European Journal of Cardiovascular Medicine

Postoperative complications following gastrointestinal surgery are a major concern for surgeons and intensivists. Among these, intraabdominal infections such as anastomotic leaks and intraabdominal abscesses are associated with high morbidity and mortality. Early diagnosis is often difficult as postoperative inflammatory response can mask early infective signs. Conventional laboratory markers like leukocyte count lack specificity, prompting the search for reliable biomarkers.

C-reactive protein is an acute-phase reactant synthesized by the liver in response to inflammation, while procalcitonin is a biomarker that rises significantly in bacterial infections and sepsis. The present study aims to evaluate and compare the diagnostic utility of CRP and PCT in detecting early intraabdominal infections following gastrointestinal surgery.1,2,3,4,5

Aim: To evaluate the role of serum C-reactive protein and procalcitonin levels in the early diagnosis of intraabdominal infections in patients undergoing gastrointestinal surgery.

This prospective observational study was conducted at Government Medical College, Kadapa, over a one-year period after obtaining institutional ethical committee approval. Inclusion Criteria: Adult patients (≥18 years), Patients undergoing elective or emergency gastrointestinal surgery, Patients requiring postoperative ICU monitoring. Exclusion Criteria: Pre-existing infections, Patients on long-term steroid or immunosuppressive therapy, Severe hepatic or renal dysfunction, Patients with postoperative non-abdominal infections only. Methodology: Demographic data, type of surgery, and clinical details were recorded. Serum CRP and PCT levels were measured at 1st, 24th, 48th, and 72nd postoperative hours. Patients were monitored clinically for fever, tachycardia, abdominal signs, and laboratory abnormalities. Imaging studies were performed when clinically indicated. Intraabdominal infections were diagnosed based on clinical, radiological, and operative findings. Statistical Analysis: Data were analyzed using appropriate statistical tests. Sensitivity, specificity, and ROC curve analysis were used to evaluate the diagnostic accuracy of CRP and PCT. A p-value <0.05 was considered statistically significant

TABLE 1: BASELINE DEMOGRAPHIC AND CLINICAL CHARACTERISTICS

TABLE 2:SURGERIES PERFORMED

TABLE 3: POST OPERATIVE CRP AND PROLACTIN LEVELS

TABLE 4: DIAGNOSTIC ACCURACY OF CRP AND PROLACTIN LEVELS

Patients who developed intraabdominal infections showed significantly elevated CRP and PCT levels compared to non-infected patients. Peak levels of both biomarkers were observed at 48 hours postoperatively. Procalcitonin demonstrated higher sensitivity and specificity than CRP, particularly at 48 and 72 hours, making it a better predictor of infective complications.

This study shows that gastrointestinal cancer surgery caused raised serum levels of CRP and PCT in practically all the patients and that the highest concentration was reached earlier for PCT than for CRP. Both proteins are useful markers in predicting postoperative intra-abdominal infection, with a very high negative predictive value (NPV), already in the first 3 postoperative days, although the positive predictive value (PPV) is low. Considering isolated values, PCT is a more valid marker in predicting PIAI than PCR, but if we consider the evolution of the values over time, we can see that the relationship between CRP values at 72h after surgery and CRP values at 48h after surgery has quite a high PPV, higher than that of the isolated determinations of PCR and PCT.

Early diagnosis of intraabdominal infections is crucial for reducing postoperative morbidity and mortality. In the present study, both CRP and PCT were useful markers; however, procalcitonin showed superior diagnostic accuracy. Serial measurements were more informative than single values, emphasizing the importance of trend analysis rather than isolated readings.

Coinciding with the results obtained in our study, other authors have shown that both CRP6 and PCT levels significantly increase in practically all patients after gastrointestinal surgery. Our study was limited to the first 3 postoperative days and does not show when they normalise, however other authors who have studied the evolution of both proteins over a longer period of time have observed that PCT normalises 5–7 days after surgery and CRP 7–10 days after surgery.6

CRP is a non-specific inflammation marker, that is persistently high levels from the third postoperative day is a good predictor of postoperative infection.7 Similarly, in our study, CRP only shows a significant relationship with the occurrence of postoperative intra-abdominal infection on the third day after surgery. Ortega-Deballon et al. demonstrated that serum levels of CRP on the fourth postoperative day are a good predictor of anastomotic leak in colorectal surgery; for a cut-off point of 125mg/l, sensitivity was 81.8%, specificity was 64.4% and the NPV 95.8%.1 García-Granero et al. obtained similar results for the values on the third, fourth and fifth postoperative days.8 Our study also shows that CRP levels on the third postoperative day are a good predictor of postoperative intra-abdominal infection, with similar sensitivity, specificity and NPV values.

