Rates and Risk Factors for 30-Day Morbidity After One-Stage Vertical Banded Gastroplasty Conversions: A Retrospective Analysis.

Background: The vertical banded gastroplasty (VBG) is a historic restrictive bariatric operation often requiring further surgery. In this investigation utilizing the 2021 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) national dataset, we aim to better define the outcomes of VBG conversions.Methods: We queried the 2021 MBSAQIP dataset for patients who underwent a conversion from a VBG to Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Demographics, comorbidities, laboratory values, and additional patient factors were examined. Rates of key consequential outcome measures 30-day readmission, reoperation, reintervention, mortality, and a composite endpoint (at least 1 of the 4) were further calculated.Results: We identified 231 patients who underwent conversion from VBG to SG (n = 23), RYGB (n = 208), or other anatomy (n = 6), of which 93% of patients were female, and 22% of non-white race. The median age was 56 years and body-mass index (BMI) was 43 kg/m2. The most common surgical indications included weight considerations (48%), reflux (25%), anatomic causes (eg, stricture, fistula, and ulcer; 10%), and dysphagia (6.5%). Thirty-day morbidity rates included reoperation (7.8%), readmission (9.1%), reintervention (4.3%), mortality (.4%), and the composite endpoint (15%). Upon bivariate analysis, we did not identify any specific risk factor for the 30-day composite endpoint.Discussion: One-stage VBG conversions to traditional bariatric anatomy are beset with higher 30-day morbidity relative to primary procedures. Additional MBSAQIP data will be required for aggregation, to better characterize the risk factors inherent in these operations.

Prediction of 30-Day Morbidity and Mortality After Conversion of Sleeve Gastrectomy to Roux-en-Y Gastric Bypass: Use of an Artificial Neural Network.

BACKGROUND: Conversion of sleeve gastrectomy to Roux-en-Y gastric bypass is indicated primarily for unsatisfactory weight loss or gastroesophageal reflux disease (GERD). This study aimed to use a comprehensive database to define predictors of 30-day reoperation, readmission, reintervention, or mortality. An artificial neural network (ANN) was employed to optimize prediction of the composite endpoint (occurrence of 1+ morbid event). METHODS: Areview of 8895 patients who underwent conversion for weight-related or GERD-related indications was performed using the 2021 MBSAQIP national dataset. Demographics, comorbidities, laboratory values, and other factors were assessed for bivariate and subsequent multivariable associations with the composite endpoint (P ≤ .05). Factors considered in the multivariable model were imputed into a three-node ANN with 20% randomly withheld for internal validation, to optimize predictive accuracy. Models were compared using receiver operating characteristic (ROC) curve analysis. RESULTS: 39% underwent conversion for weight considerations and 61% for GERD. Rates of 30-day reoperation, readmission, reintervention, mortality, and the composite endpoint were 3.0%, 7.1%, 2.1%, .1%, and 9.1%, respectively. Of the nine factors associated with the composite endpoint on bivariate analysis, only non-white race (P < .001; odds ratio 1.4), lower body-mass index (P < .001; odds ratio .22), and therapeutic anticoagulation (P = .001; odds ratio 2.0) remained significant upon multivariable analysis. Areas under ROC curves for the multivariable regression, ANN training, and validation sets were .587, .601, and .604, respectively. DISCUSSION: Identification of risk factors for morbidity after conversion offers critical information to improve patient selection and manage postoperative expectations. ANN models, with appropriate clinical integration, may optimize prediction of morbidity.

Effect of beta-blocker therapy on weight loss outcomes after sleeve gastrectomy & Roux-en-Y gastric bypass.

