Changes in satiety, supra- and infraband transit, and gastric emptying following laparoscopic adjustable gastric banding: a prospective follow-up study.

BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) induces and sustains weight loss, likely by activating the peripheral satiety mechanism. Recent data suggests that food is not retained above the optimally adjusted LAGB, suggesting that an alternate mechanism is inducing satiety. How transit and gastric emptying change following LAGB and correlate with satiety and weight loss have not been adequately defined. METHODS: LAGB patients underwent preoperative and 12-month follow-up nuclear scintigraphic assessments of esophageal transit and gastric emptying. A new technique that allowed the calculation of emptying times and transit through the supra- and infraband compartments was used to assess emptying and transit patterns postoperatively. RESULTS: Postoperatively, patients reported increased satiety both after a standard fast (3.7 ± 2.3 vs. 4.8 ± 2.1, p = 0.04) and following a standard semisolid meal (5.9 vs. 7.8 ± 1.7, p = 0.003). The mean percent excess weight loss was 48.5 ± 23.2%. The gastric emptying half-time (minutes) did not change significantly (63.5 ± 41.1 vs. 73.3 ± 26.8, p = 0.64). Semisolid transit into the infraband stomach was delayed briefly postoperatively in more patients (11 vs. 2, p = 0.001). There was minimal retention of the meal above the LAGB 2 min after commencing the gastric emptying study (median, 3%; interquartile range, 1.75-10); therefore, an emptying half-time of the supraband region could not be defined. CONCLUSIONS: Weight loss, satiety, and early satiation following LAGB were associated with briefly delayed bolus transit into the infraband stomach. Retention of the semisolid meal above the LAGB was not observed. This is further evidence that suggests satiety develops following LAGB without physical restriction of meal size.

Effects of adjustable gastric bands on gastric emptying, supra- and infraband transit and satiety: a randomized double-blind crossover trial using a new technique of band visualization.

BACKGROUND: The laparoscopic adjustable gastric band (LAGB) has previously been classified as a restrictive procedure; physically limiting meal size. Recently, the key mechanism has been hypothesized to be the induction of satiety without restriction. Effects can be controlled by modifying LAGB volume, possibly as a result of effects on gastric emptying or transit through the LAGB. METHODS: Successful LAGB patients underwent paired, double blinded, esophageal transit and gastric emptying scintigraphic studies; with the LAGB at optimal volume and near empty. A new technique allowed assessment of emptying and transit through the infra- and supraband compartments. RESULTS: Fourteen of 17 patients completed both scans (six males; mean age, 48.9 ± 11.3 years, % excess weight loss 69.0 ± 15.2). At optimal volume a delay in transit of semi-solids into the infraband compartment was observed in ten patients vs. three when the LAGB was empty, (p = 0.01). The median retention of a meal in the supraband compartment immediately after cessation of intake was: empty 2.8% (2.3-7.9) vs. optimal 3.6% (1.7-4.5), (p = 0.57). Overall gastric emptying half time (minutes) was normal at both volumes: optimal 64.2 ± 29.8 vs. empty 95.2 ± 64.1, (p = 0.14). LAGB volume did not affect satiety before the scan: optimal 4.3 ± 1.9 vs. empty 4.0 ± 2.2, (p = 0.49), or 90 min later: optimal 6.1 ± 1.9 vs. empty 5.9 ± 1.4, (p = 0.68). CONCLUSIONS: The optimally adjusted LAGB briefly delays semi-solid transit into the infraband stomach without physically restricting meal size. The supraband compartment is usually empty of an ingested meal 1-2 min after intake ceases and overall gastric emptying is not affected.

Predicting outcomes of intermediate term complications and revisional surgery following laparoscopic adjustable gastric banding: utility of the CORE classification and Melbourne motility criteria.

