**5. Bariatric surgery and orthotopic liver transplantation**

Some transplant centers have a strict criteria of not performing orthotopic liver transplantation with BMI > 35. Orthotopic liver transplantation in morbidly obese patients is technically difficult and can be associated with increased bleeding, postoperative complications, morbidity, and mortality [61]. The longevity of morbidly obese transplanted patients is also shortened. Pretransplant bariatric surgery is considered in these patients to reach the BMI goal for liver transplantation. Lin et al. did a retrospective study in pretransplant morbidly obese patients and found that laparoscopic sleeve gastrectomy was safe and successful in causing significant weight loss and improving candidacy for liver transplantation [62]. On the other hand, one third of post-liver transplant patients become obese, and some of them become morbidly obese due to increased appetite, increased calorie intake, sedentary lifestyle, and corticosteroid therapy. A proportion of these patients may develop metabolic syndrome and NAFLD in the transplanted liver. Both RYGB and laparoscopic sleeve gastrectomy have been found to be safe and feasible in post-liver transplant morbidly obese patients [63, 64]. Another small study showed combined liver transplantation and sleeve gastrectomy in morbidly obese patients led to effective weight loss and less metabolic complications. There was no mortality or graft loss in those patients [65]. So bariatric surgery has been found to be safe before, during, and after liver transplantation in selected patients in small studies although there is no consensus about the optimal timing yet.
