Letter to the Editor concerning "Long-term outcomes in patients with obesity and renal disease after sleeve gastrectomy".

Abstract

To the Editor: We read with interest the article by Kassam et al1 regarding laparoscopic sleeve gastrectomy (LSG) among patients with end-stage renal disease (ESRD), of whom 45 underwent subsequent kidney transplant (KT).1 In their series, they demonstrated both weight loss of 18.9 ± 10.8% and metabolic improvements. We recently reported on 24 patients who were candidates for transplant using LSG in 17 patients and laparoscopic Roux-en-Y gastric bypass (LRYGB) in 7 patients with a mean follow-up of 44 months.2 Of the 8 pretransplant after bariatric surgery (BS) patients, 5 are on the waitlist and 2 patients died. Sixteen (67%) of the 24 operated patients successfully proceeded to KT, of whom 11 were living and 5 were cadaveric transplants. The average time from BS to transplant was 1.5 years (range 1 month to 4.3 years). The average pretransplant body mass index (BMI) was 28 kg/m2 (range 19-36). The mean percentage of excess weight loss was 66% (n = 21), and the total percentage of weight loss was 29% (n = 21). In this study, we report our results with both LSG and LRYGB in the pre-KT patients and in the post-KT follow-up, which show good bariatric results continuing after the KT. We were limited by the small number of post-BS and post-KT patients (total n = 16, of them; LSG, n = 13; LRYGB, n = 3) to claim superiority of one procedure over another. It should be noted that in the first several years, we chose LSG as the procedure of choice for transplanted patients due to its relatively shorter operative time, technical simplicity, lower overall morbidity, and the fact that it is a purely restrictive and nonmalabsorptive procedure. With time and experience, we realized that LSG is less effective in the long term than previously thought and is problematic since leaks after LSG tend to have a chronic course as opposed to leaks after RYGB, which generally heal better.3 There are several studies supporting the safety and efficacy of BS in the transplant population; however, data are lacking on how BS may alter the PK of modern immunosuppression, such as calcineurin inhibitors, particularly tacrolimus. We provided further important findings on the absorption of immunosuppressive drugs following BS by showing a slightly beneficial effect of BS on immunosuppressive stability and weight loss in solid organ transplanted patients. Another important finding is that primary tacrolimus trough levels can be used to predict immunosuppressive stability after BS.4 Unlike in the Kassam et al series, where the pretransplant BMI was 33.37, we aimed to reach a lower target weight before transplant by selecting patients with BMI < 50 kg/m2. In our series the 16 patients’ mean weight before the transplant was 84 kg, their mean pretransplant BMI was 29 kg/m2, and indeed none of these patients had wound complications or lymphoceles. In the Kassam et al series, the mean BMI prior to BS was 43.95 ± 6.33 (34.98-69.73). It is crucial in our mind to select the appropriate candidates based not only on their anthropometric parameters but also on significant comorbidities and their compliance after the BS to ensure a long-lasting effect of weight loss during the waiting time and after transplant to prevent metabolic complications. We agree with Kassam et al that it is almost impossible to achieve weight reduction below a BMI of 35 in this population of patients with ESRD on dialysis because of their diet restrictions and limited physical activity. We truly believe that this vicious cycle of obesity, end-stage disease, transplant, and obesity (Figure 1) can be broken by BS either before or after transplant. Comparative data regarding optimal timing and type of bariatric procedure and long-term results are warranted. Although BS in the transplant population is not yet extensively studied and is mostly reported in small series, it seems a useful approach for the treatment of morbid obesity in these high-risk patients. Such a strategy is better planned when there is an option of live donation. The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation.