Challenges in multi-centric generalization: phase and step recognition in Roux-en-Y gastric bypass surgery.

PURPOSE: Most studies on surgical activity recognition utilizing artificial intelligence (AI) have focused mainly on recognizing one type of activity from small and mono-centric surgical video datasets. It remains speculative whether those models would generalize to other centers. METHODS: In this work, we introduce a large multi-centric multi-activity dataset consisting of 140 surgical videos (MultiBypass140) of laparoscopic Roux-en-Y gastric bypass (LRYGB) surgeries performed at two medical centers, i.e., the University Hospital of Strasbourg, France (StrasBypass70) and Inselspital, Bern University Hospital, Switzerland (BernBypass70). The dataset has been fully annotated with phases and steps by two board-certified surgeons. Furthermore, we assess the generalizability and benchmark different deep learning models for the task of phase and step recognition in 7 experimental studies: (1) Training and evaluation on BernBypass70; (2) Training and evaluation on StrasBypass70; (3) Training and evaluation on the joint MultiBypass140 dataset; (4) Training on BernBypass70, evaluation on StrasBypass70; (5) Training on StrasBypass70, evaluation on BernBypass70; Training on MultiBypass140, (6) evaluation on BernBypass70 and (7) evaluation on StrasBypass70. RESULTS: The model's performance is markedly influenced by the training data. The worst results were obtained in experiments (4) and (5) confirming the limited generalization capabilities of models trained on mono-centric data. The use of multi-centric training data, experiments (6) and (7), improves the generalization capabilities of the models, bringing them beyond the level of independent mono-centric training and validation (experiments (1) and (2)). CONCLUSION: MultiBypass140 shows considerable variation in surgical technique and workflow of LRYGB procedures between centers. Therefore, generalization experiments demonstrate a remarkable difference in model performance. These results highlight the importance of multi-centric datasets for AI model generalization to account for variance in surgical technique and workflows. The dataset and code are publicly available at https://github.com/CAMMA-public/MultiBypass140.

Efficacy and Safety of Rivaroxaban for Postoperative Thromboprophylaxis in Patients After Bariatric Surgery: A Randomized Clinical Trial.

Importance: Venous thromboembolism (VTE) is a leading cause of morbidity and mortality after bariatric surgery. Clinical end point studies on thromboprophylaxis with direct oral anticoagulants in patients undergoing bariatric surgery are lacking. Objective: To assess the efficacy and safety of a prophylactic dose of 10 mg/d of rivaroxaban for both 7 and 28 days after bariatric surgery. Design, Setting, and Participants: This assessor-blinded, phase 2, multicenter randomized clinical trial was conducted from July 1, 2018, through June 30, 2021, with participants from 3 academic and nonacademic hospitals in Switzerland. Intervention: Patients were randomized 1 day after bariatric surgery to 10 mg of oral rivaroxaban for either 7 days (short prophylaxis) or 28 days (long prophylaxis). Main Outcomes and Measures: The primary efficacy outcome was the composite of deep vein thrombosis (symptomatic or asymptomatic) and pulmonary embolism within 28 days after bariatric surgery. Main safety outcomes included major bleeding, clinically relevant nonmajor bleeding, and mortality. Results: Of 300 patients, 272 (mean [SD] age, 40.0 [12.1] years; 216 women [80.3%]; mean body mass index, 42.2) were randomized; 134 received a 7-day and 135 a 28-day VTE prophylaxis course with rivaroxaban. Only 1 thromboembolic event (0.4%) occurred (asymptomatic thrombosis in a patient undergoing sleeve gastrectomy with extended prophylaxis). Major or clinically relevant nonmajor bleeding events were observed in 5 patients (1.9%): 2 in the short prophylaxis group and 3 in the long prophylaxis group. Clinically nonsignificant bleeding events were observed in 10 patients (3.7%): 3 in the short prophylaxis arm and 7 in the long prophylaxis arm. Conclusions and Relevance: In this randomized clinical trial, once-daily VTE prophylaxis with 10 mg of rivaroxaban was effective and safe in the early postoperative phase after bariatric surgery in both the short and long prophylaxis groups. Trial Registration: ClinicalTrials.gov Identifier: NCT03522259.