BACKGROUND: Patients taking beta-blockers (BBs) commonly experience weight gain. There is limited research exploring how BBs impact weight loss after bariatric surgery. OBJECTIVES: We examined how BBs impact 12-month weight loss in patients undergoing sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB). SETTING: Large midwest health system. METHODS: We reviewed health records of SG and RYGB patients (2011-2022) and categorized them by BB usage (none, pre-, post-, or pre- and postoperative). Multivariable linear regression models examined the relation between BB use, percent total body weight loss (%TBWL), and percent excess body mass index lost (%EBMIL). RESULTS: A total of 889 individuals (SG, n = 485; RYGB, n = 404) had complete data. RYGB led to greater %TBWL compared to SG (31% versus 26%, P < .01) and greater %EBMIL (79% versus 64%, P < .01). BB status did not significantly affect 12-month %TBWL or %EBMIL. CONCLUSIONS: BB use may not significantly affect weight loss 12 months after bariatric surgery. This finding could enable physicians to prescribe BBs for improved blood pressure control in bariatric surgery patients with less concern of blunting weight loss. Longer term follow-up with a larger sample size would be an important next step to better characterize the relationship between BB usage and bariatric surgery.

Prediction of thirty-day morbidity and mortality after duodenal switch using an artificial neural network.

BACKGROUND: Understanding factors that increase risk of both mortality and specific measures of morbidity after duodenal switch (DS) is important in deciding to offer this weight loss operation. Artificial neural networks (ANN) are computational deep learning approaches that model complex interactions among input factors to optimally predict an outcome. Here, a comprehensive national database is examined for patient factors associated with poor outcomes, while comparing the performance of multivariate logistic regression and ANN models in predicting these outcomes. METHODS: 2907 DS patients from the 2019 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database were assessed for patient factors associated with the previously validated composite endpoint of 30-day postoperative reintervention, reoperation, readmission, or mortality using bivariate analysis. Variables associated (P ≤ 0.05) with the endpoint were imputed in a multivariate logistic regression model and a three-node ANN with 20% holdback for validation. Goodness-of-fit was assessed using area under receiver operating curves (AUROC). RESULTS: There were 229 DS patients with the composite endpoint (7.9%), and 12 mortalities (0.4%). Associated patient factors on bivariate analysis included advanced age, non-white race, cardiac history, hypertension requiring 3 + medications (HTN), previous foregut/obesity surgery, obstructive sleep apnea (OSA), and higher creatinine (P ≤ 0.05). Upon multivariate analysis, independently associated factors were non-white race (odds ratio 1.40; P = 0.075), HTN (1.55; P = 0.038), previous foregut/bariatric surgery (1.43; P = 0.041), and OSA (1.46; P = 0.018). The nominal logistic regression multivariate analysis (n = 2330; R2 = 0.02, P < 0.001) and ANN (R2 = 0.06; n = 1863 [training set], n = 467 [validation]) models generated AUROCs of 0.619, 0.656 (training set) and 0.685 (validation set), respectively. CONCLUSION: Readily obtainable patient factors were identified that confer increased risk of the 30-day composite endpoint after DS. Moreover, use of an ANN to model these factors may optimize prediction of this outcome. This information provides useful guidance to bariatricians and surgical candidates alike.

Care of the Patient After Metabolic and Bariatric Surgery.

Weight loss surgery, also known as metabolic and bariatric surgery (MBS), is an effective weight loss treatment and is associated with reduced mortality and improvements in obesity-related health conditions and quality of life. Postsurgical anatomical and physiologic changes include decreased absorption of micronutrients and alterations in gut-brain hormonal regulation that affect many aspects of health. Patients require ongoing monitoring of their physical and mental health for lasting success. Internists, particularly primary care clinicians, are in an ideal position to monitor for nonserious complications in the short and long term, adjust management of chronic diseases accordingly, and monitor for mental health changes. This article reviews key issues that internists should be aware of for supporting patients' health in the short and long term after MBS.

Gastroesophageal Reflux Disease Outcomes After Vertical Sleeve Gastrectomy and Gastric Bypass.

