Heart

OPTN/SRTR 2017 Annual Data Report: Heart

Abstract

In 2017, 3273 heart transplants were performed in the United States. New listings continued to increase, and 3769 new adults were listed for heart transplant in 2017. Over the past decade, posttransplant mortality has declined. The number of new pediatric listings increased over the past decade, as did the number of pediatric heart transplants, although some fluctuation has occurred more recently. New listings for pediatric heart transplants increased from 481 in 2007 to 623 in 2017. The number of pediatric heart transplants performed each year increased from 330 in 2007 to 432 in 2017, slightly fewer than in 2016. Short-term and long-term mortality improved. Among pediatric patients who underwent transplant between 2015-2016, 4.8% had died by 6 months and 6.2% by 1 year.

Introduction

The most significant occurrence in heart transplantation in recent years was approval of the new heart allocation policy in 2016 and its implementation in October 2018. This new algorithm attempts to address broader sharing and risk stratification through development of a 6-status system that combines Zone A and donation service area (DSA) as the first point of allocation for higher urgency statuses. This important new development also increased the data that OPTN will collect, with the goal of providing a dynamic policy that can continue to evolve over time. In addition, mechanical circulatory support technology continues to improve, with newer pumps designed to decrease risk of thrombosis. These improvements, if they result in better patient outcomes, will likely affect future heart allocation policy. In this iteration of the annual data report, we review the significant trends in heart transplantation in 2017.

Adult Heart Transplant

Waitlist Trends

Between 2006 and 2017, the number of new active listings for heart transplant increased 49%, from 2424 to 3623 (Figure HR 1). Despite a decline between 2015 and 2017, the number of candidates actively awaiting heart transplant increased dramatically since 2006, from 1243 to 2727 (Figure HR 2), an increase of 119%, suggesting that transplant rates have not increased at the same rate as listings. The most remarkable demographic trends in heart transplantation include the following: a continued increase in the proportion of heart transplant candidates aged 65 years or older to 18.5% in 2017 (Figure HR 3); an increase in the proportion of racial/ethnic minorities, with black candidates comprising 25.5% of patients awaiting heart transplant (Figure HR 5); and a continued increase in patients with non-ischemic cardiomyopathy (Figure HR 6). The proportion of candidates with extended waiting times decreased. In 2006, 15.9% of candidates waited 5 years or more; this proportion gradually declined to 4.1% in 2017 (Figure HR 7). The proportion of candidates awaiting transplant as status 1A increased to 45.0% in 2017 (Figure HR 8). The proportion of status 1B candidates increased similarly, while the proportion waiting as status 2 declined from 29.8% to 15.7%. The proportion of candidates with ventricular assist devices (VADs) at listing increased from 9.1% in 2006 to 32.6% in 2017(Figure HR 9). Sex distribution has not changed (Figure HR 4). In 2017, 85.1% of candidates resided in a metropolitan area (Table HR 1). The number of candidates listed for heart-kidney transplant increased from 69 to 208 between 2007 and 2017, and the proportion of heart-lung candidates declined to 1.2% (Table HR 3). The number of patients receiving circulatory support prior to transplant increased from 1610 in 2012 to 2427 in 2017 (Table HR 6). Of these, 47.6% had left VADs (LVADs), which increased by 594 over the 5-year period. The number of patients receiving IV inotropes increased by 224 and the number of those with intra-aortic balloon pumps (IABPs) increased by 115. The number of patients with extracorporeal membrane oxygenation increased notably, from 15 to 32.

