The data analyzed cover the clinical characteristics of recipients and donors, surgical procedures, immunosuppression, and mortality in the 18 active heart transplant programs in Spain (Table 1). Of the participating centers, 6 carry out pediatric heart transplants, 2 of them exclusively, and 2 of the centers carry out combined heart-lung transplants. The numbers of procedures performed since the first use of this therapeutic modality are summarized in Figure 1. Since 1984, 8173 heart transplant procedures have been carried out in Spain. The types of procedures performed in the whole series are summarized in Table 2.

Figure 1.

Yearly number of transplant procedures performed (1984-2017), in the total series and by age group.

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The present report analyzes results from the past 10 years (2008-2017). To analyze time trends, most results were grouped into 3-year transplant periods (2008-2010, 2011-2013, and 2014-2016). The percentage of urgent transplants, the type of circulatory support, and donor age were analyzed by year of transplant.

The database structure and RETC practices concerning data collection, data handling, auditing, and data protection have been described previously.2 An effort has been made to present statistical data from before 2017 in a format consistent with previous studies; however, the process of continually updating the registry database may have led to the introduction of minor discrepancies in decimals. Nevertheless, any such minor discrepancies do not significantly affect the trends in proportions shown with this same updating procedure, which reveals large changes in pretransplant circulatory support (Figure 2).

Figure 2.

Type of pretransplant circulatory support used by year (2008-2017). ECMO, extracorporeal membrane oxygenation; VAD, ventricular assist device.

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Continuous variables are expressed as mean±standard deviation, and categorical variables as as percentages. Between-group differences in categorical variables were analyzed by the Kendall tau nonparametric test for a time series trend, whereas between-group differences in continuous variables were examined by analysis of variance with polynomial adjustment. Survival curves were calculated using the Kaplan-Meier method and were compared by the log-rank test. Differences were considered statistically significant at P <.05.

The main recipient characteristics by 3-year transplant period are summarized in Table 3. In 2017, there were 304 transplant procedures, 23 (7.6%) of them in recipients younger than 16 years. Approximately 3 of every 4 recipients were men, and mean recipient age was 48.5 (range, 0.05-73.0) years. The mean age of adult recipients was 51.8 years. Most procedures were de novo heart-only transplants (97%), with retransplants and combined transplants accounting for less than 3% of the total. Most combined transplant procedures were heart and lung or heart and kidney. These rates have remained largely unaltered since 2008.

Since 2008, there have been statistically significant trends toward lower pulmonary resistance (P <.001), increased percentages of recipients with diabetes (P <.001) and a history of cardiac surgery before transplant (P <.025), and a lower percentage of recipients receiving mechanical ventilation at the time of transplant (P <.04). Over the same period, there was an appreciable but nonsignificant trend toward an increase in the number of recipients with obstructive pulmonary disease (P <.10).

In 2017, 44% of transplant procedures were urgent (Figure 3), and 39.1% of transplant recipients received pretransplant circulatory support. Compared with previous years, there was a higher use of continuous-flow ventricular assist devices, with a marked reduction in the use of balloon pump counterpulsation. There were no changes in the use of extracorporeal membrane oxygenation (ECMO) and pulsatile-flow ventricular assist devices (Figure 2).

Figure 3.

Percentage of urgent transplant procedures performed by year in the total series (2008-2017).

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Donor characteristics for the 3-year transplant periods and for 2017 are summarized in Table 4. The trend toward a higher mean donor age continued in 2017, with donors older than 45 years now accounting for 60% of the total (Figure 4). There was a further increase in the percentage of donors who died due to stroke (54.9%), accompanied by corresponding decreases in the percentage who died due to trauma (17.4%) and in the number of donors with pretransplant cardiac arrest. In contrast, cold ischemia time decreased slightly in 2017, with a decrease in ischemia times >4hours (25.3%) and an increase in times <2hours.

Figure 4.

Yearly changes in donor age and percentage of donors older than 45 years (2008-2017). 95%CI, 95% confidence interval; ECMO, extracorporeal membrane oxygenation; VAD, ventricular assist device.

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The drugs used for induction immunosuppression during the study period are summarized in Table 5. As in previous years, induction therapy in 2017 mostly consisted of tacrolimus (90.5%), mycophenolate (and to a much lower extent mycophenolic acid) (96.6%), and steroids (98%). Approximately 85% of transplant recipients in 2017 also received antibody-based induction therapy, mostly basiliximab (76.1%).

Recipient survival in the 2008 to 2017 and 1984 to 2007 periods is compared in Figure 5. Compared with the earlier period, the 2008 to 2017 period showed a statistically significant improvement in survival, attributable to increased survival rates both at 1 year and over the longer term. The 1-year survival rate showed a mean improvement of 2.5%. Beyond the first year, the yearly death rate decreased from 2.2% to 1.6%. This trend toward improved survival continued within the 2008 to 2017 study period, approaching significance (P <.056) for the comparison between the 2014 to 2016 and 2008 to 2011 3-year transplant periods (Figure 6).

Figure 5.

Comparison of survival curves for the 2008-2017 and 1984-2007 periods.

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Figure 6.

Comparison of survival curves for 2008-2016 by 3-year period.

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The dominant variables influencing survival during the study period were recipient age and the type of pretransplant circulatory support (Table 6). Compared with pediatric recipients (< 16 years old), recipients older than 60 years at the time of transplant had a 70% higher mortality risk (P <.001), whereas the increased risk in recipients between the ages of 16 and 60 years was > 30% (P <.07). Previous ECMO increased the mortality risk by more than 40% (P <.008) compared with patients with no circulatory support device. However, results for recipients with a balloon pump or ventricular assist device were indistinguishable from those of patients with no support device (Table 6). During the 2008 to 2017 study period, there was no evidence that survival was influenced by donor age or urgent vs elective transplant.

During the study period, the principal cause of death in the first posttransplant year was primary graft failure (32.6%), especially in the first month (43.5%), followed by infection (22.9%). Between the first and fifth posttransplant years, the most frequent causes of death were graft vascular disease/cardiac arrest (27.8%) and cancer (21.1%) (Figure 7). Overall, acute rejection caused 8% of posttransplant deaths, with the rate almost 3-fold higher (17.8%) between the first and fifth posttransplant years than in the first year (6.1%).

Figure 7.

Main causes of death by time since transplant in the 2008-2017 period. CA, cardiac arrest; GVD, graft vascular disease.

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Almost all patients included in the present analysis survived the first year after transplant. Among those who did not, infection increased significantly as the cause of death between the 2008 to 2010 and 2011 to 2013 transplant periods, thereafter remaining stable (Figure 8). In contrast, primary graft failure showed a progressive and statistically significant decline as the cause of death in the first posttransplant year. Mortality due to transplant rejection has remained stable over the last decade (Figure 8).

Figure 8.

Main causes of death occurring in the first year after transplant (2008-2016) by 3-year period. P values indicate the significance of the trend between 3-year periods, excluding 2017. Only 17 patients receiving a heart transplant in 2017 had completed ≥ 1-year follow-up at the time of database closure.

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