Joachim H. Schneider

Functional Importance of Laparoscopic Sleeve Gastrectomy for the Lower Esophageal Sphincter in Patients with Morbid Obesity

Background Obesity is characterized by excess body fat measured in body mass index (BMI), which is the weight in kilograms (kg) divided by the height in square meters [m2]. In the Northern Hemisphere, the prevalence of overweight has increased by up to 34%. This situation is associated with high incidence of comorbidities such as gastroesophageal reflux disease. Bariatric surgery is the only effective treatment for severe obesity, resulting in amelioration of obesity comorbidities. Data on LES competence following sleeve gastrectomy (SG), one of the several bariatric procedures, are conflicting.

Transient Lower Esophageal Sphincter Relaxation in Morbid Obesity

BackgroundThere is strong evidence that morbid obesity is often accompanied by gastroesophageal reflux. Gastroesophageal reflux is caused predominantly by transient lower esophageal sphincter relaxations (TLESRs). Only few data are available about TLESRs in patients with stage III obesity (body mass index > 35). The aim of this study was to analyze the frequency and types of TLESRs in patients with morbid obesity in different physiological stages (postprandial: upright and recumband) compared to patients with normal weight gastroesophageal reflux disease (GERD) and diffuse esophagus spasm (DES).MethodsIn order to measure TLESRs in obese patients with and without GERD, three subgroups were prospectively performed: group I consisted of seven healthy controls, group II consisted of seven obese patients, group III consisted of seven non-obese patients with GERD, and in group IV, five patients were recruited with diffuse esophageal spasm. All participants underwent both conventional water-perfused stationary esophagus manometry and a 24-h ambulatory esophagus manometry, 24-h ambulatory pH monitoring, and esophago-gastroscopy. In order to measure the lower esophageal sphincter pressure (LESP) over a prolonged time under physiological conditions, a special solid-state sleeve catheter was used. Additionally, all patients were interviewed using a standardized questionnaire.ResultsCompared to normal subjects, patients with morbid obesity and patients with gastroesophageal reflux show a substantial increase of TLESRs in the postprandial phase. There was a tendency towards more TLESRs per hour in patients with DES than in healthy subjects, but the difference was not statistically significant. The types of TLESRs differed with the LESP. The majority of isolated TLESRs were complete and incomplete. Some of the isolated TLESRs were accompanied by contractions of the tubular esophagus.ConclusionMorbid obesity is associated with gastroesophageal reflux. The frequency of TLESRs has significantly increased compared to healthy subjects and does not differ statistically from patients with GERD. Isolated TLESRs are mostly incomplete in patients with a hypotonic LES.

Multichannel Intraluminal Impedance Measurement of Gastroesophageal Reflux in Patients with Different Stages of Morbid Obesity

BackgroundObesity is now one of the world’s major chronic diseases. The etiology of the severe comorbid conditions associated with morbid obesity is not fully understood, and in particular the relationship between gastroesophageal reflux and obesity.MethodsSixty-seven patients were enrolled in this prospective study. Patients and control individuals were divided into four subgroups according to their body mass index (BMI). Esophageal motility was assessed using a conventional water-perfused esophageal manometry catheter, and 24-h pH-metry was carried out using multichannel intraluminal impedance equipment.ResultsIn the group with the highest BMI (>50), contraction amplitudes in the middle and distal esophagus were significantly higher in comparison both with the control group and groups with a lower BMI (P < 0.05). Lower esophageal sphincter pressure was reduced in the majority of patients with morbid obesity and differed significantly from the control group (P < 0.001). Significant differences between the control group and the patient groups were also observed on 24-h pH-metry (P < 0.05). The 24-h impedance measurements distinguished between acid and nonacid status and between the upright and recumbent positions. The total number of reflux episodes differed significantly between the control and patient groups and between groups III and IV, with lower and higher BMI values (P < 0.008 and P < 0.05, respectively).ConclusionsThe impedance data obtained in this study confirm that patients with morbid obesity are at risk of developing gastroesophageal reflux disease. However, there is no evidence of a direct correlation between the severity of reflux and the extent of obesity.

