Principles and results of bariatric surgery

Executive Summary: Collected Papers of the American College of Surgeons Metabolic Surgery Symposium

On August 9-10, 2017, the American College of Surgeons hosted a symposium on metabolic surgery, with 12 follow-on papers published serially in the Bulletin of the College. The current synopsis outlines the varied contents of these papers, often in the original words of their authors, who are cited within their topic sections. Topics covered include the following: history and definition of metabolic surgery, bariatric surgery, international bariatric surgery, mechanisms of metabolic surgery, diabetes and the metabolic syndrome, frontiers of metabolic surgery, institutional collaborations, accreditations and quality initiatives, professional training, the role of the National Institutes of Health, and advocacy. Based on these insights, an enthusiastic affirmation for the future of metabolic surgery is warranted.

Laparoscopic Sleeve Gastrectomy on the Horizon as a Promising Treatment Modality for NAFLD

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is viewed as the hepatic manifestation of the metabolic syndrome with hepatic fatty infiltration is the common liver pathology. NAFLD can lead to nonalcoholic steatohepatitis (NASH), liver cirrhosis, liver cell failure, and liver malignancy.The present work aims to prospectively study the histological changes that occur in NAFLD obese patients 1-year post-laparoscopic sleeve gastrectomy (LSG) based on standardized NAS (NAFLD activity score).

PATIENTS

This prospective study included 94 obese patients who underwent laparoscopic sleeve gastrectomy. Intraoperative wedge liver biopsy was taken from all patients with a follow-up liver biopsy at 12 months after the operation.

RESULTS

LSG produced a marked reduction in body weight with a mean reduction in BMI from 44.54 + 5.45 to 34.23 + 2.66 kg/m² at 12 months. There were statistically highly significant improvements regarding metabolic comorbidities, blood pressure, lipid profile, and HbA1C at 12-month post-LSG (P < 0.001). The current study showed a highly statistically significant improvement at 1-year post LSG regarding steatosis grade, hepatocyte ballooning, lobular inflammation as well as fibrosis stage (P < 0.001). Moreover, the present study showed that NAS score significantly decreased from 5.20 + 1.96 at baseline to 2.63 + 1.55 at 1-year follow-up (P < 0.001).

CONCLUSION

Our relatively large patient cohort shows a significant improvement of steatosis, steatohepatitis, and fibrosis at a 1-year follow-up. LSG can lead to resolution of NAFLD, and it may be in the near future another routine indication for bariatric surgery.

Histologic improvement of NAFLD in patients with obesity after bariatric surgery based on standardized NAS (NAFLD activity score)

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in industrialized countries. Nonalcoholic steatohepatitis is the fastest growing cause for liver failure. Bariatric surgery represents a treatment option for NAFLD with an established effect on liver histology.

OBJECTIVES

We aimed to assess the impact of bariatric surgery on standardized liver histology using the NAFLD activity score.

SETTING

Retrospective comparison of metabolic data before and after bariatric surgery and comparison of sleeve gastrectomy and Roux-en-Y gastric bypass. The study was performed in an academic center, the university hospital Schleswig-Holstein in Kiel, Germany.

METHODS

Between 2009 and 2012, bariatric surgery was performed in 257 patients according to the national guidelines, and a liver biopsy was obtained in 150 of these patients during surgery. A follow-up biopsy was available in 53 of these patients at a median of 192 days. Liver histology was analyzed using the NAFLD activity score. In this subgroup of 53 patients an analysis of the metabolic improvement after bariatric surgery and a comparative analysis between the 2 different operative procedures was performed.

RESULTS

The study cohort showed improvement of preoperative pathologic liver histology findings after operative procedures took place. Both surgery methods improved the NAFLD activity score significantly, all improvement -2.0 (confidence interval -2.5 to -1.0; P < .001); Roux-en-Y gastric bypass, improvement -1.0 (confidence interval -2.0 to -.0; P = .038); sleeve gastrectomy, improvement -2.5 (confidence interval -3.5 to -1.5; P < .001). No differences were found with regard to histologic recovery between gastric bypass and sleeve gastrectomy (P = .22).

CONCLUSIONS

Bariatric surgery significantly improves NAFLD.

