The value of CT imaging and CRP quotient for detection of postbariatric complications

BACKGROUND: The diagnosis of major complications seems to be more challenging in obese patients. We aimed to show the relevance of routinely assessed clinical and paraclinical parameters as well as the relevance of CT scans in the diagnosis of major complications after bariatric procedures.

METHODS: All patients who underwent operations (primary or revisional) in a 3-year period were retrospectively studied after bariatric surgery with a specific focus on the routinely assessed clinical parameters (tachycardia, temperature), paraclinical parameters on postoperative day (POD) 1 and 3 (C-reactive protein (CRP), leukocytes), and additional computed tomography (CT) scan results for the diagnosis of leakage, bleeding, intraabdominal abscess, superficial abscess, and other complications.

RESULTS: A total of 587 patients were examined. In this cohort, 73 CT scans were performed due to suspected intraabdominal or pulmonary complication according to our hospital standard operating procedure. In total, 14 patients (2.4%) had a major complication (Clavien-Dindo grade IV/V). Of those, 10 patients (1.7%) had postoperative leakage. While the correct leakage diagnosis was only found in 33% of the patients by CT scan, the overall specificity of CT as a diagnostic tool for all kinds of complications remained high. Especially for abscess detection, CT scan showed a sensitivity and specificity of 100%. Multivariate analysis showed a significantly higher risk of leakage development characterized by a doubling of postoperative CRP level (odds ratio 4.84 (95% confidence interval 2.01-11.66, p < 0.001)). To simplify the use of CRP as a predictive factor for the diagnosis of leakage, a cut-off value of 2.4 was determined for the CRP quotient (POD3/POD1) with a sensitivity of 0.88 and a specificity of 0.89.

CONCLUSION: CT diagnostic after bariatric surgery has a high positive predictive value, especially for intraabdominal abscess formation. Nevertheless, CT scan for the diagnosis of leakage has a low sensitivity. Thus, a negative CT scan does not exclude the presence of a leakage. Using the described CRP quotient with a cut-off of 2.4, the risk of early leakage can be easily estimated. Furthermore, in any uncertain case of clinically suspected leakage, diagnostic laparoscopy should be performed.