Risk factors for bariatric surgery in patients over 65 years of age-a multicenter retrospective cohort study.

PURPOSE: Societies are aging, life expectancy is increasing, and as a result, the percentage of elderly people in the population is constantly increasing. When qualifying patients over 65 years of age for bariatric surgery, the benefits and risks should be carefully assessed. Weighing risk factors against each other to improve the quality of life and better control of obesity-related diseases. The study aimed to determine risk factors for bariatric surgery among patients over 65 years of age. METHODS: A multicenter, retrospective analysis of patients undergoing laparoscopic bariatric procedures from 2008 to 2022. The patients were divided into two groups: complicated (C) and uncomplicated (UC). Uni- and multivariate logistic regression analysis was performed to obtain significant, independent risk factors. RESULTS: There were 20 (7.0%) patients in C group and 264 (93.0%) patients in UC group. The most common complication was intraperitoneal bleeding (8, 2.8). There was no postoperative mortality. The mean follow-up was 47.5 months. In a multivariate logistic regression analysis, length of stay and %EWL significantly corresponded to general complications (OR 1.173, OR 1.020). A higher weight loss before surgery lowered the risk for hemorrhagic events after surgery (OR 0.889). A longer length of stay corresponded to leak after surgery (OR 1.175). CONCLUSIONS: Bariatric and metabolic surgery appears to be a safe method of obesity treatment in patients over 65 years of age. The most common complication was intraperitoneal bleeding. A prolonged hospital stay may increase the risk of leakage, while a higher weight loss before the surgery may lower the risk of bleeding.

Effect of Primary Versus Revisional One Anastomosis Gastric Bypass (OAGB) on Fatty Acid Profile.

INTRODUCTION: One anastomosis gastric bypass (OAGB) is one option of a revisional procedure for failed sleeve gastrectomy. Moreover, it can be used as a primary bariatric procedure, and is an effective surgery resulting in significant weight loss and the resolution or improvement of obesity-associated medical problems, accompanied by low perioperative complications. However, as with any therapy, OAGB has its limitations, including micronutrient deficiency or malnutrition. In our study, we compared the fatty acid (FA) profile in serum of patients after both primary OAGB (pOAGB) and revisional OAGB (rOAGB) to identify potential postsurgical FA alterations. METHODS: This is a retrospective study on patients with obesity who underwent OAGB procedures (pOAGB n=68; rOAGB n=17), conducted from 2016 to 2018. In blood, we analyzed a series of biochemical parameters, and in the serum, the FA profile was determined using gas chromatography-mass spectrometry. RESULTS: The percentage of excess BMI loss (% EBMIL) after pOAGB was 73.5 ± 2.47% in comparison to 45.9 ± 4.15% in the rOAGB group (p<0.001). In contrast to the lack of effect of rOAGB on most polyunsaturated FAs, in the pOAGB group, there was a decrease in eicosapentaenoic acid, and eicosatetraenoic and docosahexaenoic acid levels (p<0.001). We also found a decrease in very long-chain FAs (VLCFAs) and an increase in branched-chain FAs (BCFAs) after both types of OAGB procedure. CONCLUSIONS: Both OAGB procedures improved the profile of most FAs, leading to a decrease in VLCFAs, which are considered harmful, and an improvement in BCFAs, which are considered to be beneficial. There is a need to further investigate the possibility of n-3 polyunsaturated FA supplementation after pOAGB, due to the large decrease in these FAs after pOAGB.

The Association of Polish Surgeons (APS) clinical guidelines for the use of laparoscopy in the management of abdominal emergencies. Part II.

Introduction: Over the past three decades, almost every type of abdominal surgery has been performed and refined using the laparoscopic technique. Surgeons are applying it for more procedures, which not so long ago were performed only in the classical way. The position of laparoscopic surgery is therefore well established, and in many operations it is currently the recommended and dominant method. Aim: The aim of the preparation of these guidelines was to concisely summarize the current knowledge on laparoscopy in acute abdominal diseases for the purposes of the continuous training of surgeons and to create a reference for opinions. Material and methods: The development of these recommendations is based on a review of the available literature from the PubMed, Medline, EMBASE and Cochrane Library databases from 1985 to 2022, with particular emphasis on systematic reviews and clinical recommendations of recognized scientific societies. The recommendations were formulated in a directive form and evaluated by a group of experts using the Delphi method. Results and conclusions: There are 63 recommendations divided into 12 sections: diagnostic laparoscopy, perforated ulcer, acute pancreatitis, incarcerated hernia, acute cholecystitis, acute appendicitis, acute mesenteric ischemia, abdominal trauma, bowel obstruction, diverticulitis, laparoscopy in pregnancy, and postoperative complications requiring emergency surgery. Each recommendation was supported by scientific evidence and supplemented with expert comments. The guidelines were created on the initiative of the Videosurgery Chapter of the Association of Polish Surgeons and are recommended by the national consultant in the field of general surgery. The second part of the guidelines covers sections 6 to12 and the following challenges for surgical practice: acute appendicitis, acute mesenteric ischemia, abdominal injuries, bowel obstruction, diverticulitis, laparoscopy in pregnancy and postoperative complications requiring a reoperation.

