New Technologies, Approaches Help Surgeons Maximize the Use of Transplant Organs

New techniques and technology to recover, preserve, and rehabilitate donor organs are optimizing the use of transplant organs and helping close the chronic gap between the supply and demand for transplant organs.

While there has been a recent increase in the number of donors, this uptick has been unable to match the growing need for transplant organs.

In the US alone, although a record 46,632 transplants were performed in 2023 (up 8.7% from the previous year),¹ 103,000 people are still waiting for organ transplants; 17 of them die each day (see Figure).²

“The greatest gap is in kidneys,” said Zoe Stewart Lewis, MD, PhD, MPH, FACS, chief of the Division of Transplant and Hepatobiliary Surgery at the University Hospitals (UH) Cleveland Medical Center in Ohio and director of the UH Transplant Institute, adding that the main causes of kidney failure are hypertension, obesity, and diabetes—all of which are rampant in the US.

In 2022, 808,000 Americans were living with end-stage kidney disease, and nearly 90,000 people are on the waiting list for kidneys—more than three times the record 25,000 transplants performed in 2022.³

In addition, organs were historically matched with recipients in a small local area, and despite a federal regulation stating that geography should not determine an individual’s chance of being a transplant candidate, a significant geographical variation remains across transplant centers in the US. This resulted in geographic inequity in terms of access to a transplant.⁴

“There has now been a push to create an allocation system with broader sharing of potential donors so that patients who live in areas where donation rates are lower still have equal access to transplants,” Dr. Stewart said.

Likewise, there are ethnic disparities, in part because diseases are more prevalent in some ethnic populations. One of four pillars of the Association of Organ Procurement Organizations’ campaign, “50K Organ Transplants in 2026,” is to reduce health inequities to improve accessibility to organ transplants in minority communities.⁵

“What we used to call fatty liver disease tends to be more present in areas where there is a high Hispanic population,” said Amit K. Mathur, MD, MS, FACS, a transplant and hepato-pancreato-biliary surgeon and surgical director of liver transplantation at the Mayo Clinic in Phoenix, Arizona. “Not enough donors in a particular area can exacerbate the mortality risk there.”

Organ Supply and Demand Are Out of Balance

Like any supply-and-demand scenario, the solution to the transplant organ imbalance is to increase the supply of organs or decrease demand for them.

Aside from efforts to increase organ donation by better educating potential donors and their families, Dr. Stewart said that more could be done to encourage living donors who may donate one of their two kidneys or part of their liver, as receiving organs from living donors often results in the smoothest recoveries and best long-term outcomes.

Of the 46,000 transplants performed in 2023, approximately 39,000 were from deceased donors, and 7,000 were from living donors.⁶ According to Dr. Stewart, efforts to increase living donors include educating the public about the safety of the procedure and reducing barriers to undergoing the procedure. For example, although living donors are often reimbursed for their travel costs, they are not fully reimbursed for other costs, such as time away from work and childcare.

Another cause of the supply and demand imbalance is the rising demand for organ transplants. End-stage kidney disease has become so prevalent in the US population due to rapid increases in hypertension, obesity, and diabetes, Dr. Stewart said. These conditions could be reduced through disease prevention strategies, including better diet and lifestyle practices and improved access to healthcare.

“If we could take a fraction of the resources and energy we spend supporting patients on dialysis or through transplants and invest it in prevention and primary care, we could reduce a lot of kidney disease in this country,” she said.

Available Organs Go Unused

Aside from too little supply and too great a demand, the process can be inefficient. Available organs are not always being used effectively or at all.

In 2022, 19.14% of all organs successfully recovered from donors were not transplanted into a recipient.⁷ Organs recovered by organ procurement organizations and not used for transplant has doubled in the last 5 years.⁸

The organ distribution system does not always get donor organs to the right recipients in a timely, efficient, and fair manner. Aside from the traditional challenges of transporting and preserving the organ, the duration of the process of offering transplant organs can sometimes exceed the time the organ is viable. Last year, as part of a broader modernization effort intended to shorten wait times, address inequities, and reduce the number of patients who die while waiting for transplant, the Biden administration proposed breaking up the United Network for Organ Sharing—the network that has long run the nation’s organ transplant system.⁹

Nevertheless, improvements have been made. One is to shorten the amount of time transplant centers have to review an organ offer and respond. Another process enhancement is the ability for transplant centers to access detailed data about what types of organs they will choose. This information helps centers identify their criteria for the organs they will choose, allowing them to filter out organ offers they are unlikely to accept and quickly send that offer to the next recipient on the list.

“As an example, if a transplant center has never transplanted a kidney from anybody over the age of 65, then it can set its organ offer filters to automatically code out any donor over the age of 65,” Dr. Stewart said. Other filtering criteria include donor’s last creatinine value, biopsy values, and how long the kidney has been in cold storage.

Still, viable organs go unused. “Probably once or twice a week, I will hear an offer that I would have accepted and transplanted but I am unable to get the kidney here in time as it’s across the country with 20 hours of cold time already,” Dr. Stewart explained. She estimates that hundreds of organs a year in the US are “lost opportunities.”

