Progressive functional adaptation of segmental bowel graft from living related donor

Outcome After Intestinal Transplantation From Living Versus Deceased Donors: A Propensity-matched Cohort Analysis of the International Intestinal Transplant Registry

OBJECTIVE

To describe the worldwide experience with living donation (LD) in intestinal transplantation (ITx) and compare short-term and long-term outcomes to a propensity-matched cohort of deceased donors.

BACKGROUND

ITx is a rare life-saving procedure for patients with complicated intestinal failure (IF). Living donation (LD)-ITx has been performed with success, but no direct comparison with deceased donation (DD) has been performed. The Intestinal Transplant Registry (ITR) was created in 1985 by the Intestinal Transplant Association to capture the worldwide activity and promote center's collaborations.

METHODS

Based on the ITR, 4156 ITx were performed between January 1987 and April 2019, of which 76 (1.8%) were LD, including 5 combined liver-ITx, 7 ITx-colon, and 64 isolated ITx. They were matched with 186 DD-ITx for recipient age/sex, weight, region, IF-cause, retransplant, pretransplant status, ABO compatibility, immunosuppression, and transplant date. Primary endpoints were acute rejection and 1-/5-year patient/graft survival.

RESULTS

Most LDs were performed in North America (61%), followed by Asia (29%). The mean recipient age was: 22 years; body mass index: 19kg/m²; and female/male ratio: 1/1.4. Volvulus (N=17) and ischemia (N=17) were the most frequent IF-causes. Fifty-two percent of patients were at home at the time of transplant. One-/5-year patient survival for LD and DD was 74.2/49.8% versus 80.3/48.1%, respectively ( P =0.826). One-/5-year graft survival was 60.3/40.6% versus 69.2/36.1%, respectively ( P =0.956). Acute rejection was diagnosed in 47% of LD versus 51% of DD ( P =0.723).

CONCLUSION

Worldwide, LD-ITx has been rarely performed. This retrospective matched ITR analysis revealed no difference in rejection and in patient/graft survival between LD and DD-ITx.

25 Years of a Standardized Technique for Living Donor Intestinal Transplantation: A Systematic Review

A safe, reproducible and standardized surgical technique for intestinal procurement and transplantation from a living donor (LD) was introduced in 1997 and has been used in the majority of cases since. The key principles are: 1. procurement of 180-200 cm of distal ileum in adults (about 60-150 cm in pediatric recipients depending on age and weight) on a vascular pedicle comprising the LD ileocolic vessels or terminal branches of the superior mesenteric vessels, 2. the terminal ileum (30-40 cm of the most distal ileum), the ileocecal valve and the cecum remain with the donor to not interfere with B12-absorption and bowel transit time, 3. systemic venous drainage with anastomoses between the LD ileocolic vessels and the recipient's infrarenal aorta and vena cava, and 4. restoration of recipient bowel continuity through proximal anastomosis and distal graft ileostomy for biopsy access and graft monitoring. Recipients of a successful LD intestinal transplant become total parenteral nutrition (TPN)-independent within a few weeks posttransplant. LD vs deceased donor (DD) intestinal transplants can be performed in a more timely fashion. Hence, LD (in contrast to DD) intestinal transplants are also pre-emptive procedures in patients with advanced, but still reversible, TPN-induced liver disease and help reduce the wait-list mortality for combined DD intestinal and liver transplants. Life-saving combined LD intestinal and liver transplants, albeit rare, have also been successfully performed either simultaneously or subsequently. There have been no reported deaths or major complications of living intestinal donors. A better metabolic profile has been reported in some donors post-donation. In total, 85 documented LD intestinal transplants have been performed worldwide at over 20 different transplant centers in 12 different countries. In about 70 transplants, the standardized technique was used. There has been no difference in outcome between LD vs DD intestinal transplants. Long-term studies have shown that > 10 year of graft function is not uncommon. Since the introduction of the standardized surgical technique, LD intestinal transplantation has evolved from an experimental to an established and standardized procedure.

Is There a Role for Living Donor Intestine Transplants?

The use of living donors with intestinal transplantation is controversial because it may not significantly improve candidate access to organs when intestine-only grafts are needed, and may involve excessive donor risk when combined liver-intestine grafts are required. Although limited data are available for comparison at this time, graft and patient survival rates for intestinal transplantations using living donors are no different than for deceased donor transplantations. Potential benefits that may be provided to the intestine transplant recipient through the use of living donors include better HLA matching, shorter ischemia times, better bowel preparation, and better opportunities for introducing immunomodulatory strategies. Conversely, living intestine donors are at risk for mortality, significant morbidity, financial loss, and psychologic trauma. The long-term outcomes of living intestine donors have not yet been reported. Ultimately, these data are essential before the wider use of living donors can be advocated for intestinal transplantation.

