'Lone' increase in C-reactive protein after cardiac surgery: prevalence, clinical characteristics, in-hospital course, and prognostic value

Piccoli et al.
European Journal of Cardiovascular Prevention & Rehabilitation:Volume 15(4)

Special Author Introduction

C-reactive protein (CRP) is an acute-phase reactant that has long been considered a classic marker for inflammation. In the past decades, numerous studies have demonstrated that CRP can predict recurrent instability in patients with coronary artery disease and hospital readmission in patients with heart failure. This body of evidence has led to the inclusion of CRP, as well as other acute-phase reactants, in the biochemical set for risk assessment of cardiovascular events.

In patients after cardiac surgery, elevated CRP levels is a very frequent finding which stimulated the hypothesis that also in this specific clinical setting this marker may predict early complications and poor outcome. However, while in some studies pre-operative levels of CRP seemed to be predictive of postoperative outcome and complications, in other they did not provide predictive information. We believe that this conflicting data may be due to the different pathophysiologic substrate of these patients. In fact, in patients after cardiac surgery CRP may be elevated either by (sub)clinical infections or by the systemic inflammatory response that occurs during the first week of surgery. Clearly, this could result in different prognostic value of the same biochemical marker.

The present study by Piccoli et al. adds useful information on this interesting topic. They avoided all the confounding effects of specific infections, with the aim of studying a very clean and selected group of patients early after cardiac surgery with isolated "lone" increase of CRP. The results of this study indicate that serum CRP in the absence of symptoms or signs of infections is frequently increased after cardiac surgery, decreases spontaneously over time, is independent from clinical or surgical variables, and does not portrait adverse outcome at follow-up.

In conclusion, it seems reasonable to keep in mind that after cardiac surgery patients with elevated CRP are not alike and often derive from two extremes: patients with signs or symptoms of infection (which require careful evaluation and proper treatment) and patients with a lone increase of CRP which can be considered a non-specific inflammatory marker with a favourable prognosis, where further diagnostic work-up as well as longer hospitalization are redundant.

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