Prediction of cardiac allograft vasculopathy using splenic switch-off on myocardial PET.

BACKGROUND: Heart transplantation (HTx) is a definitive therapy for refractory heart failure. Cardiac allograft vasculopathy (CAV), characterized by diffuse arteriopathy involving the epicardial coronary arteries and microvasculature, is the major cause of death for patients with HTx. 13N-ammonia positron emission tomography (NH3-PET) can offer diagnostic and prognostic utility for CAV. The splenic switch-off (SSO) detected in NH3-PET is a hemodynamic indicator of favorable response to adenosine. We hypothesized that both CAV and SSO reflected a pathology that progresses in parallel with systemic vascular endothelial dysfunction. Therefore, we quantitatively evaluated splenic adenosine reactivity measured using NH3-PET as an index of endothelial function, and examined its predictability for CAV. METHODS: Forty-eight patients who underwent NH3-PET after HTx were analyzed. The spleen ratio was calculated as the mean standardized uptake value, measured by placing an ROI on the spleen, at stress divided by that at rest. SSO was defined by a cutoff determined using receiver operating characteristic (ROC) analysis for the spleen ratio. The endpoint was appearance or progression of CAV. Predictability of SSO was analyzed using Kaplan-Meier analysis. RESULTS: The endpoint occurred in 9 patients during a mean follow-up of 45 ±â€¯17 months. ROC curve analysis demonstrated a cutoff of 0.94 for spleen ratio. Patients without SSO displayed a significantly higher CAV rate than those with SSO (p = 0.022). CONCLUSIONS: SSO reflects the endothelial function of systemic blood vessels and was a predictor of CAV in patients with HTx.

Novel Scoring System to Risk Stratify Patients Receiving Durable Left Ventricular Assist Device From J-MACS Registry Data.

BACKGROUND: Recently, destination therapy (DT) was approved in Japan, and patients ineligible for heart transplantation may now receive durable left ventricular assist devices (LVADs). Several conventional risk scores are available, but a risk score that is best to select optimal candidates for DT in the Japanese population remains unestablished.Methods and Results: A total of 1,287 patients who underwent durable LVAD implantation and were listed for the Japanese registry for Mechanically Assisted Circulatory Support (J-MACS) were eligible for inclusion. Finally, 494 patients were assigned to the derivation cohort and 487 patients were assigned to the validation cohort. According to the time-to-event analyses, J-MACS risk scores were newly constructed to predict 3-year mortality rate, consisting of age, history of cardiac surgery, serum creatinine level, and central venous pressure to pulmonary artery wedge pressure ratio >0.71. The J-MACS risk score had the highest predictability of 3-year death compared with other conventional scores in the validation cohort, including HeartMate II risk score and HeartMate 3 risk score. CONCLUSIONS: We constructed the J-MACS risk score to estimate 3-year mortality rate after durable LVAD implantation using large-scale multicenter Japanese data. The clinical utility of this scoring to guide the indication of DT should be validated in the next study.

[Proposal to Development of the Heart Transplant in Our Country in the Future].

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.

Complete remission from post-heart transplant lymphoproliferative disorder: A case report.

We report a case of Burkitt's lymphoma, post-transplant lymphoproliferative disorder (BL-PTLD) that was treated with intensive chemotherapy. The patient was a 4-year-old boy who underwent heart transplantation at 7 months of age for refractory heart failure due to dilated cardiomyopathy. He was admitted to our hospital with a chief complaint of abdominal pain associated with an abdominal mass. Computed tomography was notable for a bulky mass arising from the terminal ileum. Fluorodeoxyglucose-positron emission tomography revealed multiple lesions in brain, bone, and lymph nodes. He was diagnosed with BL-PTLD stage III by pathological and clinical scoring. He was Epstein-Barr virus (EBV)-seronegative with a low EBV viral DNA load. No EBV-encoded small RNAs were in his intra-abdominal lymph nodes by in situ hybridization. On cytogenetic examination, the intra-abdominal lymph nodes revealed both a MYC rearrangement and a t(8;14)(q24;32), t(16;19)(q24;q13.1) translocation. Administration of tacrolimus and mycophenolate mofetil was discontinued; immunosuppression was maintained with everolimus. Intensive chemotherapy based on the modified LMB 96 protocol for BL was initiated, resulting in complete remission achieved. During the intensive chemotherapy and immunosuppressive switching period, cardiac dysfunction and allograft rejection had not been shown. The patient has remained well for two years after the treatment with no evidence of relapse. .

