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sSa1194

The Effect of a pH Neutral Meal on Acid Gastroesophageal RefluxKarthik Ravi, David A. Katzka, Dawn L. Francis, Jacalyn A. See, Debra M. Geno

Background: The standard clinical practice of excluding the meal period during ambulatorypH monitoring has largely been based upon the idea that the ingested meal completelybuffers stomach acid and that early acid reflux may represent acidic foods rather than gastricacid. Aims: Isolate and measure early postprandial acid reflux and gastric buffering capacityby performing ambulatory pH monitoring with a pH neutral meal. Methods: Eighteen patientsundergoing clinically indicated ambulatory pH monitoring off all reflux therapy consumeda meal consisting of potatoes, hamburger, ice cream, and milk with a total of 1126 calories,53g of fat, and a pH of 5.9 while in the upright position. In addition to usual data analysis,monitoring of esophageal pH during the meal and during 15 minute intervals for 1 hourpostprandially was included. Results: Pathologic gastroesophageal reflux was present in 44%(8/18) of patients, while 56% (10/18) had physiologic esophageal acid exposure. Isolatedupright reflux occurred in 38% (3/8) with pathologic reflux, while 62% (5/8) had recumbentreflux. One patient had esophageal acid exposure during the meal (pH <4 for 0.6% of time).Gastroesophageal acid reflux was seen in 33% (6/18) of patients within 60 minutes of themeal, with 22% (4/18) demonstrating an esophageal pH <4 for >4.2% of the time. Totalesophageal acid exposure was abnormal in 50% (3/6) of patients with acid reflux withinone hour of the meal. Esophageal acid exposure time during the first hour after the mealtended to be greater in patients with pathologic esophageal acid exposure versus those withphysiologic acid exposure, but this did not reach statistical significance (5.9% ± 3.5% versus0.5% ± 0.5%, p=0.1). Isolated upright reflux was seen in 50% (3/6) patients with postprandialesophageal acid exposure, while the other half had recumbent reflux. Gastroesophagealreflux was seen within 15 minutes of the meal in 11% (2/18) of patients, with 9% (1/18)demonstrating an esophageal pH <4 for >4.2% during this period. In a subset of 5 patientswho had gastric and esophageal pH monitoring, the percent of time with gastric pH <4during the meal was 19.2%, 23.5%, 30%, 97.1%, and 99.9% while for 1 hour postprandialit was 21.2%, 21.8%, 41.4%, 70.4%, and 99.9% . This was consistent with incompletebuffering of gastric acid by the pH neutral meal. Further, 2 patients demonstrated esophagealacid exposure within 30 minutes of the meal despite a gastric pH > 4, suggesting gastroeso-phageal reflux of pooled acid in the gastric cardia despite buffering of acid in the gastricbody. Conclusions: The use of a pH neutral meal during pH monitoring may unmask earlypostprandial reflux of gastric acid and provide data on true gastric buffering. Whether thisprotocol should become standard for ambulatory monitoring needs further study.

Sa1195

Characteristics of Upright and Recumbent Reflux in Patients on PPI ThearpyShahid Ali, Nasser Hajar, Sonia Brar, Ronald Szyjkowski, Amine Hila

BACKGROUND: 24-hour multichannel intraluminal impedance and pH (MII-pH) esophagealmonitoring allows detection gastroesophageal reflux (GER). MII-pH allows identification ofacid and nonacid reflux, changes in esophageal pH, proximal extent of the refluxate andtotal duration of the reflux episodes. AIM: To assess reflux characteristics regarding proximalextent, acidity, and duration of the reflux episodes between upright position and recumbency.METHODS: We reviewed 59 consecutive ambulatory MII-pH studies performed in ourlaboratory between 2008 and 2009 (42 females; mean age = 48.3 yrs). All patients weretested while on acid suppressive therapy (PPI once or twice daily). Impedance detected thereflux episodes, pH defined their acidity. All tracings were analyzed and all reflux episodeswere assessed for: - bolus clearance time at 3 and 5 cm above the LES. The longest BCTwas retained as indicative of the duration of reflux. - baseline pre-reflux esophageal pH,lowest pH, and change in pH, calculated as the difference between baseline pH just priorto reflux, and the nadir. - proximal extent of the refluxate, as seen on the MII segments forevery reflux episode. All reflux episodes (both acid and non-acid) were included. Patient'sposition for each reflux episode was noted. RESULT: We had a total of 3032 MII-pHdetected reflux episodes, of which 481 (16%) occurred during recumbency. Comparingreflux characteristics between upright and recumbency we found that recumbent refluxcompared to upright position: 1) lasted significantly longer (mean BCT 58.3 vs 33.5 secrespectively; p<0.0001, unpaired t test). 2) had a significantly lower baseline pH (meanbaseline pH 5.4 vs 6.6 respectively; p<0.0001, unpaired t test). 3) was significantly moreacid (mean pH nadir 4.1 vs 5 respectively; p<0.0001, unpaired t test). 4) showed significantlyless change in pH (mean pH change 1.2 vs 1.6 respectively; p=0.014, unpaired t test). 5)did not reach higher in the esophagus (mean height 11.6 vs 11.8 cm respectively; p=0.36,unpaired t test). CONCLUSION: In patients on PPI therapy, nocturnal reflux lasts longer,is more acid, and causes less change in pH than daytime reflux in patients on PPI therapy.However, nocturnal reflux in these patients clearly did not reach higher in the esophagus.Since nocturnal reflux is known to have a higher risk of complications, this indicates thatlonger esophageal exposure time to reflux is probably a greater factor for damage thanproximal extent of reflux.

