Faculty Bibliography

Over the past 40 years, the incidence of neuroendocrine tumors (NETs) has been increasing. Distal small bowel (i.e., midgut) NETs most often cause carcinoid syndrome manifested as cutaneous flushing, diarrhea, bronchial constriction, and cardiac involvement. Carcinoid abdominal crisis occurs when submucosal tumors impede the vascular supply to the gut leading to mesenteric ischemia and worsening abdominal pain. Here, we report the case of a young woman with progressively worsening abdominal pain. J. Surg. Oncol. 2014 110:348-351. (c) 2014 Wiley Periodicals, Inc.

BACKGROUND: Hyperinsulinemic hypoglycemia is common after Roux-en-Y gastric bypass (RYGB) and may result in weight regain. The purpose of our investigation was to compare the effect of RYGB, vertical sleeve gastrectomy (VSG), and duodenal switch (DS) on insulin and glucose response to carbohydrate challenge. METHODS: Patients meeting National Institutes of Health criteria for bariatric surgery selected their bariatric procedure after evaluation and education in this prospective nonrandomized study. Preoperatively and at 6, 9, and 12 months' follow-up, patients underwent blood draw to determine levels of fasting glucose, fasting insulin, glycated hemoglobin (HbA1c), C-peptide, and 2-h oral glucose challenge test. Homoeostatic Model Assessment (HOMA)-IR, fasting to 1-h and 1- to 2-h ratios of glucose and insulin, were calculated. Statistical analysis was performed using ANOVA and Student's paired t test. All procedures were performed via a laparoscopic technique at a single institution. RESULTS: Data from a total of 38 patients (13 RYGB, 12 VSG, 13 DS) were available for analysis. At baseline, all groups were similar; the only statistically significant difference was that DS patients had a higher preoperative weight and body mass index (BMI). All operations caused weight loss (BMI 47.7 +/- 10-30.7 +/- 6.4 kg/m2 in RYGB; 45.7 +/- 8.5-31.1 +/- 5.5 kg/m2 in VSG; 55.9 +/- 11.4-27.5 +/- 5.6 kg/m2 in DS), reduction of fasting glucose, and improved insulin sensitivity. RYGB patients had a rapid rise in glucose with an accompanying rise in 1-h insulin to a level that exceeded preoperative levels. This was followed by a rapid decrease in glucose level. In comparison, DS patients had a lower increase in glucose and 1-h insulin, and the lowest HbA1c. These differences were statistically significant at various data points. For VSG, the results were intermediary. CONCLUSIONS: Compared to gastric bypass, DS results in greater weight loss and improves insulin sensitivity and glucose homeostasis without causing a hyperinsulinemic response. Because the response to challenge after VSG is intermediary, pyloric preservation alone cannot account for this difference.

BACKGROUND: Symptoms secondary to dumping have been suggested to help patients refrain from simple carbohydrate ingestion after Roux-en-Y gastric bypass (RYGB). During follow-up examinations, we noted many patients with weight regain complaining of fatigue shortly after eating. Thus, we decided to study the glucose tolerance test (GTT) results in a cohort of post-RYGB patients. METHODS: A total of 63 RYGB patients, >6 months postoperatively, were studied with a GTT and measurement of insulin levels. The mean age was 48.5 +/- 10.8 years, mean preoperative body mass index was 49.0 +/- 6.5 kg/m(2), mean percentage of excess body mass index lost was 64.5% +/- 29.0%, mean weight regain at follow-up was 11.6 +/- 12.4 lb, and mean follow-up period was 47.9 months. RESULTS: Of the 63 patients, 49 had abnormal GTT results. Of the 63 patients, 6 were diabetic; however, only 1 of these patients had an elevated fasting glucose level. All 6 patients were diabetic preoperatively. Of the 63 patients, 43 had evidence of reactive hypoglycemia at 1-2 hours after the glucose load. Of these patients, 22 had a maximum/minimum glucose ratio >3:1, including 7 with a ratio >4:1. CONCLUSION: The results of the present study have demonstrated that an abnormal GTT result is a common finding after RYGB. Reactive hypoglycemia was found in 43 of 63 patients, with insulin values that do not support nesidioblastosis. It is our hypothesis, that rather than preventing simple carbohydrate ingestion, the induced hypoglycemia that occurs might contribute to weight regain and maladaptive eating in certain post-RYGB patients.