The Association of Polish Surgeons (APS) clinical guidelines for the use of laparoscopy in the management of abdominal emergencies. Part I.

Introduction: Over the past three decades, almost every type of abdominal surgery has been performed and refined using the laparoscopic technique. Surgeons are applying it for more procedures, which not so long ago were performed only in the classical way. The position of laparoscopic surgery is therefore well established, and in many operations it is currently the recommended and dominant method. Aim: The aim of the preparation of these guidelines was to concisely summarize the current knowledge on laparoscopy in acute abdominal diseases for the purposes of the continuous training of surgeons and to create a reference for opinions. Material and methods: The development of these recommendations is based on a review of the available literature from the PubMed, Medline, EMBASE and Cochrane Library databases from 1985 to 2022, with particular emphasis on systematic reviews and clinical recommendations of recognized scientific societies. Recommendations were formulated in a directive form and evaluated by a group of experts using the Delphi method. Results and conclusions: There are 63 recommendations divided into 12 sections: diagnostic laparoscopy, perforated ulcer, acute pancreatitis, incarcerated hernia, acute cholecystitis, acute appendicitis, acute mesenteric ischemia, abdominal trauma, bowel obstruction, diverticulitis, laparoscopy in pregnancy, and postoperative complications requiring emergency surgery. Each recommendation was supported by scientific evidence and supplemented with expert comments. The guidelines were created on the initiative of the Videosurgery Chapter of the Association of Polish Surgeons and are recommended by the national consultant in the field of general surgery. The first part of the guidelines covers 5 sections and the following challenges for surgical practice: diagnostic laparoscopy, perforated ulcer, acute pancreatitis, incarcerated hernia and acute cholecystitis. Contraindications for laparoscopy and the ERAS program are discussed.

Short-Chain Fatty Acids-A Product of the Microbiome and Its Participation in Two-Way Communication on the Microbiome-Host Mammal Line.

PURPOSE OF REVIEW: The review aims to describe short-chain fatty acids (SCFAs) as metabolites of bacteria, their complex influence on whole-body metabolism, and alterations in the SCFA profile in obesity and after bariatric surgery (BS). RECENT FINDINGS: The fecal profile of SCFAs in obese patients differs from that of lean patients, as well as their gut microbiota composition. In obese patients, a lower diversity of bacteria is observed, as well as higher concentrations of SCFAs in stool samples. Obesity is now considered a global epidemic and bariatric surgery (BS) is an effective treatment for severe obesity. BS affects the structure and functioning of the digestive system, and also alters gut microbiota and the concentration of fecal SCFAs. Generally, after BS, SCFA levels are lower but levels of branched short-chain fatty acids (BSCFAs) are elevated, the effect of which is not fully understood. Moreover, changes in the profile of circulating SCFAs are little known and this is an area for further research. Obesity seems to be inherently associated with changes in the SCFA profile. It is necessary to better understand the impact of BS on microbiota and the metabolome in both feces and blood as only a small percentage of SCFAs are excreted. Further research may allow the development of a personalized therapeutic approach to the BS patient in terms of diet and prebiotic intervention.

Analysis of the risk factors for perioperative morbidity after laparoscopic revisional bariatric procedures: results from the multicenter Polish Revision Obesity Surgery Study.

