Thoracic organ transplantation in the United States, 1994–2003

Using OPTN/SRTR data, this article reviews the state of thoracic organ transplantation in 2003 and the previous decade. Time spent on the heart waiting list has increased significantly over the last decade. The percentage of patients awaiting heart transplantation for >2 years increased from 23% in 1994 to 49% by 2003. However, there has been a general decline in heart waiting list death rates over the decade. In 2003, the lung transplant waiting list reached a record high of 3,836 registrants, up slightly from 2002 and more than threefold since 1994. One-year patient survival for those receiving lungs in 2002 was 82%, a statistically significant improvement from 2001 (78%). The number of patients awaiting a heart-lung transplant, declining since 1998, reached 189 in 2003. Adjusted patient survival for heart-lung recipients is consistently worse than the corresponding rate for isolated lung recipients, primarily due to worse outcomes for heart-lung recipients with congenital heart disease. A new lung allocation system, approved in June 2004, derives from the survival benefit of transplantation with consideration of urgency based on waiting list survival, instead of being based solely on waiting time. A goal of the policy is to minimize deaths on the waiting list.     

Thoracic Organ Transplantation in the United States, 1995–2004

This article reviews trends in thoracic organ transplantation based on OPTN/SRTR data from 1995 to 2004. The number of active waiting list patients for heart transplants continues to decline, primarily because there are fewer patients with coronary artery disease listed for transplantation. Waiting times for heart transplantation have decreased, and waiting list deaths also have declined, from 259 per 1000 patient-years at risk in 1995 to 156 in 2004. Fewer heart transplants were performed in 2004 than in 1995, but adjusted patient survival increased to 88% at 1 year and 73% at 5 years. Emphysema, idiopathic pulmonary fibrosis and cystic fibrosis were the most common indications among lung transplant recipients in 2004. Waiting time for lung transplantation decreased between 1999 and 2004. Waiting list mortality decreased to 134 per 1000 patient-years at risk in 2004. One-year survival following transplantation has improved significantly in the past decade. The number of combined heart-lung transplants performed in the United States remains low, with only 39 performed in 2004. Overall unadjusted survival, at 58% at 1 year and 40% at 5 years, is lower among heart-lung recipients than among either heart or lung recipients alone.     

Pediatric transplantation, 1994–2003

This article uses OPTN/SRTR data to review trends in pediatric transplantation over the last decade. In 2003, children younger than 18 made up 3% of the 82,885 candidates for organ transplantation and 7% of the 25,469 organ transplant recipients. Children accounted for 14% of the 6,455 deceased organ donors. Pediatric organ transplant recipients differ from their adult counterparts in several important aspects, including the underlying etiology of organ failure, the complexity of the surgical procedures, the pharmacokinetic properties of common immunosuppressants, the immune response following transplantation, the number and degree of comorbid conditions, and the susceptibility to post-transplant complications, especially infectious diseases. Specialized pediatric organ transplant programs have been developed to address these special problems, The transplant community has responded to the particular needs of children and has provided them special consideration in the allocation of deceased donor organs. As a result of these programs and protocols, children are now frequently the most successful recipients of organ transplantation; their outcomes following kidney, liver, and heart transplantation rank among the best. This article demonstrates that substantial improvement is needed in several areas: adolescent outcomes, outcomes following intestine transplants, and waiting list mortality among pediatric heart and lung candidates,     

Liver and intestine transplantation: summary analysis, 1994–2003

With nearly two years of data available since the inception of the MELD and PELD allocation system, this article examines national OPTN/SRTR data to describe trends in waiting list composition, waiting list mortality, transplant rates, and patient and graft outcomes for liver transplantation.
Following a 6% reduction in the size of the waiting list after MELD was implemented in 2002, the number of patients on the waiting list grew by 2% from 2002 to 2003, while the number of liver transplants increased by 6%. The overall death rate while on the liver waiting list has decreased from 225 deaths per 1,000 patient years in 1994 to 124 deaths in 2003. As with the waiting list death rates, post-transplant death rates have also decreased over the past decade. Unadjusted one-year patient survival was lower for older donor age groups (88% for donors aged 18–34, 87% for donors aged 35–49, 85% for donors aged 50-64); a similar trend was observed at three and five years following transplantation.
Intestine transplantation is performed with slowly increasing frequency and success. Early graft losses and rejection rates have changed little since 1994, but rejection is easier to control and long-term survival is improving.     

