Distal Acid Exposure Research Articles

Three year’s experience with the Stretta procedure: did it really make a difference?

Endoscopic treatment is merging as a new option for GERD treatment. Many modalities have been used with modest short-term success, but no long-term follow-ups have been published. We present our 3-yr experience at Vanderbilt University using endoscopic radiofrequency energy (Stretta procedure) for GERD treatment. Patients with follow-up >6 months were prospectively studied under IRB protocol. All were mailed SF-12 health status questionnaire and GERD specific quality-of-life (QOLRAD) questionnaires, queries about satisfaction with Stretta, and medication use. All were invited for 24-hour pH study. Eighty-six Stretta procedures were performed between 8/2000 and 7/2003 on 85 patients; all were outpatients, 89% under conscious sedation. Seventy-seven patients qualified for the study; 61 completed the survey, 24 returned for pH study. Follow-up was 26.2 +/- 7.5 months (6-36). All were on daily PPIs, with proven GERD by pH study or endoscopy. Mean preoperative acid exposure time was 7.8+/-2.6%, mean DeMeester score was 40.2+/-17.6. Postoperative mean acid exposure time was 5.1+/-3.3 (p=0.001), DeMeester score was 29.5+/-20.5 (p=0.041). Normal postoperative acid exposure time (pH<4 in <4.2%) was achieved in 42% of patients tested. Patients were then divided according to medication use at the end of f/u in 2 groups: Responders (off or >50% decrease in PPI dose), and nonresponders (on >50% of original PPI dose, or had fundoplication). Response rate was 60% (39 patients), 8 nonresponders underwent fundoplication (12%). Satisfaction rate was 73%. Statistically significant difference was found between the 2 groups in all measurements; SF-12 physical and mental score for responders were 45.5+/-10.2, and 52.6+/-7.8; and for nonresponders were 37.8+/-11.2 and 40.9+/-11.3 (p=0.012, p=0.0001), respectively. Statistically significant difference was also found between responders and nonresponders in postoperative acid exposure (4.5+/-3.34 vs 7.2+/-2.3, p=0.034), and DeMeester score (26.3+/-20.4 vs 39.7+/-20.2, p=0.05). Paired T test was used to compare pre- and postoperative acid exposure in each group; statistically significant difference was found only among responders: total reflux time was 7.50+/-2.3 preop and 4.5+/-3.34 postop (p=0.0001), whereas for nonresponders it was 8.6+/-3.7 and 7.2+/-2.3 (p=0.8), DeMeester scores pre- and postop among responders were 40.0+/-19.7 and 26.3+/-20.4, respectively (p=0.016), whereas for nonresponders it was 40.5+/-14.3 and 39.7+/-20.2 (p=0.79). Stretta is a safe modestly effective, totally endoscopic treatment for GERD. Symptomatic improvement when achieved is often associated with correlating improvement in distal acid exposure. This exposure normalizes in nearly half the treated patients.

Simultaneous two-level esophageal 24-hour pH monitoring in patients with mild and severe esophagitis. Does probe position influence results of esophageal monitoring?

Simultaneous ambulatory esophageal pH monitoring was performed in 10 patients (group 1) with normal distal acid exposure and in 40 patients (group 2) with pathological distal reflux. The probes were placed 5 and 10 cm above the lower esophageal sphincter to quantify variations of pH values that can be due to a displacement of pH sensor. In group 1 the median percent time with pH < 4 for total and upright monitoring periods and composite score were significantly lower at the proximal than the distal level. In group 2 all pH data were significantly lower at the proximal than the distal level. The patients with pathological reflux were subdivided into two subgroups based on endoscopic findings (mild and severe esophagitis). The patients with severe esophagitis showed a proximal acid reduction higher than in patients with mild esophagitis. Nine patients with mild esophagitis showed normal values at 10 cm, but all patients with severe esophagitis had abnormal proximal acid exposure.

Frequency and Site of Gastroesophageal Reflux in Patients With Chest Symptoms: Studies Using Proximal and Distal pH Monitoring

Prolonged ambulatory pH monitoring was performed on 89 patients with previous diagnosis of asthma (27 patients), chronic cough (28 patients), noncardiac chest pain (34 patients), and on 27 healthy control subjects. The extent of gastroesophageal reflux (GER) was determined using a catheter containing two antimony pH electrodes positioned 5 cm and 20 cm above the superior border of the manometrically determined lower esophageal sphincter. Reflux was defined as a drop in pH to <4 in the distal esophagus. We compared both pH <4 and pH <5 as the beginning of reflux episodes for the proximal esophagus. Considering the confidence interval of 95% in healthy control subjects as a normality criterion, we found a prevalence of abnormal distal GER in 44% of asthmatics, 50% of patients with cough, and 53.8% of patients with noncardiac chest pain. Abnormal proximal acid exposure was found in 24% of asthmatics, 10.7% of patients with cough and 44.1% of patients with chest pain. Distal acid exposure was significantly longer than proximal esophageal acid exposure in all patient groups (p<0.05). There were no differences in the evaluation of proximal GER comparing pH <4 with pH <5. The data also indicate a tendency toward upright, rather than supine acid exposure. These results support the use of 24-h pH monitoring in patients with chest complaints and indicate that GER may frequently be involved in the pathogenesis. They do not support the theory that proximal GER is a specific etiologic factor in chronic cough or asthma. Prolonged ambulatory pH monitoring was performed on 89 patients with previous diagnosis of asthma (27 patients), chronic cough (28 patients), noncardiac chest pain (34 patients), and on 27 healthy control subjects. The extent of gastroesophageal reflux (GER) was determined using a catheter containing two antimony pH electrodes positioned 5 cm and 20 cm above the superior border of the manometrically determined lower esophageal sphincter. Reflux was defined as a drop in pH to <4 in the distal esophagus. We compared both pH <4 and pH <5 as the beginning of reflux episodes for the proximal esophagus. Considering the confidence interval of 95% in healthy control subjects as a normality criterion, we found a prevalence of abnormal distal GER in 44% of asthmatics, 50% of patients with cough, and 53.8% of patients with noncardiac chest pain. Abnormal proximal acid exposure was found in 24% of asthmatics, 10.7% of patients with cough and 44.1% of patients with chest pain. Distal acid exposure was significantly longer than proximal esophageal acid exposure in all patient groups (p<0.05). There were no differences in the evaluation of proximal GER comparing pH <4 with pH <5. The data also indicate a tendency toward upright, rather than supine acid exposure. These results support the use of 24-h pH monitoring in patients with chest complaints and indicate that GER may frequently be involved in the pathogenesis. They do not support the theory that proximal GER is a specific etiologic factor in chronic cough or asthma.