BACKGROUND: Our group has reported a high incidence of reactive hypoglycemia following Roux-en-Y gastric bypass (RYGB) with specific interest in postprandial insulin and the ratio of 1- to 2-h serum glucose levels. The purpose of this study is to compare the 6-month response to oral glucose challenge in patients undergoing RYGB, duodenal switch (DS), and vertical sleeve gastrectomy (VSG). METHODS: Thirty-eight patients meeting the NIH criteria for bariatric surgery who have reached the 6-month postoperative mark are the basis of this report. Preoperatively and at 6 months follow-up, patients underwent blood draw to determine levels of fasting glucose, fasting insulin, HbA1c, C peptide, and 2 h oral liquid glucose challenge test (OGTT). HOMA-IR and 1 to 2 h ratios of glucose and fasting to 1 h ratio of insulin were calculated. RESULTS: All patients underwent a successful laparoscopic bariatric procedure (VSG =13, DS =13, and RYGB = 12). All operations reduced BMI, HgbA1c, fasting glucose, and fasting insulin. HOMA IR and glucose tolerance improved with all procedures. In response to OGTT at 6 months, there was a 20-fold increase in insulin at 1 h in RYGB, which was not seen in DS. At 6 months, 1-h insulin was markedly lower in DS (p < .05), yet HbA1C was also lower in DS (p < .05). This resulted in 1- to 2-h glucose ratio of 1.9 for RYGB, 1.8 for VSG, and 1.3 for DS (p < .05). CONCLUSIONS: All operations improve insulin sensitivity and decrease HgbA1c. Six-month weight loss was substantial in all groups between 22-29% excess body weight. RYGB results in marked rise in glucose following challenge with corresponding rise in 1-h insulin. VSG has a similar response to RYGB. In comparison, at 6 months following surgery, DS causes a much lower rise in 1-h insulin, with this difference being statistically significant at p < .05. As a result, DS results in a less abrupt reduction in blood glucose. Although 1-h insulin is lower, DS patients had the lowest HbA1C at 6 months (p < .05). We believe that these findings have important implications for the choice of bariatric procedure for both diabetic and non-diabetic patients.

BACKGROUND: Symptoms of reactive hypoglycemia have been reported by patients after Roux-en-Y gastric bypass (RYGB) surgery who experience maladaptive eating behavior and weight regain. A 4-h glucose tolerance test (GTT) was used to assess the incidence and extent of hypoglycemia. METHODS: Thirty-six patients who were at least 6 months postoperative from RYGB were administered a 4-h GTT with measurement of insulin levels. Mean age was 49.4+/-11.4 years, mean preoperative body mass index (BMI) was 48.8+/-6.6 kg/m2, percent excess BMI lost (%EBL) was 62.6 +/- 21.6%, mean weight change from nadir weight was 8.2+/-8.6 kg, and mean follow-up time was 40.5+/-26.7 months. Twelve patients had diabetes preoperatively. RESULTS: Thirty-two of 36 patients (89%) had abnormal GTT. Six patients (17%) were identified as diabetic based on GTT. All six of these patients were diabetic preoperatively. Twenty-six patients (72%) had evidence of reactive hypoglycemia at 2 h post glucose load. Within this cohort of 26 patients, 14 had maximum to minimum glucose ratio (MMGR)>3:1, 5 with a ratio>4:1. Eleven patients had weight regain greater than 10% of initial weight loss (range 4.9-25.6 kg). Ten of these 11 patients (91%) with weight recidivism showed reactive hypoglycemia. CONCLUSIONS: Abnormal GTT is a common finding post RYGB. Persistence of diabetes was noted in 50% of patients with diabetes preoperatively. Amongst the nondiabetic patients, reactive hypoglycemia was found to be more common and pronounced than expected. Absence of abnormally high insulin levels does not support nesidioblastosis as an etiology of this hypoglycemia. More than 50% of patients with reactive hypoglycemia had significantly exaggerated MMGR. We believe this may be due to the nonphysiologic transit of food to the small intestine due to lack of a pyloric valve after RYGB. This reactive hypoglycemia may contribute to maladaptive eating behaviors leading to weight regain long term. Our data suggest that GTT is an important part of post-RYGB follow-up and should be incorporated into the routine postoperative screening protocol. Further studies on the impact of pylorus preservation are necessary.

BACKGROUND: Surgical revision for weight regain after Roux-en-Y gastric bypass (RYGB) has been tempered by the high complication rates associated with standard approaches. Endoluminal revision of stoma and pouch dilation should intuitively confer a better risk profile. However, questions of clinical safety, durability, and weight loss need to be answered. We report our multicenter intraoperative experience and postoperative follow-up to date using the Incisionless Operating Platform for this patient subset. METHODS: The patients who had regained significant weight >or=2 years after RYGB after losing >or=50% of excess body weight after RYGB were endoscopically screened for stomal and/or pouch dilation. Qualified patients underwent incisionless revision using the Incisionless Operating Platform to reduce the stoma and pouch size by placing anchors to create tissue plications. Data on the safety, intraoperative performance, postoperative weight loss, and anchor durability were recorded to date as a part of 2 years of postoperative follow-up. RESULTS: A total of 116 consecutive patients were prospectively studied. Anchors were successfully placed in 112 (97%) of 116 patients, with an average intraoperative stoma diameter and pouch length reduction of 50% and 44%, respectively. The operating room time averaged 87 minutes. No significant complications occurred. At 6 months after the procedure (n = 96), an average of 32% of weight regain that had occurred after RYGB had been lost. The percentage of excess weight loss averaged 18%. The 12-month esophagogastroduodenoscopy results confirmed the presence of the anchors and durable tissue folds. CONCLUSIONS: Incisionless revision of stoma and pouch dilation using the Incisionless Operating Platform can be performed safely. The data to date have demonstrated mild-to-moderate weight loss, and the early 12-month endoscopic images have confirmed anchor durability. Patients were actively followed up to document the long-term durability of this intervention in the entire patient subset.