title: Serum amylase measured four hours after endoscopic sphincterotomy is a reliable predictor of postprocedure pancreatitis.
abstract: OBJECTIVE
  Acute pancreatitis is a common complication after endoscopic sphincterotomy (ES) and endoscopic retrograde cholangiopancreatography (ERCP). The aim of this study was to detect the time when the peak of serum amylase was predictive for pancreatitis or severe hyperamylasemia, to plan a prolonged 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 compared with those at 24 h and with the outcome. Sensitivity for long-lasting severe hyperamylasemia (more than five times the upper normal limit) and pancreatitis 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 pancreatitis. There was a significant difference (p < 0.01 at all sampling times) between 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 assessment appears to be a reliable predictor in practice, as more than two-thirds of cases of pancreatitis (all but one with computed tomography-confirmed 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.
authors.affiliation: Department of Biomedical Sciences, University of Milan, IRCCS San Raffaele Hospital, Italy.
authors.forename: P A
authors.initials: PA
authors.lastname: Testoni
authors.forename: F
authors.initials: F
authors.lastname: Bagnolo
authors.forename: S
authors.initials: S
authors.lastname: Caporuscio
authors.forename: F
authors.initials: F
authors.lastname: Lella
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000681:Amylases / Q000097:blood*; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000009:adverse effects; D004796:Clinical Enzyme Tests; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000175:diagnosis* / Q000209:etiology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D016717:Sphincterotomy, Endoscopic / Q000009:adverse effects*; D013997:Time Factors
chemical_list: D000681:Amylases