The Evaluation of Gastric Emptying Using Nuclear Scintigraphy Compared to Three-Dimensional Multi-detector Computed Tomography (3D-MDCT) Gastric Volumetry in the Assessment of Poor Weight Loss Following Sleeve Gastrectomy.

BACKGROUND: Poor weight loss and weight regain are principal challenges following laparoscopic sleeve gastrectomy (LSG). There is a lack of standardised assessments and diagnostic tests to stratify the status post-LSG and determine whether anatomical or physiological problem exists. We aimed to compare nuclear scintigraphy gastric emptying with CT volumetric analysis of sleeve anatomy and determine the impact of anatomy on physiological function and its correlation with weight loss. MATERIALS AND METHODS: Patients greater than 12 months post-LSG were categorised into optimal weight loss (OWL) (n = 29) and poor weight loss groups (PWL) (n = 50). All patients underwent a protocolised nuclear scintigraphy and three-dimensional multi-detector computed tomography (3D-MDCT) gastric volumetry imaging. RESULTS: Post-operative % total weight loss in OWL was 26.2 ± 10.5% vs. 14.2 ± 10.7% in the PWL group (p value < 0.0001). The PWL group had significantly more delayed gastric emptying half-time than OWL (34.1 ± 18.8 vs. 19.5 ± 4.7, p value < 0.0001). Gastric emptying half-time showed statistically significant correlations with weight loss parameters (BMI; r = 0.215, p value 0.048, %EWL; r = - 0.336, p value 0.002 and %TWL; r = - 0.379, p value < 0.001). The median gastric volume on 3D-MDCT did not differ between the OWL (246 (IQR 50) ml) and PWL group (262 (IQR 129.5) ml), p value 0.515. Nuclear scintigraphy gastric emptying half-time was the most highly discriminant measure. A threshold of 21.2 min distinguished OWL from PWL patients with 86.4% sensitivity and 68.4% specificity. CONCLUSION: Nuclear scintigraphy is a potentially highly accurate tool in the functional assessment of sleeve gastrectomy physiology. It appears to perform better as a diagnostic test than volumetric assessment. Gastric volume did not correlate with weight loss outcomes. We have established diagnostic criteria of greater than 21 min to assess sleeve failure, which is linked to suboptimal weight loss outcomes.

Changes in Oesophageal Transit, Macro-Reflux Events, and Gastric Emptying Correlate with Improvements in Gastro-Intestinal Symptoms and Food Tolerance Early Post Sleeve Gastrectomy.

PURPOSE: There are significant alterations in gastro-intestinal function, food tolerance, and symptoms following sleeve gastrectomy (SG). These substantially change over the first year, but it is unclear what the underlying physiological basis for these changes is. We examined changes in oesophageal transit and gastric emptying and how these correlate with changes in gastro-intestinal symptoms and food tolerance. MATERIAL AND METHODS: Post-SG patients undertook protocolised nuclear scintigraphy imaging along with a clinical questionnaire at 6 weeks, 6 months, and 12 months. RESULTS: Thirteen patients were studied: mean age (44.8 ± 8.5 years), 76.9% females, pre-operative BMI (46.9 ± 6.7 kg/m2). Post-operative %TWL was 11.9 ± 5.1% (6 weeks) and 32.2 ± 10.1% (12 months), p-value < 0.0001. There was a substantial increase of meal within the proximal stomach; 22.3% (IQR 12%) (6 weeks) vs. 34.2% (IQR 19.7%) (12 months), p = 0.038. Hyper-accelerated transit into the small bowel decreased from 6 weeks 49.6% (IQR 10.8%) to 42.7% (IQR 20.5%) 12 months, p = 0.022. Gastric emptying half-time increased from 6 weeks 19 (IQR 8.5) to 12 months 27 (IQR 11.5) min, p = 0.027. The incidence of deglutitive reflux of semi-solids decreased over time; 46.2% (6 weeks) vs. 18.2% (12 months), p-value < 0.0001. Reflux score of 10.6 ± 7.6 at 6 weeks vs. 3.5 ± 4.4 at 12 months, (p = 0.049) and regurgitation score of 9.9 ± 3.3 at 6 weeks vs. 6.5 ± 1.7, p = 0.021 significantly reduced. CONCLUSIONS: These data demonstrate that there is an increase in the capacity of the proximal gastric sleeve to accommodate substrate over the first year. Gastric emptying remains rapid but reduce over time, correlating with improved food tolerance and reduced reflux symptoms. This is likely the physiological basis for the changes in symptoms and food tolerance observed early post-SG.