BACKGROUND: Patients with laparoscopic adjustable gastric bands (LAGB) present at times with adverse symptoms or unsatisfactory weight loss, where a liquid contrast swallow or upper gastrointestinal endoscopy is not diagnostic. Stress barium and high resolution manometry are promising investigations, however, have not yet been established as clinically useful. METHODS: Patients with an unsatisfactory outcome following LAGB, where liquid contrast swallow and endoscopy were not diagnostic, were evaluated using high resolution video manometry and a stress barium. Pre-operative and follow-up clinical data were collected. Esophageal motility was assessed using the Melbourne criteria. RESULTS: There were 143 participants in the study. Stress barium identified the following appearances: gastric enlargement (n = 57), transhiatal enlargement (n = 44), pan-esophageal dilatation (n = 9), and anatomically normal (n = 33). Twenty-four (72%) of the anatomically normal patients had deficient esophageal motility. Revisional LAGB surgery was performed in 56 patients. This was successful in gastric enlargements when motility was intact (percentage of excess weight loss (%EWL) 58.3 ± 16.2 vs. 35.4 ± 19.7, p = 0.002). Revisional surgery for transhiatal enlargements improved symptoms but did not improve poor weight loss (%EWL 20.6 ± 24.9 vs. 17.2 ± 25, p = 0.1). CONCLUSIONS: The CORE classification combines anatomical change with esophageal motility and has been defined for intermediate term complications following LAGB where conventional investigations have not been diagnostic. Revisional LAGB surgery is helpful for patients with a gastric enlargement above the LAGB if esophageal motility is intact. If motility is deficient or there is an esophageal anatomical abnormality, intervention is not likely to remedy poor weight loss.

Mechanisms of bolus clearance in patients with laparoscopic adjustable gastric bands.

BACKGROUND: The components of esophageal function important to success with laparoscopic adjustable gastric banding (LAGB) are not well understood. A pattern of delayed, however, successful bolus transit across the LAGB is observed. METHODS: Successful LAGB patients underwent a high-resolution video manometry study in which bolus clearance, flow, and intraluminal pressures were recorded. Liquid and semi-solid swallows and stress barium (a combination of semi-solid swallows and liquid barium) were performed. A new measurement, the lower esophageal contractile segment (LECS), was defined and evaluated. RESULTS: Twenty patients participated (mean age 48.3 +/- 12.0 years, four men, %excess weight loss 65.6 +/- 18.0). During semi-solid swallows, two patterns of esophageal clearance were observed: firstly, a native pattern (n = 10) similar to that which is expected in non-LAGB patients; secondly, a lower esophageal sphincter-dependent pattern (n = 7), where flow only occurred when the intrabolus pressure increased during the lower esophageal sphincter (LES) aftercontraction. In both patterns, if there was incomplete bolus clearance, reflux was observed and was usually followed by another swallow. A mean of 4.5 +/- 2.9 contractions were required to clear the semi-solid bolus. Contractions with an intact LECS demonstrated longer flow duration: 7.1 +/- 3.8 vs.1.6 +/- 3.2 s, p < 0.005. During the stress barium, an intrabolus pressure of 44.5 +/- 16.0 mm Hg leads to cessation of intake. CONCLUSIONS: In LAGB patients, normal esophageal peristaltic contractions transition to a LES aftercontraction, producing trans-LAGB flow. Repeated contractions are required to clear a semi-solid bolus. Incorporating measurements of the LECS into assessments of esophageal motility in LAGB patients may improve the usefulness of this investigation.

Criteria for assessing esophageal motility in laparoscopic adjustable gastric band patients: the importance of the lower esophageal contractile segment.

BACKGROUND: Esophageal function appears critical in laparoscopic adjustable gastric band (LAGB) patients; however, conventional motility assessments have not proven to be clinically useful. Recent combined video fluoroscopic and high-resolution manometric studies have identified important components of esophageal function in LAGB patients. METHODS: Successful and symptomatic LAGB patients, with normal or mildly impaired esophageal peristalsis, underwent a standardized, water swallow, high-resolution manometry protocol designed specifically to assess the lower esophageal contractile segment (LECS), in combination with conventional measures of esophageal motility. Differences in response to changes in LAGB volume were assessed. RESULTS: There were 101 symptomatic and 29 successful patients. More symptomatic patients had a mild impairment in esophageal motility (39.6% vs. 3.4%, p < 0.005). Successful patients demonstrated an intact LECS during normal swallows more frequently than symptomatic patients (95% vs. 43%, p < 0.005). Absolute intraluminal pressures were not different between the groups. Removing all fluid from the LAGB revealed more hypotensive swallows in the symptomatic patients (30% vs. 17%, p = 0.002), an effect not observed when the LAGB volume was increased (8% vs. 5%, p = 0.21). Receiver operator characteristic analysis determined that an intact LECS in 70% of normal swallows defined normal motility in LAGB patients. CONCLUSIONS: The LECS is a valuable measure of esophageal function in LAGB patients and complements conventional manometric criteria. Symptomatic patients have less normal swallows; however, these also frequently demonstrate a deficient LECS. Further information can be elucidated by performing swallows at differing LAGB volumes. High-resolution manometry, using these adapted criteria, is now a useful in the investigation in symptomatic LAGB patients.

