胸部外科

The number of older donors is increasing in the limited number of donors in Japan. The number of older donors is increasing, and recipients are also ageing as the waiting period for transplantation becomes longer. The age of 60 years is one of the most important criteria for heart transplantation in Japan. Forty-two heart transplantations performed in our institution, and 12 cases were from donors aged over 60 years and seven recipients were older than 60 years at the time of transplantation. In four cases, both donor and recipient were over 60 years of age. All of these patients were discharged home after transplantation. As the number of older donors and recipients is expected to increase in the future, the number of marginal cases based on the status of not only the donor but also the recipient is expected to increase. The evaluation of coronary lesions and the identification of comorbid diseases, including malignant diseases, will become more important. A positive and careful overall decision at the time of transplantation is essential.

In this article, we analyzed 114 adult heart transplantation（ HTx） cases from 1999 to 2021. Of these cases, 94％ of patients underwent left ventricular assist device （ LVAD） implantation before HTx. The mean period of LVAD support was 3.0 ±1.2 years. Thirty-day mortality was 0.8％ and the 10-year survival rate was 89％ after HTx. Preoperative and postoperative renal function was the prognostic factors. Long LVAD support was not associated with the long-term survival after HTx.

Background：Size-mismatched heart transplantation（ HTx） is associated with a risk of stenosis of the caval anastomosis site or low cardiac output syndrome. We developed a modified bicaval anastomosis technique（ mBCAT） that achieved an adjustable caval anastomosis to compensate for the size mismatch. This study clarified clinical outcomes of HTx with mBCAT technique according to the degree of the size mismatch. Methods and Results：This study consisted of 130 adult patients who underwent HTx with the mBCAT during a 22-year period and were followed up for at least 1 year. The cohort was divided into three groups according to the donor-to-recipient body weight ratio：＜0.8, undersized group （n＝19）；0.8 ～1.3, size-matched group（ n＝89）；and ＞1.3, oversized group（ n＝22）. The undersized, size-matched, and oversized groups showed no significant differences in the rate of mild or worse tricuspid regurgitation on echocardiography at 1 month ［ 1（ 5.3％）, 8（ 9.0％）, and 1（ 4.6％）, respectively；p＝0.683］ or the survival rate at 10 years（ 100％, 96％, and 95％, respectively；p＝0.452）. The right heart catheter study revealed no pressure gradient across the orifices of both cavae in any patient. Additionally, the cardiac index immediately post-HTx was low in the undersized group, but improved over time in all groups, achieving the comparable value at 6 and 12 months post-HTx. Conclusions：The mBCAT prevented caval anastomosis-related complications in size-mismatched HTx and achieved excellent hemodynamics regardless of donor size.

The number of heart transplantation in Japan has gradually increased since the revised organ transplantation act became effective in July 2010. The long-term survival after heart transplantation is superior, compared to the survival in Europe and United States of America（ USA）. However, the number of patients on a waiting list is rapidly increasing due to an extreme donor shortage. Because of stagnating heart transplantation, there is a need for an optimal solution to an insufficient donor organ supply. We have experienced 125 adult heart transplantations with acceptable survival rate of over 90％ at five years. On the other hand, an expected waiting period is lengthening to far longer than five years. Here, based on our experience, we describe the “real world” outcomes and mention the future aspect of the patients on the waiting list on ventricular assist device （VAD）. Our suggestions are 1） to promote VAD weaning in patients with myocardial recovery, 2） to aggressively utilize marginal donors, and 3） to expand the indication to destination therapy.

Although the first heart transplantation in Japan by Dr. Wada had influenced the establishment of heart transplantation in Japan for many years, many efforts for re-starting and establishing heart transplantation in Japan have also occurred in the past 40 years. The Japanese Society for Heart Transplantation was established in 1983, which was two years after the establishment of the International Society for Heart Transplantation. Much effort had been made to pass the Act on Organ Transplantation in 1997 and revise it in 2010. However, very few heart transplantations are performed in our country because there have been very few deceased donors according to a 2015 report. Currently, more than 10 times the number of donors are awaiting heart transplantation in Japan. Compared to countries using an opt-in system for organ donation such as the United States and South Korea, earlier referral of possible donors to transplant coordination teams should be incorporated in Japan to increase the possibility of organ donation. The medical consultant system developed in Japan is a unique partnership between transplant consultant physicians and local physicians that should put more effort into increasing the number of organs for donation. The current number of transplant physicians is very low. This number should be increased for pre- and post-transplant management as well as medical consultation for donation in the emergency room. Another reason for the shortage of donors is that there are two judgement standards of death in Japan. One standard is brain death only at the time of donation for transplantation. This definition should be re-considered in various fields in Japan.

Tokyo Women’s Medical University has a long history with leading development in the field of cardiovascular surgery in Japan, including ventricular assist device （VAD） and heart transplantation（HT）. Our institute has performed implantable VAD implantation in 73 patients with refractory heart failure as a bridge to transplantation. The long-term survival rate of that showed 94％, 85％, and 61％ in 1, 3, and 5 years, respectively. In addition, orthotopic HT has been provided for 38 patients, with survival after both 10 and 20 years shown to be 85％. In this era of destination therapy, it is considered that VAD and HT treatments will become standardized options for heart failure cases even in Japan. To achieve this target, we re-organized our heart team named “BIND” in 2018, providing a more seamless multidisciplinary approach. We believe that these actions can contribute to the development of HT in our country.

The donation of the organs after brain death （DBD） has increased after the revision of the law in 2010 and the total number of heart transplantation（ HTx） has reached to over 500 in Japan. However, donor shortage is critical as the annual number as remaining under 100 with unneglectable number of waiting deaths. Recently, HTx under donation after controlled circulatory death（ cDCD） has been promoted in United Kingdom （UK） and Australia with promising outcomes. The cDCD appears to be an important option to expand the donor pool in Japan. Nation-wide and cross-cutting action among transplantation organs is warranted. Status of cDCD HTx in abroad and the domestic issues are reviewed.