Preoperative Methods to Reduce Liver Volume in Bariatric Surgery: a Systematic Review

Short-Term Preoperative Weight Loss and Postoperative Outcomes in Bariatric Surgery

BACKGROUND

Preoperative weight loss is often encouraged before undergoing weight loss surgery. Controversy remains as to its effect on postoperative outcomes. The aim of this study was to determine what impact short-term preoperative excess weight loss (EWL) has on postoperative outcomes in patients undergoing primary vertical sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB).

STUDY DESIGN

All patients who underwent SG (n = 167) or RYGB (n = 188) between 2014 and 2016 and who completed our program-recommended low calorie diet (LCD) for 4 weeks immediately preceding surgery were included. These patients (N = 355) were then divided into 2 cohorts and analyzed according to those who achieved ≥8% EWL (n = 224) during the 4-week LCD period and those who did not (n = 131). Primary endpoints included percent excess weight loss (% EWL) at 1, 3, 6, and 12 months postoperatively.

RESULTS

Patients achieving ≥8% EWL preoperatively experienced a greater % EWL at postoperative month 3 (42.3 ± 13.2% vs 36.1 ± 10.9%, p < 0.001), month 6 (56.0 ± 18.1% vs 47.5 ± 14.1%, p < 0.001), and month 12 (65.1 ± 23.3% vs 55.7 ± 22.2%, p = 0.003). Median operative duration (117 minutes vs 125 minutes; p = 0.061) and mean hospital length of stay (1.8 days vs 2.1 days; p = 0.006) were also less in patients achieving ≥8% EWL. No significant differences in follow-up, readmission, or reoperation rates were seen. Linear regression analysis revealed that patients who achieved ≥8% EWL during the 4-week LCD lost 7.5% more excess weight at postoperative month 12.

CONCLUSIONS

Based on these data, preoperative weight loss of ≥8% excess weight, while following a 4-week LCD, is associated with a significantly greater rate of postoperative EWL over 1 year, as well as shorter operative duration and hospital length of stay.

Nutritional Status Prior to Laparoscopic Sleeve Gastrectomy Surgery

BACKGROUND

Two main causes for nutrient deficiencies following bariatric surgery (BS) are pre-operative deficiencies and favoring foods with high-energy density and poor micronutrient content. The aims of this study were to evaluate nutritional status and gender differences and the prevalence of nutritional deficiencies among candidates for laparoscopic sleeve gastrectomy (LSG) surgery.

METHODS

A cross-sectional analysis of pre-surgery data collected as part of a randomized clinical trial on 100 morbidly obese patients with non-alcoholic fatty liver disease (NAFLD) admitted to LSG surgery at Assuta Medical Center between February 2014 and January 2015. Anthropometrics, food intake, and fasting blood tests were evaluated during the baseline visit.

RESULTS

One-hundred patients completed the pre-operative measurements (60 % female) with a mean age of 41.9 ± 9.8 years and a mean BMI of 42.3 ± 4.7 kg/m(2). Pre-operatively, deficiencies for iron, ferritin, folic acid, vitamin B1, vitamin B12, vitamin D, and hemoglobin were 6, 1, 1, 6, 0, 22, and 6 %, respectively. Pre-surgery, mean energy, protein, fat, and carbohydrate intake were 2710.7 ± 1275.7 kcal/day, 114.2 ± 48.5, 110.6 ± 54.5, and 321.6 ± 176.1 gr/day, respectively. The intakes for iron, calcium, folic acid, vitamin B12, and vitamin B1 were below the Dietary Reference Intake (DRI) recommendations for 46, 48, 58, 14, and 34 % of the study population, respectively.

CONCLUSION

We found a low prevalence of nutritional deficiencies pre-operatively except for vitamin D. Most micronutrient intake did not reach the DRI recommendations, despite high-caloric and macronutrient intake indicating a poor dietary quality.

Radiographic Improvement of Hepatic Steatosis After Laparoscopic Roux-en-Y Gastric Bypass

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common form of liver disease and the leading cause of cirrhosis in developed nations. Studies confirm improvement of liver histopathology after significant weight loss, but biochemistry and sonography do not always show this. Computed tomographic (CT) findings of NAFLD include low attenuation of liver parenchyma and hepatomegaly. We hypothesized that patients experiencing significant weight loss after laparoscopic Roux-en-Y gastric bypass (LRYGB) would show CT improvement of NAFLD.