OBJECTIVE: The objective of this study is to assess whether vertical sleeve gastrectomy (VSG) increases the incidence of gastroesophageal reflux disease (GERD), esophagitis and Barrett esophagus (BE) relative to patients undergoing Roux-en-Y gastric bypass (RYGB) in patients with and without preoperative GERD. SUMMARY OF BACKGROUND DATA: Concerns for potentiation of GERD, supported by multiple high-quality retrospective studies, have hindered greater adoption of the VSG. METHODS: From the OptumLabs Data Warehouse, VSG and RYGB patients with ≥2 years enrollment were identified and matched by follow-up time. GERD [reflux esophagitis, prescription for acid reducing medication (Rx) and/or diagnosis of BE], upper endoscopy (UE), and re-admissions were evaluated beyond 90 days. RESULTS: A total of 8362 patients undergoing VSG were matched 1:1 to patients undergoing RYGB, on the basis of post-operative follow-up interval. Age, sex, and follow-up time were similar between the 2 groups (P > 0.05). Among all patients, postoperative GERD was more frequently observed in VSG patients relative to RYGB patients (60.2% vs 55.6%, respectively; P < 0.001), whereas BE was more prevalent in RYGB patients (0.7% vs 1.1%; P = 0.007). Postoperatively, de novo esophageal reflux symptomatology was more common in VSG patients (39.3% vs 35.3%; P < 0.001), although there was no difference in development of the histologic diagnoses reflux esophagitis and BE. Furthermore, postoperative re-admission was higher in the RYGB cohort (38.9% vs 28.9%; P < 0.001). CONCLUSIONS: Compared to RYGB, VSG may not have inferior long-term GERD outcomes, while also leading to fewer re-hospitalizations. These data challenge the prevailing opinion that patients with GERD should undergo RYGB instead of VSG.

The Role of Preoperative Anemia in Predicting Short-Term Morbidity and Mortality After Roux-en-Y Gastric Bypass.

BACKGROUND: Preoperative anemia has been suggested as a contraindication to gastric bypass. Using the Metabolic and Bariatric Surgery Accreditation and Quality Improvement database, this study sought to determine the role of preoperative hematocrit on 30-day morbidity and mortality after laparoscopic Roux-en-Y gastric bypass for weight loss. METHODS: A cohort of 31 981 patients was reviewed for factors associated with a composite primary end point including 30-day reoperation, readmission, reintervention, or mortality, including degree of anemia. Analyzed separately by gender, factors significant on bivariate analysis were included in nominal logistic multivariate analysis to assess for independent significance of the hematocrit level as a risk factor for the primary end point. RESULTS: Upon multivariate analysis, the hematocrit level was significantly associated with the 30-day end point in the male cohort (P = .05), specifically, severe anemia (hematocrit <35%) conferred an increased risk relative to a normal hematocrit (odds ratio 1.5, P = .03). There was no association of hematocrit with the 30-day end point in the female cohort. CONCLUSION: Bariatricians should carefully consider the appropriateness of a gastric bypass over a less anemogenic procedure such as sleeve gastrectomy in patients, particularly men with preoperative anemia.

Marijuana use does not affect the outcomes of bariatric surgery.

BACKGROUND: The decriminalization of marijuana and legalization of derived products requires investigation of their effect on healthcare-related outcomes. Unfortunately, little data are available on the impact of marijuana use on surgical outcomes. We aimed to determine the effect of marijuana use on 30-day complications and 1-year weight loss following laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG). METHODS: At a large academic center, 1176 consecutive patients undergoing primary bariatric surgery from 2012 to 2017 were identified and separated into cohorts according to marijuana use. The only exclusions were 19 patients lost to follow-up. Propensity score matching, using logistic regression according to preoperative age, gender, BMI, and comorbid conditions, yielded 73 patient pairs for the control and study arms. All patients were followed two years postoperatively. RESULTS: Excess BMI lost did not differ between marijuana users and controls at 3 weeks (23.0% vs 18.9%, p = 0.095), 3 months (42.0% vs 38.1%, p = 0.416), 6 months (60.6% vs 63.1%, p = 0.631), 1 year (78.2% vs 77.3%, p = 0.789), or 2 years (89.1% vs 74.5%, p = 0.604). No differences in the rate of major 30-day postoperative complications, including readmission, infection, thromboembolic events, bleeding events and reoperation rates, were found between groups. Follow-up rate at two years was lower in marijuana users (12.3% vs 27.4%, p = 0.023). CONCLUSION: This study suggests marijuana use has no impact on 30-day complications or weight loss following bariatric surgery, and should not be a contraindication to bariatric surgery.

