Faculty Bibliography

The following review is being published by the American Society for Metabolic and Bariatric Surgery in response to numerous inquiries made to the Society by patients, physicians, society members, hospitals, and others regarding one-anastomosis gastric bypass as a primary treatment for obesity or metabolic disease. The review is based on current clinical knowledge, expert opinion, and published peer-reviewed scientific evidence available at this time. The review is not intended as, and should not be construed as, stating or establishing a local, regional, or national standard of care.

BACKGROUND: Bariatric surgery is frequently recommended prior to total joint arthroplasty (TJA) for morbidly obese patients with end-stage arthropathy. Current published data on the efficacy of bariatric surgery for preoperative medical optimization has yielded mixed results, and the effect of time from bariatric surgery to TJA on the preoperative risk profile is not well defined. Our study evaluated the effect of time from bariatric surgery to TJA on 90-day complication and readmission rates. METHODS: We utilized the Healthcare Cost and Utilization Project (HCUP) California State Inpatient Database (SID) to identify patients who underwent TJA following bariatric surgery between 2007 and 2011. Primary endpoints were 90-day complication rates and all-cause 90-day readmission rates following TJA. RESULTS: We identified 330 cases of bariatric surgery followed by total hip arthroplasty (THA) and 1017 cases followed by total knee arthroplasty (TKA). There were no significant demographic differences among patients who underwent TJA greater than or less than 6 months after bariatric surgery. Patients undergoing THA more than 6 months after bariatric surgery were significantly less likely to be readmitted within 90 days for any cause. There was no association between time from bariatric surgery to THA or TKA and 90-day complications. DISCUSSION: Delaying THA at least 6 months after bariatric surgery may help reduce the rate of 90-day readmissions in this high-risk patient population. Arthroplasty surgeons recommending bariatric surgery as preoperative risk modification should consider the patient's overall nutritional status, medical comorbidities, and overall response to surgery prior to booking for TJA.

OBJECTIVE: High-density lipoprotein cholesterol efflux capacity (CEC) is inversely associated with incident cardiovascular events, independent of high-density lipoprotein cholesterol. Obesity is often characterized by impaired high-density lipoprotein function. However, the effects of different bariatric surgical techniques on CEC have not been compared. This study sought to determine the effects of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on CEC. APPROACH AND RESULTS: We prospectively studied severely obese, nondiabetic, premenopausal Hispanic women not using lipid medications undergoing RYGB (n=31) or SG (n=36). Subjects were examined before and at 6 and 12 months after surgery. There were no differences in baseline characteristics between surgical groups. Preoperative CEC correlated most strongly with Apo A1 (apolipoprotein A1) concentration but did not correlate with body mass index, waist:hip, high-sensitivity C-reactive protein, or measures of insulin resistance. After 6 months, SG produced superior response in high-density lipoprotein cholesterol and Apo A1 quantity, as well as global and non-ABCA1 (ATP-binding cassette transporter A1)-mediated CEC (P=0.048, P=0.018, respectively) versus RYGB. In multivariable regression models, only procedure type was predictive of changes in CEC (P=0.05). At 12 months after SG, CEC was equivalent to that of normal body mass index control subjects, whereas it remained impaired after RYGB. CONCLUSIONS: SG and RYGB produce similar weight loss, but contrasting effects on CEC. These findings may be relevant in discussions about the type of procedure that is most appropriate for a particular obese patient. Further study of the mechanisms underlying these changes may lead to improved understanding of the factors governing CEC and potential therapeutic interventions to maximally reduce cardiovascular disease risk in both obese and nonobese patients.

OBJECTIVE: The objective of this study was to determine whether the DiaRem, a score that predicts type 2 diabetes (T2D) remission following roux-en-y gastric bariatric surgery (RYGB), also predicts remission following laparoscopic adjustable gastric banding (LAGB) and laparoscopic sleeve gastrectomy (LSG) in white and Hispanic patients. BACKGROUND: While bariatric surgery is highly effective in reversing insulin resistance, there are patients for whom surgery will not lead to remission. To date, there is no score for predicting remission following LAGB or LSG surgery. Additionally, there is little known about how to predict whether Hispanic patients will experience remission. METHODS: We conducted a retrospective cohort study of white and Hispanic patients with T2D who received bariatric surgery. There were 361 white and 130 Hispanic patients among whom 328 had RYGB surgery, 107 had LSG surgery, and 56 had LAGB surgery. We used age, diabetes treatment, and hemoglobin A1c to calculate DiaRem scores. Mann-Whitney U test was used to determine the association between DiaRem scores and remission. Area under the receiver operant curve (AUC) was used to assess the ability of the DiaRem to discriminate between patients who did and did not remit. RESULTS: The DiaRem was associated with partial remission in all surgery types for white and Hispanic patients (Mann-Whitney, p < 0.001). The DiaRem had moderate to high discriminant ability (AUC > 0.70) for all surgical and racial/ethnic groups. CONCLUSIONS: The DiaRem distinguishes between patients likely and unlikely to experience remission, informing expectations of patients making T2D treatment decisions.