Randomized, Double-Blind, Placebo-Controlled Crossover Trial of Once Daily Empagliflozin 25 mg for the Treatment of Postprandial Hypoglycemia After Roux-en-Y Gastric Bypass.

Aims: To investigate the effect of empagliflozin on glucose dynamics in individuals suffering from postbariatric hypoglycemia (PBH) after Roux-en-Y gastric bypass (RYGB). Methods: Twenty-two adults with PBH after RYGB were randomized to empagliflozin 25 mg or placebo once daily over 20 days in a randomized, double-blind, placebo-controlled, crossover trial. The primary efficacy outcome was the amplitude of plasma glucose excursion (peak to nadir) during a mixed-meal tolerance test (MMTT). Outcomes of the outpatient period were assessed using continuous glucose monitoring (CGM) and an event-tracking app. Results: The amplitude of glucose excursion during the MMTT was 8.1 ± 2.4 mmol/L with empagliflozin versus 8.1 ± 2.6 mmol/L with placebo (mean ± standard deviation, P = 0.807). CGM-based mean amplitude of glucose excursion during the 20-day period was lower with empagliflozin than placebo (4.8 ± 1.3 vs. 5.2 ± 1.6. P = 0.028). Empagliflozin reduced the time spent with CGM values >10.0 mmol/L (3.8 ± 3.5% vs. 4.7 ± 3.8%, P = 0.009), but not the time spent with CGM values <3.0 mmol/L (1.7 ± 1.6% vs. 1.5 ± 1.5%, P = 0.457). No significant difference was observed in the quantity and quality of recorded symptoms. Eleven adverse events occurred with empagliflozin (three drug-related) and six with placebo. Conclusions: Empagliflozin 25 mg reduces glucose excursions but not hypoglycemia in individuals with PBH. Clinical Trial Registration: Clinicaltrials.gov: NCT05057819.

Gastroesophageal Junction and Pylorus Distensibility Before and After Sleeve Gastrectomy-pilot Study with EndoFlipTM.

Sleeve gastrectomy (SG) is the most frequently performed bariatric surgical intervention worldwide. Gastroesophageal reflux disease (GERD) is frequently observed after SG and is a relevant clinical problem. This prospective study investigated the gastroesophageal junction (GEJ) and pyloric sphincter by impedance planimetry (EndoFlipTM) and their association with GERD at a tertiary university hospital center. Between January and December 2018, patients undergoing routine laparoscopic SG had pre-, intra-, and postoperative assessments of the GEJ and pyloric sphincter by EndoFlipTM. The distensibility index (DI) was measured at different volumes and correlated with GERD (in accordance with the Lyon consensus guidelines). Nine patients were included (median age 48 years, preoperative BMI 45.1 kg/m2, 55.6% female). GERD (de novo or stable) was observed in 44.4% of patients one year postoperatively. At a 40-ml filling volume, DI increased significantly pre- vs. post-SG of the GEJ (1.4 mm2/mmHg [IQR 1.1-2.6] vs. 2.9 mm2/mmHg [2.6-5.3], p VALUE=0.046) and of the pylorus (6.0 mm2/mmHg [4.1-10.7] vs. 13.1 mm2/mmHg [7.6-19.2], p VALUE=0.046). Patients with postoperative de novo or stable GERD had a significantly increased preoperative DI at 40 ml of the GEJ (2.6 mm2/mmHg [1.9-3.5] vs. 0.5 mm2/mmHg [0.5-1.1], p VALUE=0.031). There was no significant difference in DI at 40 mL filling in the preoperative pylorus and postoperative GEJ or pylorus. In this prospective study, the DI of the GEJ and the pylorus significantly increased after SG. Postoperative GERD was associated with a significantly higher preoperative DI of the GEJ but not of the pylorus.

Counter-regulatory responses to postprandial hypoglycaemia in patients with post-bariatric hypoglycaemia vs surgical and non-surgical control individuals.

