Serum amylase measured four hours after endoscopic sphincterotomy is a reliable predictor of postprocedure pancreatitis

OBJECTIVE: Acute pancreatitis is a common complication after endoscopic sph incterotomy (ES) and endoscopic retrograde cholangiopancreatography (ERCP). The aim of this study was to detect the time when the peak of serum amylas e was predictive for pancreatitis or severe hyperamylasemia, to plan a prol onged follow-up in the hospital and for outpatients. METHODS: In a prospective series of 409 consecutive patients undergoing ES, serum amylase activity was measured immediately before the procedure and 2 , 4, 8, and 24 h thereafter; the data obtained at 2, 4, and 8 h were compar ed with those at 24 h and with the outcome. Sensitivity for long-lasting se vere hyperamylasemia (more than five times the upper normal limit) and panc reatitis were also defined for all sampling times. RESULTS: At 24 h after ES, amylase was still more than five times the upper normal limit in 26 patients, 19 of whom had mild/moderate acute pancreatit is. There was a significant difference (p < 0.01 at all sampling times) bet ween the 26 patients with 24-h severe hyperamylasemia and those with lower levels. The sensitivity of amylase measurement in detecting pancreatitis or long-lasting severe hyperamylasemia was highest at 8 h. However, the 4-h a ssessment appears to be a reliable predictor in practice, as more than two- thirds of cases of pancreatitis (all but one with computed tomography-confi rmed pancreatitis) occurred among patients whose 4-h amylasemia was higher than five times the upper normal limit. CONCLUSIONS: Serum amylase assessment 4 h after ES minimizes the likelihood of underestimating the risk of postprocedure pancreatitis. It is therefore a reliable, cost-effective follow-up, particularly in outpatients. (C) 199 9 by Am. Cell. of Gastroenterology.