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T1106 Duration of Reflux Events is an Important Factor in Induction of Reflux Symptoms in Patients on PPI Therapy
T1104 A Bayesian Method Using Esophageal Acid Exposure to Diagnose GERD Jerry D. Gardner, Sheldon Sloan, Malcolm Robinson, Philip B. Miner Introduction. The diagnosis of GERD is frequently based on the percent time pH<4 from a 24-hour esophageal pH recording. Values above a particular cutpoint, such as 5%, are defined as positive whereas values below this cutpoint are defined as negative. Intuitively, however, physicians know that there is little clinical difference between values of 5.1% and 4.9% even though only the former would be positive for GERD. In addition, one cutpoint might be useful for the clinical diagnosis of GERD, whereas another cutpoint might be useful for selecting GERD subjects to participate in a clinical trial. Bayes' rule can address these problems by providing a method to calculate the probability of GERD for a wide range of values for time esophageal pH<4. Methods. Bayes' rule (Posterior Probability = Prior Probability x Likelihood / Total Probability) was used to analyze values for time pH<4 from 24hour esophageal pH recordings from 26 healthy subjects and 56 GERD subjects who experienced heartburn at least 4 times/week for at least 6 months. Results. The area (95% CI) under the receiver-operator characteristic curve was 0.90 (0.83, 0.97). The value for time esophageal pH<4 that gave the largest difference between true-positive results and false-positive results was 4.8% and this cutpoint had a sensitivity of 89% and a specificity of 81%. The figure gives the posterior probability of GERD for all values of time esophageal pH<4 calculated using an unbiased prior probability of 0.5. As time esophageal pH<4 increases, the probability of GERD increases progressively to reach 1.0 at values greater than 10.8%. Conclusion. Bayes' rule can be used to calculate the probability of GERD for each of a range values for time esophageal pH<4 and can provide important quantitative insight that is not provided by simply labeling a given value “positive” or “negative” for GERD.
T1106 Duration of Reflux Events is an Important Factor in Induction of Reflux Symptoms in Patients on PPI Therapy Shahid Ali, Nasser Hajar, Richard Rackett, Ronald Szyjkowski, Amine Hila BACKGROUND: 24-hour multichannel intraluminal impedance and pH (MII-pH) esophageal monitoring allows detection of both acid and non-acid gastroesophageal reflux (GER). MIIpH allows the calculation of the duration of each reflux episode by providing bolus clearance time (BCT). We hypothesized that reflux episodes with longer duration are more likely to induce reflux symptoms. AIM: To assess the influence of BCT of refluxate on induction of reflux symptoms. METHODS: We reviewed 30 consecutive ambulatory MII-pH studies performed in our laboratory in 2008 (20 females; mean age = 46.3 yrs). All patients were tested while on acid suppression therapy (PPI once or twice daily). All tracings were analyzed and the BCT of each refluxate at 3 and 5 cm above the LES for every reflux episode (both acid and non-acid), were noted. The longest BCT was retained as indicative of the duration of reflux episode. RESULTS: We had a total of 1872 MII detected reflux episodes, of which 152 were associated with reflux symptoms. This association was defined by the patient reporting a symptom within the 5 minutes following a reflux event. 1293 episodes represented non-acid refluxes (pH remained above 4). Reflux events inducing a symptom showed longer BCT (mean 50 seconds) compared to reflux events not associated with symptoms (mean 41 seconds). This difference was statistically significant (p=0.0006; Mann-Whitney test). Symptoms reported were heartburn, regurgitation, throat clearing, cough and belching. CONCLUSION: In patients on PPI therapy, longer duration reflux events are more likely to induce GER symptoms. T1107 Influence of Symptom Index Time Windows on Association to Reflux Episodes Amit Aravapalli, Lubin F. Arevalo, Jason Roberts, Janice Freeman, Donald