AIMS/HYPOTHESIS: Post-bariatric hypoglycaemia is an increasingly recognised complication of bariatric surgery, manifesting particularly after Roux-en-Y gastric bypass. While hyperinsulinaemia is an established pathophysiological feature, the role of counter-regulation remains unclear. We aimed to assess counter-regulatory hormones and glucose fluxes during insulin-induced postprandial hypoglycaemia in patients with post-bariatric hypoglycaemia after Roux-en-Y gastric bypass vs surgical and non-surgical control individuals. METHODS: In this case-control study, 32 adults belonging to four groups with comparable age, sex and BMI (patients with post-bariatric hypoglycaemia, Roux-en-Y gastric bypass, sleeve gastrectomy and non-surgical control individuals) underwent a postprandial hypoglycaemic clamp in our clinical research unit to reach the glycaemic target of 2.5 mmol/l 150-170 min after ingesting 15 g of glucose. Glucose fluxes were assessed during the postprandial and hypoglycaemic period using a dual-tracer approach. The primary outcome was the incremental AUC of glucagon during hypoglycaemia. Catecholamines, cortisol, growth hormone, pancreatic polypeptide and endogenous glucose production were also analysed during hypoglycaemia. RESULTS: The rate of glucose appearance after oral administration, as well as the rates of total glucose appearance and glucose disappearance, were higher in both Roux-en-Y gastric bypass groups vs the non-surgical control group in the early postprandial period (all p<0.05). During hypoglycaemia, glucagon exposure was significantly lower in all surgical groups vs the non-surgical control group (all p<0.01). Pancreatic polypeptide levels were significantly lower in patients with post-bariatric hypoglycaemia vs the non-surgical control group (median [IQR]: 24.7 [10.9, 38.7] pmol/l vs 238.7 [186.3, 288.9] pmol/l) (p=0.005). Other hormonal responses to hypoglycaemia and endogenous glucose production did not significantly differ between the groups. CONCLUSIONS/INTERPRETATION: The glucagon response to insulin-induced postprandial hypoglycaemia is lower in post-bariatric surgery individuals compared with non-surgical control individuals, irrespective of the surgical modality. No significant differences were found between patients with post-bariatric hypoglycaemia and surgical control individuals, suggesting that impaired counter-regulation is not a root cause of post-bariatric hypoglycaemia. TRIAL REGISTRATION: ClinicalTrials.gov NCT04334161.

Proposal and multicentric validation of a laparoscopic Roux-en-Y gastric bypass surgery ontology.

BACKGROUND: Phase and step annotation in surgical videos is a prerequisite for surgical scene understanding and for downstream tasks like intraoperative feedback or assistance. However, most ontologies are applied on small monocentric datasets and lack external validation. To overcome these limitations an ontology for phases and steps of laparoscopic Roux-en-Y gastric bypass (LRYGB) is proposed and validated on a multicentric dataset in terms of inter- and intra-rater reliability (inter-/intra-RR). METHODS: The proposed LRYGB ontology consists of 12 phase and 46 step definitions that are hierarchically structured. Two board certified surgeons (raters) with > 10 years of clinical experience applied the proposed ontology on two datasets: (1) StraBypass40 consists of 40 LRYGB videos from Nouvel Hôpital Civil, Strasbourg, France and (2) BernBypass70 consists of 70 LRYGB videos from Inselspital, Bern University Hospital, Bern, Switzerland. To assess inter-RR the two raters' annotations of ten randomly chosen videos from StraBypass40 and BernBypass70 each, were compared. To assess intra-RR ten randomly chosen videos were annotated twice by the same rater and annotations were compared. Inter-RR was calculated using Cohen's kappa. Additionally, for inter- and intra-RR accuracy, precision, recall, F1-score, and application dependent metrics were applied. RESULTS: The mean ± SD video duration was 108 ± 33 min and 75 ± 21 min in StraBypass40 and BernBypass70, respectively. The proposed ontology shows an inter-RR of 96.8 ± 2.7% for phases and 85.4 ± 6.0% for steps on StraBypass40 and 94.9 ± 5.8% for phases and 76.1 ± 13.9% for steps on BernBypass70. The overall Cohen's kappa of inter-RR was 95.9 ± 4.3% for phases and 80.8 ± 10.0% for steps. Intra-RR showed an accuracy of 98.4 ± 1.1% for phases and 88.1 ± 8.1% for steps. CONCLUSION: The proposed ontology shows an excellent inter- and intra-RR and should therefore be implemented routinely in phase and step annotation of LRYGB.