BACKGROUND: Portomesenteric vein thrombosis (PMVT) has been increasingly reported after laparoscopic sleeve gastrectomy (LSG). Factor VIII (FVIII) is a plasma sialoglycoprotein that plays an essential role in hemostasis. There is increasing evidence that FVIII elevation constitutes a clinically important risk factor for venous thrombosis. OBJECTIVES: To report the prevalence of FVIII elevation as well as other clinical characteristics in a multicenter series of patients who developed PMVT after LSG. SETTING: University hospitals. METHODS: A retrospective review was conducted of all patients that developed PMVT after laparoscopic bariatric surgery from 2006 to 2016 at 6 high-volume bariatric surgery centers. RESULTS: Forty patients who developed PMVT postoperatively, all after LSG, were identified. During this timeframe, 25,569 laparoscopic bariatric surgery cases were performed, including 9749 LSG (PMVT incidence after LSG = .4%). Mean age and body mass index were 40 years (18-65) and 43.4 kg/m2 (35-59.7), respectively. Abdominal pain was the most common (98%) presenting symptom. Of patients, 92% had a hematologic abnormality identified, and of these, FVIII elevation was the most common (76%). The vast majority (90%) was successfully managed with therapeutic anticoagulation alone. A smaller number of patients required small bowel resection (n = 2) and surgical thrombectomy (n = 1). There were no mortalities. CONCLUSIONS: A high index of clinical suspicion and prompt diagnosis/treatment of PMVT usually leads to favorable outcomes. FVIII elevation was the most common (76%) hematologic abnormality identified in this patient cohort. Further studies are needed to determine the prevalence of FVIII elevation in patients seeking bariatric surgery.

BACKGROUND: At our medical center, female patients who have undergone bariatric surgery are advised to defer pregnancy for 2 years after surgery to avoid the following complications and their potential consequences for the fetus: inadequate gestational weight gain, inadequate postsurgical weight loss, hyperemesis gravidarum, nutritional deficiencies, gestational diabetes, and gestational hypertension. OBJECTIVES: To examine the effect of time from surgery to conception on pregnancy course and outcomes in bariatric patients. SETTING: University. METHODS: We identified 73 pregnancies in 54 women who became pregnant after undergoing bariatric surgery. Surgery to conception interval was compared between pregnancies that were carried to delivery and 8 pregnancies that resulted in spontaneous abortion. Of 41 pregnancies that were carried to delivery, 26 occurred in women who had undergone surgery less than 2 years before conception, and 15 occurred in women who had undergone surgery greater than 2 years before conception. Gestational age at delivery, number of neonatal intensive care unit admissions, gestational weight gain, hyperemesis gravidarum, nutritional deficiencies, gestational diabetes, and gestational hypertension during pregnancy were compared for the 2 groups. RESULTS: Eight patients who had spontaneous abortion had a significantly shorter time from surgery to conception. There were no significant differences between our 2 groups in rates of preterm deliveries, neonatal intensive care unit admission, gestational weight gain, hyperemesis, nutritional deficiencies, gestational diabetes, or gestational hypertension. CONCLUSIONS: Becoming pregnant within the first 2 years after bariatric surgery appears to have no effect on pregnancy course and outcomes. Women who miscarried had a significantly lower mean surgery to conception interval. These results fail to show an increased rate of pregnancy complications during the first 2 years after bariatric surgery.

Background: At our medical center, female patients who have undergone bariatric surgery are advised to defer pregnancy for two years after surgery, due to the theoretical risk that becoming pregnant during the period of rapid weight loss after surgery will adversely affect long term weight loss. Methods: We examined our database of bariatric surgery patients from a large, urban, public hospital from March 2011 to January 2014. Out of over 2000 patients, we identified 49 women who became pregnant and carried to term after undergoing bariatric surgery. 29 pregnancies occurred in women who had undergone bariatric surgery less than 2 years prior to conception, and 20 occurred in women who had undergone bariatric surgery greater than 2 years prior to conception. Weight data were recorded and BMI was calculated for each patient from pre-op to post-delivery. Percentage of excess weight loss (%EWL) based on an ideal BMI of 25 at three different time points after delivery (3-12 months, 1-2 years, > 2 years) was compared for the two groups. Results: The two groups were statistically similar with regards to baseline weight, BMI, and BMI loss from surgery to conception. The mothers with <2 years between bariatric surgery and conception had a higher percentage of RYGB and LSG surgeries (p=0.020). %EWL was significantly higher for the <2 year group at 3-12 months post-delivery (57.1% vs. 37.5%, p=0.028), 12-24 months post-delivery (61.1% vs. 37.7%, p=0.012), and >2 years post-delivery (59.9% vs. 38.7%, p=0.044). However, when stratifying by surgery type, there were no significant differences in %EWL between the two groups at any time point (Table). A multiple linear repeated measures model showed that mothers in the <2 year group had significantly greater %EWL after adjusting for age of mother, surgery type, and baseline BMI (+5.6% EWL at 3-12 months post-delivery, +11.1% at 12-24 months, and +16.5% at >2 years; p=0.031). Conclusions: In this study, long term weight loss was significantly greater in women who conceived earlier than 2 years after undergoing bariatric surgery. This result may also have been affected by surgery type, as there were higher percentages of RYGB and LSG in the early pregnancy group. However, after controlling for this difference between the two groups, there remained a significant difference in %EWL at all three time points, suggesting that patients who become pregnant within 2 years after surgery may have greater long term weight loss