Thomas Rabenstein

Impact of skill and experience of the endoscopist on the outcome of endoscopic sphincterotomy techniques

BACKGROUND Our aim was to assess the influence of the skill and experience of the endoscopist on the success and risk of endoscopic sphincterotomy techniques. METHODS The outcome of all endoscopic sphincterotomies (n = 1335) carried out between 1988 and 1995 were retrospectively analyzed with respect to the endoscopist performing the procedure. Endoscopists were differentiated according to whether they had previous experience with endoscopic sphincterotomy techniques (n > 100) and the frequency of endoscopic sphincterotomy during the study period (>40, 26 to 40, 10 to 25, <10 per year). RESULTS Indications for endoscopic sphincterotomy techniques and technical execution had only a minor influence on the results of endoscopic sphincterotomy and were comparable for the individual endoscopists. The overall success rate of endoscopic sphincterotomy was 94.4% and did not significantly differ among the endoscopists. The overall complication rate of endoscopic sphincterotomy was 7.3%. Endoscopists learning endoscopic sphincterotomy techniques with a case frequency of less than 10 procedures per year had a consistently high complication rate (10.5%). Those learning endoscopic sphincterotomy techniques with a case frequency of more than 25 procedures per year had an above-average complication rate for their first 40 endoscopic sphincterotomy procedures and a significant decrease in complication rate as the number of procedures increased. The complication rate for experienced endoscopists was 7.7%. There were distinct and, in one case, significant differences in complication rates between individual endoscopists (11.5% vs. 4.8%, p = 0.01). However, when corrected for multiple testing, there were no significant differences at the p < 0. 05 level. The endoscopic sphincterotomy frequency of the endoscopist was the only significant risk factor for complications. Endoscopists with a frequency of more than 40 procedures per year had a significantly lower complication rate (5.6%) than endoscopists with a lower case frequency (9.3%, p < 0.05). CONCLUSIONS A low endoscopic sphincterotomy frequency is, even for endoscopists with previous experience with the procedure, a risk factor for complications after endoscopic sphincterotomy. The learning of endoscopic sphincterotomy techniques requires a minimum of 40 procedures, but also after 100 procedures a further decrease of the complication rate can be expected.

Is endoscopic drainage of common bile duct stenoses in chronic pancreatitis up-to-date?

OBJECTIVE:Common bile duct (CBD) stenoses often complicate chronic pancreatitis (CP). Although endoscopic drainage is employed as a standard procedure in malignant CBD stenoses, it is not yet the approved standard therapy of CBD stenosis in CP.METHODS:The records of 31 patients with CBD stenosis in CP who had undergone endoscopic placement of plastic endoprostheses into the bile duct between January 1991 and February 1997 were analyzed retrospectively. In all, 18 patients suffered from jaundice and 13 patients exclusively showed serological cholestasis. Upstream dilation of the CBD (19 ± 6.6 mm, 12–35 mm) was detected by ERCP in all patients. In total, 101 endoprostheses were implanted endoscopically, exchanged after 3 ± 2 months, and removed after 10 ± 8 months.RESULTS:All jaundiced patients showed immediate improvement of cholestasis after drainage. At the time of last exchange or after stent removal, prestenotic CBD dilation was reduced in 55% of all patients. Complete regression of stenosis and prestenotic dilation was accomplished only in 13%; dilation remained unchanged in 10%, and even showed progression in 22%. A total of 29 patients were followed-up over 24 months. Cholestatic parameters remained normal in all patients with complete normalization of the CBD, and were only moderately increased in another 10 patients, 7 and 28 months after stent removal, respectively.CONCLUSIONS:Technical and immediate clinical success of CBD stenting in patients with CBD stenoses due to CP is high; however, long-term complete normalization of the bile duct is rare. Endoscopic drainage of CBD-stenosis in patients with CP can be recommended to alleviate acute cholestasis, but not yet as a definite treatment.

Low-molecular-weight heparin does not prevent acute post-ERCP pancreatitis.

