Addressing morbid obesity as a barrier to renal transplantation with laparoscopic sleeve gastrectomy

The Impact of Total Gastrectomy on Pharmacokinetics in Kidney Transplant Immunosuppressive Drug Regimes: A Case Study

BACKGROUND

Ensuring reliable gastrointestinal drug absorption of orally administered immunosuppressive medications posttransplant is critical to ensuring graft survival.

METHODS

A 66-year-old man of East Asian origin with a previous total gastrectomy was evaluated for living donor kidney transplantation. Pretransplant pharmacokinetic testing was performed to determine the most appropriate posttransplant medication strategy. The Gastrointestinal Quality of Life Index and Gastrointestinal Rating Scale questionnaires were administered to gauge immunosuppressive medication-related side effects in the absence of a stomach.

RESULTS

The patient's ability to absorb cyclosporin, tacrolimus (Tac), enteric-coated mycophenolate sodium (EC-MPS) and sirolimus (SRL) in oral dosage forms was well-preserved. Compared to nongastrectomy reference populations, the rate and extent of absorption of SRL and mycophenolic acid from EC-MPS were similar. The absorption of Tac and cyclosporin was greater than expected. Mycophenolate mofetil did not provide mycophenolic acid absorption as well as EC-MPS. The patient had worsened gastrointestinal symptoms with mycophenolate mofetil or EC-MPS in combination with Tac and cyclosporin, but this was not seen with isolated SRL.

CONCLUSIONS

This case demonstrates that commonly used postkidney transplantation immunosuppressive regimes may be prescribed after total gastrectomy as long as their limitations are noted.

Waitlist Hospital Admissions Predict Resource Utilization and Survival After Renal Transplantation

OBJECTIVE

To determine whether fitness for transplant can be determined by candidates' hospitalizations although waitlisted.

BACKGROUND

Renal transplantation must increasingly serve a population of multiply comorbid patients in an environment defined by organ scarcity and premiums on value-based care. Determining those at excess risk for transplant is critical to these imperatives.

METHODS

United States Renal Data Systems patient and claims data for all adult renal transplant recipients between 2000 and 2010 with continuous primary Medicare coverage for 1 year before and after transplantation were examined. Outcomes included readmissions within the first-year post-transplant and 3-year graft and patient survival. Chi-square statistics, Kaplan-Meier methods (log-rank test), and goodness of fit calculations (c-statistics) were performed for models of transplant outcome.

RESULTS

Among 37,623 patients, the percentages of patients admitted for 0, 1 to 7, 8 to 14, or 15 or more days in the pretransplant year were 51%, 25%, 11%, and 13%. Overall readmission-free survival at 1 year was 31%. Heavily preadmitted patients were more likely to have a greater length of stay during their transplant admission, and had a greater service needs at discharge. Pretransplant admission strongly predicted more frequent post-transplant admission. Among all factors studied, preadmission was the strongest predictor of post-transplant death, and had a dose-dependent effect on both death and graft loss.

CONCLUSIONS

In summary, hospitalization in the year before transplant is an objective, readily ascertainable, and powerful predictor of excess resource utilization and inferior outcome. Incorporation of a rolling assessment of patient hospitalization has potential policy implications for maximizing value in renal transplantation.

Single Center Experience With Robotic Kidney Transplantation for Recipients With BMI of 40 kg/m2 Or Greater: A Comparison With the UNOS Registry

BACKGROUND

Obesity represents a barrier to kidney transplantation, but the increasing prevalence among renal failure patients has forced some centers to carefully consider such candidates. Morbidly obese patients may be at increased risk of delayed graft function, higher postoperative complications, and inferior graft outcomes. Nevertheless, mortality on the waiting list remains significantly higher than after transplant. We have applied minimally invasive surgery to perform kidney transplant in individuals with body mass index (BMI) of 40 kg/m or greater. We compared our results to the national United Network of Organ Sharing database.

METHODS

The United Network of Organ Sharing registry was reviewed for adult living donor kidney transplant recipients with BMI of 40 kg/m or greater performed from September 2009 to December 2014. We compared transplants performed with robotic technique (RKT) versus patients performed with open surgery at all US centers including our own (open kidney transplant). Subgroup analysis in patients with BMI of 45 kg/m or greater was conducted. We compared outcomes including patient and graft survival, renal function, and technical complications.

