Background: Serum C-reactive protein (CRP) is involved in the acute phase reaction after surgery, even though its clinical significance remains a matter of debate. We evaluated CRP levels in cardiac surgery patients without clinical or laboratory signs of infection.
Methods: We screened 737 consecutive patients referred to our center 8+/-5 days after cardiac surgery. Patients with fever (>37.2 degrees C), elevated white blood cell count (>11,000/ml), neutrophilia (>70%), or any inflammatory, infective or malignant disease were excluded. CRP levels were measured on admission and at discharge and the values were related to the following variables: age, sex, diabetes mellitus, renal failure, type of surgery, postoperative atrial fibrillation, pericardial or pleural effusion, and length of hospital stay. Follow-up (mean: 23+/-8.5 months) was available for 175 patients (94%).
Results: In the 187 patients enrolled in the study, the CRP values were significantly elevated (median: 4.23 mg/dl, interquartiles range: 2.68-6.64) independent of any variable analyzed. At discharge, CRP levels were significantly reduced compared with values on admission (median: 1.55 mg/dl, interquartiles range: 0.84-2.37, P<0.001). At follow-up, 19 events (10.8%) occurred (two noncardiac deaths, 17 hospital readmissions for cardiac reasons); nonetheless, no correlation was found with CRP values either on admission or at discharge.
Conclusion: Early after cardiac surgery, in patients without clinical or laboratory signs of acute infection, CRP levels are significantly elevated, do not correlate with clinical variables, and decrease at discharge. These findings suggest a systemic inflammatory response to surgery-related stress, which carries a favorable prognosis at follow-up.