1. Validation study of the Prague Barrett’s C&M Criteria
Prateek Sharma, M.D. Kansas City, USA
Chairman of the Barrett’s Oesophagus Working Subgroup of the International Working Group for the Classification of Oesophagitis

2. The Development and Validation of an Endoscopic Grading System for Barrett’s Esophagus: The Prague Barrett’s C&M Criteria
The aim of this exercise was to develop and validate explicit, consensus-driven criteria for the endoscopic diagnosis and grading of Barrett’s Esophagus
An international working group agreed on criteria and developed materials which included video endoscopic recordings gathered in a standardized manner
The criteria included assessment of the Circumferential (C) and Maximum (M) extent of the endoscopically visualized Barrett’s segment and other endoscopic landmarks
Sharma P, Dent J, Armstrong D et al., Gastroenterology 2006

3. Aims of the validation study of the Prague Barrett’s C&M Criteria
To determine inter-observer agreement on:
Circumferential extent of Barrett’s
Maximum extent of Barrett’s
Location, by cm of endoscope insertion of:
gastro-esophageal junction
diaphragmatic hiatus

4. Validation study materials (1)
Best possible image quality video-endoscopic recordings were made during 1 cm stepwise withdrawals of the endoscope from the upper stomach to above the maximum extent of endoscopic columnar metaplasia
Every attempt was made to display landmarks and other pertinent findings at each cm withdrawal station
The depth of endoscope insertion in cm from the incisors was documented during withdrawals and edited onto the video clips beside the endoscopic image

5. Validation study materials (2)
The video clip collection was reviewed by the Working Subgroup and the 29 most suitable clips were selected for scoring in the validation study
The selected video clips showed a full spectrum of different lengths and findings in relation to esophageal columnar metaplasia
The Working Subgroup developed detailed instructions and a standard score sheet for each video clip

6. Validation study processes
The numerically coded selected video clips arranged in random order, the instructions for evaluation, and the score sheets were sent on a DVD to 29 assessors in 14 countries
The selected assessors all had a strong interest in Barrett’s Esophagus
Assessors returned score sheets on each video clip to a central data collection point for entry into a database and analysis

7. Contributing assessors
R. Ackroyd U.K
A. Barkun Canada
T. Clarke Australia
G. Costamagna Italy
A. Edebo Sweden
R. Enns Canada
G. Falk USA
P. Fockens Netherlands
J. Hatlebakk Norway
R. Holloway Australia
G. Holtmann Australia
P. Katelaris Australia
A. Kruse Denmark
N. Marcon Canada
G. May Canada
S. Nandurkar Australia
H. Neuhaus Germany
M-A. Ortner Switzerland
G. Overholt USA
U. Peitz Germany
J. Regula Poland
J-F. Rey France
R. Sampliner USA
M. Schoeman Australia
S. Spechler USA
N.B. Vakil USA
J.L. Van Laetherm Belgium
K. Wang USA
H. Worth Boyce USA

8. Criteria for assessing the validation study video clips
For all landmarks, depth of insertion of endoscope was recorded, at the point where the feature was located
Assessors were instructed to locate the gastro-esophageal junction by either the most proximal position of the gastric folds or by the circumferential ring or pinch
Similarly, the assessors also recorded the position of the diaphragmatic hiatus and the circumferential and maximum extents of esophageal columnar metaplasia

9. Validation study data analysis
Inter-observer agreement was evaluated with the:
Reliability coefficient: a measure of agreement when there are more than 2 observers which compensates for agreement by chance
Reliability coefficient
<0.4 Poor
Fair/Good
>0.75 Excellent

10. Results - the Prague Barrett’s C&M Criteria validation study
22 assessors completed all ‘C’ and ‘M’ values for all 29 video clips
These data were used for analysis
Reliability coefficient values for both ‘C’ and ‘M’ were in the excellent range

11. Prague Barrett’s C&M Criteria: Results
Reliability coefficient values for
‘C’ extent 0.94 (95% CI: )
‘M’ extent 0.93 (95% CI: )
Sharma P, Dent J, Armstrong D et al., Gastroenterology 2006

12. Prague Barrett’s C&M Criteria: Results
Reliability coefficient values for
Proximal margin of gastric folds 0.88
Pinch at the distal esophagus 0.78
Diaphragmatic hiatus
Sharma P, Dent J, Armstrong D et al., Gastroenterology 2006

13. Prague Barrett’s C&M Criteria: Results
Kappa values for
Barrett’s any length 0.49
Barrett’s length < 1cm
Barrett’s length > 1cm
Sharma P, Dent J, Armstrong D et al., Gastroenterology 2006

14. Summary - Validation of the Prague Barrett’s C&M Criteria
The Prague Barrett’s C&M Criteria represent a major advance in the endoscopic recognition and grading of Barrett’s Esophagus
The reliability of these criteria is excellent
Endoscopic recognition of lengths of Barrett’s <1 cm has very low reliability