Delayed Gastric Emptying After Sleeve Gastrectomy Is Associated with Poor Weight Loss.

BACKGROUND: Intermediate to long-term weight regain is a major challenge following sleeve gastrectomy (SG). Physiological changes that mediate the extent of weight loss remain unclear. We aimed to determine if there were specific esophago-gastric transit and emptying alterations associated with weight regain. MATERIAL AND METHODS: Participants greater than 12 months post-SG were categorized into optimal (n = 29) and poor weight loss (PWL) (n = 72). All patients underwent a liquid contrast barium swallow demonstrating normal post-surgical anatomy and a protocolized nuclear scintigraphy designed specifically to characterize gastric emptying following SG. RESULTS: The %total weight loss in the optimal group was 26.2 ± 10.5 vs. 14.3 ± 8.8% in the PWL group (p = 0.001). Scintigraphy showed PWL had relatively increased gastric emptying half-time (GE 1/2t) 35 (IQR 23) min vs 19 (IQR 5.5) min (p = 0.001). The multivariate regressions delineated GE 1/2t as the best diagnostic measure for PWL (OR 1.16; CI 1.04-1.29, p-value 0.021). The probability of PWL increased by 16% for every 1-min increase above 21 min of GE 1/2t. A threshold of 21 min was found to have 88% sensitivity and 69% specificity predicting poor weight loss. CONCLUSION: Gastric emptying half-times greater than 21 min appear to reliably correlate with poor weight loss following SG. Additionally, further elevations above 21 min in emptying half-time increase the risk of poor weight loss. We have shown nuclear scintigraphy represents a simple and accurate diagnostic tool in patients who experience poor weight loss after SG, provided substantially altered reporting references in interpreting nuclear scintigraphy are applied.

Radiation Oncology AcaDemic Mentorship Program (ROADMAP) for Junior Faculty: One-Year Results of a Prospective Single Institution Initiative.

PURPOSE: Although mentorship has been associated with promotion, job satisfaction, and retention, data are limited on the mentorship experience of clinical- versus research-track physicians as well as feasibility and relative priority of formal program components. METHODS AND MATERIALS: Within a single-institution, multi-site, academic network, we implemented a Radiation Oncology AcaDemic Mentorship Program (ROADMAP) for junior faculty. Validated surveys assessing mentee satisfaction were distributed at baseline and 1 year. The statistical analysis included Wilcoxon rank sum and signed tests. Mentees assessed the likelihood to recommend each program component (10-point Likert-type scale), and means with standard error (SE) are reported. RESULTS: Among 42 eligible junior faculty, 36 (86%) opted into the program. The median time since residency was 2.5 years (interquartile range, 1.75-5.25) on the clinical track (n = 12) and 3 years (interquartile range, 2.75-5.00) on the research track (n = 24). At baseline, research-track physicians reported higher satisfaction with mentoring than physicians on the clinical track (2.92 vs 2.16; P = .02). Among 32 physicians completing 1 year, overall satisfaction with mentoring increased compared with baseline (2.72 vs 3.87; P < .001), which persisted on subset analysis for both clinical- (2.16 vs 4.03; P < .001) and research-track physicians (2.99 vs 3.77; P = .005). At 1 year, 28 mentees (88%) opted to continue the program. Program components were rated 8.25 (SE, 0.37) for mentor-mentee pairings, 7.22 (SE, 0.39) for goal setting, 6.84 (SE, 0.47) for administrative support, 6.69 (SE, 0.44) for peer mentoring, and 6.53 (SE, 0.45) for steering committee oversight. Ratings of peer mentoring were not associated with track (P = .59) or years in practice (P = .29). CONCLUSIONS: Clinical-track physicians may be less satisfied with mentorship than research-track faculty. However, all junior faculty, regardless of track, appeared to benefit from formalizing dyadic mentor-mentee relationships, goal setting, and peer mentoring. Further work is needed to determine the role of mentorship in addressing physician burnout.

Clinical utility of stimulated cholescintigraphy using a standardized Ensure-Plus fatty meal protocol in patients with suspected functional gallbladder disorder: a retrospective study of seven-years clinical experience.

