Should CT scan be performed when CRP is elevated after colorectal surgery? Results from the inflammatory markers after colorectal surgery study

SummaryIntroductionSerum concentration of C-reactive protein (CRP) that exceeds a pre-defined threshold between the 3rd and 5th postoperative day is a reliable marker of infectious complications after colorectal surgery. However, the optimal strategy to follow when a high CRP is found has not been defined. The aim of this study was to analyze the usefulness of computed tomography (CT) scan in this situation in a prospective cohort of patients following colorectal surgery.MethodsBetween November 2011 and April 2015, patients at two surgical centers who had undergone elective colorectal resection with anastomosis and who had a CRP > 12.5 mg/dL on the 4th postoperative day (POD) were prospectively included in a database. Data were collected concerning all complications occurring during the 30 days following surgery, method of diagnosis, management and clinical course. The decision to perform a CT scan between POD 4 and POD 6 day was guided only by the elevation of CRP in the absence of any other clinical signs; results were analyzed to evaluate the diagnostic value of elevated CRP. Uni- and multivariable analyses were performed to identify risk factors for postoperative infection.ResultsThe study included a total of 174 patients: 56 (32.1%) had a CT between POD 4 and 6, and this helped detect a postoperative complication in 55.4% of cases. Patients who did not undergo CT had lower CRP values (16.3 vs. 18.5, P = 0.02). Among the 118 patients who did not undergo CT, 50.8% eventually developed an infectious complication. The sensitivity of CRP-guided CT was 76.7% with a negative predictive value of 78.8%.ConclusionIf an elevated CRP is found on POD 4, an abdominopelvic CT should be performed. A normal result does not formally eliminate the existence of intra-abdominal complication. A study protocol should be set up to evaluate whether systematic revisional surgery or repeat CT scan is the appropriate management if CRP in the next two days reveals persistent inflammation.