Sa1196

Increased Frequency of Transient Lower Esophageal Sphincter Relaxations: ACharacteristic in GERD PatientsHoon Il Kim, Su Jin Hong, Jae Pil Han, Seung Hyo Han, Won Young Cho, Tae Hee Lee,Joo Young Cho, Joon Seong Lee, Moon Sung Lee

Background: Transient lower esophageal sphincter relaxations (TLESRs) have been reportedas the main mechanism of gastroesophageal reflux disease (GERD). Longitudinal muscle(LM) contraction is related to development of TLESRs and lower esophageal sphincter (LES)lift is a possible surrogate marker of the LM contraction. Aim: Goal of this study was tocompare the characteristics (the LES lift, frequency and duration of TLESRs) between theGERD patients and the normal subjects by using high-resolution manometry (HRM). Thepressure and impedance data were displayed as superimposed color plots using the SierraScientific program. Methods: Studies were conducted in 9 patients with symptomatic GERDand 9 asymptomatic volunteers. All patients had typical symptoms of GERD more than once

S-250AGA Abstracts

a week and had evidence of endoscopic esophagitis. We used a custom designed HRMcatheter equipped with 36 solid-state pressure transducers, located 1 cm apart. The HRMtests were performed in semirecumbent position during one hour after intake of mixedliquid/solid meal (500 kcal) with 200 ml of orange juice. The characteristics of TLESRs weredetermined from the HRM. Results: Mean number of TLESRs per a subject was 2.8 in GERDgroup and 1.1 in healthy controls during one hour recording (p=0.0371). Duration ofTLESRs was 16.3±1.0 (mean±SE) seconds in GERD group and 16.0±4.0 seconds in healthycontrols (p=0.863). LES lift was 4.3±0.4 cm in GERD group and 4.6±0.6 cm in healthycontrols (p=0.372). Conclusions: Our study shows that GERD patients have significantlymore TLESRs in comparison with healthy subjects. We speculate that increased frequencyof LM contractions which induce TLESRs may have a major role in GERD.

Sa1197

Wireless pH Capsule Testing: The Effects of Diabetes and Narcotic Use andthe Safety of Clopidogrel and Warfarin During TestingBrian E. Lacy, Raymond T. Finn, Michael D. Crowell

