Posttransplant complications: molecular mechanisms and therapeutic interventions

Posttransplantation complications pose a major challenge to the long-term survival and quality of life of organ transplant recipients. These complications encompass immune-mediated complications, infectious complications, metabolic complications, and malignancies, with each type influenced by various risk factors and pathological mechanisms. The molecular mechanisms underlying posttransplantation complications involve a complex interplay of immunological, metabolic, and oncogenic processes, including innate and adaptive immune activation, immunosuppressant side effects, and viral reactivation. Here, we provide a comprehensive overview of the clinical features, risk factors, and molecular mechanisms of major posttransplantation complications. We systematically summarize the current understanding of the immunological basis of allograft rejection and graft-versus-host disease, the metabolic dysregulation associated with immunosuppressive agents, and the role of oncogenic viruses in posttransplantation malignancies. Furthermore, we discuss potential prevention and intervention strategies based on these mechanistic insights, highlighting the importance of optimizing immunosuppressive regimens, enhancing infection prophylaxis, and implementing targeted therapies. We also emphasize the need for future research to develop individualized complication control strategies under the guidance of precision medicine, ultimately improving the prognosis and quality of life of transplant recipients.

Short- and long-term outcomes of acute diverticulitis in patients with transplanted kidneys

AIM

The safety of nonoperative treatment for patients with transplanted kidneys who develop acute diverticulitis is unclear. Our primary aim was to examine the long-term sequelae of nonoperative management in this group.

METHOD

We performed a population-based retrospective cohort study using linked administrative databases housed at ICES in Ontario, Canada. We included adult (≥18 years) patients admitted with acute diverticulitis between April 2002 and December 2019. Patients with a functioning kidney transplant were compared with those without a transplant. The primary outcome was failure of conservative management (operation, drainage procedure or death due to acute diverticulitis) beyond 30 days. The cumulative incidence function and a Fine-Grey subdistribution hazard model were used to evaluate this outcome accounting for competing risks.

RESULTS

We examined 165 patients with transplanted kidneys and 74 095 without. Patients with transplanted kidneys were managed conservatively 81% of the time at the index event versus 86% in nontransplant patients. Short-term outcomes were comparable, but cumulative failure of conservative management at 5 years occurred in 5.6% (95% CI 2.3%-11.1%) of patients with transplanted kidneys versus 2.1% (95% CI 2.0%-2.3%) in those without. Readmission for acute diverticulitis was also higher in transplanted patients at 5 years at 16.7% (95% CI 10.1%-24.7%) versus 11.6% (95% CI 11.3%-11.9%). Adjusted analyses showed increased failure of conservative management [subdistribution hazard ratio (sHR) 3.24, 95% CI 1.69-6.22] and readmissions (sHR 1.55, 95% CI 1.02-2.36) for patients with transplanted kidneys.

CONCLUSION

Most patients with transplanted kidneys are managed conservatively for acute diverticulitis. Although long-term readmission and failure of conservative management is higher for this group than the nontransplant population, serious outcomes are infrequent, substantiating the safety of this approach.

Treating acute diverticulitis in pre- and post-solid-organ transplant patients: a single-institution cohort study

AIM

Immunosuppressed patients are more likely to fail nonoperative management of acute diverticulitis and have more postoperative complications than the immunocompetent. Transplant recipients form a subcategory among the immunosuppressed with unique challenges. The aim of this work is to report 30-day postoperative complications after colectomy for acute diverticulitis and success rates of nonoperative management in pre- and post-transplant patients.

METHOD

This is a retrospective cohort study at a single-institution tertiary referral centre. Patients with a history of acute diverticulitis were extracted from a database of 6152 recipients of solid-organ abdominal transplant between 2000 and 2015 and stratified by the index episode of diverticulitis: before or after solid-organ transplant surgery. Outcomes included 30-day postoperative complications and failure of nonoperative management.

RESULTS

Acute diverticulitis occurred in 93 patients, 69 (74%) posttransplant. Postcolectomy complications were higher posttransplant than pretransplant (43% vs. 13%, p = 0.04). Posttransplant status was not an independent risk factor for complications (odds ratio 3.59, 95% CI 0.79-16.31) when adjusting for sex and surgical acuity. Immediate urgent colectomy (29% vs. 31%, p = 0.84) and failure of nonoperative management (7% vs. 9%, p = 0.82) were similar. Complications occurred equally in those requiring urgent colectomy after nonoperative management and those undergoing immediate urgent colectomy.

CONCLUSION

Urgent colectomy rates are similar in solid-organ abdominal transplant recipients pre- and posttransplant. Posttransplant complication rates appear to be increased but transplant status as an independent factor is not significantly associated with an increased risk in this study cohort. These findings should be considered when counselling patients on the relative risks and benefits of surgical intervention for diverticulitis before versus after solid-organ transplantation.

The Role of Gastroenterologists in Preoperative Assessment and Management of Prospective Renal Transplantation Candidates

Renal transplant is the most common organ transplant worldwide, accounting for 65% of the total number of transplants. End-stage renal disease (ESRD) often has multiple significant comorbidities. Among the gastrointestinal (GI) disorders, peptic ulcer disease (PUD), cholelithiasis, and colon and liver diseases increase the risk of posttransplant morbidity. Potential renal transplantation (RT) candidates need a multidisciplinary assessment of coexisting illnesses, which may affect the perioperative risk and survival after transplantation. Successful outcome of RT depends on careful selection of the recipients by a thorough medical evaluation and screening. This review summarizes the role of gastroenterologists and hepatologists in preoperative assessment and management of renal transplant recipients.

How to cite this article

Giri S, Dash KA, Varghese J, et al. The Role of Gastroenterologists in Preoperative Assessment and Management of Prospective Renal Transplantation Candidates. Euroasian J Hepato-Gastroenterol 2023;13(1):18-25.

Totally laparoscopic and totally robotic surgery in patients with left-sided colonic diverticulitis

BACKGROUND

Introduction of the da Vinci Xi system has facilitated the use of robotics in colorectal surgery. Nevertheless, data on the outcomes of robotic surgery for the treatment of colonic diverticulitis have remained scarce.

METHODS

Patient demographics, clinical characteristics, and perioperative outcomes of the patients undergoing totally robotic with the da Vinci Xi system or laparoscopic surgery for left-sided colonic diverticulitis (LCD) were compared.

RESULTS

Laparoscopic and robotic groups included 22 and 20 patients, respectively. There were no significant differences between the two groups in terms of patient demographics, clinical characteristics, operative time, and postoperative complications. There were three conversions in the laparoscopy group and no conversion in the robotic group (P = 0.23). Conversion to open surgery was associated with postoperative morbidity (P = 0.02).

CONCLUSION

Robotic surgery is an applicable alternative for the treatment of LCD. Robotic approach may potentially lower the risk of operative morbidity by reducing the requirement of conversion.