Abstract Book UEG Week 2020 - 92

Sunday, October 11, 2020

Results: Nulliparous HV (median: 32, range: 18-67, n=41) were significantly
younger than parous HV (45, 31-64, p < 0.01, n=32) and FI (45, 30-72, p <
0.01, n=50). By conventional HR-ARM measures, 20% of patients had hypotonia, 38% had hypocontractility, 6% had hypotonia with hypocontractility, and 36% had normal findings. The dominant slow wave frequency in all
groups was ~16 cpm, with a second peak frequency at ~1.5 cpm. Patients
with FI had significantly lower amplitude across all frequencies compared
to both parous and nulliparous HV. Parous HV also had a significantly
lower amplitude across all frequencies compared to healthy nulliparous
females. In all three groups there was a biphasic direction of propagation
of slow waves; retrograde at 16 cpm; antegrade at ~4 cpm. This did not
differ between the groups.

Tuesday, October 13, 2020

Monday, October 12, 2020

Anal slow wave frequency (cpm)
Group

0.5

1

1.4

2.8

4

8

16

23

32

Nulliparous
HV

1.43
(2.5)

1.89
(2.65)

2.18
(2.36)

2.02
(1.84)

1.87
(1.75)

1.39
(2.04)

3.43
(2.44)

1.49
(2.03)

0.33
(1.81)

Parous HV

1.05
(2.39)

1.34
(2.53)

1.55
(2.33)

1.46
(1.81)

1.35
(1.68)

1.02
(1.86)

2.54
(2.24)

1.11
(1.89)

0.25
(1.7)

FI

0.84
(2.43)

0.98
(2.44)

1.12
(2.39)

1.09
(1.95)

1.05
(1.79)

0.84
(1.93)

2.13
(2.5)

0.94
(2.15)

0.21
(1.77)

Values represent mean amplitude (SD)

[Table. Amplitude of slow wave frequencies between groups ]
Conclusion: Wavelet analysis represents a novel, computational method
for analysing anal slow waves captured by HR-ARM. The dominant frequency demonstrated herein agrees with findings from conventional manometry4 and animal studies5. This analysis indicates that slow wave amplitude is reduced in female FI compared to both healthy nulliparous and
parous women. Childbirth also appears to reduce slow wave amplitude in
comparison to nulliparous women. Retrograde propagation observed at
~16 cpm may represent an important physiological mechanism to 'clean'
the anal canal and help maintain continence.
References: 1. Carrington EV, et al. (2020) The international anorectal
physiology working group (IAPWG) recommendations: Standardized
testing protocol and the London classification for disorders of anorectal function. Neurogastroenterology & Motility 32:e13679. 2. Wiklendt L,
et al. (2020) Autonomic Neuroscience: A Novel Method for Electrophysiological Analysis of EMG Signals using MesaClip. Manuscript submitted for
publication. 3. Wiklendt, L. et al. (2019) Bayesian Functional Mixed-Effects
Model with Gaussian Process Responses for Wavelet Spectra of Spatiotemporal Colonic Manometry Signals. arXiv preprint arXiv:1912.02389.
Unpublished. 4. Sun WM and Rao S. Manometric assessment of anorectal
function. Gastroenterology Clinics of North America, 2001; 30 (1): 15-32. 5.
Hall KA, et al. Spatial organization and coordination of slow waves in the
mouse anorectum. J Physiol 2014;592:3813-3829
Disclosure: MS has received honoraria for teaching from Laborie. CHK has
received financial remuneration from Medtronic Inc. as speaker fees and
for expert advisory committees

92

OP132

TOPOGRAPHICAL DISTRIBUTION OF MICROSCOPIC COLITIS, NUMBER
OF BIOPSIES NECESSARY FOR DIAGNOSIS, AND IMPORTANCE OF
ORIENTATION OF PARAFFIN EMBEDDED BIOPSIES

Kanstrup Feihn A.-M.1, Engel P.J.H.2, Lanzarotto F.3, Goudkade D.4,
Landolfi S.5, Munck L.K.6,7, Villanacci V.8
1
Zealand University Hospital, Pathology and Surgery, Koege,
Denmark, 2Zealand University Hospital, Patholgy, Roskilde,
Denmark, 3Spedali Civili - Brescia Dept. of Gastroenterology,
Brescia, Italy, 4Zuyderland Medical Centre, Pathology, Geleen,
Netherlands, 5Hospital Universitari Vall d'Hebron, Pathology,
Barcelona, Spain, 6Zealand University Hospital Koege,
Gastroenterology, Koege, Denmark, 7University of Copenhagen,
Departement of Clinical Medicine, Copenhagen, Denmark, 8Spedali
Civili - University of Brescia, Pathology, Brescia, Italy
Contact E-Mail Address: lkmu@regionsjaelland.dk
Introduction: The diagnosis microscopic colitis (MC) in patients with
chronic watery diarrhea relies on specific histopathological findings in colon biopsies. The number of biopsies and targeted colon segments needed to diagnose MC remains unknown. Consensus on the MC subgroup
diagnosis of patients enrolled in a European prospective follow-up study
has been established.
Aims & Methods: To determine the number and site of biopsies necessary
for the diagnosis and the effect of perpendicular orientation when embedding the biopsies. This multicenter European study included 42 patients
with a consensus diagnose of collagenous colitis (CC), 51 with lymphocytic
colitis (LC) and three with incomplete lymphocytic colitis. The number of
individually diagnostic biopsies from each patient were determined by a
retrospective reevaluation of all biopsies from each of these patients.
Results: Overall, the diagnostic rate of 744 individual biopsies from 96 patients with MC was 69.5% for the specific MC subgroup, increasing to 79.4%
for MC and 93.4% when including both MC and incomplete MC (MCi). The
risk of missing a diagnosis of the specific subgroup of MC when analyzing four biopsies was 0.87% decreasing to 0.18% for MC and 0.0019% if
accepting MCi as diagnostic. More biopsies from the right colon were diagnostic for the specific MC subgroup (76.3% vs. 64.0%, p=0.0014). The
number of patients with biopsies not diagnostic for the consensus diagnosis in either the right or the left colon was four and six, respectively. Use of
cellulose filters for embedding biopsies with a perpendicular orientation
resulted in a higher diagnostic rate for the specific MC subgroup (73.1% vs.
65.0%, p=0.0201) mainly related to the diagnosis of CC in the right colon.
Conclusion: Histological changes diagnostic for MC were present in most
of the examined biopsies with right colon and orientated biopsies more
often being diagnostic. Our findings indicate that four biopsies from the
colon, rectum excluded, are sufficient to diagnose MC.
Disclosure: The study was partly funded by a UEG link award

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