Intestinal Transplantation from Living Donors

Intestinal transplantation (ITx) represents the physiologic alternative to total parenteral nutrition (TPN) for patients suffering from life-threatening complications of irreversible intestinal failure. The number of transplants performed worldwide has been increasing for several years until recently. ITx has recently become a valid therapeutic option with a graft survival rate between 80 % and 90 % at 1 year, in experienced centers. These results have been achieved due to a combination of several factors: better understanding of the pathophysiology of intestinal graft, improved immunosuppression techniques, more efficient strategies for the monitoring of the bowel graft, as well as control of infectious complications and posttransplant lymphoproliferative disease (PTLD). In fact, this procedure is associated with a relatively high rate of complications, such as infections, acute rejection, graft versus host disease (GVHD), and PTLD, if compared to the transplantation of other organs. These complications may be, at least in part, the consequence of the peculiarity of this graft, which contains gut-associated lymphoid tissue and potentially pathogenic enteric flora. Furthermore, in these patients, the existing disease and the relative malnutrition could predispose them to infectious complications. Additionally, other factors associated with the procedure, such as laparotomy, preservation injury, abnormal motility, and lymphatic disruption, could all be implicated in the development of complications.

Short bowel syndrome: parenteral nutrition versus intestinal transplantation. Where are we today?

Current management of short bowel syndrome (SBS) revolves around the use of home TPN (HPN). Complications include liver disease, catheter-related infections or occlusions, venous thrombosis, and bone disease. Patient survival with SBS on TPN is 86% and 75% at 2 and 5 years, respectively. Surgical management of SBS includes nontransplant surgeries such as serial transverse enteroplasty and reanastomosis. Small bowel transplant has become increasingly popular for management of SBS and is usually indicated when TPN cannot be continued. Posttransplant complications include graft-versus-host reaction, infections in an immunocompromised patient, vascular and biliary diseases, and recurrence of the original disease. Following intestinal-only transplants, patient and graft survival rate is 77% and 66% after 1 year. After 5 years the survival figures are 49% and 34%, respectively. Future improvements in survival and quality of life will enhance small bowel transplant as a viable treatment option for patients with SBS.

Living related segmental bowel transplantation: from experimental to standardized procedure

INTRODUCTION

Living donor bowel transplantation has recently emerged as a valuable alternative to cadaver bowel transplant. We herein present our single-center experience with this procedure.

MATERIALS AND METHODS

From April 1998 to October 2004, 12 living donor intestinal transplants were performed in 11 patients (7 males, 4 females; average age, 26 years). Four of the patients were children under 5 years. A segment of distal ileum 150 to 180 cm long in pediatric recipients and 200 cm long in adult was used. The immunosuppressive protocol consisted of induction with thymoglobulin and maintenance with tacrolimus with or without mycophenolate mofetil and steroids.

RESULTS

All donors recovered well and did not experience any early or late complications. The overall 1- and 3-year patient survival was 82% with a graft survival of 75%. In the last 8 patients, transplanted after January 2000, the 1-year patient and graft survival has been 100% and 88%, respectively. The median hospital stay was 36 days (range, 13-290 days). During the first year after transplant only, the patient who received a totally mismatched graft experienced one episode of rejection (8%). All the surviving patients are currently supported by enteral diet without fluid requirements.

CONCLUSIONS

Living donor bowel transplantation is a valuable strategy in the treatment of irreversible intestinal failure. The results have improved over the years thanks to increased experience of the team.

Intestinal mucosal adaptation

Intestinal failure is a condition characterized by malnutrition and/or dehydration as a result of the inadequate digestion and absorption of nutrients. The most common cause of intestinal failure is short bowel syndrome, which occurs when the functional gut mass is reduced below the level necessary for adequate nutrient and water absorption. This condition may be congenital, or may be acquired as a result of a massive resection of the small bowel. Following resection, the intestine is capable of adaptation in response to enteral nutrients as well as other trophic stimuli. Identifying factors that may enhance the process of intestinal adaptation is an exciting area of research with important potential clinical applications.

