Erik Stenberg

Early Complications After Laparoscopic Gastric Bypass Surgery : Results From the Scandinavian Obesity Surgery Registry

Objective:To identify risk factors for serious and specific early complications of laparoscopic gastric bypass surgery using a large national cohort of patients. Background:Bariatric procedures are among the most common surgical procedures today. There is, however, still a need to identify preoperative and intraoperative risk factors for serious complications. Methods:From the Scandinavian Obesity Surgery Registry database, we identified 26,173 patients undergoing primary laparoscopic gastric bypass operation for morbid obesity between May 1, 2007, and September 30, 2012. Follow-up on day 30 was 95.7%. Preoperative data and data from the operation were analyzed against serious postoperative complications and specific complications. Results:The overall risk of serious postoperative complications was 3.4%. Age (adjusted P = 0.028), other additional operation [odds ratio (OR) = 1.50; confidence interval (CI): 1.04–2.18], intraoperative adverse event (OR = 2.63; 1.89–3.66), and conversion to open surgery (OR = 4.12; CI: 2.47–6.89) were all risk factors for serious postoperative complications. Annual hospital volume affected the rate of serious postoperative complications. If the hospital was in a learning curve at the time of the operation, the risk for serious postoperative complications was higher (OR = 1.45; CI: 1.22–1.71). The 90-day mortality rate was 0.04%. Conclusions:Intraoperative adverse events and conversion to open surgery are the strongest risk factors for serious complications after laparoscopic gastric bypass surgery. Annual operative volume and total institutional experience are important for the outcome. Patient related factors, in particular age, also increased the risk but to a lesser extent.

Closure of mesenteric defects in laparoscopic gastric bypass: a multicentre, randomised, parallel, open-label trial

BACKGROUND Small bowel obstruction due to internal hernia is a common and potentially serious complication after laparoscopic gastric bypass surgery. Whether closure of surgically created mesenteric defects might reduce the incidence is unknown, so we did a large randomised trial to investigate. METHOD This study was a multicentre, randomised trial with a two-arm, parallel design done at 12 centres for bariatric surgery in Sweden. Patients planned for laparoscopic gastric bypass surgery at any of the participating centres were offered inclusion. During the operation, a concealed envelope was opened and the patient was randomly assigned to either closure of mesenteric defects beneath the jejunojejunostomy and at Petersens space or non-closure. After surgery, assignment was open label. The main outcomes were reoperation for small bowel obstruction and severe postoperative complications. Outcome data and safety were analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01137201. FINDINGS Between May 1, 2010, and Nov 14, 2011, 2507 patients were recruited to the study and randomly assigned to closure of the mesenteric defects (n=1259) or non-closure (n=1248). 2503 (99·8%) patients had follow-up for severe postoperative complications at day 30 and 2482 (99·0%) patients had follow-up for reoperation due to small bowel obstruction at 25 months. At 3 years after surgery, the cumulative incidence of reoperation because of small bowel obstruction was significantly reduced in the closure group (cumulative probability 0·055 for closure vs 0·102 for non-closure, hazard ratio 0·56, 95% CI 0·41-0·76, p=0·0002). Closure of mesenteric defects increased the risk for severe postoperative complications (54 [4·3%] for closure vs 35 [2·8%] for non-closure, odds ratio 1·55, 95% CI 1·01-2·39, p=0·044), mainly because of kinking of the jejunojejunostomy. INTERPRETATION The results of our study support the routine closure of the mesenteric defects in laparoscopic gastric bypass surgery. However, closure of the mesenteric defects might be associated with increased risk of early small bowel obstruction caused by kinking of the jejunojejunostomy. FUNDING Örebro County Council, Stockholm City Council, and the Erling-Persson Family Foundation.

