation (IABP) support. Predictive values of plasma levels at admission (T0), after 24 hours (T1), and after 72 hours (T2) were examined according to 30-day mortality.

Results: Significant differences between survivors (n = 59) and nonsurvivors (n = 28) were seen for Nt-proBNP at T0, for IL-6 at T0 and T1, and for PCT at T1 and T2. According to ROC analyses, the highest accuracy predicting 30-day mortality was seen at T0 for IL-6, at T1 for PCT, and at T2 for PCT. In univariate analysis, significant values were found for Nt-proBNP at T1, and for IL-6 and PCT at all points in time. Within the multivariate analysis, age, creatinine, and IL-6 were significant determinants of 30-day mortality, in which IL-6 showed the highest level of significance.

Conclusions: In patients with MI complicated by CS, IL-6 represented a reliable independent early prognostic marker of 30-day mortality. PCT revealed a significant value at later points in time, whereas Nt-proBNP seemed to be of lower relevance.

Figure 1

Serial measurements of Nt-proBNP (a), interleukin-6 (IL-6) (b) and procalcitonin (PCT) (c) in survivors versus nonsurvivors at admission (T₀), after 24 hours (T₁), and after 72 hours (T₂). In the box-and-whisker plot, the central box represents the interquartile range (IQR); the middle line represents the median. Outside values (○) are smaller/larger than the lower/upper quartile ± 1.5 × the IQR; far-out values (*) are smaller/larger than the lower/upper quartile ± 3 × the IQR.

Figure 2

Receiver operating characteristic (ROC) curves for 30-day mortality. Analysis of 30-day mortality calculated from values of Nt-proBNP, interleukin-6 (IL-6), and procalcitonin (PCT) at admission (T₀) (a), after 24 hours (T₁) (b), and after 72 hours (T₂) (c). ROC curve analysis with area under the curve and significance levels.

Figure 3

Kaplan-Meier survival curves according to cut-off levels of interleukin-6 (IL-6) (a) and procalcitonin (PCT) (b, c). Estimated 30-day survival in patients with levels of IL-6 above or below the cut-off level (307 pg/ml) at admission (T₀) (a); of PCT (1.23 µg/L) after 24 hours (T₁) (b); of PCT (0.71 µg/L) after 72 hours (T₂) (c). P values were estimated by log-rank test.