METHODS

A retrospective review was performed on primary LRYGB patients at this institution from 2006 to 2014. We identified patients with either a preoperative abdominal CT or an early postoperative scan (prior to significant weight loss) as well as those with scans performed at >60 days postoperation. Radiologic interpretations were reviewed; descriptions of steatosis, hypodensity, fatty infiltration, fatty liver, fatty changes, or liver parenchyma measuring ≤40 Hounsfield units averaged at three locations on non-contrast CT were documented. Later, scans were reviewed for improvement by these criteria.

RESULTS

Nineteen patients had perioperative radiographic evidence of NAFLD, with 89.5 % female, average age 41.5, and median body mass index (BMI) 46.9 kg/m². Sixteen (84.2 %) showed radiographic improvement of NAFLD. The median time between scans was 826 days, with median BMI at that point of 30.5 kg/m². The three without radiographic improvement still experienced significant weight loss (average BMI points lost = 19.3 kg/m², ±5.6).

CONCLUSIONS

While weight loss and comorbidity improvement are common, they are not universal after LRYGB. Radiographic improvement of NAFLD in 84 % of patients was salutary.

Impact of Intragastric Balloon Before Laparoscopic Gastric Bypass on Patients with Super Obesity: a Randomized Multicenter Study

BACKGROUND

Super obese patients are recommended to lose weight before bariatric surgery. The effect of intragastric balloon (IGB)-induced weight loss before laparoscopic gastric bypass (LGBP) has not been reported. The aim of this prospective randomized multicenter study was to compare the impact of preoperative 6-month IGB with standard medical care (SMC) in LGBP patients.

METHODS

Patients with BMI >45 kg/m² selected for LGBP were included and randomized to receive either SMC or IGB. After 6 months (M6), the IGB was removed and LGBP was performed in both groups. Postoperative follow-up period was 6 months (M12). The primary endpoint was the proportion of patients requiring ICU stay >24 h; secondary criteria were weight changes, operative time, hospitalization stay, and perioperative complications.

RESULTS

Only 115 patients were included (BMI 54.3 ± 8.7 kg/m²), of which 55 underwent IGB insertion. The proportion of patients who stayed in ICU >24 h was similar in both groups (P = 0.87). At M6, weight loss was significantly greater in the IGB group than in the SMC group (P < 0.0001). Three severe complications occurred during IGB removal. Mean operative time for LGBP was similar in both groups (P = 0.49). Five patients had 1 or more surgical complications, all in the IGB group (P = 0.02). Both groups had similar hospitalization stay (P = 0.59) and weight loss at M12 (P = 0.31).

CONCLUSION

IGB insertion before LGBP induced weight loss but did not improve the perioperative outcomes or affect postoperative weight loss.

Effects of very low calorie diets on liver size and weight loss in the preoperative period of bariatric surgery: a systematic review

Restrictive diet implementation in bariatric surgery (BS) preoperative period is common, although its benefits are not well established. This study aimed to assess the effects of very low calorie diets (VLCD) on liver size and weight loss during BS preoperative period. Surgery-related complications were also assessed. A systematic review of the literature was performed. Terms such as "bariatric surgery" and "very low energy diet" were included in the search strategy. Inclusion criteria were adult patients (aged>18 yr); VLCD treatment in BS preoperative period (10 d to 12 wk); and assessment of 1 the following outcomes: weight loss, liver volume reduction, and surgical complications. There were 9 studies included (849 patients including 250 controls, 196 controls without VLCD). Of the studies, 3 were randomized clinical trials and 6 were observational studies. VLCD treatment led to weight loss (-2.8 to -14.8 kg) and to liver size reduction by 5% to 20% of the initial volume. VLCD treatment did not significantly reduce perioperative complications. However, 1 study (n = 273) reported a protective effect 30 days after surgery. This systematic review found VLCD treatment led to significant weight loss and liver volume reduction when applied to patients with obesity in BS preoperative period. The effect of VLCD on surgical risks is not clear. Standardization of dietary characteristics is needed, because weight loss and decrease in liver size were not connected to higher caloric restriction. This is an important matter in clinical practice as to avoid unnecessary prolonged and/or excessive dietary restriction.

Evidence Base for Optimal Preoperative Preparation for Bariatric Surgery: Does Mandatory Weight Loss Make a Difference?

PURPOSE OF REVIEW

Preoperative weight loss regimens prior to bariatric surgery have been a routine and common practice for many centers, in the US and around the world. The mandated participation in such programs has largely been influenced by loco-regional payer requirements. The relationship between adherence to a mandatory weight loss regimen and achieved preoperative weight loss as well as the clinical impact of preoperative weight loss on bariatric outcomes remains uncertain.