BACKGROUND: The growing number of primary bariatric operations has led to an increase in demand for revision surgeries. Higher numbers of revisional operations are also observed in Poland, yet their safety and efficacy remain controversial because of a lack of current recommendations and guidelines. OBJECTIVE: To review risk factors influencing perioperative morbidity. METHODS: A retrospective study was conducted to analyze the results of surgical treatment among 12 Polish bariatric centers. Inclusion criteria were laparoscopic revisional bariatric surgeries and patients ≥18 years of age. The study included 795 patients, of whom 621 were female; the mean age was 47 years (range: 40-55 years). RESULTS: Perioperative morbidity occurred in 92 patients (11.6%) enrolled in the study, including 76 women (82.6%). The median age was 45 years (range: 39-54 years). Statistically significant risk factors in univariate logistic regression models for perioperative complications were the duration of obesity, revisional surgery after Roux-en-Y gastric bypass (RYGB) or adjustable gastric band (AGB), difference in body mass index before revisional surgery and the lowest achieved after primary surgery, and postoperative morbidity of the primary surgery as the cause for revisional bariatric surgery. These factors were included in the multivariate regression model. Revisional surgery after AGB (odds ratio [OR] = 2.18; 95% confidence interval [CI]: 1.28-3.69; P = .004), revisional surgery performed after RYGB (OR = 6.52; 95% CI: 1.98-21.49; P = .002), and revisions due to complication of the primary surgery (OR = 1.89; 95% CI: 1.06-3.34; P = .030) remained independent risk factors for perioperative morbidity. CONCLUSION: Revisional operations after RYGB or AGB and those performed because of postoperative morbidity after primary surgery as the main cause for revisional surgery were associated with a significantly increased risk of postoperative morbidity.

Comparison of the Long-term Outcomes of RYGB and OAGB as Conversion Procedures After Failed LSG - a Case-Control Study.

OBJECTIVE: To compare the effect of RYGB and OAGB on patients after failed treatment of obesity by laparoscopic sleeve gastrectomy (LSG). STUDY DESIGN: A case-control study based on a prospectively maintained database of reoperated patients after failed LSG, which included 33 patients who underwent RYGB conversion and 47 patients who underwent OAGB conversion. RESULT: The mean %EBWL after a 5-year follow-up for RYGBc vs OAGBc was 84.04% vs 72.95% (p = 0.2176), respectively. Complete long-term diabetes remission was observed significantly more frequently in the OAGBc than in the RYGBc group (97.3% vs 33%; p = 0.035). There were no other statistically significant differences in the remission rate of comorbidities between RYGBc and OAGBc: hypertension 30% vs 27.3% (p = 0.261), dyslipidemia 83.3% vs 59.1% (p = 0.277), OSAS 100% vs 60% (p = 0.639), and GERD 40% vs 71.4% (p > 0.99), respectively. 7 patients were newly diagnosed with GERD after OAGBc and none after RYGBc. There were no statistically significant differences in the number of complications between the OAGBc and RYGB groups. The Comprehensive Complication Index was 17.85 (± IQR 29.6) in the OAGBc group and 14.92 (± IQR 21.75) in the RYGBc group (p = 0.375). CONCLUSION: The authors recognized complete long-term type 2 diabetes remission after conversion surgery as the most relevant difference, where the OAGB variety was found superior for its better efficacy. Any other statistically significant differences in the consequences after both conversion procedures used after the failure of LSG have not been stated. Both methods therefore can be considered to complete the initial treatment, considering the preferences and individual burdens of the patients.

Kidney Transplantation in Patients After Bariatric Surgery: High-Volume Bariatric and Transplant Center Experience.

BACKGROUND: Kidney transplantation (KTx) is the best type of treatment for patients with end-stage renal disease (ESRD). Unfortunately, obesity may be a contraindication for transplantation. Our study aimed to evaluate the results of KTx in patients who had bariatric surgery (BS) prior to transplantation. METHODS: A single center, with experience in bariatric and transplant surgery, presents a retrospective study of 13 patients who received a kidney transplant after a gastric bypass (GB) operation between 2012 and 2019. RESULTS: Thirteen patients, who were potential candidates for KTx, were previously qualified for BS because of a body mass index (BMI) > 35 kg/m2. Additionally, all patients had arterial hypertension, 60% of patients had diabetes, and 30% of patients had coronary artery disease. Patients were activated on the waiting list when their BMI was < 35 kg/m2. KTx was performed between 5 and 29 months after BS. One patient needed reoperation due to a urinary leak and another patient needed reoperation because of a high-pressure lymphocele. We diagnosed 2 delayed graft functions (DGFs) and 1 acute rejection. One patient died for reasons independent of surgery. The KTx observation period ranged from 3 to 8 years. Currently, 11 patients has stable renal function: creatinine concentration is 0.8-1.8 mg/dL and BMI is between 23 and 35 kg/m2. CONCLUSIONS: Despite the small group of patients, we can assume that kidney transplantation can be safely performed in patients with end-stage renal disease (ESRD) who have previously undergone gastric bypass (GB) as a graft bridging procedure. In some cases, BS may be the only chance of getting an organ.

