Upper Esophageal Sphincter (UES) Dynamics in Gastroesophageal Reflux (GERD).
ABSTRACT:
	Studies
of the response of the UES to infused acid or to GER have provided
varied results. We studied UES and GER in 93 consecutive patients
with stationary manometry followed by pH monitoring for 24 hours.
Following solid-state esophageal manometry, pH probes were placed
proximally (20 cm above the  LES) and distally (5 cm above the LES)
and acid exposure was recorded for 24 hours. Proximal refluxers ( PR;
N=28) had proximal % time pH < 4 of > 1.3 % upright or > 1.0
% or more supine. Distal  refluxers (DR; N=29) distal acid exposure >
6.3 % upright and/or > 1.2 % supine. Normal refluxers (NR; N=36)
had acid exposure below the above limits. Manometry was performed on
all 93 patients blindly to determine the resting pressure (UESP), UES
relaxation residual pressure (RP), and UES relaxation duration (UESD)
as well as the onset of  pharyngeal contraction to the onset of UES
relaxation (On/On). Results: Statistical comparisons of UES function
in the 3 patient groups shown below as mean (SE).

UESP (mmHg) NR 73.4 (4.6), PR
64.3(6.9)*, DR 88.8(9.3)*; RP(mmHg)  1.1(1.0), 0.15(1.4), 1.2(0.7)
respectively; UESD (msec) 574 (24), 530 (34), 564 (24) respectively;
and On/On (msec) -102 (42), -148 (38), -124 (30) respectively. *p
=0.04 (ANOVA). Mean resting UESP was significantly lower in PR
patients than DR patients, but neither differed from NR patients. All
other parameters were not different for the 3 patient groups.
Conclusion: GER has no consistant effect on UES dynamics. In
particular, we find no support for the suggestion that abnormal
proximal reflux results in increased UES resting pressure.



Introduction:
	Our
understanding of the UES dynamics in the setting of GER has been a
contraversial subject throughout the last 20 years. The UES
properties are subtle and complex. As a consequece of  the limited
technological modalities utilized in the past, we have lacked an
accurate and objective system to explore the UES properties and
functions (1).  Among clinicians and researchers alike, this subject
could shed light on the possible etiologies of chest dyscomfort and
other symptoms that has ailed man throughout history. But the dilemma
remains and this has lead to great interest in how GER influences the
UES.
	There
are theories which propose  acid exposure causes a direct stimulus by
irritation of the UES area and thus increasing the  UES tonicity (2).
Others have postulated that GERD disrupts the normal function of the
UES and hence leads to variois pharyngeal symptoms (3). All studies,
thus far, continue to produce variable results and much speculation.
With the advent of solid-state computerized manometry, it is now
possible to obtain more reliable and reproducible data (4). 

	
The purpose of our study is to measure the pressure and response of
the UES in the setting of gastroesophageal reflux and to reveal any
differences between subjects that have abnormal reflux and those that
do not.
Patients
and Methods:
	
117 consecutive patients were studied using stationary  manometry and
24 hour pH  monitoring. These patients had been referred to our
laboratory with symptoms ranging from hoarseness, dysphagia to
chestpain. Patients with a diagnosis of scleroderma or achalasia were
excluded from the study. We divided the remaining 93 patients into
groups based on the extent of their esophageal reflux. 

	Manometric
studies were done using a catheter containing 4 solid state
transducers spaced at 5, 3, and 2 cm intervals(from proximal to
distal). The two most distal transducers were circumferential
transducers and the remaining 2 most proximal transducers were
unidirectional (Koningsbberg Instruments). This was connected to a
computerized recording system (Synectics polygram). The catheter was
inserted through the nostril until a gastric pressure reading
registered.  A slow station pull through technique was used to locate
and measure the UES and LES pressures.  Manometry was performed
blindly to obtain  resting UES pressure (UESP), UES relaxation
residual pressure (RP), and UES relaxation duration (UESD) and  onset
of pharyngeal contraction to the onset of UES relaxation (on/on).
	Esophageal
 pH monitoring was done using  a 24 hour pH monitoring device
consisting of a triple  pH electrodes ( Gastric, Proximal / Distal
Esophagus). The esophageal pH probes were placed  proximally at 20 cm
above the LES and distally at 5 cm above the LES. The patients were
instructed to pursue there usual daily activities and to keep a diary
documenting  any symptoms, eating or time spent in the recumbent  or
upright position. Based on these results, the patients were divided
into 3 groups. The groups were defined as Proximal Refluxers (PR;
N=29) who had % time that pH < 4, greater than 1.3% in upright
position or greater than 1.0% in the supine position. Distal
Refluxers (DR; n=29) were those with % time that pH <4 in the
distal esophagus  was  greater than 6.3% in the upright position or
greater than 1.2 % in the supine position. Normal Refluxers (NR;
N=36) had % time less than the above. 

