Expanding the Donor Pool in Lung Transplantation Through Donation After Circulatory Determination of Death
March 29, 2019
Author: Pablo G. Sanchez, MD, PhD, FACS
More than 90% of lung transplants in the United States are performed using lungs acquired from donors after brain death (DBD). Unfortunately, the number of lungs available from DBD is plateauing, but the need for donated lungs is not. As a result, patients with end-stage lung disease continue to die while waiting for a transplant.
One way to increase the number of lungs suitable for transplantation is utilizing organs acquired through donation after circulatory determination of death (DCDD). This procedure has not been the norm for lung transplantation in the United States, but advanced transplant centers, such as UPMC, are embracing it with good results. I have been performing lung transplant using DCDD donors for more than six years and brought this expertise to UPMC in October 2017.
DCDD is also referred to as donation from non-heart beating donors or donation after cardiac death, which is a misnomer because the heart itself is still viable. DCDD can be controlled, after withdrawal of lifesustaining cardiorespiratory support, or uncontrolled, after an unexpected and irreversible cardiac arrest. Only controlled DCDD is used for lung donation at UPMC, as is the current policy at most U.S. centers. Controlled DCDD most frequently occurs after withdrawal of life support in patients with a catastrophic brain injury or brain disease. The decision to withdraw cardiopulmonary support must be completely separate from the decision for organ donation. Additionally, the transplant team must not interact with the patient, the patient’s family, or the patient’s caregivers during the care-withdrawal process.
Criteria for Determining DCDD
After support is withdrawn, the patient is monitored for death by circulatory criteria. Most donors (>70%) meet the circulatory criteria for death within 90 minutes of support withdrawal.1 The length of time between support withdrawal and death by circulatory criteria influences whether the donated organs can be transplanted, and depends on organ tolerances for warm ischemia. Organs from controlled DCDD donors are exposed to a greater duration of warm ischemia than those from DBD donors.2 Most clinicians feel comfortable waiting one hour for lung donation, but there is evidence suggesting that longer wait times are still associated with good outcomes.3 After the heart stops beating, there is a five-minute, no-touch period before organ retrieval to ensure that both respiration and consciousness have ceased.2
DCDD is frequent in kidney and liver transplantation but has been uncommon in lung transplantation. This is due in part to the differing logistics and in part to a lack of familiarity with the process within the lung transplant community. Fortunately, the lung transplant community is beginning to adopt DCDD because most patients who become DCDD donors have many qualities that define good lung donors. DCDD is relatively new, but initial results indicate good transplant outcomes.
Standardized Protocols for DCDD
Donors Like all organ transplantation, using DCDD organs requires standardized protocols approved by institutional committees that adhere to national standards set by organ procurement organizations. This ensures fair and ethical care for both donors and recipients. It is very important to remember that the DCDD donors are patients first. Their interests as a patient must take precedence, even if that means foregoing tests or procedures that could benefit the recipient. The testing permitted varies from institution to institution, but institutional procedures should be consistent and transparent. The policies in place at the hospital and the family’s awareness of the donation process play a major role. CT scanning and bronchoscopy are commonly accepted due to their minimally invasive nature. Medications can be given for comfort, but some issues arise with the administration of opioids, which give comfort but can hasten death, or heparin, which improves the quality of the lungs after harvest but can accelerate death in patients with certain conditions. Currently, the consensus views in the United States allow more measures, especially administration of anticoagulants, after the decision to donate has been made.
Occasionally, the lungs acquired through DCDD are placed on ex vivo lung perfusion (EVLP) for evaluation. In our experience, EVLP can aid lung transplant centers with nascent DCDD programs. With EVLP, the transplant team can see the lungs, helping them feel more confident in the safety of transplant. Typically, as the transplant team becomes more experienced, EVLP is used less frequently. Additionally, EVLP may be a particularly useful tool as the lung transplant community examines how much time can pass between withdrawal of support and organ harvest while still allowing good post-transplant outcomes.
Conclusion
There are many potential benefits of lung transplant using DCDD. Extending donation criteria to include DCDD in addition to DBD unlocks a new donor pool and will increase the number of lungs available for transplant. DCDD may also lead to better outcomes after transplantation. From studies to date, we know that outcomes are at least equivalent to those seen with DBD. Potential DCDD donors tend to be younger and in better health prior to the trauma leading to their death as compared to DBD donors.4,5 Additionally, the lungs from DCDD donors may be better than lungs from DBD, because the hormonal disarray generated during brain death is avoided, which may minimize the stress on the lungs.
Because of these potential benefits, some centers worldwide, particularly in Australia, the United Kingdom, and the Netherlands, have been extremely aggressive in recruiting DCDD donors. At transplant centers in these regions, DCDD lungs represent up to one-third of transplanted lungs. The rates of DCDD vary widely from country to country due to differences in medical practice, public attitudes, laws, and resources. In the United States, acquiring 10% of lung allografts by DCDD is considered good. Moreover, increasing the number of lungs available for transplant by 10% is a huge improvement. By adopting DCDD as part of our innovative lung transplant program at UPMC, we have increased the number of high-quality lungs available for transplantation as we continue to challenge the status quo.
References
1 DeVita MA, Brooks MM, Zawistowski C, Rudich S, Daly B, Chaitin E. Donors after cardiac death: validation of identification criteria (DVIC) study for predictors of rapid death. Am J Transplant. 2008;8:432-441.
2 Manara AR, Murphy PG, O’Callaghan G. Donation after circulatory death. Br J Anaesth. 2012;108 Suppl 1:i108-121.
3 Cypel M, Levvey B, Van Raemdonck D, et al. International Society for Heart and Lung Transplantation Donation After Circulatory Death Registry Report. J Heart Lung Transplant. 2015;34:1278-1282.
4 Costa J, Shah L, Robbins H, et al. Use of Lung Allografts From Donation After Cardiac Death Donors: A Single-Center Experience. Ann Thorac Surg. 2018;105:271-278.
5 Sanchez PG, Rouse M, Pratt DL, et al. Lung Donation After Controlled Circulatory Determination of Death: A Review of Current Practices and Outcomes. Transplant Proc. 2015;47:1958-1965.
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