Between 2006 and 2017, heart transplant rates fluctuated, but overall remained the same, 77.2 per 100 waitlist-years (Figure HR 14). The decade low of 61.5 per 100 waitlist-years occurred in 2015, and was followed by an increase; this trend was similar for all age groups, racial/ethnic groups, blood types, and status groups (Figure HR 11, Figure HR 12, Figure HR 13, Figure HR 14). Transplant rates peaked for most groups in 2006 and 2007, and reached a nadir in 2014 and 2015. Transplant rates by age group remained similar, but varied widely by blood type and medical urgency status. By age, 2017 transplant rates were highest for patients aged 65 or older and lowest for those aged 35-49 years, 66.6 per 100 waitlist-years. Between 2006 and 2010, transplant rates were highest for patients aged 18-34 yeas, but this shifted in 2011. Transplant rates have consistently been highest for candidates with blood type AB (208.8 per 100 waitlist-years) and for those listed as status 1A (277.3 per 100 waitlist-years). In 2017, blood type O candidates underwent transplant at a rate of 52.9 per 100 waitlist-years, nearly half the rate of blood type A and B candidates and 25% of the rate of blood type AB candidates. Candidates with blood type A underwent transplant at a rate of 105.7 per 100 waitlist-years, higher than in previous years, and higher than candidates with blood type B. Transplant rates declined substantially for all status groups between 2006 and 2015, but in 2017 appeared to be increasing again. In 2017, candidates residing in non-metropolitan areas underwent transplant at slightly higher rates than those in metropolitan areas, 80.5 per 100 waitlist-years vs. 76.8 (Figure HR 15). Although trends based on candidate distance from the donor hospital have been similar over the past decade, in 2017 candidates residing 150-250 nautical miles (NM) from the donor hospital underwent transplant at the highest rate, 92.8 per 100 waitlist-years, and those residing 100-150 NM away at the lowest rate, 67.2 per 100 waitlist-years (Figure HR 16).

Multiple factors have contributed to the trends in transplant rates over the past decade, and the variations may have been affected by policy changes and by changes in program practices in response to policy changes and evolving mechanical circulatory support. The median waiting time in 2016-2017 was 7.9 months, an increase from 4.0 months in 2006-2007 (Figure HR 18). Waiting times peaked in 2014-2015, then declined again. In 2016-2017, median waiting time was longest for blood type O candidates, 13.8 months (Figure HR 19), and candidates with body mass index ? 31 kg/m², 12.2 months (Figure HR 21). Women waited on average 6.1 months, and men 8.4 months (Figure HR 18). Status 2 candidates had the longest median waiting times, 17.7 months in 2016-2017 (Figure HR 20). Over the past decade, the proportion of candidates undergoing transplant within 1 year of listing declined overall, but appears to be increasing since 2014. Of candidates listed in 2016, 56.3% underwent transplant within 1 year (Figure HR 22). Geographic variability in transplant rates persisted, and in 2017, the proportion of candidates undergoing transplant within 1 year varied from 23.1% to 94.1% depending on DSA (Figure HR 23). Similar variability occurred by state, ranging from 20.0% to 100% (Figure HR 24).

Among candidates listed in 2014, 48.6% underwent transplant during the first year on the waiting list, 33.8% were still waiting, 9.4% were removed from the list, and 8.2% had died (Figure HR 17). At 3 years, 63.1% had undergone transplant, 9.7% were still waiting, 17.4% had been removed from the list, and 9.8% had died. Despite slight increases since 2016 in proportions of patients who were still waiting, who were removed from the list, or who died, most patients undergo transplant within 3 years, and less than 10.0% die on the waiting list. Between 2015 and 2017, fewer patients were removed from the waiting list due to death and more were removed due to undergoing transplant (Table HR 5).