O. Castell, Daniel Pohl Background: Symptom association is used in the evaluation of symptoms presumably originating from both acid and non-acid reflux. A commonly used tool is the symptom index (SI). Data regarding time intervals between reflux episodes and symptom events are limited. In our lab, symptoms are considered as being related to reflux if they occurred within a 5 minute window after the onset of the reflux episode. Aims: Report associations for typical and atypical symptoms in association with acid and non-acid reflux episodes using time windows from 1 to 5 minutes. Methods: Tracings from 200 patients either on or off PPI therapy were screened. Patients with less than 2 total symptoms were excluded from the study (13 patients on PPI and 12 patients off PPI were excluded). We evaluated the SI for typical and atypical symptoms using 5, 4, 3, 2, and 1 minute time windows . A symptom was defined +SI if associated >50% with gastroesophageal reflux episodes. Results: Data from 87 symptomatic patients (52f, 35m) off PPI and 88 on PPI (57f, 31m) were eligible for analysis. Of 395 total reported symptoms, 126 (31.8%) were associated with reflux episodes (45% typical, 25.5% atypical, p<0.05) using a 5 minute SI. Symptoms were associated with 50 (12.6%) acid related and 60 (15.1%) non-acid related reflux episodes. Symptom association increased 56% for acid reflux and 365% for non-acid reflux episodes when increasing the time window from 1 to 5 minutes. Typical symptoms increased 90% (versus 142% atypical) when increasing the time window from 1 to 5 minutes. Conclusion: Typical symptoms are more often associated with reflux episodes. The increase in symptom association with lengthening of time window is more marked for non-acid reflux suggesting differences in mechanism of esophageal perception. Time intervals shorter than 5 minutes would potentially miss symptoms associated with non-acid reflux. Frequency of reflux related symptoms based on acid versus non-acid reflux
T1105 Comparison of Esophageal pH, Impedance, and High Resolution Manometry in Detecting Reflux After a Meal Seong Ran Jeon, Joon Seong Lee, Hee Hyuk Im, Yun Jung, Tae Hee Lee, Hyun Gun Kim, Won Young Cho, Bong Min Ko, Su Jin Hong, Jin-Oh Kim, Joo Young Cho, Moon Sung Lee Background & Aim: The 24-hour ambulatory esophageal pH monitoring has been extensively used in the detection of gastroesophageal reflux (GER). However, major drawback of this method is low sensitivity. Manometric method using common cavity phenomenon somewhat improved sensitivity with difficult interpretation. Development of impedance (Imp) monitoring improved sensitivity to detect GER. Recent introduction of high-resolution manometry (HRM) could increase diagnostic yield of various esophageal motor disorders. HRM may increase the detection of GER event using transient lower esophageal sphincter relaxation with common cavity. Aim of this study was to compare three methods (pH, Imp and HRM)
S-489
AGA Abstracts
AGA Abstracts
in GER detection. Patients & Methods: Twelve healthy volunteers (median age, 24 year; 10 males) were recruited. All underwent pH, Imp, and HRM tests simultaneously for 2 hours after standardized meal. A solid-state manometric assembly with 36 circumferential sensors in 1 cm intervals (ManoViewTM, Sierra Scientific, Inc., USA) was used for HRM. We investigated the frequency of GER event in each three methods irrespective of specificity. Results: There were total 252 GER events in all subjects. HRM detected more GER events (87.7 %, 221/252) than Imp (44.4 %, 112/252) or pH (16.3 %, 41/252) (p < 0.05). Only 8.7 % were detected simultaneously by all three methods. HRM was the only method to detect 48 % (121/252), while detection rate only by pH (7.5 %, 19/252) or Imp (4.8 %, 12/252) was rare. Most GER events detect by HRM were not detected by the pH monitoring (Figure 1). Conclusions: HRM is more sensitive than Imp and pH monitoring in GER detection after a meal, irrespective of specificity. These may reflect the finding that HRM could detect minute reflux events under 5 cm above lower esophageal sphincter.