	All
statistical analysis were done on Microsoft Excel software using
ANOVA  and data description analysis.
RESULTS:
	Of
the 116  patients in our study, those that had a diagnosis of either
achalasia or scleroderma were excluded . Based on the % time of
reflux in either the upright and supine position we devided the
individuals into three groups. The total number of distal refluxers
was 29 individuals,  9 of which were females and 20 males and ages
ranging from 20 to 70 years. The average UES pressure for this group
equaled 88.82 mmHg; average UESR pressure equaled -1.16; UESD in msec
equaled 563; and the average time for Onset of pharyngeal relaxation
to the onset of UES relaxation (On/On) equaled -124.1 msec. The
proximal refluxers totaled 28 individuals, 14 of which were females
and 14 males, ages ranging from 22-80 years of age. The average UES
pressure for the proximal refluxers equaled 65.06 mmHg; the
averageUES presser equaled 0.15 mmHg; the average time for UESD in
msec equaled 538.3; and the average On/On equaled -162.7 msec. The
total number of normal refluxers equaled 36,  19 of which were 
female and 17 males and ages that ranged from 27 to 75 years. The
average UES pressure equaled 73.38 mmHg; the average UESR pressure
equaled -1.056; the average time for UESD in msec equaled 574 msec;
the average On/On time in msec equaled -101.8. These parameters are
illustrated in averages on figure 1. These averages were compared
using the t-Test  assuming Unequal Variances (Table. 1). In all four
parameters, our study did not reveal a statistically significant
difference between normal refluxers and abnormal refluxers. There was
an appreciable difference in  UES pressure  between the proximal
refluxers and the distal refluxers.    

DISCUSSION:
	It
had been suggested since the 1970’s by Hunt et al, that resting
UES pressure was elevated secondary to GER. This study was limited by
the use of a nonperfused catheter manometric device (). Previous to
this, Winans, Harris and Pope had established that a constant
perfusion catheter system was warranted to measure wide ranging
sphincter pressures (). They went further to point out that the
spacial orientation of the cathater side-hole can affect overall
accuracy if not maintained constant. Nevertheless, Winan’s
finding failed to show any significant difference in UES pressure
between normals and refluxers (). 


	The issue continued to exhibit
contention when other studies had different results. Watson and
Sullivan conducted a study using  a continuos perfusion system and 
by manipulating catheter orientation he was able to achieve optimal
pressure recordings of the UES. Taking  Winans observation into
account, Watson et al concluded that previous data on the UES
pressures were inaccurate. Watson’s data revealed higher UES
resting pressures in subjects with globus symptoms. From this it was
concluded that globus was related to elevated UES pressures ().  A
study by  Stanciu and Bennett using a polyvinyl continuous perfusion
catheter, demonstrated data that again contradicted the preceding
theories (). By the mid  70’s, it was well recognized that our
inability to accurately measure UES pressure dynamics, prevented us
from defining normal values ().  


	With the advent of computerized solid
state manometry, we have demonstrated that it is now possible to
measure the UES dynamics with greater accuracy  and reproducibility
().This reproducibility has been documented  in previous studies
conducted within our lab (). Based on this advantage that are
predecessors lacked,  our study sought to establish weather or not a
relation exists between GRE and upper esophageal sphincter dynamics .
Our results clearly demonstrate that there is no  consistant effect
of GER on the UES dynamics. These results are in agreement with
Winnan Stanciu and Bennetts previous results. We recognize that our
study may not reflect the general population since it is based on a
referral population. Yet these patients were studied consecutively
and prospectively within our laboratory.
  It
is noteworthy to mention that all proximal refluxers are
simultaneously distal refluxers. This  overlap likely accounts for
the statistically significant  difference seen between our defined
proximal and distal refluxers. One can expand on this by 
hypothesizing that the mechanism may involve a chronic
pathophysiological condition; where the proximal refluxers UES
mechanics have deteriorated into low  UESP. The relatively functional
UES in distal refluxers (in the setting of a relatively intact
esophageal stroma) could respond with a slight increase of UESP. This
could explain the significant difference between the UESP of distal
and proximal relfluxers.  Could  it be that the nauseous stimuli in
“normal refluxers”  never reaches the threshold required
to induce a UES response?  Since our study does not account for the
duration of  this pathological process, the  chronicity of esophageal
exposure to acid could hold the  key to understanding the function of
the UES mechanics in this setting. This would be better understood if
the study included a random sample of the population of normal
individuals without symptoms and compare them to patients within our
study. Our study concludes that UESP  in response to GERD  has no
significant direct causative role  in the symptomatology of GERD. 




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