The impact of bariatric and metabolic surgery on cancer development.

Obesity (BMI ≥ 30 kg/m2) with related comorbidities such as type 2 diabetes mellitus, cardiovascular disease, sleep apnea syndrome, and fatty liver disease is one of the most common preventable risk factors for cancer development worldwide. They are responsible for at least 40% of all newly diagnosed cancers, including colon, ovarian, uterine, breast, pancreatic, and esophageal cancer. Although various efforts are being made to reduce the incidence of obesity, its prevalence continues to spread in the Western world. Weight loss therapies such as lifestyle change, diets, drug therapies (GLP-1-receptor agonists) as well as bariatric and metabolic surgery are associated with an overall risk reduction of cancer. Therefore, these strategies should always be essential in therapeutical concepts in obese patients. This review discusses pre- and post-interventional aspects of bariatric and metabolic surgery and its potential benefit on cancer development in obese patients.

Vasoconstrictor nasal spray causing life-threatening complications after bariatric surgery: A case report.

INTRODUCTION AND IMPORTANCE: Bariatric surgery is an evolving surgical field with increasing cases per year, as obesity is prevalent, especially in developed countries. Complication diagnosis and management can be challenging. Marginal ulcers and anastomosis perforation are rare, but their incidence is likely underestimated. CASE PRESENTATION: To the best of our knowledge, we present the first case with a two and a half years history of recurrent ischemia, marginal ulcers, and recurrent perforation after laparoscopic omega loop gastric bypass, most likely due to an abuse of an over-the-counter (OTC) sympathomimetic nasal spray. The complications (Clavien-Dindo classification IIIb) caused the necessity of recurrent hospitalizations and diagnostic interventions and an open conversion into Roux-Y gastric bypass in a damage control manner. CLINICAL DISCUSSION AND CONCLUSION: Conclusively, we advocate evaluating drug abuse, including OTC medications that patients might not report on a daily-based medical history, as an etiology for marginal ulcers and anastomosis perforation, especially in late and recurrent cases.

The impact of postbariatric hypoglycaemia on driving performance: A randomized, single-blind, two-period, crossover study in a driving simulator.

Postbariatric hypoglycaemia (PBH) is an increasingly recognized complication of bariatric surgery, but its effect on daily functioning remains unclear. In this randomized, single-blind, crossover trial we assessed driving performance in patients with PBH. Ten active drivers with PBH (eight females, age 38.2 ± 14.7 years, body mass index 27.2 ± 4.6 kg/m2 ) received 75 g glucose to induce PBH in the late postprandial period and aspartame to leave glycaemia unchanged, on two different occasions. A simulator was driven during 10 minutes before (D0) and 20 (D1), 80 (D2), 125 (D3) and 140 minutes (D4) after the glucose/aspartame ingestion, reflecting the expected blood glucose (BG) increase (D1), decrease (D2) and hypoglycaemia (D3, D4). Seven driving features indicating impaired driving were integrated in a Bayesian hierarchical regression model to assess the difference in driving performance after glucose/aspartame ingestion. Mean ± standard deviation peak and nadir BG after glucose were 182 ± 24 and 47 ± 14 mg/dL, while BG was stable after aspartame (85 ± 4 mg/dL). Despite the lack of a difference in symptom perception, driving performance was significantly impaired after glucose versus aspartame during D4 (posterior probability 98.2%). Our findings suggest that PBH negatively affects driving performance.

Malnutrition and Alcohol in Patients Presenting with Severe Complications of Cirrhosis After Laparoscopic Bariatric Surgery.