Prediction of thirty-day morbidity and mortality after laparoscopic sleeve gastrectomy: data from an artificial neural network.

BACKGROUND: Multiple patient factors may convey increased risk of 30-day morbidity and mortality after laparoscopic vertical sleeve gastrectomy (LVSG). Assessing the likelihood of short-term morbidity is useful for both the bariatric surgeon and patient. Artificial neural networks (ANN) are computational algorithms that use pattern recognition to predict outcomes, providing a potentially more accurate and dynamic model relative to traditional multiple regression. Using a comprehensive national database, this study aims to use an ANN to optimize the prediction of the composite endpoint of 30-day readmission, reoperation, reintervention, or mortality, after LVSG. METHODS: A cohort of 101,721 LVSG patients was considered for analysis from the 2016 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program national dataset. Select patient factors were chosen a priori as simple, pertinent and easily obtainable, and their association with the 30-day endpoint was assessed. Those factors with a significant association on both bivariate and multivariate nominal logistic regression analysis were incorporated into a back-propagation ANN with three nodes each assigned a training value of 0.333, with k-fold internal validation. Logistic regression and ANN models were compared using area under receiver-operating characteristic curves (AUROC). RESULTS: Upon bivariate analysis, factors associated with 30-day complications were older age (P = 0.03), non-white race, higher initial body mass index, severe hypertension, diabetes mellitus, non-independent functional status, and previous foregut/bariatric surgery (all P < 0.001). These factors remained significant upon nominal logistic regression analysis (n = 100,791, P < 0.001, r2= 0.008, AUROC = 0.572). Upon ANN analysis, the training set (80% of patients) was more accurate than logistic regression (n = 80,633, r2= 0.011, AUROC = 0.581), and it was confirmed by the validation set (n = 20,158, r2= 0.012, AUROC = 0.585). CONCLUSIONS: This study identifies a panel of simple and easily obtainable preoperative patient factors that may portend increased morbidity after LSG. Using an ANN model, prediction of these events can be optimized relative to standard logistic regression modeling.

Obesity in Liver Transplantation: A Risk Factor for Unplanned Reoperation and Prolonged Operative Time.

Selection of orthotopic liver transplantation (OLT) candidates is increasingly inclusive of patients with high BMI. We aim to characterize the influence of obesity on the surgical outcome measures of prolonged operative time and unplanned reoperation. We reviewed the records of obese and normal weight OLT recipients over a 10-year period from a single institution. Variables that trended (P < 0.1) with endpoints on univariate analysis were put into multivariate logistic regression models to determine independent association (P < 0.05). We included 195 obese and 171 normal weight OLT recipients in our study. On multivariate analysis, obesity was the only preoperative risk factor that trended with unplanned reoperation (odds ratio 2, P = 0.05). Similarly, only obesity remained independently associated with prolonged length of operation (defined as ≥275 minutes) on multivariate analysis (odds ratio 1.7, P = 0.04). In summary, obesity may make OLT more technically challenging and, thus, represents an independent risk factor for unplanned reoperations and prolonged operative time.

A Structured Remediation Program Results in Durable Improvement of American Board of Surgery In-Training Examination (ABSITE®) Performance.

The objective of this study was to assess the results of a structured remediation program for surgical residents scoring poorly on the American Board of Surgery In-Training Examination®. Residents scoring below the threshold (<20th percentile) were placed in a remediation program consisting of textbook-based review and mandatory weekly quizzes overseen by the program director. The effects of the program were assessed over a five-year period (2014-2018). Of 168 tests taken, 23 (13.7%) instances of scoring below the threshold occurred (average percentile 11, range 1-19). Postremediation scores in the subsequent year improved with a median (IQR) percentile increase of 29 [23.5, 46] (P < 0.001). Two residents scored below the threshold twice; all others continued to score above the threshold. Participation in a structured remediation program results in dramatic improvement in American Board of Surgery In-Training Examination® performance, and a single occurrence of poor performance does not necessarily lead to a permanent handicap in academic performance.