Heart and Lung Transplantation in the United States, 1996–2005

This article examines the Organ Procurement and Transplantation Network/Scientific Registry of Transplant Recipients data on heart and lung transplantation in the United States from 1996 to 2005. The number of heart transplants performed and the size of the heart waiting list continued to drop, reaching 2126 and 1334, respectively, in 2005. Over the decade, post-transplant graft and patient survival improved, as did the chances for survival while on the heart waiting list. The number of deceased donor lung transplants increased by 78% since 1996, reaching 1407 in 2005 (up 22% from 2004). There were 3170 registrants awaiting lung transplantation at the end of 2005, down 18% from 2004. Death rates for both candidates and recipients have been dropping, as has the time spent waiting for a lung transplant. Other lung topics covered are living donation, recent surgical advances and changes in immunosuppression regimens. Heart-lung transplantation has declined to a small (33 procedures in 2005) but important need in the United States.     

Pediatric transplantation

Analysis of the OPTN/SRTR database demonstrates that, in 2002, pediatric recipients accounted for 7% of all recipients, while pediatric individuals accounted for 14% of deceased organ donors. For children fortunate enough to receive a transplant, there has been continued improvement in outcomes following all forms of transplantation. Current 1-year graft survival is generally excellent, with survival rates following transplantation in many cases equaling or exceeding those of all other recipients. In renal transplantation, despite excellent early graft survival, there is evidence that long-term graft survival for adolescent recipients is well below that of other recipients. A causative role for noncompliance is possible. While the significant improvements in graft and patient survival are laudable, waiting list mortality remains excessive. Pediatric candidates awaiting liver, intestine, and thoracic transplantation face mortality rates generally greater than those of their adult counterparts. This finding is particularly pronounced in patients aged 5 years and younger. While mortality awaiting transplantation is an important consideration in refining organ allocation strategies, it is important to realize that other issues, in addition to mortality, are critical for children. Consideration of the impact of end-stage organ disease on growth and development is often equally important, both while awaiting and after transplantation.     

Heart and Heart-Lung Transplantation: Standards and Improvements

Standards and new developments of thoracic organ transplantation are reviewed with particular focus on current treatment strategies, alternatives to transplantation, and xenotransplantation. The current indications for heart, single and bilateral sequential lung, and heart-lung transplantation as well as the technical aspects of each procedure are presented. Criteria for transplant recipients and absolute and relative contraindications are pointed out. Criteria for donor selection are also reviewed. The results of single, double-sequential, and heart-lung transplantation over the past 10 years as reported by the International Society for Heart and Lung Transplantation Database are stated. In addition, the experience of the lung and heart-lung transplantation program at the Hannover Medical School is reviewed, including the current immunosuppression regimens. This experience includes 1075 heart,heart-lung, and lung transplantations since 1983. The 1- and 5-year actuarial survival rates for heart transplant recipients are 81% and 70%, for heart-lung recipients 76% and 61%, and for single and double lung transplant recipients 77% and 59%, respectively. During the past decade there has been continuous improvement in the results of heart, lung, and heart-lung transplantation. Alternatives to thoracic organ transplantation, living-related lobar transplantation, new antirejection agents, and xenograft transplantation are areas for continuing and future investigation.     