Factors and outcomes associated with decompensation of liver disease and liver failure in obese patients who underwent modern bariatric surgery are unclear. We present here a cohort of seventeen consecutive patients referred because of decompensation of liver disease following laparoscopic bariatric surgery. All patients showed signs of malnutrition (sarcopenia in 76.5%). In ten (58.8%), decompensation was associated with alcohol ingestion, which started after bariatric surgery in six patients. One patient died and three patients required liver transplantation, in one case preceded by transjugular intrahepatic portosystemic shunt (TIPS). However, thirteen patients achieved stabilization or full re-compensation with medical therapy and nutritional support. Our cases underline the risk of alcohol intake and malnutrition after laparoscopic bariatric surgery as causes of severe liver decompensation and underline the need for careful interdisciplinary care of these patients after surgery to early identify and treat alcohol misuse, malnutrition, and liver disease.

Determination of bile acids from human gallbladder by 1 H-MRS-Protocol optimization and estimation of reproducibility.

Bile exerts multiple functions in the liver and gut and is involved in multiple disease processes. It is secreted continuously from the liver and stored in the gallbladder until needed, and closely reflects the available bile acid pool. The study objective was therefore to develop a reliable MRS protocol and to assess variability of bile acid determination in human gallbladder. MRS measurements were performed on a 3 T MR scanner with 20 subjects to optimize protocols (26 measurements) and conduct a prospective reproducibility study (18 measurements). Measurements were carried out with subjects lying in either supine (23 scans) or prone positions (21 scans) to compare results from the two positions. For reproducibility determination, six of the 20 volunteers (three males, three females, age = 34.9 ± 10.9 years, BMI = 23.4 ± 2.1 kg/m2 ) were measured three times: back to back to assess technical variability and once again after three weeks to assess total variability, including additional physiological variability. A single voxel was measured in the gallbladder with respiratory triggering. For quantification, apparent T2 times were determined and a non-water-suppressed spectrum was acquired. Total bile acids, glycine and taurine conjugated bile acids, and lipids including choline-containing phospholipids were determined. Higher quality and reliability of gallbladder spectra were obtained with subjects measured in prone compared with supine position. All measurements of the reproducibility sub-study were of sufficient quality to be included in the analysis. Average coefficients of variation within subjects for the main compounds were 37% for total variation (including physiological and technical variation) and 24% for technical variation alone. These values were much smaller than those between subjects, which were >54% for both back-to-back and three weeks separated measurements. These results suggest diagnostic applicability of the method, especially for longitudinal studies aiming at non-invasive characterization of bile composition in humans with various diseases and/or interventional maneuvers.

Ulcer Disease in the Excluded Segments after Roux-en-Y Gastric Bypass: a Current Review of the Literature.

Ulcer disease in excluded segments after Roux-Y gastric bypass (RYGB) is rare but can evolve into a life-threatening situation. The excluded segments exhibit a different behavior from that of non-altered anatomy; perforated ulcers do not result in pneumoperitoneum or free fluid, and therefore must be met with a low threshold for surgical exploration. The anatomical changes after RYGB impede routine access to the remnant stomach and duodenum. There are various options to address bleeding or perforated ulcers. While oversewing and drainage preserves the anatomy and forgoes resection, remnant gastrectomy offers a definitive solution. The importance of traditional risk factors such as smoking or use of non-steroidal anti-inflammatory drugs is unclear. Eradication of Helicobacter pylori and secondary prophylaxis with proton-pump inhibitors is advisable, albeit in double-dose.

Tailored access to the hepatobiliary system in post-bariatric patients: a tertiary care bariatric center experience.