Ambulatory pH: monitoring with a wireless system.

BackgroundCurrently, pH monitoring is the gold standard for assessing esophageal acid exposure in patients with gastroesophageal reflux disease (GERD). The shortcomings of 24-h pH-monitoring wires led to the development of a 48-h, catheter-free pH measurement system using the telemetry technique with the BRAVO capsule. This prospective study aimed to compare conventional 24-h pH monitoring with the BRAVO catheter-free pH-monitoring system in patients with GERD, patients after antireflux surgery, and a healthy control group.MethodsA sample of 133 participants were enrolled in the current trial and divided into three subgroups. Group 1 consisted of 10 healthy volunteers. Group 2 consisted of 123 patients with symptomatic gastroesophageal reflux and endoscopic signs of esophagitis. Group 3 consisted of 43 GERD patients (extracted from group 2) who underwent a laparoscopic 360° “floppy” Nissen fundoplication. All the patients underwent both conventional 24-h pH monitoring and BRAVO catheter-free pH monitoring. The data for both methods were recorded and compared in line with the different patient groups regarding their validity and reliability. Additionally, all the patients were interviewed with a standardized questionnaire concerning their subjective perception of the two different methods.ResultsBoth the 24-h pH monitoring and the 48-h BRAVO catheter-free pH monitoring could be successfully performed for all the patients. During measurement, 122 of the patients (92%) continued working or performing daily activities. A significant difference could not be found regarding objective outcome between the two measurement methods in the three patient groups. The two methods showed comparable results in terms of data and measurement reliability. The validity also was comparable, with no significant differences within the groups. Concerning the patients’ subjective estimation of the two methods, the patients reported reduced regular activities and a higher level of discomfort during measurement with the conventional 24-h pH-monitoring system (p < 0.001 and p< 0.0001, respectively).ConclusionBoth conventional 24-h pH monitoring and the 48-h catheter-free pH monitoring are valid and reliable recording devices for measuring esophageal acid exposure. However, from the patients’ point of view, the BRAVO capsule affords less discomfort in the throat and allows more normal daily activities.

Quantitative Assessment of Intrahepatic Lipids Using Fat-selective Imaging With Spectral-spatial Excitation and In-/opposed-phase Gradient Echo Imaging Techniques Within a Study Population of Extremely Obese Patients: Feasibility on a Short, Wide-bore Mr Scanner

Objectives:The aim of this study was to evaluate the feasibility of 2 established magnetic resonance imaging based techniques to quantify intrahepatic lipids (IHL) within a study population of extremely obese patients by means of a short, wide-bore MR scanner. Fat-selective imaging using a spectral-spatial excitation technique and in-phase/opposed-phase (IN/OP) gradient echo imaging were applied and results were compared. Results for IN/OP technique were corrected for T1- and T2*- relaxation effects. Furthermore, image quality was assessed for both techniques. Differences in regional fat distribution were assessed using parameter maps of voxel-wise calculated IHL. Materials and Methods:MR examinations of 20 extremely obese patients were included in the study (7 males, 13 females; mean age 40.4 ± 12.6 years; mean body mass index 46.3 ± 6.6 kg/m2). IHL, in terms of fat signal fractions, was calculated from simultaneously acquired IN/OP-images using a double-echo gradient echo technique. For correction of transverse relaxation effects an additional multiecho gradient echo sequence was applied in each subject, whereas correction of longitudinal relaxation was performed using literature values for T1 of water and lipid protons in the liver parenchyma. A highly selective spectral-spatial excitation technique with 6 binomial radiofrequency pulses was used for fat-selective imaging. In this case, signal intensity of adjacent subcutaneous adipose (∼100% fat) was used as an internal reference for IHL quantification. Results:IN/OP-imaging provided sufficient image quality in all subjects, whereas fat-selective imaging was hampered by insufficient homogeneity of the static magnetic field in 1 of 20 subjects. Hepatic T2* values ranged from 20.1 milliseconds to 42.2 milliseconds. Results for IHL from both techniques were highly correlated with rs = 0.915 (P < 0.0001). Mean values for IHL were 16.5% ± 9.2% and 10.6% ± 7.3%, for IN/OP and spectral-spatial excitation technique, respectively, showing a slightly lower estimation of IHL by the spectral-spatial excitation method. In the examined cohort of extremely obese subjects a relatively high number of 4 out of 20 cases (20%) were found with uneven distribution of IHLs. Conclusions:The presented data confirm that both methods are reliable tools for quantification of IHL, if inherent drawbacks and limitations are taken into account. Inhomogeneity of the static magnetic field observed in examinations of extremely obese patients limits the use of spectral-spatial excitation, if performed without time-consuming shimming procedures. Necessity to correct for transverse and longitudinal relaxation effects using the IN/OP method requires additional measurements and postprocessing procedures, which might hamper the clinical applicability. Moreover, significant regional differences in IHL may exist in some patients especially if pronounced hepatic steatosis is present.