Laparoscopic Sleeve Gastrectomy has a Lower Risk of Postoperative Bleeding Than Laparoscopic Roux-en-Y Gastric Bypass.

Measures to reduce postoperative bleeding (POB) after bariatric surgery is skewed toward laparoscopic sleeve gastrectomy (LSG). We use 2015 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) to characterize the differences in bleeding rates between LSG and laparoscopic Roux-en-Y gastric bypasses (LRYGB). Propensity score matching and multivariable logistic regressions tested for independent differences in POB rates. A total of 168,093 patients from 742 centers were identified in the data set. After selection 36,925 patients with LRYGB and 20,020 patients with LSG were included in the analysis. A total of 710 (1.25%) patient suffered a POB. The independent odds of POB were 38% lower for patients having LSG compared with those having LRYGB (odds ratio, 0.62; 95% confidence interval=0.51-0.76). This difference is more pronounced with intraoperative securing of the staple line. Appropriate measures to reduce POB after each type of bariatric procedure is warranted.

Postoperative bleeding after laparoscopic Roux en Y gastric bypass: predictors and consequences.

BACKGROUND: Laparoscopic Roux-en-Y gastric bypass (LRYGB) is a common, safe and effective bariatric procedure. Bleeding is a significant source of postoperative morbidity. We aimed to determine the incidence, outcomes, and predictors of postoperative bleeding after LRYGB. METHODS: LRYGB patients included in the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) 2015 dataset were identified. Preoperative and intraoperative factors were tested for associations with bleeding using univariable and multivariable logistic regression analysis. Outcomes of length of stay, in-hospital mortality, 30-day mortality, discharge disposition, and 30-day complications among patients with and without clinically significant postoperative bleeding were compared using multivariable regression. RESULTS: In the 43,280 LRYGB patients included in this analysis, postoperative bleeding occurred in 652 (1.51%) patients. Of these, 165 (25.3%) underwent a re-operation and 97 (14.9%) underwent an unplanned endoscopy for 'bleeding'. Postoperative bleeding was associated with a longer median postoperative length of stay (4 vs. 2 days), higher in-hospital mortality (1.23 vs. 0.04%), higher 30-day mortality (1.38 vs. 0.15%), discharge to an extended-care facility (3.88 vs. 0.6%), and higher rates of major complications (all P < 0.05). Independent predictors of postoperative bleeding included; a history of renal insufficiency (OR 2.55, 95% CI 1.43-4.52), preoperative therapeutic anticoagulation (OR 2.44, 95% CI 1.69-3.53), and revisional surgery (OR 1.45, 95% CI 1.06-1.97). Intraoperative associated factors included conversions (OR 3.37, 95% CI 1.42-7.97), and drain placement (OR 1.40, 95% CI 1.18-1.67). Robotic approaches resulted in independently lower postoperative bleeding rates (OR 0.50, 95% CI 0.32-0.77). CONCLUSIONS: Postoperative bleeding occurs in 1.5% of patients undergoing a LRYGB and is associated with significantly increased morbidity and mortality. We have identified patient and operative factors that are independently associated with postoperative bleeding.

A Novel Risk Score Predicts Operative Mortality After Acute Type A Aortic Dissection Repair.

BACKGROUND: Current stratification systems for patients presenting with acute type A aortic dissection rely on signs of malperfusion to predict mortality. The authors sought to develop an algorithm to readily risk stratify these patients using admission characteristics. METHODS: Two hundred sixty-nine consecutive patients who underwent type A repair between 2002 and 2015 were reviewed for easily obtainable preoperative demographics and laboratory values deemed a priori as potential predictors of operative mortality. Multiple logistic regression analysis was performed to determine independent significance, and linear regression was performed to generate the concomitant regression expression of the variables significant on bivariate analysis. RESULTS: Operative mortality was 16% (43/269) and was 29% (34/119) among patients who presented with malperfusion. Upon multivariate analysis, creatinine (p = 0.008), liver malperfusion (p = 0.006), and lactic acid level (p = 0.0007) remained independent significant predictors. Regression coefficients allowed the generation of a risk score as 5.5 × (lactic acid [mmol/L]) + 8 × (creatinine [mg/dL]) ± 8 (+ if liver malperfusion presents, - if no liver malperfusion). Upon receiver-operating characteristic curve analysis this model generated a c-statistic of 0.75. Operative mortality among patients within the lowest tertile (risk score < 7) was 4%, whereas patients in the middle (7 to 20) and highest (≥20) tertiles had mortality rates of 14% 37%, respectively. CONCLUSIONS: Although still requiring external validation, the innovative risk score presented necessitates knowledge of lactic acid, serum creatinine, and liver function tests. The algorithm predicts operative mortality with high accuracy and offers clinicians a novel tool to improve preoperative guidance and prognosis.