BACKGROUND: In bariatric surgery patients, pancreaticobiliary access via endoscopic retrograde cholangiopancreatography (ERCP) is technically challenging and the optimal approach for the evaluation and treatment of biliary tree-related pathologies has been debated. Besides laparoscopy-assisted ERCP (LA-ERCP) as standard of care, EUS-directed transgastric ERCP (EDGE) and hepaticogastrostomy (HGS) with placement of a fully covered metal stent have emerged as novel techniques. The objective of this study was to evaluate safety and efficacy of three different endoscopic approaches (LA-ERCP, EDGE, and HGS) in bariatric patients. METHODS: In this retrospective review, consecutive patients with Roux-en-Y gastric bypass (RYGB) and Sleeve Gastrectomy (SG) who underwent from 2013 to 2019 a LA-ERCP, an EDGE, or a HGS at a tertiary care reference center for bariatric surgery were analyzed. Patient demographics, type of procedure and indication, data regarding cannulation and therapeutic intervention of the common bile duct (procedure success), and clinical outcomes were analyzed. RESULTS: A total of 19 patients were included. Indications for LA-ERCP, EDGE, or HGS were mostly choledocholithiasis (78.9%) and in a few cases papillitis stenosans. Eight patients (57.1%) with LA-ERCP underwent concomitant cholecystectomy. Procedure success was achieved in 100%. Adverse events (AEs) were identified in 15.7% of patients (all ERCP related). All AEs were rated as moderate and there were no serious AEs. CONCLUSION: This case series indicates that ERCP via a transgastric approach (LA-ERCP, EDGE, or HGS) is a minimally invasive, effective, and feasible method to access the biliary tree in bariatric patients. These techniques offer an appealing alternative treatment option compared to percutaneous transhepatic cholangiography and drainage- or deep enteroscopy-assisted ERCP. In bariatric patients who earlier had a cholecystectomy, EUS-guided techniques were the preferred treatment options for biliary pathologies.

De novo gastroesophageal reflux disease after sleeve gastrectomy: role of preoperative silent reflux.

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) has become the most frequently performed bariatric procedure to date. However, LSG is known to worsen pre-operative and result in de novo gastroesophageal reflux disease (GERD). Pre-operative evaluation reveals a high percentage of silent GERD of so far unknown influence on post-operative GERD. METHODS: Prospective data of patients undergoing primary LSG between 01/2012 and 12/2015 were evaluated. Pre-operative GERD-specific evaluation consisted of validated questionnaires, upper endoscopy, 24 h-pH-manometry, and esophagograms. Patients were followed-up with questionnaires every 6 months, upper endoscopies after 1 year and 24 h-pH-metry after 2 years. Silent GERD was defined as esophagitis grade > B and/or abnormal esophageal acid exposure in absence of symptoms. LSG was performed over a 32F bougie, hiatal hernias > 1 cm were addressed with posterior hiatoplasty. Excluded were patients with hiatal hernias > 4 cm, patients with incorrect anatomy (stenosis, fundus too large) and conversion to RYGB for early leaks. RESULTS: 222 patients were included. Mean follow-up was 32 ± 16 months, mean preoperative body mass index 49.6 ± 7.2 kg/m2. 116 patients (52%) presented with post-operative GERD-symptoms, of which 85 (73%) had de novo symptoms. Of those, 48 (of 85, 56%) had no preoperative GERD and 37 (of 85, 44%) silent GERD. 57 patients (26%) had neither pre- nor post-operative GERD, 7 (3%) had silent pre-operative and no postop GERD, and in 19 patients (9%) GERD was cured with LSG. 31 patients (14%) stayed symptomatic. Of 56 patients (25%) with pre-operative silent GERD, 37 (of 54, 66%) became symptomatic. CONCLUSION: LSG leads to a considerable rate of post-operative GERD. De novo-GERD consist of around half of pre-operative silent GERD and completely de novo-GERD. Most patients with pre-operative silent GERD became symptomatic.

Mental Illness Has a Negative Impact on Weight Loss in Bariatric Patients: a 4-Year Follow-up.