Heart and Lung Transplantation in the United States, 1997–2006

This article highlights trends in heart and lung transplantation between 1997 and 2006, drawing on data from the OPTN and SRTR. The total number of candidates actively awaiting heart transplantation declined by 45% over the last decade, dropping from 2414 patients in 1997 to 1327 patients in 2006. The overall death rates among patients awaiting heart transplantation declined over the same period. The distribution of recipients among the different status groups at the time of heart transplantation changed little between the inception of the new classification system in 1999 and 2005. Deaths in the first year after heart transplantation have steadily decreased. At the end of 2006, 2885 candidates were awaiting a lung transplant, up 10% from the 1997 count. The median time-to-transplant for listed patients decreased by 87% over the decade, dropping from 1053 days in 1997 to 132 days in 2006. Selection for listing and transplantation has shifted toward more urgent patients since the May 2005 implementation of a new lung allocation system based on survival benefit and urgency rather than waiting time. Only 31 heart-lung transplants were performed in 2006, down from a high of 62 in 1997.     

Lung and Heart Allocation in the United States

Lung and heart allocation in the United States has evolved over the past 20–30 years to better serve transplant candidates and improve organ utilization. The current lung allocation policy, based on the Lung Allocation Score, attempts to take into account risk of death on the waiting list and chance of survival posttransplant. This policy is flexible and can be adjusted to improve the predictive ability of the score. Similarly, in response to the changing clinical phenotype of heart transplant candidates, heart allocation policies have evolved to a multitiered algorithm that attempts to prioritize organs to the most infirm, a designation that fluctuates with trends in therapy. The Organ Procurement and Transplantation Network and its committees have been responsive, as demonstrated by recent modifications to pediatric heart allocation and mechanical circulatory support policies and by ongoing efforts to ensure that heart allocation policies are equitable and current. Here we examine the development of US lung and heart allocation policy, evaluate the application of the current policy on clinical practice and explore future directions for lung and heart allocation.     

Time-to-Event Modeling of Competing Risks With Intervening States in Transplantation

The criteria for the selection of who among the persons on the waiting is to receive an organ that has become available and who is to be placed on the list to begin with are the most contentious issues in organ transplantation. The decisions of whom to list and whom to transplant should take into account the net benefit to the individual patient and to the affected group as a whole. We present a method to compute the survival benefit by means of fully parametric modeling of the competing events (transplantation, death while awaiting the transplant, removal for other reasons), taking into account the transplant as an intervening state on the path to death post-transplant, and apply it to decisions whether to list or not list and whether to transplant or to leave on the waiting list or to remove from the list. The data were obtained from the Organ Procurement and Transplantation Network. They describe the outcomes of listings in January, 1996 through June, 1999, with a follow up of at least 1 year possible for all cases. The models produce estimates of event probabilities that accord well with the observed probabilities and predictions of the survival benefit due to transplantation that range from small negative values to increases in survival probability of 20-40% points in liver and heart transplantation, with the larger benefits generally seen in the more severely ill transplant candidates. These estimates are stable under variations of case mix, as ascertained by bootstrap analysis. The survival benefit of alternative actions can be calculated for the complex circumstances encountered clinically - competing sequential events whose probability evolves over time. The range and stability of the estimates are sufficient to permit the use of this measure to rank candidates for listing and for transplantation.     

Pediatric heart allocation and transplantation in Eurotransplant

Pediatric heart allocation in Eurotransplant (ET) has evolved over the past decades to better serve patients and improve utilization. Pediatric heart transplants (HT) account for 6% of the annual transplant volume in ET. Death rates on the pediatric heart transplant waiting list have decreased over the years, from 25% in 1997 to 18% in 2011. Within the first year after listing, 32% of all infants (<12 months), 20% of all children aged 1–10 years, and 15% of all children aged 11–15 years died without having received a heart transplant. Survival after transplantation improved over the years, and in almost a decade, the 1‐year survival went from 83% to 89%, and the 3‐year rates increased from 81% to 85%. Improved medical management of heart failure patients and the availability of mechanical support for children have significantly improved the prospects for children on the heart transplant waiting list.     