RESULTS

Robotic kidney transplantation group had a significantly higher mean BMI overall. The 1-year patient and graft survival rates were similar between groups. Renal function was also similar at 6, 12, and 36 months. Thrombosis caused 1.3% of the graft losses in open kidney transplant and 0% in the RKT group. Interestingly, 52.8% of the overall experience in patients with BMI of 45 kg/m or greater was performed with the robotic technique.

CONCLUSIONS

Robotic surgery offers similar patient and graft survivals with comparable renal function to open technique. Robotic kidney transplantation permits transplantation in extreme BMI categories without additional technical complications. Further studies are required to establish the role of RKT for obese candidates but preliminary data are encouraging.

Pharmacokinetic and pharmacogenetic analysis of immunosuppressive agents after laparoscopic sleeve gastrectomy

BACKGROUND

Severe obesity has been shown to limit access to renal transplantation in patients with end-stage renal disease (ESRD). Laparoscopic sleeve gastrectomy (LSG) has been performed in the ESRD population to assist in achieving waitlist and transplant eligibility. Little is known about how LSG impacts the bioequivalence of tacrolimus products and immunosuppression pharmacokinetics.

METHODS

This was a prospective, open-label, single-dose, crossover, two-period pharmacokinetic (PK) study. The purpose of this study was to assess single-dose PK of immediate-release tacrolimus (IR-TAC), extended-release tacrolimus (ER-TAC), and mycophenolic acid (MPA) in adult ESRD patients post-LSG.

RESULTS

Twenty-three subjects were included in the 24-hour PK assessments. The ratio of geometric means between ER-TAC and IR-TAC was 103.5% (90% CI; 89.6%-119.6%) for AUC_0-24 and 92.5% (90% CI; 80.4%-106.4%) for C_max . PK parameters were similar between ER-TAC and IR-TAC, except for C_min (P=.004) and C_max (P=.04). MPA AUC_0-24 was similar when given with either ER-TAC or IR-TAC (P=.32). Patients expressing CYP3A5*1 genotypes had lower tacrolimus AUC_0-24 values vs those with CYP3A5*3/*3 (IR-TACP<.001; ER-TACP=.008). Genotype did not impact MPA PK.

CONCLUSION

Dose modification of immunosuppressants post-LSG may not be necessary aside from standard therapeutic drug monitoring.

Addressing the challenges of sleeve gastrectomy in end-stage renal disease: Analysis of 100 consecutive renal failure patients

BACKGROUND

While previous studies have demonstrated short-term efficacy of laparoscopic sleeve gastrectomy in candidates awaiting renal transplantation, the combination of morbid obesity and end-stage renal disease presents unique challenges to perioperative care. We demonstrate how increasing experience and the development of postoperative care guidelines can improve outcomes in this high-risk population.

METHODS

Single-center medical records were reviewed for renal transplantation candidates undergoing laparoscopic sleeve gastrectomy between 2011 and 2015 by a single surgeon. Postoperative care protocols were established and continually refined throughout the study period, including a multidisciplinary approach to inpatient management and hospital discharge planning. The first 100 laparoscopic sleeve gastrectomy patients were included and divided into 4 equal cohorts based on case sequence.

RESULTS

Compared with the first 25 patients undergoing laparoscopic sleeve gastrectomy, the last 25 patients had shorter operative times (97.8 ± 27.9 min vs 124.2 ± 33.6 min), lower estimated blood loss (6.6 ± 20.8 mL vs 34.0 ± 38.1 mL), and shorter hospital duration of stay (1.7 ± 2.1 days vs 2.9 ± 0.7 days) (P < .01 each). Readmission rates, complications, and 1-year mortality did not differ significantly.

CONCLUSION

Increasing experience and the development of clinical care guidelines in this high-risk population is associated with reduced health care resource utilization and improved perioperative outcomes.