BACKGROUND: Mental health disorders are highly prevalent among bariatric surgery patients. Bariatric surgery induces weight loss with continuous health improvements. However, long-term follow-up data on weight loss and quality of life data of patients who have a mental illness after bariatric surgery are scarce, and it is not clear whether mental illness is associated with more pronounced weight regain. The aim was to investigate the impact of preoperative mental illness on the course of long-term weight changes after bariatric surgery. METHODS: Patients with sleeve gastrectomy (SG) or Roux-en-Y gastric bypass surgery (RYGB) between 2005 and 2013 with a follow-up of at least 3 years were included. The study population was divided into two groups: patients with mental illness (MI) and patients without (No-MI). Weight loss outcomes over time were compared using mixed models up to 4 years after surgery. RESULTS: In total, 254 patients (RYGB 61.0%, SG 39%) were included. The distribution of baseline characteristics was similar between the MI (n = 108) and No-MI groups (n = 146). The most prevalent mental illness was depressive disorder (63.9%). In the MI group, the percent of total weight loss (%TWL) was significantly smaller over the study period. After 36 months, the predicted mean group-difference of %TWL was 4.6% (95% CI 1.9, 7.2; p = 0.001), and the predicted odds ratio for weight regain was 4.9 (95% CI 1.6, 15.1) for patients in the MI group. CONCLUSION: Preoperative mental illness leads to lower long-term weight loss and an increased risk of weight regain after bariatric surgery.

[Internal hernias after bariatric and metabolic surgery]. / Innere Hernien nach bariatrischer und metabolischer Chirurgie.

Internal hernias after bariatric and metabolic surgery Abstract. Internal hernias are among the most common long-term complications of morbid obesity following gastric bypass procedures. The diagnosis of an internal hernia after a gastric bypass is often uncertain due to unspecific clinical symptoms and is difficult despite various diagnostic procedures. This fact requires special attention in the postbariatric follow-up after gastric bypass surgery and the knowledge of the possibility of the development of internal hernias. In addition, the recurrence rate after surgical treatment is not insignificant.

The effect of bariatric surgery on the direct oral anticoagulant rivaroxaban: the extension study.

BACKGROUND: Thromboembolic disease is a potentially serious complication in bariatric surgery patients. Direct oral anticoagulants (DOAC) have been investigated in orthopedic surgery patients. DOAC data after bariatric surgery are still limited to the early postsurgical period. Whether postsurgical midterm adaptations due to anatomic and physiologic alterations influence drug pharmacology is currently not known. OBJECTIVE: The aim of this study was to investigate the influence of weight loss and type of bariatric surgery on midterm postsurgical pharmacokinetic and pharmacodynamic parameters of rivaroxaban. SETTING: University hospital. METHODS: In this monocentric study, bariatric patients received a single oral dose of rivaroxaban (10 mg) 6 to 8 months after sleeve gastrectomy (SG) or Roux-en-Y-gastric bypass (RYGB). Pharmacokinetic and pharmacodynamic parameters were assessed and compared with prebariatric surgery results. RESULTS: We included 6 RYGB and 6 SG patients. Percent excess weight loss was 71.4% (interquartile range 56.4, 87.9) in the SG group and 76.6% (64.5, 85.7) in the RYGB group. Rivaroxaban mean areas under the curve 6 to 8 months after the bariatric procedure (922.4 µg × h/L, coefficient of variation 43.2) were comparable to those measured preoperatively (952.6 µg × h/L, 16.8). There was no relevant difference between the 2 surgical procedure groups. Rivaroxaban led to a decrease of prothrombin fragments F1+2 over 12 hours after oral intake confirming in vivo efficacy. CONCLUSIONS: Significant weight loss and altered anatomy after RYGB and SG procedures do not appear to affect the pharmacokinetics and pharmacodynamics of prophylactic rivaroxaban. A single dose of Rivaroxaban was well tolerated and considered safe in this trial.

Perforated duodenal ulcers after Roux-Y Gastric Bypass.

Even though the incidence of complicated peptic ulcer disease (PUD) has decreased in the last decades, it remains a condition with a significant mortality. Whilst diagnosis and treatment of PUD in morbidly obese patients can be challenging, patients with excluded segments - such as after Roux-Y Gastric Bypass (RYGB) - present an even greater problem, as the subsequent altered anatomy impedes the common modalities used for diagnostic and therapeutic measures. We report the cases of two patients after RYGB with perforated duodenal ulcers in the intention to highlight problems regarding diagnosis and treatment. Patients with perforation after RYGB usually present without signs of hollow organ perforation in clinical examination but also in computed tomography scans. Diagnostic laparoscopy was performed to address the discrepancy between pain and non-diagnostic examinations. An aggressive approach in case of unexplained symptoms in these patients is not only justified but mandatory.