Fibroblast growth factor 23 in acute myocardial infarction complicated by cardiogenic shock: a biomarker substudy of the Intraaortic Balloon Pump in Cardiogenic Shock II (IABP-SHOCK II) trial.

INTRODUCTION: Cardiogenic shock (CS) is the leading cause of death in patients hospitalized with acute myocardial infarction (AMI). Biomarkers might help in risk stratification and understanding of pathophysiology. Preliminary data suggests that patients with CS face a profound increase in the osteocyte-derived hormone fibroblast growth factor 23 (FGF-23), which acts as a negative regulator of serum phosphate levels. The present study aimed to assess the predictive role of FGF-23 for clinical outcome in a large cohort of CS patients with and without renal dysfunction. METHODS: In the randomized Intraaortic Balloon Pump in Cardiogenic Shock II (IABP-SHOCK II) trial, 600 patients with CS complicating AMI were assigned to therapy with or without IABP. Our predefined biomarker substudy included 182 patients. Blood sampling was performed in a standardized procedure at three different time points (day 1 (day of admission), day 2 and day 3). Differences in outcome of patients with FGF-23 levelsmedian were compared by log-rank testing. Stepwise logistic regression modeling was performed to identify predictors of death at 30 days and Cox regression analysis for time to death during the first year. RESULTS: At all three time points, nonsurvivors had significantly higher FGF-23 levels compared to survivors (P<0.001 for all). Patients with FGF-23 levels above the median (395 RU/mL [interquartile range 102;2,395]) were characterized by an increased 30-day mortality and 1-year mortality. In multivariable analysis FGF-23 levels remained independent predictors for 30-day (odds ratio per 10log 1.80, 95% confidence interval (CI) 1.11 to 2.92; P=0.02) and 1-year mortality (hazard ratio 1.50, 95% CI 1.11 to 2.04, P=0.009). After stratifying the patients according to their baseline serum creatinine levels, the negative prognostic association of increased FGF-23 was only significant in those with serum creatinine greater than median. CONCLUSIONS: In CS, high levels of FGF-23 are independently related to a poor clinical outcome. However, this prognostic association appears only to apply in patients with impaired renal function. TRIAL REGISTRATION: ClinicalTrials.gov NCT00491036. Registered 22 June 2007.

Angiopoietin-2 in acute myocardial infarction complicated by cardiogenic shock--a biomarker substudy of the IABP-SHOCK II-Trial.

AIMS: Angiopoietin-2 (Ang-2) is a mediator of capillary leakage, and increased Ang-2 levels were associated with poor in-hospital outcome in a pilot study in cardiogenic shock (CS). In this larger study, we followed this hypothesis and aimed at assessing the predictive role of Ang-2 on short- and long-term mortality, investigating the effect of intra-aortic balloon pump (IABP) treatment on Ang-2 levels, and identifying clinical and procedural predictors of increased Ang-2. METHODS AND RESULTS: In the IABP-SHOCK II-trial, 600 patients with CS complicating acute myocardial infarction were assigned to therapy with or without IABP. This substudy included 189 randomized patients with serial blood sampling performed at days 1, 2, and 3. No significant differences in Ang-2 levels were found between patients with or without IABP. The Ang-2 levels above the median at day 1 were associated with 30-day [hazard ratio (HR) 1.98, 95% confidence interval (CI) 1.26-3.10, P = 0.002) and 1-year mortality (HR 2.21, 95% CI 1.49-3.27, P < 0.001). Stratification of patients according to Ang-2 levels at day 3 increased these associations (30 days HR 5.15, 95% CI 2.80-9.45, P < 0.001; 1 year HR 5.24, 95% CI 3.19-8.58, P < 0.001). The Ang-2 concentrations were independent predictors for mortality in multivariate analysis (30 days HR 4.82, 95% CI 1.52-15.23, P = 0.007; 1 year HR 2.01, 95%CI 1.24-3.24, P = 0.005). Predictors of increased Ang-2 levels at day 3 were baseline Ang-2, development of acute kidney injury, bleeding events or transfusion, and impaired reperfusion. CONCLUSION: In CS, high levels of Ang-2 are independently associated with poor short- and long-term outcome and associated with the reperfusion success as well as complications. CLINICAL TRIAL REGISTRATION: URL: www.clinicaltrials.gov; unique identifier: NCT00491036.

Prognostic impact of established and novel renal function biomarkers in myocardial infarction with cardiogenic shock: A biomarker substudy of the IABP-SHOCK II-trial.

BACKGROUND: In cardiogenic shock (CS) renal dysfunction is an important parameter of inadequate end-organ perfusion and an independent predictor of adverse outcome. Early detection of renal dysfunction is therefore important, and novel biomarkers such as Neutrophil Gelatinase-Associated Lipocalin (NGAL), Kidney Injury Molecule 1 (KIM1) and Cystatin C (CysC) have been suggested. However, in high-risk CS patients their role for assessing renal injury has not yet been investigated in comparison to the most widely used serum creatinine. METHODS: This predefined substudy included 190 patients of the randomized Intraaortic Balloon Pump in Cardiogenic Shock II (IABP-SHOCK II)-trial. Blood samples were collected directly during primary percutaneous coronary intervention, one day and two days after randomization. The primary endpoint for outcome assessment was 1 year mortality. RESULTS: Creatinine, NGAL and KIM-1 were significantly higher in non-survivors in comparison to survivors over time in ANOVA (p<0.001; p=0.002 and p=0.04, respectively). In contrast, CysC levels were not associated with the primary endpoint (p=0.15). Receiver operator characteristics revealed that creatinine at any time point had the best predictive value for 1 year mortality. This was also true when comparing creatinine to different equations for glomerular filtration rate. In multivariable Cox-regression analysis creatinine remained the only significant independent predictor of kidney biomarkers of time to death during the first year. CONCLUSIONS: Assessment of novel biomarkers such as CysC, NGAL and KIM-1 or calculation of glomerular filtration rate provide no additional prognostic information in patients with CS complicating acute myocardial infarction in comparison to creatinine.