Early sST2 Liberation after Implantation of a Left Ventricular Assist Device in Patients with Advanced Heart Failure

Abstract

Background. The use of left ventricular assist device (LVAD) has increased considerably over the past decade; however, there is limited literature to assist in patient selection and monitoring. The frequency of adverse events remains high. We examined the early expression of circulating soluble ST2 (sST2), a biomarker with immunosuppressive and profibrotic activity, and assessed the risk of death at 1 year in patients receiving LVAD implant. Methods. We prospectively enrolled 20 heart failure patients and measured sST2, IL-33, and IL-6 serum concentrations over three weeks after LVAD implantation. We compared the kinetics of IL-6, sST2, and IL-33 release in survivors with those of nonsurvivors using mixed model two-way analysis of variance for repeated measures. We also collected data on hemodynamic parameters (i.e., cardiac output) and frequency of infections during the hospital stay. Results. LVAD therapy led to an immediate and significant improvement of the hemodynamic parameters in 1-year survivors and nonsurvivors alike. The 1-year survival rate was 65%. IL-6 concentrations showed a significant ( $p=0.03$ ) peak at admission to the intensive care unit following LVAD implantation, whereas sST2 levels were massively increased ( $p<0.0003$ ) on day 1. While 1-year survivors had persistently lower sST2 values compared to nonsurvivors during the first 3 weeks after LVAD implantation ( $p=0.012$ ), no differences were observed in the temporal pattern of IL-6 or IL-33. The odds of detecting Candida species in the bronchoalveolar lavage fluid were 14 times higher in nonsurvivors than in survivors (OR 13.7, CI 1.4-127, $p=0.02$ ). Conclusion. In patients implanted with LVAD, circulating sST2 levels and frequency of Candida colonisation were associated with higher mortality. Awareness of this early immune response can guide physicians in risk-benefit analysis.