Revisional operations among patients after surgical treatment of obesity: a multicenter Polish Revision Obesity Surgery Study (PROSS).

Introduction: Revisional surgery is more technically challenging and associated with increased morbidity and mortality. Nevertheless, the frequency of revisional bariatric surgery (RBS) is increasing. Therefore, investigating this group of patients appears to be currently valid. Aim: The objective of this multicenter study was to collect, systematize and present the available data on RBS after surgical treatment of morbid obesity among Polish patients. Material and methods: This multicenter study included a retrospective analysis of a prospectively maintained database. Outcomes included an analysis of the indications for RBS, the type of surgery most frequently chosen as RBS and the course of the perioperative period of treatment among patients undergoing RBS. Results: The group consisted of 799 patients (624 (78.1%) women, 175 (21.9%) men). The mean age was 38.96 ±9.72 years. Recurrence of obesity was the most common indication for RBS. The most frequently performed RBS procedures were one anastomosis gastric bypass (OAGB) - 294 (36.8%) patients, Roux-en-Y gastric bypass (RYGB) - 289 (36.17%) patients and sleeve gastrectomy (SG) - 172 (21.52%) patients. After primary surgery 63.58% of patients achieved sufficient weight loss, but after RBS only 38.87%. Complications were noted in 222 (27.78%) cases after RBS with GERD being the most common - 117 (14.64%) patients. Conclusions: RBS most often concerns patients after SG. The main indication for RBS is weight regain. OAGB and RYGB were the two most frequently chosen types of RBS. Secondary operations lead to further weight reduction. However, RBS are associated with a significant risk of complications.

Bariatric Surgery Induced Changes in Blood Cholesterol Are Modulated by Vitamin D Status.

The effect of metabolically active bariatric surgery treatment on lipid metabolism is inconclusive. The authors of this study presume that initial vitamin D status may play a regulating role in influencing the beneficial post-effects of bariatric surgery, especially the lipid profile. The biochemical data obtained from 24 patients who had undergone laparoscopic one-anastomosis gastric bypass (OAGB) at baseline, 3 months before the surgery, at the time of surgery, and 6 months later, demonstrate that vitamin D status influenced the postoperative lipid profile. The baseline established the partition line which divided patients into two groups according to the stated calcidiol initial concentration level of 32 ng/mL. The data shows that OAGB induces a decrease in TG and hsCRP while increasing HDL. Conversely, in patients whose 25(OH)D3 was below 32 ng/mL TC significantly increased while those above this concentration remained in the normal physiological range. The changes induced by OAGB in TG, glucose, and hsCRP were similar in both groups. Unexpectedly, the surgery did not affect vitamin D metabolites. In conclusion, the results of the study suggest that a higher concentration of serum 25(OH)D3 may enhance the protective effects of OAGB.

Serum free fatty acid levels and insulin resistance in patients undergoing one-anastomosis gastric bypass.

INTRODUCTION: One anastomosis gastric bypass (OAGB) leads to improvement in glucose homeostasis; however, the mechanism of this beneficial effect is not fully understood. Increased serum free fatty acid (FFA) concentrations in obese subjects contribute to the development of insulin resistance and type 2 diabetes. AIM: The authors hypothesized that improvement in glucose homeostasis after OAGB may be associated with a decrease in FFA concentration. MATERIAL AND METHODS: Serum FFA levels were measured by gas chromatography-mass spectrometry before and 3 months after OAGB and, for comparison, in patients who underwent laparoscopic sleeve gastrectomy (LSG). Serum insulin was assayed by immunoenzymatic method, and other parameters by standard laboratory methods. RESULTS: OAGB resulted in a large decrease in FFA levels and great improvement in insulin sensitivity. These effects in patients after LSG were less prominent. CONCLUSIONS: Results suggest that decreased serum FFA levels after OAGB contribute to resolution of insulin sensitivity after this type of bariatric surgery.

One-anastomosis gastric bypass modulates the serum levels of pro- and anti-inflammatory oxylipins, which may contribute to the resolution of inflammation.