Since 2006-2007, pretransplant mortality declined, from 16.3 to 12 deaths per 100 waitlist-years in 2016-2017 (Figure HR 25). Declines occurred in all age and racial/ethnic groups, with the most notable declines for candidates aged 18-34 years and black and Hispanic candidates (Figure HR 25, Figure HR 26). Pretransplant mortality declined notably for candidates with VADs at listing, from 47.8 to 11.8 deaths per 100 waitlist-years, now making pretransplant mortality nearly identical for candidates with and without VADs at listing (Figure HR 30). Pretransplant mortality rates were highest for candidates listed as status 1A, but declined dramatically since 2005-2006, from 91.9 to 30.4 deaths per 100 waitlist-years (Figure HR 29). Similarly, pretransplant mortality among candidates listed as status 1B declined from 36.3 to 8.1 deaths per 100 waitlist-years. Pretransplant mortality was slightly higher for candidates residing in nonmetropolitan areas than for those in metropolitan areas (Figure HR 31).

Pretransplant mortality varied by DSA from 2.1 to 23.9 deaths per 100 waitlist-years (Figure HR 33). Among candidates removed from the waiting list for reasons other than transplant, 18.4% died within 6 months of removal. The proportion of deaths within 6 months of removal from the waiting list fluctuated over the past decade, peaking at 33.2% in 2013 (Figure HR 34). In 2017, 87 patients died within 6 months of removal from the waiting list. In 2017, 48.5% of candidates listed as status 1A died within 6 months of removal, reflecting the acuity of illness. The percentage of candidates aged 18-34 years who died within 6 months decreased notably, from 21.0% in 2006 to 6.8% in 2017, and the percentage of candidates aged 65 years or older who died within 6 months of removal increased from 20.0% in 2006 to 25.7% in 2017 (Figure HR 35).

Donor Trends

Deceased donor heart donations continued to increase, with 3272 donors in 2017, the highest number to date, and an increase of 45% since 2006. The majority of these, 51.6%, were from donors aged 18-34 years (Figure HR 37), increasing from 1087 in 2007 to 1687 in 2017 (Figure HR 36). The rate of discards reached a nadir of 0.6% between 2008 and 2011 and has trended upward since, with a slight downtrend in 2016-2017 (Figure HR 40). In 2016-2017, 1.0% of recovered hearts were not transplanted. The discard rate was highest among donors age 50 years or older, 2.7%. In 2016-2017, hearts from Public Health Service high-risk donors were discarded at a lower rate, 0.8%, than hearts from donors not considered high risk, 1.1% (Figure HR 41).

The largest proportion of heart donor deaths, 47.1%, were caused by head trauma, despite head trauma declining in prevalence from 63.3% in 2006. Anoxia continued to increase as a cause of death among heart donors, and was 37.2% in 2017 from 14.0% in 2006 (Figure HR 42). While pediatric organs can be donated to adults, the proportion of pediatric hearts transplanted into an adult is low, varying by state from 0% to 1% in 2017 (Figure HR 39).

Overall Trends in Heart Transplant

In 2017, 3273 heart transplants were performed, an increase of 64 since 2016; 432 transplants occurred in pediatric recipients and 2841 in adult recipients (Figure HR 43). Over the past decade, adult heart transplants reached a nadir in 2008, and have been increasing since, while pediatric transplants increased until 2015 and have declined by 28 since (Figure HR 43). The number of heart transplants increased in all age groups, but the distribution increased more for recipients aged 65 years or older (Figure HR 44). Transplants increased in all racial/ethnic groups (Figure HR 46). In 2017, 66.4% of adult heart transplants were performed in candidates listed as status 1A, compared with 44.4% in 2007 (Table HR 8). In 2017, 85.0% of recipients resided in a metropolitan area; 60.4% of recipients lived within 50 miles of the transplant program (Table HR 7). In 2017, 49.4% of recipients had LVADs. Although 25.2% of patients underwent transplant within 31 days of listing in 2017, the proportion who underwent transplant after waiting 1 year or more increased over the past decade: 21.7% in 2017 vs. 11.4% in 2007 (Table HR 9). Dual organ transplant remained a small proportion of heart transplants. The proportion of heart-lung transplants declined from 1.5% to 0.9% between 2007 and 2017, heart-kidney transplants increased to 6.5% from 2.8%, and heart-liver transplants increased from 0.5 to 1.0% (Table HR 9).