Pathophysiology of laparoscopic adjustable gastric bands: analysis and classification using high-resolution video manometry and a stress barium protocol.

BACKGROUND: Symmetrical pouch dilatation has become the most common problem following laparoscopic adjustable gastric banding (LAGB). Although, in a significant number of symptomatic patients, no explanation for the underlying problem is identified with a contrast swallow. There is a need for a better understanding of the pathophysiology of LAGBs and more sensitive diagnostic tests. METHODS: LAGB patients with adverse symptoms or poor weight loss (symptomatic patients), in whom a contrast swallow had not shown an abnormality, underwent high-resolution video manometry. This incorporated a semi-solid, stress barium, swallow protocol. Outcomes were categorized based on anatomical appearance, transit through the LAGB, and esophageal motility. Cohorts of successful (>50% excess weight loss with no adverse symptoms) and pre-operative patients were used as controls. RESULTS: One hundred twenty-three symptomatic patients participated along with 30 successful and 56 pre-operative patients. Five pathophysiological patterns were defined: transhiatal enlargement (n = 40), sub-diaphragmatic enlargement (n = 39), no abnormality (n = 30), aperistaltic esophagus (n = 7), and intermittent gastric prolapse (n = 3). Esophageal motility disorders were more common in symptomatic and pre-operative patients than in successful patients (p = 0.01). Differences between successful and symptomatic patients were identified in terms of the length of the high-pressure zone above the LAGB (p < 0.005), peristaltic velocity (p < 0.005), frequency of previous surgery(p = 0.01), and lower esophageal sphincter tone (p = 0.05). CONCLUSIONS: Video manometry identified abnormalities in three quarters of symptomatic patients where conventional contrast swallow had not been diagnostic. Five primary patterns of pathophysiology were defined. These were used to develop a seven category, clinical, classification system based on the anatomical appearance at stress barium. This system stratifies the spectrum of symmetrical pouch dilatation and can be used to logically guide treatment.

Effects of gastric band adjustments on intraluminal pressure.

BACKGROUND: Understanding of the effects of adjustments to laparoscopic adjustable gastric band (LAGB) volume is limited. Changes in intraluminal pressure may be important and explain patients reporting a tighter LAGB after saline is removed and an identical volume replaced. METHODS: Using high-resolution manometry, changes in the basal intraluminal pressure at the level of the LAGB in response to sequential, small alterations in LAGB volume were recorded. All fluid was removed from the LAGB and replaced, pressures and motility were reassessed. RESULTS: Sixteen patients (four males, age 45.4+/-13.2 years) participated. A linear increase (r2=0.87+/-0.12) in intraluminal pressure was observed after a threshold volume was reached. The threshold volume varied considerably (1.0 to 5.8 ml). The gradient of the linear increase was 21.2+/- 8.7 mmHg/ml. The mean basal intraluminal pressure at the level of the LAGB was initially 19.1+/-8.9 mmHg and increased to 37.0+/-20.4 mmHg (p=0.001) after removing and replacing the same volume of saline. There was an increase in distal esophageal peristaltic pressure (123.5+/- 34.7 vs. 157.4+/-52.6 mmHg, p=0.003) and a decrease in the proportion of normal swallows (0.85+/-0.22 vs. 0.53+/- 0.47, p=0.02). Nine patients also developed adverse symptoms. CONCLUSIONS: Intraluminal pressure at the level of the LAGB is an objective measure of the restriction produced by LAGBs. The addition of fluid to the LAGB results in a linear increase in intraluminal pressure once a threshold volume is reached. The removal and replacement of the same volume of saline from the LAGB may temporarily increase intraluminal pressure.