BACKGROUND/OBJECTIVES: Oxylipins are polyunsaturated fatty acid derivatives involved in the regulation of various processes, including chronic inflammation, insulin resistance and hepatic steatosis. They can be synthesized in various tissues, including adipose tissue. There is some evidence that obesity is associated with the deregulation of serum oxylipin levels. The aim of this study was to evaluate the effect of bariatric surgery (one-anastomosis gastric bypass) on the serum levels of selected oxylipins and their fatty acid precursors and to verify the hypothesis that their changes after surgery can contribute to the resolution of inflammation. Moreover, we compared the oxylipin levels (prostaglandin E2, 13-HODE, maresin 1 and resolvin E1), fatty acids and the expression of enzymes that synthesize oxylipins in adipose tissue of lean controls and subjects with severe obesity. SUBJECTS/METHODS: The study included 50 patients with severe obesity that underwent bariatric surgery and 41 subjects in lean, control group. Fatty acid content was analyzed by GC-MS, oxylipin concentrations were measured with immunoenzymatic assay kits and real-time PCR analysis was used to assess mRNA levels in adipose tissue. RESULTS: Our results show increased expression of some enzymes that synthesize oxylipins in adipose tissue and alterations in the levels of oxylipins in both adipose tissue and serum of subjects with obesity. After bariatric surgery, the levels of anti-inflammatory oxylipins increased, whereas pro-inflammatory oxylipins decreased. CONCLUSIONS: In patients with obesity, the metabolism of oxylipins is deregulated in adipose tissue, and their concentrations in serum are altered. Bariatric surgery modulates the serum levels of pro- and anti-inflammatory oxylipins, which may contribute to the resolution of inflammation.

The impact of severe postoperative complications on outcomes of bariatric surgery-multicenter case-matched study.

BACKGROUND: Bariatric surgery has relatively low complication rates, especially severe postoperative complications (defined by Clavien-Dindo classification as types 3 and 4), but these rates cannot be ignored. In other than bariatric surgical disciplines, complications affect not only short-term but also long-term results. In the field of bariatric surgery, this topic has not been extensively studied. OBJECTIVES: The aim of the study was to assess the outcomes of bariatric treatment in patients with obesity and severe postoperative complications in comparison to patients with a noneventful perioperative course. SETTING: Six surgical units at Polish public hospitals. METHODS: We performed a multicenter propensity score matched analysis of 206 patients from 6 Polish surgical units and assessed the outcomes of bariatric procedures. A total of 103 patients with severe postoperative complications (70 laparoscopic sleeve gastrectomy [SG] and 33 with laparoscopic Roux en Y gastric bypass [RYGB]) were compared to 103 patients with no severe complications in terms of peri- and postoperative outcomes. RESULTS: The outcomes of bariatric treatment did not differ between compared groups. Median percentage of total weight loss 12 months after the surgery was 28.8% in the group with complications and 27.9% in patients with no severe complications (P = 0.993). Remission rates of both type 2 diabetes mellitus and arterial hypertension showed no significant difference between SG and RYGB (36% versus 42%, P = 0.927, and 41% versus 46%, P = 0.575. respectively). CONCLUSIONS: The study suggests that severe postoperative complications had no significant influence either on weight loss effects or obesity-related diseases remission.

Evaluation of esophageal pathology in a group of patients 2 years after one-anastomosis gastric bypass (OAGB) - Cohort study.

BACKGROUND: One-anastomosis gastric bypass (OAGB) is a well established surgical procedure for morbid obesity. There are ongoing speculations and a debate regarding biliary reflux (BR) following OAGB. Studies considered OAGB as a risk for symptomatic and asymptomatic BR and marginal ulceration. The aim of the study was to evaluate the rate of gastroesophageal reflux disease (GERD) and esophagitis in microscopic and macroscopic evaluations among post OAGB patients diagnosed by means of upper endoscopy (UE) with a mucosal biopsy, and to assess the influence of comorbidities and medical history on endoscopic findings. METHODS: Patients operated between 1st January 2016 to 31st December 2017 were schedule, two years after OAGB for UE with a biopsy. In all cases, biopsies from the distal esophagus were obtained. All patients received a validated GERD-Health-Related Quality of Life questionnaire to assess their current symptoms. RESULTS: Fifty patients were finally enrolled in the study. Twenty-four (48%) had grade A or B esophagitis. Four patients (8%) had endoscopically suspected esophageal metaplasia (ESEM). 34/50 (68%) patients had various histopathological esophageal changes, based on the conducted endoscopy, among which four cases of Barrett's esophagus were observed. CONCLUSIONS: Despite the high rates of esophagitis in our cohort, most of the patients did not report any symptoms which confirm the thesis of the essential role of asymptomatic bile reflux following OAGB. Theoretically, chronic bile reflux can degenerate Barrett's esophagus into esophageal cancer.

