Current Opinion in Organ Transplantation最新文献

Purpose of review: Significant advancements have been made in the field of vascularized composite allotransplantation (VCA); however, like solid organ transplantation, bypassing the recipient's immune response remains a significant obstacle to long-term allograft survival. Therefore, strategies to overcome acute and chronic rejection and minimize immunosuppressive therapy are crucial for the future of VCA. This review highlights recent attempts to induce tolerance in VCA and discusses key findings through a clinical lens.

Recent findings: Promising VCA tolerance protocols are being investigated, with five recent studies illustrating various successes. These preclinical approaches demonstrate a correlation between the presence of donor-derived T cells and VCA tolerance, the importance of using clinically available reagents within preclinical protocols, and the ability to induce sustained tolerance through nonmyeloablative methods. Furthermore, environmental factors, such as NB-UVB light are being investigated for their immunomodulation properties and may influence VCA graft rejection.

Summary: To widen the scope of VCA, minimization of immunosuppression is needed. Overall, tolerance induction protocols should have a low-toxicity level, minimally invasive induction therapies, and utilize short-term immunosuppressive medications. By examining the milestones of recent studies, researchers can gain new technical approaches to immune modulation and make data-driven amendments to tolerance protocols in preparation for clinical translation.

Purpose of review: Allograft vasculopathy in vascularized composite allografts (VCA) remains understudied. This review explores the vascular changes in VCA, focused on recent literature.

Recent findings: Allograft vasculopathy in VCA generally includes progressive concentric myointimal thickening and luminal narrowing of arterial vessels through endothelial deterioration and proliferation of smooth muscle cells. Microvascular changes are also noted, with thrombosis and lumen narrowing in microvessels of the skin even in the absence of large vessel vasculopathy. Histopathologic reports of skin containing VCA rejection document arteriosclerosis in deep vessels that are not always reflected in skin punch biopsies. The first revision of the Banff VCA scoring system 2022 was developed to include vascular changes in VCA. The scoring system for chronic changes and antibody mediated rejection continues to be under development.

Summary: The study of vascular changes in VCA continues to progress. Important data and advances in experimental and clinical VCA have been reported and continue to take place. Challenges ahead include capture of clinical data that will evolve beyond transient report forms and approaching on the problem of graft failure well grounded in sound scientific methodology.

Purpose of review: While multidisciplinary collaboration is a tenant of quality heart failure care and critical to the success of transplant programs, this essay challenges the temptation to shoehorn adult congenital heart disease (ACHD) patients into preexisting processes and paradigms. We explore the development of more relevant models, purposefully designed to improve ACHD transplant volumes and outcomes.

Recent findings: Globally, the rapid acceleration of ACHD patients living with and dying from HF stands in stark contrast to their access to transplant. Inferior early outcomes after ACHD transplant remain an undeniable barrier. And yet while all large registry datasets attest to this statistic, a few centers have achieved results comparable to those in acquired heart disease. This despite increases in both ACHD candidate complexity and referrals for Fontan Circulatory Failure. Perhaps something in their approach to care delivery is key?.

Summary: Alone, neither ACHD nor transplant programs can provide optimal management of HF in ACHD. A siloed approach is similarly inadequate. Building new ACHD-HF-Transplant teams, centered on the patient and supplemented by ad hoc expert partnerships, is an exciting approach that can improve outcomes, create a high-quality training environment, and in our experience, is a truly rewarding way of working together.

Purpose of review: This review delves into the intricate landscape of airway complications post lung transplantation. With the rising prevalence of end-stage lung disease and the increasing number of lung transplantation worldwide, understanding and effectively managing airway complications are crucial. Given the nuanced nature of these complications and the array of treatment options available, this review aims to provide a comprehensive overview of how to identify, classify, mitigate risk factors for, and manage these complications.

Recent findings: Several donor, recipient, and surgical risk factors are associated with the increased risk of airway complications. In managing these complications, bronchoscopic interventions, notably balloon dilation and stenting, are pivotal. Although self-expanding metallic stents offer versatility, silicone stents are preferred in certain scenarios for their durability. Emerging techniques such as biodegradable stents and advancing imaging modalities show promise in mitigating complications and improving outcomes.

Summary: These findings underscore the significance of a multidisciplinary approach and personalized treatment algorithms in managing airway complications post lung transplantation. By elucidating specific indications and complications of treatment modalities, this review serves as a valuable resource for optimally managing airway complications. Ongoing research into novel interventions holds promise for further enhancing outcomes in this challenging clinical setting.

