Kinetics of procalcitonin, C-reactive protein and interleukin-6 in cardiogenic shock - Insights from the CardShock study

Abstract

Background: Inflammatory responses play an important role in the pathophysiology of cardiogenic shock (CS). The aim of this study was to investigate the kinetics of procalcitonin (PCT), C-reactive protein (CRP), and interleukin-6 (IL-6) in CS and to assess their relation to clinical presentation, other biochemical variables, and prognosis.

Methods: Levels of PCT, CRP and IL-6 were analyzed in serial plasma samples (0-120h) from 183 patients in the CardShock study. The study population was dichotomized by PCT_max ≥ and < 0.5 μg/L, and IL-6 and CRP_max above/below median.

Results: PCT peaked already at 24 h [median PCT_max 0.71 μg/L (IQR 0.24-3.4)], whereas CRP peaked later between 48 and 72 h [median CRP_max 137 mg/L (59-247)]. PCT levels were significantly higher among non-survivors compared with survivors from 12 h on, as were CRP levels from 24 h on (p < 0.001). PCT_max ≥ 0.5 μg/L (60% of patients) was associated with clinical signs of systemic hypoperfusion, cardiac and renal dysfunction, acidosis, and higher levels of blood lactate, IL-6, growth-differentiation factor 15 (GDF-15), and CRP_max. Similarly, IL-6 > median was associated with clinical signs and biochemical findings of systemic hypoperfusion. PCT_max ≥ 0.5 μg/L and IL-6 > median were associated with increased 90-day mortality (50% vs. 30% and 57% vs. 22%, respectively; p < 0.01 for both), while CRP_max showed no prognostic significance. The association of inflammatory markers with clinical infections was modest.

Conclusions: Inflammatory markers are highly related to signs of systemic hypoperfusion in CS. Moreover, high PCT and IL-6 levels are associated with poor prognosis.

Keywords: C-reactive protein; Cardiogenic shock; Inflammation; Interleukin 6; Procalcitonin.