Internal hernia in late pregnancy after laparoscopic Roux-en-Y gastric bypass

A 27-year-old patient in late pregnancy presented to the department of obstetrics with crampy abdominal pain located in the right flank, 3 years after a laparoscopic Roux-en-Y gastric bypass. Clinical investigation showed tenderness on palpation in the upper abdomen without signs of peritonitis. The cardiotocogram and blood tests were normal. The ultrasound showed a hydronephrosis on the right side, and a pigtail catheter was inserted. The abdominal symptoms did not abate and the abdominal surgeon was consulted 36 hours after admission. Diagnostic laparoscopy was performed promptly because of high suspicion of internal hernia (IH). Laparoscopy showed IH at the mesojejunal intermesenteric defect with a herniated common channel and volvulus of the anastomosis. Conversion to open reduction and complete closure with non-absorbable interrupted sutures was performed. Small bowel resection was avoided. The patient was discharged 10 days after the operation and a healthy boy was born 4 weeks later.

Laparoscopic revolution in bariatric surgery

The history of bariatric surgery is investigational. Dedicated surgeons have continuously sought for an ideal procedure to relieve morbidly obese patients from their burden of comorbid conditions, reduced life expectancy and low quality of life. The ideal procedure must have low complication risk, both in short- and long term, as well as minimal impact on daily life. The revolution of laparoscopic techniques in bariatric surgery is described in this summary. Advances in minimal invasive techniques have contributed to reduced operative time, length of stay, and complications. The development in bariatric surgery has been exceptional, resulting in a dramatic increase of the number of procedures performed world wide during the last decades. Although, a complex bariatric procedure can be performed with operative mortality no greater than cholecystectomy, specific procedure-related complications and other drawbacks must be taken into account. The evolution of laparoscopy will be the legacy of the 21^st century and at present, day-care surgery and further reduction of the operative trauma is in focus. The impressive effects on comorbid conditions have prompted the adoption of minimal invasive bariatric procedures into the field of metabolic surgery.

DNA methylation analysis in nonalcoholic fatty liver disease suggests distinct disease-specific and remodeling signatures after bariatric surgery

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in industrialized countries. Liver samples from morbidly obese patients (n = 45) with all stages of NAFLD and controls (n = 18) were analyzed by array-based DNA methylation and mRNA expression profiling. NAFLD-specific expression and methylation differences were seen for nine genes coding for key enzymes in intermediate metabolism (including PC, ACLY, and PLCG1) and insulin/insulin-like signaling (including IGF1, IGFBP2, and PRKCE) and replicated by bisulfite pyrosequening (independent n = 39). Transcription factor binding sites at NAFLD-specific CpG sites were >1,000-fold enriched for ZNF274, PGC1A, and SREBP2. Intraindividual comparison of liver biopsies before and after bariatric surgery showed NAFLD-associated methylation changes to be partially reversible. Postbariatric and NAFLD-specific methylation signatures were clearly distinct both in gene ontology and transcription factor binding site analyses, with >400-fold enrichment of NRF1, HSF1, and ESRRA sites. Our findings provide an example of treatment-induced epigenetic organ remodeling in humans.

Lifestyle modifications and surgical options in the treatment of patients with obesity and type 2 diabetes mellitus

This article reviews recent developments in the behavioral and surgical treatment of obesity and type 2 diabetes mellitus (T2DM). Randomized controlled trials of comprehensive lifestyle-modification programs, which include dietary interventions, physical activity, and behavioral therapy, have shown weight losses of 7% to 10% of initial body weight within 4 to 6 months after treatment. These programs also reduce the likelihood of developing T2DM by 58% for individuals with impaired glucose tolerance. Long-term maintenance of these improvements requires continued implementation of the program diet, physical activity, and self-regulatory behaviors. This can be successfully facilitated by continued patient-provider contact, which is frequently delivered by phone, mail, email, or online. However, these benefits may have less impact on those with extreme obesity or more significant health problems. For these individuals, bariatric surgery may be a more appropriate treatment. Bariatric surgical procedures induce mean weight losses of 15% to 30% of initial body weight (depending on the procedure) within 2 years after surgery, as well as a 45% to 95% rate of diabetes remission. Familiarity with these developments can help physicians and patients to determine which combinations of behavioral, medical, and surgical interventions are appropriate for the treatment of obesity and T2DM.