Use of induction therapy has changed little since 2006. In 2017, 52.4% of adult heart transplant recipients received either IL2-RA or T-cell depleting therapy (Figure HR 49). In 2017, 95.2% of recipients received a tacrolimus-based immunosuppression regimen, while 3.6% received other regimens (Figure HR 50).

Transplant program volume has increased since 2006, with 50% of programs performing at least 20 transplants per year in 2017 (Figure HR 53). In 2006, the median volume was 12 transplants per year. The proportion of transplants performed at higher- and lower-volume programs has shifted since 2006. In 2006, 10.8% of heart transplants were performed at programs with fewer than 10 transplants per year, compared with 3.6% in 2017. In contrast, 15.0% of transplants in 2006 were performed at programs with 60 or more transplants per year, compared with 21.1% in 2017 (Figure HR 54).

Posttransplant Survival and Morbidity

Overall 1-year survival for patients who underwent heart transplant in 2010-2012 was 90.5%, 3-year survival was 84.1%, and 5-year survival was 79.1% (Figure HR 57). One-year survival in most subgroups was similar, but tended to be lower among recipients aged 65 years or older (Figure HR 55) and black recipients (Figure HR 56). Asian recipients tended to have better survival at all time points. Survival at 1, 3, and 5 years was similar between recipients with VADs and those without circulatory support; however, survival was lower at 1, 3, and 5 years for recipients with IABPs, 88.4%, 80.4%, and 75.0%, respectively. This reduction in survival for patients with IABPs occurred as early as 1 month posttransplant (Figure HR 58). Survival among new transplants and re-transplants was similar, except at 5 years, when survival was slightly better for recipients undergoing re-transplant, 83.1% vs. 79.1% (Figure HR 59). Survival was lower for recipients in non-metropolitan areas than for those in metropolitan areas (Figure HR 61). Finally, while recipients residing 250 miles or farther from the transplant program fared similarly to other recipients early after transplant, at 1, 3, and 5 years, their survival tended to be lower compared with survival of recipients living closer to the transplant program. Five-year survival in this group was 74.2%, lowest of all groups, followed by black recipients and recipients with IABPs (Figure HR 62). Since 2006, patient death after transplant has decreased overall at 6 months and at 1, 3, and 5 years, despite slight increases between 2011 and 2014 (Figure HR 63). The number of heart transplant survivors has increased by approximately 10,000 since 2006. On June 30, 2017, 32,210 heart transplant recipients were alive with a functioning graft. Most survivors had undergone transplant at age 50 years or older (Figure HR 64).

The incidence of acute rejection in the first year posttransplant was 25.4% for recipients undergoing transplant in 2015-2016 (Figure HR 65). Posttransplant lymphoproliferative disorder (PTLD) remained uncommon, with an overall cumulative incidence of only 1.1% by 5 years posttransplant (Figure HR 67). The incidence was comparatively higher in recipients who were Epstein-Barre virus (EBV) seronegative, 1.1%, 1.9%, and 2.6% at 1, 3, and 5 years, respectively. The most common documented cause of death in the first posttransplant year was infection (Figure HR 68); however, by the second year, cardiovascular/cerebrovascular disease emerged as the leading documented cause of death through year 5 (Figure HR 69). Malignancy was a relatively infrequent cause of death, 1.4% of deaths at 5 years.