BACKGROUND: The clinical utility of fatty meal stimulated cholescintigraphy particularly using a standardized formulation in patients with suspected functional gallbladder disorder has not been extensively studied. We present our seven-year clinical experience using an Ensure plus protocol. METHODS: A retrospective study was performed on patients undergoing stimulated cholescintigraphy using Ensure Plus for evaluation of suspected functional gallbladder disorder. A gallbladder ejection fraction (GBEF) of <33% was considered abnormal. RESULTS: Of the 173 patients evaluated, 57 (33%) had an abnormal GBEF, 112 (65%) had a normal GBEF and 4 (2%) had no gallbladder visualization. Of the 57 patients with an abnormal GBEF, symptom improvement occurred in 30/31 (97%) who underwent cholecystectomy and in 17/26 (65%) who were managed conservatively (p = 0.003). Of the 112 patients with a normal GBEF, symptom improvement occurred in 8/10 (80%) who underwent cholecystectomy and 74/102 (73%) who were managed conservatively (p = 1.000). In the subgroup of 102 patients with a normal GBEF managed conservatively, those without symptomatic improvement had lower GBEFs compared to those with symptomatic improvement (median GBEF 46% versus 57%, p = 0.019). CONCLUSION: Our retrospective results support a clinical role for stimulated cholescintigraphy using Ensure Plus in the evaluation of patients with suspected functional gallbladder disorder. While an abnormal GBEF predicts good surgical outcome, our results suggest that using an absolute GBEF cut off value of <33% may not apply to all patients and hence GBEF results should only be used as an adjunct in the surgical decision-making process.

Pathophysiological Mechanisms of Gastro-esophageal Reflux After Sleeve Gastrectomy.

OBJECTIVE: To evaluate the mechanisms associated with reflux events after sleeve gastrectomy (SG). SUMMARY BACKGROUND DATA: Gastro-esophageal reflux (GERD) post-SG is a critical issue due to symptom severity, impact on quality of life, requirement for reoperation, and potential for Barrett esophagus. The pathophysiology is incompletely delineated. METHODS: Post-SG patients, stratified into asymptomatic and symptomatic, underwent protocolized nuclear scintigraphy (n = 83), 24-hour esophageal pH monitoring, and stationary manometry (n = 143) to characterize reflux patterns. Ten patients underwent fasting and postprandial concurrent manometry and pH for detailed analysis of reflux events. RESULTS: Baseline demographics between cohorts were similar: Age 47.2 ± 11.6 versus 44.1 ± 11.3 years ( P = 0.121); females 73.2% versus 90.8% ( P = 0.005); excess weight loss 53.8 ± 28.1% versus 57.4 ± 25.5% ( P = 0.422), follow-up duration 12.3 versus 7.4 months ( P = 0.503). Nuclear scintigraphy delineated bolus-induced deglutitive reflux events (29.6% vs 62.5%, P = 0.005) and postprandial reflux events [4 (IQR2) versus 4 (IQR 3) events, P = 0.356]. Total acid exposure was significantly elevated in the symptomatic population (7.7% vs 3.6%, P < 0.001), especially fasting acid exposure (6.0% vs 1.3%, P < 0.001). pH/manometry analysis demonstrated acute elevations of the gastro-esophageal pressure gradient (>10 mm Hg) underpinned most reflux events. Swallow-induced intragastric hyper-pressur-ization was associated with individual reflux events in most patients (90% in fasting state and 40% postprandial). CONCLUSIONS: We found reflux to be strongly associated with SG and identified 3 unique categories. Bolus-induced deglutitive and postprandial reflux occurred in most patients. Elevated fasting esophageal acid exposure mediated symptoms. Frequent, significant elevation in the gastro-esophageal pressure gradient was the mechanism of reflux and seemed to relate to the noncompliant proximal stomach.

Expected Values of Esophageal Transit and Gastric Emptying Scintigraphy Post-uncomplicated Sleeve Gastrectomy.