The American Board Style Practice In-Training Examination as a Predictor of Performance on the American Board of Surgery In-Training Examination.

BACKGROUND: The American Board of Surgery In-Training Examination (ABSITE), is an annual 250 question, multiple-choice test that assesses residents' surgical knowledge in preparation for board examinations. At our program, we developed a Surgical Council on Resident Education-based American Board Style Practice In-Training Examination: The ABSPITE. The 40-question examination was designed to help with test preparation. The purpose of this study was to evaluate the ABSPITE's predictive value on ABSITE performance. METHODS: From 2013 to 2016, the ABSPITE was administered to residents at our program. Performances (N = 134) were graded based on a standardized scale to determine resident percent and percentile performance, then compared to average ABSITE performance. RESULTS: Combined analysis showed a statistically significant positive correlation between average ABSITE and ABSPITE percentages and percentiles. This held true when categorical and preliminary residents were compared. When stratified by resident PGY level, the same results were seen for PGY 1 and PGY 2 residents but correlations failed to reach statistical significance for higher resident training levels. CONCLUSIONS: The practice ABSPITE examination strongly correlates with ABSITE performance among junior residents at our program, and may be a valuable tool to predict ABSITE performance and guide review efforts.

Staple Line Treatment and Bleeding After Laparoscopic Sleeve Gastrectomy.

BACKGROUND AND OBJECTIVES: Staple line treatment during laparoscopic sleeve gastrectomy (LSG) remains a controversial issue among bariatric surgeons. The objective of this study was to compare rates of postoperative bleeding (POB) among various methods of staple line reinforcement. METHODS: The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program 2015 dataset was queried for patients undergoing an LSG. Patients were stratified by staple line treatment groups-no treatment (NT), suture oversewing (OVERSEW), buttressing by a commercial product (BUTTRESS), and both buttress and oversew (COMBINATION). The primary outcome was POB. Multivariable logistic regression was used to compare POB rates among the treatment groups. RESULTS: In the 98,142 LSG patients meeting selection criteria, 623 (0.63%) patients had POB and 181 (0.18%) required reoperation. POB occurred in 0.80% for the NT group, 0.68% for the OVERSEW group, 0.57% for the BUTTRESS group, and 0.55% for the COMBINATION group. On multivariable analyses, all treatment groups were less likely to have POB compared with the NT group-OVERSEW (odds ratio [OR] 0.73, 95% confidence interval [CI] 0.54-0.98), BUTTRESS (OR 0.70, 95% CI 0.57-0.84), and COMBINATION (OR 0.66, 95% CI 0.50-0.89) (all P < .01). Subset analysis revealed no difference between BUTTRESS and OVERSEW (OR 0.95, 95% CI 0.71-1.26, P = .71). CONCLUSIONS: Relative to an NT staple line, the use of OVERSEW or BUTTRESS can decrease the rates of POB by up to 30%. The use of these techniques should be strongly considered by the bariatric surgeon.

The Right Way to Teach Left-Handed Residents: Strategies for Training by Right Handers.

PURPOSE: Left-handed (LH) residents remain underrepresented among surgical trainees, and there are few available data on how best to train them. The challenge is amplified when pairing a LH resident with a right-handed (RH) mentor. This report provides recommendations on how to improve the training of LH surgeons in a safe and effective manner. METHODS: A comprehensive literature review was performed using different databases and search engines to identify all articles relevant to the training of LH residents. RESULTS: A total of 40 articles highlighted the challenges for LH surgical residents and RH mentors. Our recommendations are based on the following 4 themes: identifying inherent differences in left vs. RH residents, providing guidance to RH mentors training LH residents, adapting the RH environment to the LH surgeon, and maximizing safety during training. CONCLUSION: An organized approach needs to be taken in training the LH resident. Changes should be instituted at program-wide and national levels to ensure that the training experience of the sinistral surgical resident is optimized.