Is glycosylated hemoglobin A1 c associated with increased risk for severe early postoperative complications in nondiabetics after laparoscopic gastric bypass

BACKGROUND Glycosylated hemoglobin A1 c (HbA1 c) has been described as a risk factor for adverse outcome after cardiovascular and colorectal surgery, but not for obese patients undergoing bariatric surgery. The objective of this study was to see if there is an association between HbA1 c and adverse outcome in laparoscopic gastric bypass surgery. METHODS From the Scandinavian Obesity Surgery Registry we identified 12,850 patients, without treatment for diabetes and operated with laparoscopic gastric bypass between January 1, 2010 and September 30, 2012, and where a baseline HbA1 c value was registered. Preoperative data were compared with data from a 30-day follow-up. Severe complications were defined according to the Clavien-Dindo-Scale as Grade 3 b or higher. RESULTS HbA1 c levels below 5.7 % were associated with a lower incidence of severe complications (2.7 %) than higher levels (HbA1 c 5.7-6.49% incidence 3.5%, P = .015; HbA1 c>6.5%, incidence 4.5%, P = .012). After multivariate analysis with patient-specific confounders the difference remained significant (HbA1 c 5.7-6.49% adjusted P = .046; HbA1 c>6.5% adjusted P = .023) CONCLUSION: Elevated HbA1 c levels in patients without pharmacologic treatment for diabetes undergoing laparoscopic gastric bypass surgery is associated with an increased risk for severe complications during the first 30 postoperative days. This is the case, even at levels not regarded as diagnostic for diabetes.

Outcomes of laparoscopic gastric bypass in a randomized clinical trial compared with a concurrent national database

RCTs are the standard for assessing medical interventions, but they may not be feasible and their external validity is sometimes questioned. This study aimed to compare results from an RCT on mesenteric defect closure during laparoscopic gastric bypass with those from a national database containing data on the same procedure, to shed light on the external validity of the RCT.

A comparative study of machine learning algorithms in predicting severe complication after bariatric surgery

Accurate models to predict severe postoperative complications could be of value in the preoperative assessment of potential candidates for bariatric surgery. Traditional statistical methods have so far failed to produce high accuracy. To find a useful algorithm to predict the risk for severe complication after bariatric surgery, we trained and compared 29 supervised machine learning (ML) algorithms using information from 37,811 patients operated with a bariatric surgical procedure between 2010 and 2014 in Sweden. The algorithms were then tested on 6,250 patients operated in 2015. Most ML algorithms showed high accuracy (>90%) and specificity (>0.9) in both the training and test data. However, none achieved an acceptable sensitivity in the test data. ML methods may improve accuracy of prediction but we did not yet identify one with a high enough sensitivity that can be used in clinical praxis in bariatric surgery. Further investigation on deeper neural network algorithms is needed.

Bleeding during laparoscopic gastric bypass surgery as a risk factor for less favorable outcome. A cohort study from the Scandinavian Obesity Surgery Registry

BACKGROUND Intraoperative adverse events are known to be associated with postoperative complications; however, little is known about whether or not blood loss during laparoscopic gastric bypass surgery affects the outcome. OBJECTIVE To see if intraoperative bleeding was associated with a less favorable outcome, and to identify patient-specific risk factors for intraoperative bleeding. SETTING Nationwide, Sweden. METHODS Patients who underwent laparoscopic gastric bypass surgery between January 8, 2007, and September 15, 2015, were included in the study. The volume of intraoperative blood loss was compared with data from follow-up at day 30 and 1 and 2 years after surgery. Patient-specific factors were analyzed as potential risk factors for intraoperative bleeding. RESULTS The study included 43,157 patients. Intraoperative bleeding was associated with an increased risk for postoperative complication (100-499 mL, odds ratio [OR] 2.97, 95% confidence interval [95%CI] 2.53-3.50;>500 mL OR 3.34, 95%CI 2.05-5.44), lower weight loss (<100 mL, 82.4±24.19% excess body mass index-loss [%EBMIL]; 100-499 mL, 76.9±24.24 %EBMIL, P<.0001;>500 mL 76.9±23.89 %EBMIL, P = .063) and lower reported quality-of-life 2 years after surgery (<100 mL, Obesity-related Problem scale (OP) 21.1±24.46; 100-499 mL, OP 25.0±26.62, P = .008;>500 mL, OP 25.2±24.46, P = .272). Diabetes (OR 1.30, 95%CI 1.08-1.58), age (OR 1.02, 95%CI 1.02-1.03), and body mass index (OR 1.03, 95%CI 1.02-1.05) were patient-specific risk factors for intraoperative bleeding≥100 mL, whereas intentional preoperative weight loss was associated with a lower risk (OR .50, 95%CI .43-.57). CONCLUSION Intraoperative bleeding was associated with less favorable outcome after laparoscopic gastric bypass surgery. Age, body mass index, and diabetes were risk factors for intraoperative bleeding, while preoperative weight reduction seems to be protective.