BACKGROUND Studies suggest that heparin has anti-inflammatory effects that could prevent acute post-ERCP pancreatitis. The aim of this investigator-initiated, prospective, randomized, double-blind, multicenter study was to determine whether low-molecular-weight heparin can prevent acute post-ERCP pancreatitis. METHODS Patients at increased risk for acute post-ERCP pancreatitis based on assessment of known risk factors were randomized to receive low-molecular-weight heparin (Certoparin 3000 IU subcutaneously) or placebo (saline solution 0.3 mL subcutaneously) the day before ERCP. The drug was given 2 hours before and 22 hours after ERCP. Documentation and follow-up included patient history, risk factors for acute post-ERCP pancreatitis, procedure-related data, assessment of pain (visual analogue scale, need for pain medication), laboratory findings before and after ERCP (0, 4, and 24 hours), as well as post-ERCP complications. The two-sided Fisher exact test was used for statistical comparison, and a p value < or =0.05 was considered significant. RESULTS A total of 458 patients were enrolled in the study. Data from 10 patients could not be evaluated, leaving 221 patients in the low-molecular-weight heparin group and 227 in the placebo group (total 448 patients; 135 men, 313 women; mean age 58 [15] years). Low-molecular-weight heparin and placebo groups were comparable with regard to risk factors for acute post-ERCP pancreatitis (gender distribution, age <65 years, history of pancreatitis, pancreas divisum, disorders of sphincter of Oddi) and procedure-related data (difficult cannulation, diagnostic or therapeutic ERCP, needle-knife papillotomy, endoscopic sphincterotomy, biliary or pancreatic procedure, pancreatic contrast injection, success and final diagnosis of ERCP). Acute post-ERCP pancreatitis occurred in 8.5% (38/448), with one death resulting from severe pancreatitis. Low-molecular-weight heparin offered no benefit compared with placebo based on the frequency of acute post-ERCP pancreatitis (low-molecular-weight heparin, 18/221 vs. placebo, 20/227; p=0.87) and the severity of acute post-ERCP pancreatitis (low-molecular-weight heparin, 14 mild, 3 moderate, one severe; placebo, 18 mild, two moderate, 0 severe). The 24-hour serum amylase values and 24-hour pain scores did not differ significantly between the low-molecular-weight heparin group and the placebo group. Bleeding complications occurred in two patients, both in the low-molecular-weight heparin group (one mild, one moderate). CONCLUSIONS Prophylactic subcutaneous administration of low-molecular-weight heparin does not prevent acute post-ERCP pancreatitis.

Endoscopic assessment and grading of Barrett's esophagus using magnification endoscopy and narrow-band imaging: accuracy and interobserver agreement of different classification systems (with videos)

BACKGROUND Three different classification systems for the evaluation of Barretts esophagus (BE) using magnification endoscopy (ME) and narrow-band imaging (NBI) have been proposed. Until now, no comparative and external evaluation of these systems in a clinical-like situation has been performed. OBJECTIVE To compare and validate these 3 classification systems. DESIGN Prospective validation study. SETTING Tertiary-care referral center. Nine endoscopists with different levels of expertise from Europe and Japan participated as assessors. PATIENTS Thirty-two patients with long-segment BE. INTERVENTIONS From a group of 209 standardized prospective recordings collected on BE by using ME combined with NBI, 84 high-quality videos were randomly selected for evaluation. Histologically, 28 were classified as gastric type mucosa, 29 as specialized intestinal metaplasia (SIM), and 27 as SIM with dysplasia/cancer. Assessors were blinded to underlying histology and scored each video according to the respective classification system. Before evaluation, an educational set concerning each classification system was carefully studied. At each assessment, the same 84 videos were displayed, but in different and random order. MAIN OUTCOME MEASUREMENTS Accuracy for detection of nondysplastic and dysplastic SIM. Interobserver agreement related to each classification. RESULTS The median time for video evaluation was 25 seconds (interquartile range 20-39 seconds) and was longer with the Amsterdam classification (P < .001). In 65% to 69% of the videos, assessors described certainty about the histology prediction. The global accuracy was 46% and 47% using the Nottingham and Kansas classifications, respectively, and 51% with the Amsterdam classification. The accuracy for nondysplastic SIM identification ranged between 57% (Kansas and Nottingham) and 63% (Amsterdam). Accuracy for dysplastic tissue was 75%, irrespective of the classification system and assessor expertise level. Interobserver agreement ranged from fair (Nottingham, κ = 0.34) to moderate (Amsterdam and Kansas, κ = 0.47 and 0.44, respectively). LIMITATION No per-patient analysis. CONCLUSIONS All of the available classification systems could be used in a clinical-like environment, but with inadequate interobserver agreement. All classification systems based on combined ME and NBI, revealed substantial limitations in predicting nondysplastic and dysplastic BE when assessed externally. This technique cannot, as yet, replace random biopsies for histopathological analysis.