Exponential decay modeling can define parameters of weight loss trajectory after laparoscopic Roux-en-Y gastric bypass.

BACKGROUND: Laparoscopic Roux-en-Y gastric bypass (LRYGB) produces durable and clinically significant weight loss. We aim to characterize the trajectory of weight loss, and demonstrate the predictive ability of three-month performance on final weight loss. METHODS: Retrospective analysis of 1097 consecutive LRYGB patients allowed for assessment of conformity of various weight loss trajectory models. Establishing exponential decay as the optimal fit, initial, three-month and final BMI values were used to determine empiric rate constants (λ3). Empirically derived weight loss curves and associated rate constants (λ) were generated. RESULTS: Exponential decay optimally characterizes post-LRYGB weight loss trajectory. Final weight loss can be characterized by λ3, as well as by the demographics black race (P = 0.008) and initial BMI (P < 0.001). Stratification by three-month weight loss allowed derivation of weight loss trajectory curves to predict weight at any point until and including plateau. CONCLUSIONS: Weight loss after LRYGB conforms well to exponential decay, and postoperative trajectory can thus be predicted early. This allows the clinician early identification and intervention upon patients at risk of poor performance.

Limiting Injury During Saphenous Vein Graft Preparation For Coronary Arterial Bypass Prevents Metabolic Decompensation.

Standard harvest and preparation of human saphenous vein (HSV) for autologous coronary and peripheral arterial bypass procedures is associated with injury and increased oxidative stress that negatively affect graft performance. In this study we investigated the global metabolomic profiles of HSV before (unprepared; UP) and after standard vein graft preparation (AP). AP-HSV showed impaired vasomotor function that was associated with increased oxidative stress, phospholipid hydrolysis and energy depletion that are characteristic of mechanical and chemical injury. A porcine model (PSV) was utilized to validate these metabolomic changes in HSV and to determine the efficacy of an improved preparation technique (OP) using pressure-regulated distension, a non-toxic vein marker, and graft storage in buffered PlasmaLyte solution in limiting metabolic decompensation due to graft preparation. Deficits in vasomotor function and metabolic signature observed in AP-PSV could be largely mitigated with the OP procedure. These findings suggest that simple strategies aimed at reducing injury during graft harvest and preparation represents a straightforward and viable strategy to preserve conduit function and possibly improve graft patency.

Unregulated saphenous vein graft distension decreases tissue viscoelasticity.

OBJECTIVES: Unregulated intraoperative distension of human saphenous vein (SV) graft leads to supraphysiologic luminal pressures and causes acute physiologic and cellular injury to the conduit. The effect of distension on tissue viscoelasticity, a biophysical property critical to a successful graft, is not well described. In this investigation, we quantify the loss of viscoelasticity in SV deformed by distension and compare the results to tissue distended in a pressure-controlled fashion. MATERIALS AND METHODS: Unmanipulated porcine SV was used as a control or distended without regulation and distended with an in-line pressure release valve (PRV). Rings were cut from these tissues and suspended on a muscle bath. Force versus time tracings of tissue constricted with KCl (110 mM) and relaxed with sodium nitroprusside (SNP) were fit to the Hill model of viscoelasticity, using mean absolute error (MAE) and r2-goodness of fit as measures of conformity. RESULTS: One-way ANOVA analysis demonstrated that, in tissue distended manually, the MAE was significantly greater and the r2-goodness of fit was significantly lower than both undistended tissues and tissues distended with a PRV (p<0.05) in KCl-induced vasoconstriction and SNP-induced vasodilation. CONCLUSIONS: Unregulated manual distension of SV graft causes loss of viscoelasticity and such loss may be mitigated with the use of an in-line PRV.