Diet Management of Patients with Chronic Kidney Disease in Bariatric Surgery.

Morbid obesity is considered a civilization disease of the 21st century. Not only does obesity increase mortality, but it is also the most important cause of the shortening life expectancy in the modern world. Obesity is associated with many metabolic abnormalities: dyslipidemia, hyperglycemia, cardiovascular diseases, and others. An increasing number of patients diagnosed with chronic kidney disease (CKD) are obese. Numerous additional disorders associated with impaired kidney function make it difficult to conduct slimming therapy and may also be associated with a greater number of complications than in people with normal kidney function. Currently available treatments for obesity include lifestyle modification, pharmacotherapy, and bariatric surgery (BS). There are no precise recommendations on how to reduce excess body weight in patients with CKD treated conservatively, undergoing chronic dialysis, or after kidney transplantation. The aim of this study was to analyze studies on the bariatric treatment of obesity in this group of people, as well as to compare the recommendations typical for bariatrics and CKD.

Influence of polish national COVID-19 lockdown on the patient characteristics and outcomes of bariatric surgery at a high-volume center-A cohort study.

INTRODUCTION: As a result of the COVID-19 pandemic, the health care systems around the world have been overburdened resulting in significant reduction of planned surgical procedures such as bariatric surgeries. The primary aim of this study is to assess the influence of the COVID-19 national lockdown in Poland on the short-term outcomes and intraoperative course of bariatric patients in a high volume IFSO certified bariatric center. MATERIAL & METHODS: This is a retrospective analysis of 158 bariatric surgery patients, who underwent bariatric procedures either prior to or after the first national lockdown in Poland. The patients were categorized as pre-lockdown group and the post-lockdown group, each comprising of 79 patients. RESULTS: The post-lockdown group had significantly lower operative weight (105.76 vs 114.25, p = 0.012) and BMI (36.99 vs 39.93, p = 0.005) compared to pre-lockdown group. The primary length of stay was significantly longer in the post-lockdown group (3.04 vs 2.44, p = 0.001). The post-lockdown group had significantly lower mean CCI score (1.90 vs 6.67, p = 0.046) and less short-term readmissions post-discharge (0 vs 8.86, p = 0.007) than pre-lockdown group. CONCLUSION: The post-lockdown group was found to have lower body weight and BMI on the day of the operation than those operated prior to the lockdown. These findings are conflicting to previous research assessing weight changes during lockdowns. Since the qualification criteria and order of operations were similar and pre-defined for both groups, possible explanations for these findings are higher patient motivation due to COVID-19 fears and longer preparation period due to elective surgery postponement. We encourage bariatric centers globally to assess the effect of national lockdowns on the patient profiles as well as the psychological and behavioral impact on the bariatric cohort.

The Effects of One-Anastomosis Gastric Bypass on Fatty Acids in the Serum of Patients with Morbid Obesity.

PURPOSE: Obesity is associated with alterations in serum fatty acid profiles. One-anastomosis gastric bypass is a type of bariatric surgery used in the treatment of morbid obesity. The aim of this study was to establish if, between 6 and 9 months after this procedure, the fatty acid composition in the serum of patients normalizes to values similar to the healthy, lean population. MATERIALS/METHODS: The study included 46 patients that underwent surgical treatment for obesity with one-anastomosis gastric bypass. The serum fatty acid composition was determined using gas chromatography-mass spectrometry. Principal component analysis was conducted to detect the differences between fatty acid profiles in patients pre- and post-surgery, and in 29 control nonobese subjects. RESULTS: Patients with morbid obesity were characterized by lowered levels of beneficial odd- and branched-chain fatty acids and polyunsaturated fatty acids. While the odd- and branched-chain fatty acid amounts normalized 6-9 months after bariatric treatment, the polyunsaturated fatty acid levels did not. Moreover, the total fatty acid profiles of patients pre- and post-bariatric surgery were still markedly different than those of lean, healthy controls. CONCLUSION: Following one-anastomosis gastric bypass, there are some beneficial changes in serum fatty acids in treated patients, possibly due to weight loss and dietary regimen changes. However, they may be insufficient to restore the proper levels of other fatty acids, which may need to be additionally supplemented.