RECENT FINDINGS

This review examines the available current literature, in the context of previous findings, regarding the impact of mandated preoperative weight loss regimens and mandatory weight loss on bariatric outcomes. The reviewed studies do not provide sufficient evidence that mandatory participation in a preoperative weight loss regimen prior to bariatric surgery is associated with achieved weight loss or durable bariatric outcome benefit. Preoperative weight loss, when achieved, may confer a positive benefit on postoperative complications; however, this is not a consistent finding in the literature and requires further validation. The practice of mandating participation in a preoperative weight loss regimen or requiring mandatory weight loss prior to bariatric surgery is not supported by current literature and may serve as an obstacle to medically necessary and potentially life-saving treatment.

Natural History of NAFLD Diagnosed in Childhood: A Single-Center Study

Little is known regarding the subsequent course of non-alcoholic fatty liver disease (NAFLD) diagnosed in childhood. The objectives of this single-center study were to gather data on long-term health outcomes and to assess the feasibility of contacting former pediatric patients. In a large pediatric medical center, electronic records were searched to initially identify 162 former patients who had a liver biopsy between 2000 and 2010. Of these, 44 subjects met the criteria for age at follow-up (≥18 year) and biopsy-proven NAFLD, and were recruited via postal and electronic mail. Participants were invited to complete a brief telephone survey on current health status. Supplemental data was also obtained from pediatric medical charts of all subjects. At NAFLD diagnosis, 18% of subjects had diabetes, 91% were obese, 61% had NASH, and 56% had fibrosis on biopsy. At follow-up, 10 subjects (23%) responded to the survey. Based on the survey and chart review, after a mean follow-up of 4.5 years, 5 additional subjects developed diabetes for a period prevalence of 30%, and most subjects (78%) remained obese at last follow-up. Additional prospective studies are needed to fully describe the longitudinal risks associated with pediatric NAFLD, and will require multi-dimensional strategies to successfully recruit former patients.

Nutritional Recommendations for Adult Bariatric Surgery Patients: Clinical Practice

Bariatric surgery is currently the most effective treatment for morbid obesity and its associated metabolic complications. To ensure long-term postoperative success, patients must be prepared to adopt comprehensive lifestyle changes. This review summarizes the current evidence and expert opinions with regard to nutritional care in the perioperative and long-term postoperative periods. A literature search was performed with the use of different lines of searches for narrative reviews. Nutritional recommendations are divided into 3 main sections: 1) presurgery nutritional evaluation and presurgery diet and supplementation; 2) postsurgery diet progression, eating-related behaviors, and nutritional therapy for common gastrointestinal symptoms; and 3) recommendations for lifelong supplementation and advice for nutritional follow-up. We recognize the need for uniform, evidence-based nutritional guidelines for bariatric patients and summarize recommendations with the aim of optimizing long-term success and preventing complications.

Lipodystrophy Due to Adipose Tissue-Specific Insulin Receptor Knockout Results in Progressive NAFLD

Ectopic lipid accumulation in the liver is an almost universal feature of human and rodent models of generalized lipodystrophy and is also a common feature of type 2 diabetes, obesity, and metabolic syndrome. Here we explore the progression of fatty liver disease using a mouse model of lipodystrophy created by a fat-specific knockout of the insulin receptor (F-IRKO) or both IR and insulin-like growth factor 1 receptor (F-IR/IGFRKO). These mice develop severe lipodystrophy, diabetes, hyperlipidemia, and fatty liver disease within the first weeks of life. By 12 weeks of age, liver demonstrated increased reactive oxygen species, lipid peroxidation, histological evidence of balloon degeneration, and elevated serum alanine aminotransferase and aspartate aminotransferase levels. In these lipodystrophic mice, stored liver lipids can be used for energy production, as indicated by a marked decrease in liver weight with fasting and increased liver fibroblast growth factor 21 expression and intact ketogenesis. By 52 weeks of age, liver accounted for 25% of body weight and showed continued balloon degeneration in addition to inflammation, fibrosis, and highly dysplastic liver nodules. Progression of liver disease was associated with improvement in blood glucose levels, with evidence of altered expression of gluconeogenic and glycolytic enzymes. However, these mice were able to mobilize stored glycogen in response to glucagon. Feeding F-IRKO and F-IR/IGFRKO mice a high-fat diet for 12 weeks accelerated the liver injury and normalization of blood glucose levels. Thus, severe fatty liver disease develops early in lipodystrophic mice and progresses to advanced nonalcoholic steatohepatitis with highly dysplastic liver nodules. The liver injury is propagated by lipotoxicity and is associated with improved blood glucose levels.