Outcomes of Induction Therapy with Rabbit Anti-Thymocyte Globulin in Heart Transplant Recipients: A Single Center Retrospective Cohort Study

Induction therapy confers survival advantage in mechanically supported patients regardless of peak CPRA in heart transplantation

Background

There is no consensus regarding induction therapy in patients on mechanically circulatory support (MCS) listed for heart transplantation. We sought to elucidate differences in outcomes between no induction and induction.

Methods

A total of 3,987 patients were analyzed from the UNOS database from January 2018 through December 2022. Patients on Extracorporeal Membrane Oxygenation (ECMO), HeartMate 3, Impella 5.0 or 5.5, and intra-aortic balloon pump (IABP) and receiving no induction, anti-IL2R antibodies, or T cell depleting agent (TCDA) were included.

Results

Of 3,987 patients, 1,288 (32.3%) received no induction, 1,566 (39.3%) received anti-IL2R antibodies, and 1,133 (28.4%) received TCDA. A total of 1,895 (47.5%) were supported with IABP; 1,098 (27.5%) with HeartMate 3; 489 (12.3%) with Impella 5.0 or 5.5; 351 (8.8%) with ECMO; and 154 (3.9%) with combination of the above devices. Comparison of 1-year survival between no induction, anti-IL2R, and TCDA groups in all MCS patients revealed significantly worse survival among those receiving no induction (p<0.0001). Subgroup analysis of peak CPRA 0% patients revealed that no induction had significantly worse survival at 1 year (p=0.002). Analysis of acute rejection at 1 year showed a significantly decreased number of rejection episodes in the TCDA group compared to no induction (OR 0.65, CI 0.47-0.88, p=0.006).

Conclusions

Patients requiring MCS prior to heart transplantation have significantly improved post-transplant survival with induction therapy, regardless of their peak CPRA. TCDA confers decreased number of acute rejection episodes at 1 year in this patient population.

New insights into the oncological risk in heart transplant recipients: could skin tumors represent a marker of increased risk for solid neoplasm?

BACKGROUND

Solid organ transplant recipients are at increased risk for skin cancers due to immune-suppressive therapies. However, little is known about the risk and the characteristics of neoplasms in heart transplant recipients (HTRs). The aim of this study is to delineate the incidence of different skin tumors in HTRs and to correlate it with the incidence of other malignancies, including solid tumors and hematological neoplasms.

METHODS

Patients who underwent to HTRs between January 1991 and November 2021 were retrieved. Clinical data on immunosuppressive therapies, skin tumors, solid and hematological neoplasms were obtained. HTRs with skin tumors were included in group A, while patients with no evidence of skin tumors during the follow-up were included in group B.

RESULTS

One hundred and eight patients were retrieved. A significant increase in solid tumors was observed in group A, while no significant difference in hematological neoplasms was detected between the two groups.

CONCLUSIONS

HTRs with skin tumors showed a significantly higher incidence of solid neoplasms. In most of the cases the skin tumor preceded the onset of the solid neoplasm, suggesting that the skin tumor could represent a 'marker' of immunosuppression eventually leading to the development of an internal malignancy.

Retrospective Evaluation of Rabbit Antithymocyte Globulin Induction in Heart Transplant Patients

The dosing intensity of antithymocyte globulin as induction therapy in heart transplantation remains controversial. We sought to evaluate the efficacy and safety of rabbit antithymocyte globulin at a total dose of 4.5 mg/kg compared with <4.5 mg/kg.

Rabbit Antithymocyte Globulin Induction in Heart Transplant Recipients at High Risk for Rejection

Background: Induction with lymphocyte-depleting antibodies may improve allograft outcomes in heart transplant recipients who are at high immunologic risk for rejection.

Methods: We conducted a single-center retrospective cohort study that compared outcomes between adult patients receiving rabbit antithymocyte globulin (rATG) induction vs no induction from 2011 through 2017. Key exclusion criteria were patients who did not receive tacrolimus and mycophenolate and patients who did not meet high immunologic risk criteria.

Results: A total of 50 patients were included in the analysis. At 1 year, the composite primary outcome of ≥2R rejection as defined by the International Society for Heart and Lung Transplantation, any treated rejection, development of cardiac allograft vasculopathy, or graft loss was not different between groups (P=0.474). Serious infections were also similar between groups (P=0.963). In accordance with institutional guidelines, prednisone exposure was decreased in the rATG induction group at 1 month (24.04 mg ± 13.74 vs 35.18 mg ± 16.95; P=0.014).

Conclusion: These results suggest that while rATG induction does not improve heart allograft outcomes, it may enable reducing early corticosteroid exposure in patients at high immunologic risk.

Induction Immunosuppression and Renal Outcomes in Adult Heart Transplantation

BACKGROUND

This study explores the use of induction therapy in orthotopic heart transplantation as it relates to preoperative renal function and evaluates the impact of its utilization on post-transplant outcomes.

METHODS

We conducted a retrospective analysis using the United Network for Organ Sharing database from 2000 to 2018 evaluating the initiation of de novo dialysis after transplantation. We examined the relationship between induction immunosuppression and pre-transplant estimated glomerular filtration rate with post-transplant outcomes, accounting for inter-center variability through a mixed-effects logistic regression model.

RESULTS

In total, 16,201 patients were included with a median age of 57 y (interquartile range 47, 63); 26% were women (n = 4222) and 28% (n = 4552) had a history of diabetes mellitus. The median estimated glomerular filtration rate (eGFR) was 67.5 mL/min (interquartile range 53.1, 86.7); 51.2% (n = 3068) of the recipients with eGFR < 60 received induction therapy compared to 42.5% (n = 4336) within the eGFR ≥ 60 group (P < 0.001). Adjusted multivariable analysis found that induction therapy was associated with de novo dialysis (odds ratio 1.25, 95% confidence interval 1.10-1.43, P < 0.001), with the most significant effect on patients with eGFR ≥ 60. Although significant, there was a weak correlation between center-level induction utilization and mean eGFR (r = -0.2, P < 0.001).

CONCLUSION

In this analysis, the use of induction immunosuppression in orthotopic heart transplantation varied widely between centers and did not correlate strongly with pre-transplant eGFR. In addition, its utilization did not mitigate the risk of renal replacement therapy after transplantation and in fact was associated with increased risk even after adjusting for confounders most notably in patients with eGFR ≥ 60.