Optimizing Outcomes for Post-ECMO Heart Transplant Patients in South Korea: Addressing Multi-Organ Failure and Allocation Challenges

The increasing utilization of extracorporeal membrane oxygenation (ECMO) as a bridge to heart transplantation (HTx), left ventricular assist device (LVAD) or cardiogenic shock has been a significant global trend in recent years.¹⁾ ECMO provides vital support for patients suffering from end-stage heart failure or severe cardiopulmonary failure, allowing time for recovery or bridging to HTx. Advances in ECMO technology, enhanced patient selection, and improved management strategies have contributed to better outcomes overall. However, survival rates for patients undergoing ECMO bridged transplantation generally remain lower compared to those who did not require ECMO prior to transplantation.²⁾

In this issue of the International Journal of Heart Failure, Lim et al.³⁾ reported a retrospective study of 96 patients who underwent HTx at a single tertiary hospital in South Korea. The study examined the use of ECMO bridging for HTx in South Korea, where ECMO patients are registered as the highest priority for HTx. Despite the improvements in patient management and technology, ECMO bridged HTx is known to have poor survival rates due to complications and reduced time for end-organ recovery. This study aims to compare the outcomes of HTx bridged with or without ECMO and investigate the effect of preoperative ventilator status and pre-existing multi-organ failure (MOF) on the clinical outcomes of ECMO bridged HTx.

Lim et al.³⁾ found that the 1-year survival rate was significantly lower in the ECMO group (72.9% vs. 95.8%, p=0.002). Patients who required mechanical ventilation (MV) in ECMO bridged HTx showed higher preoperative MOF rates and early mortality than those extubated. The study highlights the importance of thorough investigation of the severity of MOF and careful patient selection when considering ECMO bridged HTx. Overall, the article provides a detailed analysis of the factors affecting the prognosis of direct ECMO bridged HTx and offers valuable information for recipient selection.

However, several important issues warrant consideration. In South Korea, the regional divisions for organ allocation include Seoul, Incheon, Gyeonggi-do, Jeju Island, and Gangwon-do as Area 1; Jeolla-do and Chungcheong-do as Area 2; and Gyeongsangnam-do and Gyeongsangbuk-do as Area 3.

Following the introduction of merit-based allocation in November 2018, the transplantation waiting period for Status 1 patients could have been markedly shorter in Busan, where this study’s authors are based, compared to hospitals in Area 1, as per this paper. The average waiting time for non-ECMO patients (those with Status 1 or lower) hovers around 35.6±51.8 days, with most waiting approximately three months. According to Korean Network for Organ Sharing data, Area 3 has the highest number of brain deaths relative to the population but fewer transplant-performing hospitals, while Area 1 has many transplant hospitals, leading to more patients waiting for extended periods.⁴⁾ Given the transportation logistics, the travel time from Seoul to Incheon is sometimes similar than from Seoul to Busan, posing additional challenges for patients grouped into the same area.

Moreover, ECMO patients with Status 0 receive transplants within an average of 2 weeks, primarily within 7 days, at the authors’ hospital. In contrast, patients with blood type B in Area 1 need an average of at least one month after ECMO insertion. Consequently, LVAD insertion is on the rise in Area 1, while Area 3 records a higher number of transplants compared to LVAD patients. It is crucial for readers to understand that this study reports a considerably shorter waiting time, with Status 1 patients waiting only around 30 days on average. This allocation system may increase the number of LVAD patients in Area 1 while fostering more transplants in Areas 2 and 3. It is essential to analyze the mortality rate and waiting time of waiting people for each region to assess the effectiveness of this allocation policy.

In contrast, the United States’ allocation system prioritizes patients based on medical urgency and the likelihood of survival following a transplant, rather than their geographic location. This change has led to a significant increase in the number of transplants performed in the United States and improved patient outcomes.⁵,⁶⁾ South Korea’s allocation policy could benefit from a similar approach, prioritizing patients based on their severity rather than their region.

Furthermore, the study by Lim et al.³⁾ underscores the importance of preoperative ventilator status in determining patient outcomes. However, the variable of awakening ECMO should be compared with other variables reflecting the patient’s condition (e.g., using multivariable regression analysis) to better understand its impact on patient outcomes.

Addressing regional disparities in HTx allocation is a crucial challenge for South Korea, considering the limited data available and the importance of suitable donor selection for post-HTx prognosis. More research and multicenter data are needed to inform recipient selection and allocation policies to ensure equitable access to transplantation and improve patient outcomes. As medical professionals, we must also consider the preferences and values of our patients and their families when making treatment decisions.