Impact of induction therapy on the risk of mortality in direct ECMO-bridged heart transplantation

The guidance regarding routine induction therapy (IT) on direct-ECMO-bridged heart transplantation (ECMO-HTx) has not been established. To date, most of the evidence has been conducted on non-ECMO patients. The purpose of this study is to investigate the impact of IT on heart transplantation bridged by ECMO, which has a high risk of infection, and multiple organ failures.

We retrospectively reviewed 338 patients who underwent ECMO-HTx between 2014 and 2023 in Korean Organ Transplant Registry. Patients with dual organ transplants and PRA > 50% were excluded. A total of 246 Patients were grouped according to induction status: no induction vs any induction therapy (including IL2 receptor antagonist and anti-thymoglobulins). Mortality and related factors were analyzed using 30-day landmark Cox regression.

Among 246 patients, 47 (19%) were grouped in the no-IT group and 199 (81%) for the IT group. The median age of the recipients was 55 (IQR: 43-62) years and the median follow-up was 2.0 (IQR: 0.3-5.0) years with 28.4% overall mortality. No-IT group had significantly longer warm ischemic time (median 65 vs 45 min, p<0.001) and higher postoperative ECMO support (42.6 vs 21.6%, p = 0.006) at the baseline. Mortality before 30 days was higher in the no-IT group (17.5 vs 4.7%, p=0.002), but there was no difference in mortality between groups after 30 days (20.0 vs 21.9%, HR = 1.025, 95% CI 0.314-3.339, p = 0.968).

In this study, the high mortality before 30 days in direct ECMO-HTx patients was thought to be more affected by the severity of medical condition before/immediately after HTx, and there was no significant difference in mortality after 30 days. Therefore, it suggests that for less-sensitized (PRA<50%) patient in the high risk of infection before and HTx, omitting IT can be considered.