Comparison of tree-based methods for prognostic stratification of survival data

Tree-based methods can be used to generate rules for prognostic classification of patients that are expressed as logical combinations of covariate values. Several splitting algorithms have been proposed for generating trees from survival data. However, the choice of an appropriate algorithm is difficult and may also depend on clinical considerations. By means of a prognostic study of patients with gallbladder stones and of a simulation study, we compare the following splitting algorithms: log-rank statistic adjusted for measurement scale with (AP) and without (AU) pruning, exponential log-likelihood loss (EP), Kaplan-Meier (KP) distance of survival curves, unadjusted log-rank statistic (LP), martingale residuals (MP), and node impurity (ZP). With the exception of the AU algorithm (based on a Bonferroni-adjusted p-value driven stopping rule), trees are pruned using the measure of split-complexity, and optimally-sized trees are selected using cross-validation. The integrated Brier score is used for the evaluation of predictive models. According to the results of our simulation study and of the clinical example, we conclude that the AU, AP, EP, and LP algorithm may yield superior predictive accuracy. The choice among these four algorithms may be based on the required parsimonity and on medical considerations.

Endoscopic assessment and grading of Barrett's esophagus using magnification endoscopy and narrow-band imaging: accuracy and interobserver agreement of different classification systems

BACKGROUND Three different classification systems for the evaluation of Barretts esophagus (BE) using magnification endoscopy (ME) and narrow-band imaging (NBI) have been proposed. Until now, no comparative and external evaluation of these systems in a clinical-like situation has been performed. OBJECTIVE To compare and validate these 3 classification systems. DESIGN Prospective validation study. SETTING Tertiary-care referral center. Nine endoscopists with different levels of expertise from Europe and Japan participated as assessors. PATIENTS Thirty-two patients with long-segment BE. INTERVENTIONS From a group of 209 standardized prospective recordings collected on BE by using ME combined with NBI, 84 high-quality videos were randomly selected for evaluation. Histologically, 28 were classified as gastric type mucosa, 29 as specialized intestinal metaplasia (SIM), and 27 as SIM with dysplasia/cancer. Assessors were blinded to underlying histology and scored each video according to the respective classification system. Before evaluation, an educational set concerning each classification system was carefully studied. At each assessment, the same 84 videos were displayed, but in different and random order. MAIN OUTCOME MEASUREMENTS Accuracy for detection of nondysplastic and dysplastic SIM. Interobserver agreement related to each classification. RESULTS The median time for video evaluation was 25 seconds (interquartile range 20-39 seconds) and was longer with the Amsterdam classification (P < .001). In 65% to 69% of the videos, assessors described certainty about the histology prediction. The global accuracy was 46% and 47% using the Nottingham and Kansas classifications, respectively, and 51% with the Amsterdam classification. The accuracy for nondysplastic SIM identification ranged between 57% (Kansas and Nottingham) and 63% (Amsterdam). Accuracy for dysplastic tissue was 75%, irrespective of the classification system and assessor expertise level. Interobserver agreement ranged from fair (Nottingham, κ = 0.34) to moderate (Amsterdam and Kansas, κ = 0.47 and 0.44, respectively). LIMITATION No per-patient analysis. CONCLUSIONS All of the available classification systems could be used in a clinical-like environment, but with inadequate interobserver agreement. All classification systems based on combined ME and NBI, revealed substantial limitations in predicting nondysplastic and dysplastic BE when assessed externally. This technique cannot, as yet, replace random biopsies for histopathological analysis.

4619 Hemorrhage after endoscopic sphincterotomy: risk factors and endoscopic managenent - final results of a prospective study.