Use of extracorporeal membrane oxygenation in pediatric thoracic organ transplantation.

OBJECTIVE: Mechanical cardiorespiratory support is occasionally required before or after pediatric thoracic organ transplantation. Extracorporeal membrane oxygenation is the most commonly used mechanical support technique in children. The goal of this study was to examine the indications for initiation and outcomes after peritransplant use of extracorporeal membrane oxygenation. METHODS: A retrospective study was conducted of 65 patients who received peritransplant extracorporeal membrane oxygenation between November 1994 and June 2000. The pretransplant group included 45 patients (average age, 38 months) supported with extracorporeal membrane oxygenation and listed for transplantation (31 heart, 8 lung, and 6 heart-lung), and the post-transplant group included 20 patients (average age, 83 months) who required extracorporeal membrane oxygenation after thoracic organ transplantation (12 heart, 6 lung, and 2 heart-lung transplants). Hospital course and outcomes were evaluated. RESULTS: With regard to pretransplant extracorporeal membrane oxygenation, patients listed for heart transplants were more likely to survive to transplantation than were those listed for lung or heart-lung transplants (12/31 [39%] vs 1/14 [7%], P =.03). There was no difference in long-term survival between heart transplant patients after extracorporeal membrane oxygenation and those without extracorporeal membrane oxygenation (12-month actuarial survival, 83% vs 73%; P =.68). Patients who survived for prolonged periods on extracorporeal membrane oxygenation (>250 hours) typically received heart transplants (7/8 [88%]). With regard to post-transplant extracorporeal membrane oxygenation, patients receiving lung or heart-lung transplants had better short-term outcomes than those receiving heart transplants (63% survived to discharge vs 33%). All 3 patients with early graft dysfunction receiving lung transplants survived to discharge. CONCLUSIONS: Long-term outcomes among those undergoing heart transplantation after support with an extracorporeal membrane oxygenator are comparable with those of patients not receiving extracorporeal membrane oxygenation. Extracorporeal membrane oxygenation can be a useful post-transplant support device, particularly in patients undergoing lung transplants.     

A change of heart: Preliminary results of the US 2018 adult heart allocation revision

In 2018, the Organ Procurement and Transplantation Network (OPTN) modified adult heart allocation to better stratify candidates and provide broader access to the most medically urgent candidates. We analyzed OPTN data that included waiting list and transplant characteristics, geographical distribution, and early outcomes 1 year before (pre: October 18, 2017‐October 17, 2018) and following (post: October 18, 2018‐October 17, 2019) implementation. The number of adult heart transplants increased from 2954 pre‐ to 3032 postimplementation. Seventy‐eight percent of transplants in the post era were for the most medically urgent (statuses 1‐3) compared to 68% for status 1A in the pre era. The median distance between the donor hospital and transplant center increased from 83 to 216 nautical miles, with an increase in total ischemic time from 3 to 3.4 hours (all P < .001). Waiting list mortality was not different across eras (14.8 vs 14.9 deaths per 100 patient‐years pre vs post respectively). Posttransplant patient survival was not different, 93.6% pre and 92.8% post. There is early evidence that the heart allocation policy has enhanced stratification of candidates by their medical urgency and broader distribution for the most medically urgent candidates with minimal impact on overall waiting list mortality and posttransplant outcomes.     