Bariatric Surgery and Kidney-Related Outcomes

The prevalence of severe obesity in both the general and the chronic kidney disease (CKD) populations continues to rise, with more than one-fifth of CKD patients in the United States having a body mass index of ≥35 kg/m². Severe obesity has significant renal consequences, including increased risk of end-stage renal disease (ESRD) and nephrolithiasis. Bariatric surgery represents an effective method for achieving sustained weight loss, and evidence from randomized controlled trials suggests that bariatric surgery is also effective in improving blood pressure, reducing hyperglycemia, and even inducing diabetes remission. There is also observational evidence suggesting that bariatric surgery may diminish the long-term risk of kidney function decline and ESRD. Bariatric surgery appears to be relatively safe in patients with CKD, with postoperative complications only slightly higher than in the general bariatric surgery population. The use of bariatric surgery in patients with CKD might help prevent progression to ESRD or enable selected ESRD patients with severe obesity to become candidates for kidney transplantation. However, there are also renal risks in bariatric surgery, namely, acute kidney injury, nephrolithiasis, and, in rare cases, oxalate nephropathy, particularly in types of surgery involving higher degrees of malabsorption. Although bariatric surgery may improve long-term kidney outcomes, this potential benefit remains unproved and must be balanced with potential adverse events.

Management of the obese kidney transplant candidate

Obesity is an increasingly common condition that can exclude end stage renal disease patients from consideration of kidney transplantation. The optimal management of obese transplant candidates is uncertain, especially the use of pharmacologic therapies or bariatric surgery. We review the rationale to consider transplantation in obese patients, the impact of obesity on access to kidney transplantation, the evidence for obese patients to lose weight loss prior to kidney transplantation, peri-operative management considerations and specific weight loss strategies prior to transplantation. We also propose an algorithm for pre-transplant management of obese transplant candidates that takes into consideration the patient's peri-operative risk, the anticipated time to transplantation and the risk of delayed graft function. Finally, we suggest a number of areas in need of further research as well as health policy considerations to improve the care of obese kidney transplant candidates.

Laparoscopic sleeve gastrectomy: gateway to kidney transplantation

BACKGROUND

The prevalence of obesity and obesity-related morbidity in end-stage renal disease patients is rising. Although it is established that obesity does not abrogate the transplant benefit with respect to lower long-term mortality and cardiovascular risk, it is associated with increased graft failure, delayed graft function, surgical complications, prolonged hospital stay, and costs.

OBJECTIVES

To examine the safety and efficacy of LSG (laparoscopic sleeve gastrectomy) in renal transplant candidates and evaluate transplant outcomes.

SETTING

Single-center prospective nonrandomized trial METHODS: We here report on a prospective single-center trial establishing a 2-step approach for obese renal transplant candidates. Patients with end-stage renal disease and a BMI (body mass index) of 35 kg/m² or higher underwent laparoscopic sleeve gastrectomy. After reaching a BMI of<35 kg/m², patients were waitlisted for kidney transplantation. Age, gender, body mass index (BMI), associated co-morbidities, cause of end-stage renal disease, surgical complications, and outcome after kidney transplantation (graft survival, incidence of delayed graft function, incidence of rejection, serum creatinine) were collected.

RESULTS

LSG was performed in 8 renal transplant candidates with a mean BMI of 38.8 kg/m² each. BMI dropped to below 35 kg/m² within a median of 3 months. Percent excess body mass index loss (%EBMIL) was 62.7% at 1 year after LSG. Within 17 months (mean) after metabolic surgery, 7 patients underwent kidney transplantation. All transplants were successful with a serum creatinine of 1.9±.8 mg/dL at discharge and stable allograft function thereafter. Mean follow-up was 3.2±1.4 years; no patient was lost to follow-up.

CONCLUSION

LSG is safe and efficacious for treatment of obesity in renal transplant candidates. Rapid and sustained weight loss and subsequent waitlisting for kidney transplantation may reduce overall and in particular posttransplant patient morbidity.

Metabolic syndrome in liver transplantation: A preoperative and postoperative concern

BACKGROUND

Metabolic syndrome is increasing among patients undergoing liver transplantation. Nonalcoholic steatohepatitis is a manifestation of metabolic syndrome and is an increasingly common cause of end-stage liver disease necessitating orthotopic liver transplantation. We sought to determine the effect of preoperative risk factors on the development of post-transplant metabolic syndrome, complications, readmissions, and mortality.