Intestinal adaptation after massive intestinal resection

Patients with short bowel syndrome require long term parenteral nutrition support. However, after massive intestinal resection the intestine undergoes adaptation and nutritional autonomy may be obtained. Given that the complications of parenteral nutrition may be life threatening or result in treatment failure and the need for intestinal transplantation, a more attractive option is to wean patients off nutrition support by optimising the adaptive process. The article examines the evidence that after extensive small bowel resection adaptation occurs in humans and focuses on the factors that influence adaptation and the strategies that have been used to optimise this process. The review is based on an English language Medline search with secondary references obtained from key articles. There is evidence that adaptation occurs in humans. Adaptation is a complex process that results in response to nutrient and non-nutrient stimuli. Successful and reproducible strategies to improve adaptation remain elusive despite an abundance of experimental data. Nevertheless given the low patient survival and quality of life associated with other treatments for irreversible intestinal failure it is imperative that clinical research continues into the optimisation of the adaptation.

Intestinal adaptation after massive intestinal resection

Patients with short bowel syndrome require long term parenteral nutrition support. However, after massive intestinal resection the intestine undergoes adaptation and nutritional autonomy may be obtained. Given that the complications of parenteral nutrition may be life threatening or result in treatment failure and the need for intestinal transplantation, a more attractive option is to wean patients off nutrition support by optimising the adaptive process. The article examines the evidence that after extensive small bowel resection adaptation occurs in humans and focuses on the factors that influence adaptation and the strategies that have been used to optimise this process. The review is based on an English language Medline search with secondary references obtained from key articles. There is evidence that adaptation occurs in humans. Adaptation is a complex process that results in response to nutrient and non-nutrient stimuli. Successful and reproducible strategies to improve adaptation remain elusive despite an abundance of experimental data. Nevertheless given the low patient survival and quality of life associated with other treatments for irreversible intestinal failure it is imperative that clinical research continues into the optimisation of the adaptation.

Is there a role for living donor intestine transplants?

The use of living donors with intestinal transplantation is controversial because it may not significantly improve candidate access to organs when intestine-only grafts are needed, and may involve excessive donor risk when combined liver-intestine grafts are required. Although limited data are available for comparison at this time, graft and patient survival rates for intestinal transplantations using living donors are no different than for deceased donor transplantations. Potential benefits that may be provided to the intestine transplant recipient through the use of living donors include better HLA matching, shorter ischemia times, better bowel preparation, and better opportunities for introducing immunomodulatory strategies. Conversely, living intestine donors are at risk for mortality, significant morbidity, financial loss, and psychologic trauma. The long-term outcomes of living intestine donors have not yet been reported. Ultimately, these data are essential before the wider use of living donors can be advocated for intestinal transplantation.

Living related small bowel transplantation: donor surgical technique

OBJECTIVE

To describe a standardized technique for ileal graft procurement in the setting of living related bowel transplantation.

SUMMARY BACKGROUND DATA

Living donor transplantation has been successfully developed for kidney, liver, pancreas, and lung transplantation. More recently, living related small bowel transplantation (LR-SBTx) has been developed with the aim of expanding the pool of intestinal graft donors and reducing the mortality in patients on the waiting list. To date, a total of 25 LR-SBTx worldwide have been reported to the international registry. We herein report the largest single center experience.

METHODS

A segment of ileum, 150 to 200 cm, is resected 20 cm proximal to the ileocecal valve (ICV), which is always preserved. The arterial inflow is given by the terminal branch of the superior mesenteric artery and venous outflow by a proximal segment of the superior mesenteric vein. The entire bowel is measured intraoperatively and at least 60% of intestine length is left in the donor.

RESULTS

Since 1998, we have performed 9 terminal ileum resections for small bowel donation. None of the donors has experienced persistent alteration of bowel habits or malabsorption; only 1 minor wound complication has occurred.

CONCLUSIONS

Terminal ileal resection with preservation of the ICV seems to assure fast functional recovery of the donor and has minimal postoperative complications.

Successful Treatment of Trauma-Induced Short Bowel Syndrome With Early Living Related Bowel Transplantation

BACKGROUND

: Total parenteral nutrition (TPN) is a life-saving therapy for patients with short bowel syndrome. However, TPN is associated with a high incidence of serious complications, poor quality of life, and elevated cost. An attempt was made to avoid TPN-related complications associated with trauma-induced short bowel syndrome by using early living related donor bowel transplantation.

METHODS

: Three men 27 to 30 years of age with trauma-induced short bowel syndrome received early living related donor bowel transplantation using segmental ileal grafts.

RESULTS

: All the donors had an uncomplicated postoperative course. After a mean follow-up period of 40 months, all three recipients were alive and well, and did not require any TPN support. The ileal graft adapted perfectly to support fully the nutritional needs of young, active individuals.

CONCLUSIONS

: Early living related donor bowel transplantation is a successful treatment for trauma-induced short bowel syndrome. It is associated with a lower incidence of complications, better quality of life, and lower cost than long-term TPN.