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Research Areas

Clinical Outcomes

Clinical Scoring System to Assess Differential Risk for NASH in Morbidly Obese Patients

Nonalcoholic steatohepatitis (NASH), a form of liver injury, is common in morbidly obese people. Liver biopsy, a diagnostic, but technically challenging procedure with attendant risks, is used to diagnose this condition. We sought to assess the differential risk for NASH among morbidly obese persons. We undertook a study to predict the probability of NASH in morbidly obese persons, thus assisting in the decision to perform liver biopsy. We developed a clinical scoring that can predict NASH in morbidly obese persons with sufficient accuracy to be considered for clinical use, identifying a very high-risk group in whom liver biopsy would be very likely to detect NASH, as well as a low-risk group in whom biopsy can be safely.

Outcomes Research & Performance Improvement

Our research studies have focused on clinical outcomes, the refinement of surgical technique and better prediction of post-operative complications. Areas of study include:

  • Spectrum and risk factors of complications after gastric bypass. 
  • Predictors, treatment, and outcomes of gastrojejunostomy stricture after gastric bypass for morbid obesity. 
  • Use of routine upper GI series to identify leaks or predict stricture formation.
  • Impact of roux limb length on weight loss after gastric bypass.
  • Safety and efficacy of accessing the peritoneal cavity using an optical, bladeless trocar without previous pneumoperitoneum in morbidly obese patients.

Gastric Bypass

Insulin Sensitivity after Gastric Bypass (GBP) Surgery

We are studying the differential effects on insulin sensitivity after gastric bypass, adjustable gastric banding and caloric restriction in persons with morbid obesity. We hope to better understand whether gastric bypass results in differential short-term effects on insulin sensitivity and gut hormone secretion in comparison with those achieved with gastric banding surgery or caloric restriction alone. We are also exploring whether gastric bypass results in different long-term effects on insulin sensitivity and gut hormones in comparison to gastric banding. We plang to conduct a pilot study to answer these questions.

Factors Associated with Poor Weight Loss after Gastric Bypass (GBP) Surgery

Gastric bypass (GBP) is the most common operation performed in the U.S. for morbid obesity. However, weight loss is poor in 10% to 15% of patients. We are interested in identifying the independent factors associated with poor weight loss after GBP.  In a recent study, we showed that gastric bypass results in substantial weight loss in most patients. The results further showed that diabetes and larger pouch size are independently associated with poor weight loss after GBP.

Transplant Eligibility

Improving Eligibility for Transplantation

Some patients are poor candidates for kidney or liver transplants due to their obesity. Bariatric surgery can improve the candidacy of these morbidly obese patients. We conducted a pilot study to evaluate the safety and efficacy of laparoscopic Roux-en-Y gastric bypass (LRYGB) in patients with end-stage renal disease (ESRD) and laparoscopic sleeve gastrectomy (LSG) in patients with cirrhosis or end-stage lung disease (ESLD). Our goal was to determine whether these procedures would make these patients become better candidates for transplantation.

The study provided preliminary evidence that LRYGB in patients with ESRD, and LSG in patients with cirrhosis or ESLD is safe, well-tolerated, and improves their candidacy for transplantation. Ongoing outcome studies are underway to examine the progress of these patients post-transplant using a number of measurements.

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