Kidney and pancreas transplantation

Data from the Scientific Registry of Transplant Recipients offer a unique and comprehensive view of US trends in kidney and pancreas waiting list characteristics and outcomes, transplant recipient and donor characteristics, and patient and allograft survival. Important findings from our review of developments during 2002 and the decade's transplantation trends appear below.
The kidney waiting list has continued to grow, increasing from 47 830 in 2001 to 50 855 in 2002. This growth has occurred despite the increasing importance of living donor transplantation, which rose from 28% of total kidney transplants in 1993 to 43% in 2002.
Policies and procedures to expedite the allocation of expanded criteria donor (ECD) kidneys were developed and implemented during 2002, when 15% of deceased donor transplants were performed with ECD kidneys. Unadjusted 1- and 5-year deceased donor kidney allograft survivals were 81% and 51% for ECD kidney recipients, and 90% and 68% for non-ECD kidney recipients, respectively.
Although more patients have been placed on the simultaneous kidney-pancreas waiting list, the number of these transplants dropped from a peak of 970 in 1998 to 905 in 2002. This decline may be due to competition for organs from increasing numbers of isolated pancreas and islet transplants.     

Liver and intestine transplantation

The most significant development in liver transplantation in the USA over the past year was the full implementation of the MELD- and PELD-based allocation policy in March 2002, which shifted emphasis from waiting time within broad medical urgency status to prioritization by risk of waiting list death. The implementation of this system has led to a decrease in pretransplant mortality without increasing post-transplant mortality, despite a higher severity of illness at the time of transplant.
The trend over the last few years of rapidly increasing numbers of adult living donor liver transplants was reversed in 2002 by a decline of more than 30% in the number of these procedures. In 2002, a greater percentage of women received livers from living donors (43%) than deceased donors (34%), possibly because of size considerations.
From 1993 to 2001, the waiting list increased more than sixfold, from 2902 patients to 18 047 patients. For the first time since 1993, the waiting list size decreased in 2002, dropping 6% to 16 974 candidates. The percentage of temporarily inactive liver candidates also increased from 2001, thus the net decrease in the active waiting list for 2002 was 12%. This may reflect a trend toward less pre-emptive listing practices under MELD.
Intestine transplantation remains a low-volume procedure limited to a few transplant centers and is still accompanied by significant pre- and post-transplantation risks. As this procedure matures, its application may increase to include recipients at an earlier stage of their disease with better likelihood of success.     

The Survival Benefit of Liver Transplantation

Demand for liver transplantation continues to exceed donor organ supply. Comparing recipient survival to that of comparable candidates without a transplant can improve understanding of transplant survival benefit. Waiting list and post-transplant mortality was studied among a cohort of 12 996 adult patients placed on the waiting list between 2001 and 2003. Time-dependent Cox regression models were fitted to determine relative mortality rates for candidates and recipients. Overall, deceased donor transplant recipients had a 79% lower mortality risk than candidates (HR = 0.21; p < 0.001). At Model for End-stage Liver Disease (MELD) 18-20, mortality risk was 38% lower (p < 0.01) among recipients compared to candidates. Survival benefit increased with increasing MELD score; at the maximum score of 40, recipient mortality risk was 96% lower than that for candidates (p < 0.001). In contrast, at lower MELD scores, recipient mortality risk during the first post-transplant year was much higher than for candidates (HR = 3.64 at MELD 6-11, HR = 2.35 at MELD 12-14; both p < 0.001). Liver transplant survival benefit at 1 year is concentrated among patients at higher risk of pre-transplant death. Futile transplants among severely ill patients are not identified under current practice. With 1 year post-transplant follow-up, patients at lower risk of pre-transplant death do not have a demonstrable survival benefit from liver transplant.     

Effects of drug abuse,smoking and alcohol on donor hearts and lungs

Potential heart and lung donors with a history of illicit drugs and/or smoking and alcohol are frequently offered, though there is no clear guidance on when it is safe to use these organs. A review of the literature on effects of drugs, alcohol and smoking on donor outcomes, and the effects of these on the intact heart and lung was undertaken. There has been a marked increase in deaths from opioid abuse in many developed countries, though recent evidence suggests that outcomes after cardiothoracic transplantation are equivalent to nonopioid donor causes of death. For donor smoking, there is an increased risk with lung transplantation; however, that risk is less when compared to further waiting on the transplant list for a nonsmoking alternative. Heavy alcohol consumption does not adversely affect heart transplantation, and there is no clear evidence of adverse outcomes after lung transplantation. There are no overall effects of cannabis or cocaine on survival after heart or lung transplantation. In all these cases, careful donor assessment can establish if a particular organ can be used. In most cases, use of drugs requires careful assessment, but is not in of itself a contraindication to cardiothoracic transplantation.     