Transient Lower Esophageal Sphincter Relaxation and Esophageal Motor Response

BACKGROUND Gastroesophageal reflux is caused by transient lower esophageal sphincter relaxations (TLESRs) in healthy individuals and in most patients with gastroesophageal reflux disease (GERD). Refluxate is normally propelled by pharyngeally induced swallowing events, but TLESRs may also be accompanied by retrograde esophageal motor responses (EMRs). These contractions have not previously been investigated and their effect on esophageal clearance is not known. The aim of this study was to assess the frequency of EMRs after TLESR in healthy individuals and GERD patients and to develop an animal model for further investigation of EMRs. MATERIALS AND METHODS The frequency of TLESRs and esophageal body contractions after TLESRs was assessed using ambulatory manometry in five healthy individuals and five GERD patients. An animal model was developed for reproducible provocation of TLESRs and subsequent EMRs. RESULTS Patients with GERD have significantly more TLESRs than healthy individuals. However, post-TLESR EMRs were not more frequent in the GERD group. All post-TLESR EMRs presented as simultaneous contractions of the esophagus. The feline model allowed reproducible initiation of the esophageal motor response after TLESR, showing that EMRs can be induced by external mechanoreceptor stimulation simultaneously with LES relaxation. This experimental design imitates the conditions after fundoplication in humans. CONCLUSIONS The study demonstrated that GERD patients have significantly more TLESRs in comparison with healthy individuals, but these were only incidental to EMRs. Further research is needed to improve our understanding of esophageal motility disorders. The animal model presented offers a feasible tool for investigating TLESR-induced esophageal motility.

Non-acid Gastroesophageal Reflux Measured Using Multichannel Intraluminal Impedance in Older Patients

BackgroundDiagnosing gastroesophageal reflux disease is challenging in the older population, as comorbid conditions can obscure the disease.MethodsThis prospective study included 97 participants: 25 healthy controls (group 1), 46 reflux patients aged 26–64 (group 2), and 26 patients over 65 (group 3). Esophageal motility was assessed using conventional esophageal manometry, and 24-h pH-metry and non-acid reflux episodes were assessed using multichannel intraluminal impedance.ResultsAmong the older patients (group 3), 34% had reflux disease. The rate of lower esophageal sphincter insufficiency in group 3 was comparable with that in group 2 and significantly different from group 1. Gastric 24-h pH-metry showed no significant differences between the groups. Esophageal pH-metry results for groups 1 and 3 differed significantly from those in group 2. Impedance assessment showed that older patients have non-acid reflux episodes in the recumbent position significantly more often in comparison with controls and reflux patients. Reflux patients and older patients had proximal reflux episodes significantly more often than healthy volunteers.ConclusionsPatients aged over 65 have non-acid reflux, particularly in the recumbent position, significantly more often than normal individuals and patients with reflux disease. Non-acid reflux may mimic a negative DeMeester score in older patients with severe reflux disease.