To determine risk factors (RF) for hemorrhage after endoscopic sphincterotomy (EST) and to evaluate the outcome of therapeutic modalities. METHODS: In all consecutive EST procedures between 09/94 and 12/98 indications, techniques, success, complications of EST, and possible RF for hemorrhage were evaluated prospectively. Pts. were followed up by physical examination and blood samples at 4, 24 and 48 hours after EST. Complications were classified according to commonly accepted criteria (Gastrointest Endosc 1991: 338). Risk factor analysis was performed using univariate methods. RESULTS: In 815 pts. (53.3% m, 46.7% f, 61±17 y); complications occured in 9.9% (81/815; 69 mild-moderate; 11 severe; 4 fatal). Bleeding during the procedure was seen in 50 pt. (self-limiting in 35 cases, successful injection therapy in 15 pt). The incidence of hemorrhage (drop of hemoglobin of at least 2 g/dl and clinical signs of hemorrhage) was 1.6% (14/815; 7 mild-moderate; 5 severe; 2 fatal). Hemorrhage was detected only in 2 pt., who showed bleeding during EST (both with prior injection therapy), and in 12 pt. without signs of bleeding during EST. The clinical onset of hemorrhage was within 4 hours after EST in 5 pt., within 2 days in 4 pt., and within 4 to 10 days in 5 pt. Univariate analysis obtained 2 RF for hemorrhage: coagulopathy (thrombocytes

4622 The endoscopist is the major risk factor for complications of endoscopc sphincterotomy: final results of a prospective study.

To determine risk factors (RF) for complications of endoscopic sphincterotomy (EST). METHODS: In all consecutive EST procedures between 09/94 and 12/98 indications, techniques, success, complications of EST and possible RF were evaluated prospectively. Pts. were followed up by physical examination and blood samples at 4, 24 and 48 hours after EST. Complications were classified according to commonly accepted criteria (Gastrointest Endosc 1991: 338). Analysis of RF was performed by uni- and multivariate methods. RESULTS: In 815 pts. (53.3% m, 46.7% f, 61±17 y); complications occured in 9.9% (81/815; 69 mild-moderate; 11 severe; 4 fatal): Pancreatitis: 6.4% (52/815; 48 mild-moderate; 4 severe; 0 fatal), Hemorrhage: 1.6% (14/815; 7 mild-moderate; 5 severe; 2 fatal), infections 1.7% (15/815; 11 mild-moderate; 2 severe; 2 fatal), perforation 0.2% (2/815; 2 mild-moderate). Others 0.1% (1/815; 1 mild). Multivariate analysis obtained a frequency of ≤40 EST/y as the only RF for complications in total (15.2% vs. 7.8%, p=0.002), and diabetes mellitus as independent protective factor (5.1% vs. 11.3%, p=0.02). No other variables reached significant levels in univariate analysis regarding complications in total. Coagulopathy (thrombocytes

4615 Prevention of acute post-ercp pancreatitis with heparin? final results of a prospective study on risk factors for ap.

Explorative analysis obtained a very low incidence of AP in patients who received heparin prior to ERCP with EST. Experimental data showed that heparin has anti-inflammatory effects, improves pancreatic microcirculation during AP and inhibits pancreatic proteases. METHODS: Potential risk factors for AP were prospectively analysed in all consecutive ERCP with EST between 09/94 and 12/98. Pts. were followed up by physical examination and blood samples at 4, 24 and 48 hours af-ter EST. Complications were classified according to commonly accepted criteria (Gastrointest Endosc 1991: 338). Confirmative analysis of RF for AP was performed by uni- and multivariate methods, and the incidence of AP was compared between pts. who received heparin (HEP) and pts. without heparin (CON; control) considering known and suspected confounding variables (RF-analysis for AP). RESULTS: 815 pts. (53.3% m, 46.7% f, 61±17 y); complications 9.9% (81/815; 69 mild-moderate; 11 severe; 4 fatal). The incidence of AP was 6.4% (52/815; 48 mild-moderate; 4 severe; 0 fatal). Heparin was administered in 33.0% (269/815). Multivariate analysis identified 4 independent RF for AP: endoscopist-frequency ≤ 40EST/y (11.8% vs. 4.2%, p=0.002), female sex (9.2% vs. 3.9%, p=0.005), SOD (37.5% vs. 6.1%; p=0.011), pancreas divisum (18.7% vs. 5.9%, p=0.013), and one independent protective factor: heparin administration (3.3% vs. 7.9%; p=0.002). Additionally, prior laparoscopic cholecystectomy (14.3% vs. 6.0%, p=0.044) and pancreatic cannulation (7.8% vs. 4.3%, p=0.057) univariately showed an increased risk for AP. Pt.-age