Pediatric Heart Transplant

Pediatric Waitlist Trends

In 2017, 623 new pediatric candidates were added to the heart transplant waiting list, with few at inactive status (Figure HR 70). At year-end 2017, 384 candidates listed before their eighteenth birthdays were awaiting heart transplant, 68.0% active (Figure HR 71). Over the past decade, the number of candidates with inactive status at year-end decreased from 164 in 2007 to 123 in 2017. The largest pediatric age group on the waiting list in 2017 was ages 11-17 years (34.4%), followed by ages younger than 1 year (27.0%), 1-5 years (24.8%), and 6-10 years (13.7%) (Figure HR 72). Almost half of heart transplant candidates were white, 21.5% were Hispanic, 21.4% were black, and 4.4% were Asian (Figure HR 73). Considering trends over time, the proportion of waitlist candidates aged younger than 1 year increased from 9.6% on December 31, 2007, to 13.5% on December 31, 2017; the proportion of candidates aged 6-10 years decreased from 23.7% to 16.7% over the same time period (Table HR 11). The proportion of white candidates decreased from 61.4% on December 31, 2007, to 47.7% on December 31, 2017. For candidates waiting on December 31, 2017, congenital defect was the leading cause of heart disease (57.5%), increased from 45.0% in 2007 (Table HR 12). The proportion of status 1B candidates increased from 9.2% in 2007 to 20.7% in 2017. The differences in status 1A and 1B listing percentages are likely due in part to changes to pediatric heart allocation policy implemented in 2016. The percentage of candidates using VADs at the time of listing increased from 2.8% in 2007 to 8.0% in 2017 (Table HR 12). Proportions of heart-only candidates increased from 91.2% at year-end 2007 to 98.9% at year-end 2017 (Table HR 13). Among the 606 candidates removed from the waiting list in 2017 (Table HR 14), 444 (73.3%) were removed due to undergoing transplant, 67 (11.1%) died, 54 (8.9%) were removed due to improved condition, and 28 (4.6%) were considered too sick to undergo transplant (Table HR 15).

Just over 70% of candidates newly listed in 2014 underwent transplant within 3 years, 12.1% died, 11.1% were removed from the list, and 5.1% were still waiting (Figure HR 78). The rate of heart transplants among pediatric waitlist candidates was 114.9 per 100 waitlist-years in 2017 (Figure HR 79). Transplant rates varied by age; rates were highest for candidates aged younger than 1 year, at 192.0 transplants per 100 waitlist-years in 2017, followed by candidates aged 11-17 years, at 119.3 transplants per 100 waitlist-years (Figure HR 79). Pretransplant mortality decreased by half over the past decade; 23.5 deaths per 100 waitlist-years in 2006-2007 to 11.9 deaths per 100 waitlist-years in 2016-2017 (Figure HR 82). By age, pretransplant mortality rates were highest for candidates aged younger than 1 year, at 41.2 deaths per 100 waitlist-years in 2016-2017. Rates were 7.2 deaths per 100 waitlist-years for candidates aged 1-5 years, 5.1 for ages 6-10 years, and 7.6 for ages 11-17 years (Figure HR 82). By medical urgency status, pretransplant mortality was highest for status 1A (40.3 deaths per 100 waitlist-years) and 1B (15.0) candidates, compared with 5.5 for status 2 candidates (Figure HR 85).

Pediatric Trends in Heart Transplant

Pediatric transplant recipients are defined as those aged 18 years or younger at the time of transplant. The number of pediatric heart transplants performed each year increased from 321 in 2006 to 432 in 2017 (Figure HR 88). In 2017, 27 of 136 total heart transplant programs performed pediatric heart transplants exclusively, 86 performed adult heart transplants, and 23 performed both adult and pediatric heart transplants (Figure HR 89). In 2017, 9.3% of transplants in recipients aged younger than 10 years were performed at programs with volume of five or fewer pediatric transplants in that year (Figure HR 90). Over the past decade, the age and sex of pediatric heart transplant recipients changed little (Table HR 16).The proportion of recipients who were white or black decreased and the proportion who were Hispanic increased (Table HR 16). Congenital defects remained the most common primary cause of disease, affecting 49.4% of recipients who underwent transplant in 2015-2017 (Table HR 17). The proportion of patients who underwent transplant as status 1A increased from 74.8% in 2005-2007 to 82.9% in 2015-2017. VAD use doubled from 12.8% of transplant recipients in 2005-2007 to 25.0% in 2015-2017 (Table HR 17). The proportion of ABO-incompatible transplants in 2015-2017 was 7.5%, increased from 3.1% a decade earlier (Table HR 18).