Another reason that viable organs go unused is that many transplant centers are reluctant to take the time to adequately assess and receive organs from older and more complex donors. Reasons include a conservative approach to choosing transplant organs, the lack of infrastructure to take care of complex patients posttransplant, and the fear of poor outcomes and associated risks with using “marginal” organs. As a result, the US is behind Europe in using medically complex organs. For example, 62% of kidneys recovered and not utilized in the US would have been transplanted in France.¹⁰

Dr. Stewart said she is surprised that some transplant programs won’t consider a kidney that has been more than 24 hours on ice. Her transplant center will accept organs that have been cold for up to 40 hours.

Refining Organ Use and Surgeons’ Role in the Process

Efforts to maximize organ use include increasing the pool of potential donor organs through closer evaluation of donation after circulatory death (DCD) organs and advancements in organ preservation, as well as expanding donor criteria and applying new technologies to better recover, rehabilitate, and preserve organs.

Willingness to take on higher-risk donors and recipients

Due to the existing gap between organ supply and demand, marginal organs are increasingly being considered. But this approach requires transplant centers to be willing to take on more risk.

“Being more aggressive with donor offers and looking at marginal donors can help get people organs more quickly and reduce death on the waitlist,” said Jordan Hoffman, MD, FACS, surgical director of heart and lung transplantation at the University of Colorado in Denver.

Large transplant centers tend to take more of an aggressive approach than smaller centers because they have the resources and infrastructure to provide individualized and intensive patient care before and after transplant, Dr. Stewart said. Nevertheless, transplant centers should more closely assess organs and be willing to stretch their acceptance criteria.

“Give every organ a chance,” Dr. Stewart said.

Reduce risk to reward innovation

Transplant centers are more likely to take on marginal donors if the outcome metrics by which they are measured are less strict, according to Dr. Stewart, who said that transplant centers are expected to maintain outcomes of 96% or more for 1-year grafts and patient survivals. “If you deviate from those high regulatory metrics, you face regulatory implications for your program,” she said.

Although the US has one of the best organ donation and transplant systems in the world, it may be too stringent when it comes to outcomes monitoring policies, said Dr. Mathur. “That can stifle practice. We need to be more responsive to innovation.”

Reducing risks of regulatory discipline for transplant centers could lower the risk of patients dying on the waiting list.

“We need to take a more holistic approach to risk management,” Dr. Stewart said. “People on the transplant waiting list shouldn’t die because transplant centers are too choosy about what organs they accept.”

DCD organ use has grown significantly

DCD organs may be compromised by hypoxic-ischemic brain injury because they cannot be removed until the donor has been declared dead, which in the US, usually happens after the donor has been pulseless for 5 minutes.¹¹ For years, when compared with donation after brain death (DBD) organs, DCD provided a lower yield of transplantable organs, decreased patient and graft survival rates, had higher complication rates, and increased delayed graft function.

In 2010, about 85% of transplant organs were DBD organs, while 15% were DCD, Dr. Stewart said. Since then, advances in perfusion technology have made DCD organs a more viable option. DCD hearts have increased the donor heart pool by about 20% to 30%, and complication rates have decreased to the point that DCD organs are on par with DBD organs.

“We use a modified pump to perfuse the organs that we want to use for transplant,” said Dr. Hoffman. “While we’re doing this, we’re also examining the function and physiology of those organs.”

In addition, transplant teams are able to travel to a donor site and perfuse the organ. This normothermic regional perfusion (NRP) technique has outcomes equivalent to ex vivo perfusion, according to Dr. Hoffman, who called NRP a “game changer” for hearts, lungs, livers, and kidneys.

At Dr. Stewart’s clinic, 50% of livers have been DCD organs in the past 6 months, compared to 0% in the year prior.

Unfortunately, DCD lungs have not grown in use as fast as other organs. Since lung recipients typically have a limited life span (medial survival of approximately 6 years or so), surgeons want to ensure that the donor lungs are in the best possible condition and do not lead to complications.

The main limitation to perfusion is expense, which means transplant programs need to find ways to recoup costs. Notably, NRP is more financially viable than any other procurement technique, including ex vivo perfusion, according to Dr. Hoffman.

Expanding the donor pool

The definition of viable organs has expanded over the years. In many cases, organs from older donors or donors who smoke or drink alcohol are not automatically eliminated.

Indications for using transplant to treat liver disease already are expanding beyond chronic liver disease, as donor livers may be used to treat diverse types of cancers, Dr. Mathur added.

Newer preservation methods, including targeted perfusion solutions and advanced machine perfusion methods, also may provide opportunities to treat, maintain, and assess marginal organs and improve transplant outcomes. New therapies in perfusion fluids hold promise to lessen tissue injury, inhibit immune responses, and maintain cellular homeostasis. Machine perfusion advancements offer means of functional maintenance, restoration, and assessment while reducing damage associated with static cold storage.¹²

Artificial intelligence (AI) also has the potential to transform transplantation through improved allocation algorithms, smart donor-recipient matching, and dynamic adaptation of immunosuppression to automated analysis of transplant pathology.¹³

Mayo Clinic researchers have suggested that AI will be able to eliminate the need for a transplant by detecting organ failure earlier; increase organs usable for transplant by identifying which organs would benefit from perfusion systems; prevent organ rejection and decrease posttransplant complications; and improve posttransplant care by gauging how a patient’s body reacts to immunosuppressants.¹⁴

The ability to transplant organs is one of the great achievements of modern medicine. Increasing the supply of organs, decreasing the need for transplants, streamlining and advancing the organ allocation process, and employing more efficient and effective use of donor organs will help create a more robust system that ultimately will help even more patients.

Jim McCartney is a freelance writer.

References

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