METHODS

We conducted a review of 114 orthotopic liver transplantations at our institution from May 2012 to April 2014.

RESULTS

Patients with (n = 19) and without (n = 95) metabolic syndrome were similar with regard to age, race, and model for end-stage liver disease at time of transplant. Donor and operative factors also were similar between the groups. Preoperative diabetes was found to be associated with an increased rate of readmission (odds ratio 3.45, P = .03). While preoperative metabolic syndrome itself was not a significant predictor of worse outcomes, postoperative metabolic syndrome was associated with significantly greater readmissions in the first year. Major predictors of new onset metabolic syndrome after orthotopic liver transplantation included preoperative diabetes and obesity (odds ratio 8.54 and odds ratio 5.49, P < .01 each).

CONCLUSION

Efforts to decrease the incidence of postoperative metabolic syndrome after orthotopic liver transplantation may decrease readmissions and improve outcomes, along with decreasing resource utilization.

From chronic kidney disease to kidney transplantation: The impact of obesity and its treatment modalities

Obesity is associated with worse short-term outcomes after kidney transplantation but the effect on long-term outcomes is unknown. Although some studies have reported worse outcomes for obese recipients when compared to recipients with a BMI in the normal range, obese recipients who receive a transplant have better outcomes than those who remain wait-listed. Whether transplant candidates should be advised to lose weight before or after transplant has been debated and this is mainly due to the gap in the literature linking pre-transplant weight loss with better outcomes post-transplantation. The issue is further complicated by the use of BMI as a metric of body fat, the obesity paradox in dialysis patients and the different ethical viewpoints of utility versus equity. Measures used to reduce weight loss, including orlistat and bariatric surgery (in particular those with a malabsorptive component), have been associated with enteric hyperoxaluria with consequent risk of nephrolithiasis and oxalate nephropathy. In this review, we discuss the evidence regarding the use of weight loss measures in the kidney transplant candidate and recipient with a view to recommending whether weight loss should be pursued before or after kidney transplantation.

Renal Transplantation in Advanced Chronic Kidney Disease Patients

Kidney transplantation is the best option for patients with end-stage kidney disease. It is associated with better quality of life, lower medical costs, less hospitalization, and improved survival compared with wait-listed patients who remain on dialysis. Timely referral for transplantation is essential to reap the maximal benefit and should begin in the advanced chronic kidney disease stage prior to starting dialysis. Shortage of donor organs remains the biggest challenge to transplantation. With the improved success of kidney transplantation, candidate acceptance criteria continue to broaden. This article provides an overview of the pretransplantation multidisciplinary evaluation process detailing the factors that determine transplant candidacy.

The impact and treatment of obesity in kidney transplant candidates and recipients

The prevalence of obesity in patients with chronic kidney failure and renal transplant candidates has paralleled the epidemic in the general population. The associated risks of surgical complications and long-term cardiovascular death are significant: most transplant centers consider obesity a relative contra-indication for transplant.

Few studies have focused on conservative weight loss strategies in transplant patients. Studies using administrative databases have found that only a minority of wait-listed patients lose weight and with no apparent benefit to transplant outcomes. The only clinical trial in this area found that an intensive weight-loss program had significantly better success (to listing) than self-directed weight loss. However, only a minority that succeeded with the help of a program (36 %), while the “diet and exercise” group had negligible results.

Laparoscopy has radically shortened the recovery time and decreased the complications associated with bariatric surgery. Reports in transplant patients, who were previously deemed too medically complex, have demonstrated a dramatic and rapid weight loss. The only randomized clinical trial in patients with CKD, which compared sleeve gastrectomy to best medical care clearly favoured the surgical arm for weight loss, but was too small to assess other outcomes. The emerging experience is small but quite promising.

Surgical complications and the effect on immunosuppression remain the chief concerns regarding the use of bariatric surgery in transplant patients. Rigorous prospective studies will be essential to properly evaluate the expected weight loss and the effect on pharmacokinetics of immunosuppressive medications. A routine role for bariatric surgery in transplantation would require evidence of improvements in patient-important outcomes and evidence of safety.