In 2017, use of T-cell depleting agents for induction continued to increase, to 72.0% of heart transplant recipients; use of interleukin-2 receptor antagonists decreased to 9.4% (Figure HR 91). The initial immunosuppression regimen used most commonly in 2017 was tacrolimus, mycophenolate (MMF), and steroid (54.2%), followed by tacrolimus and MMF in 37.5% (Figure HR 92).

Pediatric Posttransplant Survival and Morbidity

Among pediatric heart transplant recipients 2015-2016, the rate of acute rejection in the first year was 19.3% overall; the highest rate observed was 21.7% in the 6-10 year age group, and the lowest 17.5% in recipients aged younger than 6 years (Figure HR 96). Among pediatric heart transplant recipients 2013-2017, 60.6% were cytomegalovirus (CMV) negative and 43.8% were EBV negative (Table HR 20). The combination of a CMV-positive donor and CMV-negative recipient occurred in 28.5% of transplants; for EBV, this combination occurred in 27.9% of transplants (Table HR 20).

Recipient death occurred in 4.8% of patients at 6 months posttransplant and in 6.2% at 1 year posttransplant among heart transplants performed in 2015-2016, in 12.0% at 3 years post-transplant for transplants performed in 2013-2014, in 15.2% at 5 years posttransplant for transplants performed in 2011-2012, and in 28.8% at 10 years posttransplant for transplants performed in 2007-2008 (Figure HR 98). Overall, 1-year and 5-year patient survival were 89.8% and 80.1%, respectively, among recipients who underwent transplant in 2005-2012 (Figure HR 99). By age, 5-year patient survival was 75.3% for recipients aged younger than 1 year, 81.5% for ages 1-5 years, 87.7% for ages 6-10 years, and 80.4% for ages 11-17 years (Figure HR 99). The leading identified causes of death in the first 12 months posttransplant were graft failure (1.5%) and cardio/cerebrovascular disease (1.5%) (Figure HR 100). At 5 years posttransplant, the leading causes were cardio/cerebrovascular disease (3.5%) and graft failure (3.5%) (Figure HR 101).

The overall incidence of PTLD was 4.0% at 5 years posttransplant, with 5.5% among EBV-negative recipients and 2.7% among EBV-positive recipients (Figure HR 97).

Figure List

Waiting list

Deceased donation

Figure HR 36. Deceased heart donor count by age
Figure HR 37. Distribution of deceased heart donors by age
Figure HR 38. Distribution of deceased heart donors by race
Figure HR 39. Percent of pediatric heart donors allocated to adult recipients
Figure HR 40. Rates of hearts recovered for transplant and not transplanted by donor age
Figure HR 41. Rates of hearts recovered for transplant and not transplanted, by donor risk of disease transmission
Figure HR 42. Cause of death among deceased heart donors

Transplant

Figure HR 43. Total heart transplants
Figure HR 44. Total heart transplants by age
Figure HR 45. Total heart transplants by sex
Figure HR 46. Total heart transplants by race
Figure HR 47. Total heart transplants by diagnosis
Figure HR 48. Total heart transplants by medical urgency
Figure HR 49. Induction agent use in adult heart transplant recipients
Figure HR 50. Immunosuppression regimen use in adult heart transplant recipients
Figure HR 51. Total HLA A, B, and DR mismatches among adult deceased donor heart transplant recipients, 2013-2017
Figure HR 52. Status of adult heart transplant recipients, 2015-2017, by age
Figure HR 53. Annual adult heart transplant center volumes, by percentile
Figure HR 54. Distribution of adult heart transplants by annual center volume

Outcomes

Pediatric transplant

Table List