T1106 Duration of Reflux Events is an Important Factor in Induction of Reflux Symptoms in Patients on PPI Therapy Shahid Ali, Nasser Hajar, Richard Rackett, Ronald Szyjkowski, Amine Hila BACKGROUND: 24-hour multichannel intraluminal impedance and pH (MII-pH) esophageal monitoring allows detection of both acid and non-acid gastroesophageal reflux (GER). MIIpH allows the calculation of the duration of each reflux episode by providing bolus clearance time (BCT). We hypothesized that reflux episodes with longer duration are more likely to induce reflux symptoms. AIM: To assess the influence of BCT of refluxate on induction of reflux symptoms. METHODS: We reviewed 30 consecutive ambulatory MII-pH studies performed in our laboratory in 2008 (20 females; mean age = 46.3 yrs). All patients were tested while on acid suppression therapy (PPI once or twice daily). All tracings were analyzed and the BCT of each refluxate at 3 and 5 cm above the LES for every reflux episode (both acid and non-acid), were noted. The longest BCT was retained as indicative of the duration of reflux episode. RESULTS: We had a total of 1872 MII detected reflux episodes, of which 152 were associated with reflux symptoms. This association was defined by the patient reporting a symptom within the 5 minutes following a reflux event. 1293 episodes represented non-acid refluxes (pH remained above 4). Reflux events inducing a symptom showed longer BCT (mean 50 seconds) compared to reflux events not associated with symptoms (mean 41 seconds). This difference was statistically significant (p=0.0006; Mann-Whitney test). Symptoms reported were heartburn, regurgitation, throat clearing, cough and belching. CONCLUSION: In patients on PPI therapy, longer duration reflux events are more likely to induce GER symptoms. T1107 Influence of Symptom Index Time Windows on Association to Reflux Episodes Amit Aravapalli, Lubin F. Arevalo, Jason Roberts, Janice Freeman, Donald O. Castell, Daniel Pohl Background: Symptom association is used in the evaluation of symptoms presumably originating from both acid and non-acid reflux. A commonly used tool is the symptom index (SI). Data regarding time intervals between reflux episodes and symptom events are limited. In our lab, symptoms are considered as being related to reflux if they occurred within a 5 minute window after the onset of the reflux episode. Aims: Report associations for typical and atypical symptoms in association with acid and non-acid reflux episodes using time windows from 1 to 5 minutes. Methods: Tracings from 200 patients either on or off PPI therapy were screened. Patients with less than 2 total symptoms were excluded from the study (13 patients on PPI and 12 patients off PPI were excluded). We evaluated the SI for typical and atypical symptoms using 5, 4, 3, 2, and 1 minute time windows . A symptom was defined +SI if associated >50% with gastroesophageal reflux episodes. Results: Data from 87 symptomatic patients (52f, 35m) off PPI and 88 on PPI (57f, 31m) were eligible for analysis. Of 395 total reported symptoms, 126 (31.8%) were associated with reflux episodes (45% typical, 25.5% atypical, p<0.05) using a 5 minute SI. Symptoms were associated with 50 (12.6%) acid related and 60 (15.1%) non-acid related reflux episodes. Symptom association increased 56% for acid reflux and 365% for non-acid reflux episodes when increasing the time window from 1 to 5 minutes. Typical symptoms increased 90% (versus 142% atypical) when increasing the time window from 1 to 5 minutes. Conclusion: Typical symptoms are more often associated with reflux episodes. The increase in symptom association with lengthening of time window is more marked for non-acid reflux suggesting differences in mechanism of esophageal perception. Time intervals shorter than 5 minutes would potentially miss symptoms associated with non-acid reflux. Frequency of reflux related symptoms based on acid versus non-acid reflux
T1105 Comparison of Esophageal pH, Impedance, and High Resolution Manometry in Detecting Reflux After a Meal Seong Ran Jeon, Joon Seong Lee, Hee Hyuk Im, Yun Jung, Tae Hee Lee, Hyun Gun Kim, Won Young Cho, Bong Min Ko, Su Jin Hong, Jin-Oh Kim, Joo Young Cho, Moon Sung Lee Background & Aim: The 24-hour ambulatory esophageal pH monitoring has been extensively used in the detection of gastroesophageal reflux (GER). However, major drawback of this method is low sensitivity. Manometric method using common cavity phenomenon somewhat improved sensitivity with difficult interpretation. Development of impedance (Imp) monitoring improved sensitivity to detect GER. Recent introduction of high-resolution manometry (HRM) could increase diagnostic yield of various esophageal motor disorders. HRM may increase the detection of GER event using transient lower esophageal sphincter relaxation with common cavity. Aim of this study was to compare three methods (pH, Imp and HRM)
S-489
AGA Abstracts
AGA Abstracts
in GER detection. Patients & Methods: Twelve healthy volunteers (median age, 24 year; 10 males) were recruited. All underwent pH, Imp, and HRM tests simultaneously for 2 hours after standardized meal. A solid-state manometric assembly with 36 circumferential sensors in 1 cm intervals (ManoViewTM, Sierra Scientific, Inc., USA) was used for HRM. We investigated the frequency of GER event in each three methods irrespective of specificity. Results: There were total 252 GER events in all subjects. HRM detected more GER events (87.7 %, 221/252) than Imp (44.4 %, 112/252) or pH (16.3 %, 41/252) (p < 0.05). Only 8.7 % were detected simultaneously by all three methods. HRM was the only method to detect 48 % (121/252), while detection rate only by pH (7.5 %, 19/252) or Imp (4.8 %, 12/252) was rare. Most GER events detect by HRM were not detected by the pH monitoring (Figure 1). Conclusions: HRM is more sensitive than Imp and pH monitoring in GER detection after a meal, irrespective of specificity. These may reflect the finding that HRM could detect minute reflux events under 5 cm above lower esophageal sphincter.