PCT as a marker of postoperative infection has also been demonstrated previously by other authors in different types of surgery; cardiothoracic9,10 and abdominal.3,4 In García-Granero et al8 study it was observed that serum levels of PCT between the third and fifth postoperative days were a good predictor of major anastomotic dehiscence, with a sensitivity greater than 90%, an NPV above 99% and a PPV of less than 17%, but not of minor dehiscence (not requiring percutaneous drainage or surgery) in patients undergoing colorectal cancer surgery.

Our findings are consistent with previous studies that report higher predictive value of PCT compared to CRP in detecting postoperative infective complications. Incorporation of PCT into routine postoperative monitoring protocols may facilitate early diagnosis and timely management.

Procalcitonin and C-reactive protein are valuable biomarkers for the early detection of intraabdominal infections following gastrointestinal surgery. Procalcitonin, particularly at 48 and 72 postoperative hours, is more sensitive and specific than CRP and can serve as an effective tool for early diagnosis and clinical decision-making.

1.       P. Ortega-Deballon, F. Radais, O. Facy, P. d’Athis, D. Masson, P.E. Charles, et al. C-reactive protein is an early predictor of septic complications after elective colorectal surgery. World J Surg, 34 (2010), pp. 808-814

2.       R. Warschkow, I. Tarantino, M. Torzewski, F. Naf, J. Lange, T. Steffen. Diagnostic accuracy of C-reactive protein and white blood cell counts in the early detection of inflammatory complications after open resection of colorectal cancer: a retrospective study of 1187 patients. Int J Colorectal Dis, 26 (2011), pp. 1405-1413

3.       H.B. Reith, U. Mittelkötter, E.S. Debus, C. Küsner, A. Thiede. Procalcitonin in early detection of postoperative complications. Dig Surg, 15 (1998), pp. 260-265

4.       D. Mokart, M. Merlin, A. Sannini, J.P. Brun, J.R. Delpero, G. Houvenaeghel, et al. Procalcitonin, interleukin 6 and systemic inflammatory reponse syndrome (SIRS): early markers of postoperative sepsis after major surgery. Br J Anaesth, 94 (2005), pp. 767-773

5.       R.R. Watkins, T.L. Lemonovich. Serum procalcitonin in the diagnosis and management of intra-abdominal infections. Expert Rev Anti Infect Ther, 10 (2012), pp. 197-205

6.       G.J. McKay, R.G. Molloy, P.J. O’Dwyer. C-reactive protein as a predictor of postoperative infective complications following elective colorectal resection. Colrectal Dis, 13 (2011), pp. 583-587

7.       M. Lindberg, A. Hole, H. Johnsen, A. Asberg, A. Rydning, H.E. Myrvold, et al. Reference intervals for procalcitonin and C-reactive protein after major abdominal surgery. Scand J Clin Lab Invest, 62 (2002), pp. 189-194

8.       García-Granero, M. Frasson, B. Flor-Lorente, F. Blanco, R. Puga, A. Carratalá, et al. Procalcitonin and C-reactive protein as early predictors of anastomotic leak in colorectal surgery: a prospective observational study. Dis Colon Rectum, 56 (2013), pp. 475-483

9.       M.A. Jebali, P. Hausfater, Z. Abbes, Z. Aouni, B. Riou, M. Ferjani. Assesment of the accuracy of procalcitonin to diagnose postoperative infection after cardiac surgery. Anesthesiology, 107 (2007), pp. 232-238

10.    P.E. Falcoz, F. Laluc, M.M. Toubin, M. Puyraveau, F. Clement, M. Mercier, et al. Usefulness of procalcitonin in the early detection of infection after thoracic surgery. Eur J Cardiothorac Surg, 27 (2005), pp. 1074-1078