Kidney and Pancreas Transplantation in the United States, 1995–2004

This article examines OPTN/SRTR data on kidney and pancreas transplantation for 2004 and the previous decade, and discusses recent changes in kidney-pancreas (KP) allocation policy and emerging issues in kidney donation after cardiac death (DCD). Although the number of kidney donors continues to increase, new waiting list registrations again outpaced the number of kidney transplants performed, rising by 11% between 2003 and 2004 and contributing to a 1-year increase of 8% in the number of patients active on the waiting list. DCD has increased steadily since 2000; 39% more DCD transplants were performed in 2004 than 2003. Both deceased donor and living donor kidney graft survival rates remain excellent and are improving. The number of people living with a functioning kidney transplant doubled between 1995 and 2004, to 101 440 with a functioning kidney-alone and 7213 with a functioning KP. Health care providers in all settings are more likely to be exposed to these transplant recipients. Patient survival following simultaneous pancreas-kidney (SPK) transplantation is excellent and has improved incrementally since 1995; death rates in the first year fell from 60 per 1000 patient-years at risk in 2001 to 45 in 2003. The number of solitary pancreas transplants increased dramatically in 2004.     

Lung transplant waiting list: differential outcome of type of end-stage lung disease, one year after registration.

BACKGROUND: Donor lung scarcity, distinct natural courses of the different types of end-stage lung diseases, and lung allocation schemes demand appropriate candidate acceptance for a lung transplant and time of listing. This study was undertaken to investigate the association between type of end-stage lung disease and outcome, 1 year after a lung transplant candidate was put on the waiting list. METHODS: From 1990 to 1995, 1376 adult patients were registered for a first lung (n = 1006) or heart-lung (n = 370) transplantation in Eurotransplant. All patients were followed for at least 1 year. For each type of end-stage lung disease (cystic fibrosis, pulmonary fibrosis, emphysema, pulmonary hypertension, congenital heart disease, and other), chances of transplantation, of death on the waiting list, and of removal for other reasons, 1 year after listing, were calculated with the competing risks method. A multivariate Cox regression model was used to assess the influence of the type of end-stage lung disease on the waiting list outflow among other prognostic variables. RESULTS: Lung transplant candidates with emphysema and with pulmonary fibrosis had the highest chance of a transplant; however, patients with pulmonary fibrosis had also the highest probability of dying while waiting, while the emphysema patients and those with the type "other" had the lowest probability. In the multivariate analysis, the type of end-stage lung disease appeared as an independent prognostic factor for both outcomes. Compared to the patients with cystic fibrosis (reference group), only patients with pulmonary fibrosis had a significantly higher chance of a transplant (RR = 1.50); the lowest chance of death for the emphysema and the "other" patients was confirmed (RR = 0.53 and RR = 0.51, respectively). Recipient size, ABO blood group, country and epoch of listing also had a significant impact on the transplant chance, while country of listing and recipient age were the other factors independently influencing the chance of dying on the waiting list. On the heart-lung waiting list, the type of end-stage lung disease solely affected the chance of death prior to transplant. Compared with cystic fibrosis, pulmonary fibrosis had a significantly higher risk (RR = 2.93), closely followed by pulmonary hypertension (RR = 2.57). Factors crucial for the chance of a heart-lung transplant were recipient size, ABO blood group and country of listing. CONCLUSIONS: The type of end-stage lung disease is a distinctive factor for predicting survival on the lung and heart-lung transplant waiting list, and should be taken into account whenever assessing waiting list outcomes. When developing lung allocation schemes, it is medically justified to incorporate the type of end-stage lung disease.