Purpose of review: With advances in the field of congenital cardiac surgery and in the management of congenital heart defects in early life, the population of adult congenital heart disease (ACHD) patients is increasing. End-stage heart failure is currently the main cause of cardiovascular mortality and is expected to increase in the coming years. This review summarizes recent innovations in transplant techniques, with special attention to what is known in the population of ACHD recipients.

Recent findings: The use of machine perfusion for heart preservation enables longer preservation times. Normothermic (organ care system - OCS) and hypothermic (hypothermic oxygenated perfusion - HOPE) machine perfusion will alleviate the time pressure associated with heart transplantation in the ACHD population, may allow for expansion of the geographical range in which donors can be matched and may improve graft quality. Donation after circulatory death (DCD) heart transplantation, either through direct procurement-machine perfusion (DP-MP) or thoraco-abdominal normothermic regional perfusion (TA-NRP) is a viable strategy to further expand the donor pool.

Summary: The use of machine perfusion and DCD donors in ACHD is feasible and shows promise. Time pressure and shortage of donors is even more critical in ACHD than in other patient populations, making these innovations particularly relevant. Further clinical experience and research is needed to elucidate their impact.

Purpose of review: Prehabilitation, defined as preparing the body physically and psychologically for upcoming surgery is of increasing prominence in presurgical care. The aim of this review is to discuss the evidence base around prehabilitation in solid organ transplantation, the use of digital health as a tool to deliver these interventions, and consider future directions.

Recent findings: Prehabilitation is of increasing interest as an adjunct to pretransplant care for individuals working up for solid organ transplantation. To date, research has shown that prehabilitation is acceptable and feasible; however, the literature base remains small. The majority of research has been delivered using in-person rehabilitation programmes, and the evidence base utilizing digital health as a means to deliver prehabilitation is limited.

Summary: To date, the research evidence base in prehabilitation for solid organ transplantation is limited. Evidence in other surgical populations has demonstrated promising results, particularly in aerobic capacity, physical function and postoperative complications. Further high-quality randomized controlled clinical trials are required to strengthen the evidence base, understand how digital health can be harnessed and utilized to deliver multimodal prehabilitation with an aim to see how this may form part of routine care in the solid organ transplantation pathway.

Purpose of review: Although lung transplantation stands as the gold standard curative therapy option for end-stage lung disease, the scarcity of available organs poses a significant challenge in meeting the escalating demand. This review provides an overview of recent advancements in ambulatory respiratory assist systems, selective anticoagulation therapies that target the intrinsic pathway, and innovative surface coatings to enable permanent respiratory support as a viable alternative to lung transplantation.

Recent findings: Several emerging ambulatory respiratory assist systems have shown promise in both preclinical and clinical trials. These systems aim to create more biocompatible, compact, and portable forms of extracorporeal membrane oxygenation that can provide long-term respiratory support. Additionally, innovative selective anticoagulation strategies, currently in various stages of preclinical or clinical development, present a promising alternative to currently utilized nonselective anticoagulants. Moreover, novel surface coatings hold the potential to locally prevent artificial surface-induced thrombosis and minimize bleeding risks.

Summary: This review of recent advancements toward permanent respiratory support summarizes the development of ambulatory respiratory assist systems, selective anticoagulation therapies, and novel surface coatings. The integration of these evolving device technologies with targeted anticoagulation strategies may allow a safe and effective mode of permanent respiratory support for patients with chronic lung disease.

Purpose of review: Mechanical circulatory support is used frequently as a method of stabilizing patients with end stage heart failure who are unable to safely await allograft availability. While this technology has been fundamentally important in supporting patients with normal cardiac anatomy, it is still used infrequently in adult patients with congenital heart disease and end-stage heart failure. Here, we review the data on mechanical circulatory support technology in this small but growing population of patients with chronic heart disease prone to the development of circulatory failure.

Recent findings: Mechanical circulatory support (MCS) has been increasingly employed in adults with congenital heart disease (ACHD) as a bridge to transplant. The new United Network for Organ Sharing listing system favoring temporary MCS use with a higher listing status offers another tool to stabilize ACHD patients and potentially shorten wait times. Both temporary and Durable MCS could help improve transplant candidacy and posttransplant outcomes in select groups of ACHD patients.

Summary: Durable and temporary MCS have the potential to significantly improve access to transplant and overall transplant outcomes in ACHD patients.