PURPOSE: Sleeve gastrectomy (SG) results in significant anatomical and physiological alterations of the esophagus and stomach, including food tolerance. Currently, there is no consensus on the parameters of abnormal esophageal transit and gastric emptying in this population. We describe standardized esophageal transit and gastric emptying protocols, and define expected values following an uncomplicated SG. MATERIALS AND METHODS: In 43 asymptomatic post-SG patients with optimal weight loss, a standardized liquid and semi-solid (oatmeal) esophageal transit study, plus a 90-min semi-solid gastric emptying study with dynamic 5-s image acquisition to assess gastroesophageal reflux, was performed. Gastric emptying half-time and retention rate was calculated. Esophageal transit and reflux were graded by visual inspection of images. RESULTS: Thirty-one female and 12 male patients participated: mean age 49.0±10.7 years, pre-operative BMI 47.6±7.0 kg/m2, excess weight loss 58.8±26.0% at median follow-up of 7.4 months. The standardized semi-solid meal and liquid preparations were well tolerated. Delays in esophageal transit of liquid and semi-solid boluses were infrequent (7.0% and 16.3% respectively). Deglutitive reflux of both semi-solids and liquids was common (48.8% and 32.6%). The median semi-solid gastric emptying half-time was 21.0 min. A large proportion of substrate transited into the small bowel on initial image acquisition (median 39.1%). Reflux events during gastric emptying were common (median 5.0 events, 12.7% of image acquisition time). CONCLUSIONS: Rapid gastric emptying with asymptomatic deglutitive and post-prandial gastroesophageal reflux events are common following SG. We have defined the expected values of standardized esophageal transit and gastric emptying scintigraphy specifically tailored to SG patients.

Mechanisms of Esophageal and Gastric Transit Following Sleeve Gastrectomy.

PURPOSE: Sleeve gastrectomy (SG) patients have substantially altered anatomy. The mechanism of rapid gastric emptying and the role of esophageal contractile function in esophago-gastric transit has not been defined. We aimed to determine the mechanisms of esophago-gastric transit and role of esophageal function following sleeve gastrectomy. METHODS: Prospective study of twenty-six asymptomatic participants post SG underwent nuclear scintigraphy and high-resolution manometry. Fourteen had semi-solid stress barium to model the emptying process. Concurrent video fluoroscopy and manometry were performed on 7 participants. RESULTS: Demographic data are as follows: age 45.3 ± 15.0 years, 73.1% female, excess weight loss 62.2 ± 28.1% at 8 months. Scintigraphy showed rapid gastric emptying (24.4 ± 11.4 vs. 75.80 ± 45.19 min in control, p < 0.001) with 35.24 ± 17.12% of bolus transited into small bowel on initial frame. Triggered deglutitive reflux was common (54.4% vs. 18.2%, p = 0.017). Stress barium delineated separate vertical and antral gastric compartments with cyclical emptying of 8 stages, including reflux-induced repeated esophageal peristalsis. During manometry, ramping effects were noted, with sequential swallows producing sustained isobaric pressurizations in proximal stomach (33.6 ± 29.5 mmHg). Video fluoroscopy showed individual esophageal peristalsis generating pressurizations at 5.0 ± 1.4 cm below lower esophageal sphincter (LES), at amplitude of 31.6 ± 13.1 mmHg, associated with intragastric transit. Pressurizations were sustained for 17.3 ± 8.2 s, similar to the prolonged LES contraction (18.5 ± 9.0 s, p = 0.355). CONCLUSIONS: Repeated esophageal peristaltic contractions induced isobaric pressurization of proximal stomach, thus providing the drive to pressurize and empty the vertical compartment of the gastric sleeve. Transit following SG appeared to be esophageal-mediated and followed a distinct cycle with strong associations with reflux.

AMPK beta subunits display isoform specific affinities for carbohydrates.

AMP-activated protein kinase (AMPK) is a heterotrimer of catalytic (alpha) and regulatory (beta and gamma) subunits with at least two isoforms for each subunit. AMPK beta1 is widely expressed whilst AMPK beta2 is highly expressed in muscle and both beta isoforms contain a mid-molecule carbohydrate-binding module (beta-CBM). Here we show that beta2-CBM has evolved to contain a Thr insertion and increased affinity for glycogen mimetics with a preference for oligosaccharides containing a single alpha-1,6 branched residue. Deletion of Thr-101 reduces affinity for single alpha-1,6 branched oligosaccharides by 3-fold, while insertion of this residue into the equivalent position in the beta1-CBM sequence increases affinity by 3-fold, confirming the functional importance of this residue.