Background: Wireless pH capsule testing is routinely performed to measure acid reflux. Theimpact of diabetes and narcotic use on wireless pH testing is unknown, while the safety ofwireless pH capsule testing in patients on clopidogrel and warfarin has not been examined.Aim: To evaluate the impact of diabetes and narcotic use on wireless pH monitoring andto evaluate the safety of wireless pH monitoring in patients taking clopidogrel or warfarin.Methods: Data was collected from consecutive patients referred for wireless pH capsuletesting. Demographics, BMI, symptoms (heartburn, regurgitation, chest pain, chronic cough,asthma, ENT symptoms), and the type, dose, and frequency of acid suppression wererecorded at the time of pH capsule placement. Charts were reviewed to determine whetherthe patient was on narcotics, warfarin, or clopidogrel at the time of testing, and to determinewhether the patient was diabetic (insulin requiring or oral medication). Patients remainedon clopidogrel during the study but stopped warfarin 3 days before the test. Standard pHdata was calculated and analyzed for Day 1, Day 2 and 48 hours (total). A study wasconsidered abnormal if the total fraction of time with acid reflux > 4.2% or if the 48-hour DeMeester score > 14.72.Adverse events were monitored by phone call after capsuleplacement and at the time the receiver was returned. Results: 1554 patients were evaluatedwith a mean (SD) age of 49.7 years (13.2) and a BMI of 28.8 (6.2). 42.3% were womenand 99% were Caucasian. 69% (n = 1077) of Pts had the wireless capsule placed transorallyin the motility lab after manometry while 31% were placed after upper endoscopy. Theprimary reason for testing was reflux symptoms (heartburn and regurgitation) in 74.5% ofPts, chest pain in 9.1%, ENT symptoms in 4.6% and pulmonary symptoms in 4.4%. 69.5%of Pts were studied off PPI therapy, while 30% were studied on PPI therapy. Of thosestudied on PPI therapy, 33.4% (n = 156) were on a q.d. PPI, while 58% (n = 271) wereon a b.i.d. PPI. 26 Pts were on clopidogrel (n = 1.7%) while 17 were on warfarin (1.1%).No complications occurred for Pts studied on either warfarin or clopidogrel. Prematuredetachment of the capsule occurred in 4.5% of Pts. 58 Pts had diabetes (3.8% of total);most of these had Type 2 DM (n = 37). 52 Pts (3.3%) were on chronic narcotics while 89(5.7%) were on p.r.n. narcotics. pH parameters were not significantly different for thosePts with DM or those on narcotics, either on or off PPI therapy, compared to those Ptswithout diabetes or not on narcotics. Conclusions: The results of wireless pH monitoringdo not seem to be affected by the use of narcotics or co-existing diabetes. No complicationsoccurred in the group of patients taking clopidogrel or warfarin. Routinely stopping clopidog-rel for wireless pH capsule testing may not be necessary.

Sa1198

Gender Differences in Results of Reflux Monitoring Studies in Patients WithSymptomatic GERDJohannes Lenglinger, Margit Eisler, Claudia Ringhofer, Martin Riegler

Background and aim: Symptomatic gastro-esophageal reflux Disease (GERD) is equallyprevalent in both genders, while complications are predominantly encountered in males.Gender differences in results of pH monitoring in healthy volunteers have been reportedpreviously, but no gender specific norm values are established. The aim of this study is toinvestigate gender differences in the results of pH- und impedance-pH-monitoring studiesin GERD patients. Methods: Distal esophageal acid exposure (% time with pH<4), numberof reflux events, and symptom correlation (using the symptom index [SI]) were rcomparedbetween male and female GERD patients. A retrospective analysis of reflux monitoring dataof adult GERD patients without previous foregut surgery or significant comorbidities, wasperformed. Reflux studies performed off proton pump inhibitor medication and a durationof 20 hours or more were included. 4.2% of recording time with pH<4, a reflux count of73 in impedance-pH studies and a SI of 50% were used as discriminators between positiveand negative test interpretation. Results: A total of 1721 data sets were eligible (1206 pH-and 515 impedance-pH-monitoring procedures). Gender distribution was balanced in pH-monitoring (m=49.7%, f=50.3%, n.s.) whereas significantly more females underwent imped-ance pH-monitoring (m=34.9%, f=65.1%, p<0.001). Acid exposure in upright position wascomparable between both types of procedures (pH<4 over 4.50% vs. 4.35% of recordingtime, n.s.). In recumbent position significantly higher acid exposure was found with pH-monitoring (4.0% vs. 0.5 %, p<0.001). Males had higher acid exposure than females (pH<4over 4.5% vs. 2.7%, p<0.001) and a higher number of reflux episodes (62 vs. 48, p<0.001).Symptom frequency of the main symptom was similar (2 vs. 3 events during monitoring,n.s.). Cough as main symptom was reported by a significantly higher percentage of females(9.0% vs. 4.1%, p<0.001). A positive SI was encountered in a comparable proportion ofpatients (m=35.2%, f=33.6%, n.s.). The rate of positive test results was higher in males thanfemales (m=75.4%, f=61.9%, p=0.003). A positive SI in studies with both acid exposureand number or refluxes in the normal range were more freuquently encountered in femalesthan males (11.0% vs. 5.1%, p=0.016). Conclusion: Results of reflux monitoring in sympto-matic GERD patients exhibit significant gender differences. Abnormal esophageal acid expo-sure and number of reflux events are significantly more frequently encountered in male thanfemale GERD patients, possibly explaining a higher prevalence of acid related complications inmales. Significantly more females than males have a positive SI as single positive parameter