The second official report from Japanese registry for mechanical assisted circulatory support (J-MACS): first results of bridge to bridge strategy.

BACKGROUND: The Japanese registry for mechanical assisted circulatory support (J-MACS) is a prospective registry to collect all data of implantable left ventricular assist device (LVAD) (and part of paracorporeal VAD) established in 2010. The first analytical report was published in 2017. The organization running J-MACS was used to be the pharmaceuticals and medical devices agency (PMDA), but has been changed to the council for clinical use of ventricular assist device related academic societies in 2017. METHODS: Since 2018, we changed the analytical methods as follows: first, we eliminated paracorporeal VAD from the analysis. Second, we included not only primary implantation but bridge to bridge (BTB) implantation of LVAD. Third, we added the analyses of adverse events that were not included in the previous analysis. RESULTS: As of Oct 2018, 711 primary LVAD implants and 168 BTB implants were enrolled. Survival rate of primary LVAD was 93% at 360 days and 91% at 720 days, and that of BTB was 86% at 360 days and 82% at 720 days. CONCLUSION: We first reported the results of BTB in the second official report of J-MACS. The prognosis after LVAD implantation has been kept good in Japanese circumstances.

Donor bone marrow cells are essential for iNKT cell-mediated Foxp3+ Treg cell expansion in a murine model of transplantation tolerance.

Mixed chimerism induction is the most reliable method for establishing transplantation tolerance. We previously described a novel treatment using a suboptimal dose of anti-CD40 ligand (anti-CD40L) and liposomal formulation of a ligand for invariant natural killer T cells administered to sub-lethally irradiated recipient mice after donor bone marrow cell (BMC) transfer. Recipient mice treated with this regimen showed expansion of a Foxp3-positive regulatory T(Treg) cell phenotype, and formation of mixed chimera. However, the mechanism of expansion and bioactivity of Treg cells remains unclear. Here, we examine the role of donor BMCs in the expansion of bioactive Treg cells. The mouse model was transplanted with a heart allograft the day after treatment. The results showed that transfer of spleen cells in place of BMCs failed to deplete host interferon (IFN)-γ-producing CD8+ T cells, expand host Ki67+ CD4+ CD25+ Foxp3+ Treg cells, and prolong graft survival. Severe combined immunodeficiency mice who received Treg cells obtained from BMC-recipients accepted skin grafts in an allo-specific manner. Myeloid-derived suppressor cells, which were a copious cell subset in BMCs, enhanced the Ki67 expression of Treg cells. This suggests that donor BMCs are indispensable for the expansion of host bioactive Treg cells in our novel treatment for transplant tolerance induction.

The successful management of respiratory complications with long-term, low-dose macrolide administration in pediatric heart transplant recipients.

We report three pediatric heart transplant (HTx) patients whose respiratory symptoms were successfully controlled with long-term, low-dose macrolide administration (clarithromycin: CAM; approximately 2.5 mg/kg bid). The first case was an 18-year-old boy who underwent HTx at the age of three for dilated cardiomyopathy (DCM). Beginning at age 5, he had repeated fevers and respiratory symptoms. He was diagnosed with chronic sinusitis at age 11 and sinobronchial syndrome with mild bronchiectasis at age 14. Administration of long-term, low-dose CAM and otolaryngeal topical therapy led to significant improvement of his symptoms. The second case was a 7-year-old boy who underwent HTx for DCM at age one. Starting at age 4, he had repeated fevers and cough due to atelectasis and pneumonia. As antibiotics and respiratory physical therapy proved ineffective, he received long-term, low-dose CAM, resulting in successful control of his atelectasis and recurrent pneumonia. The third case was a 13-year-old boy who underwent HTx at age 6 for DCM. He had chronic sinusitis starting at age 7, and was diagnosed with obstructive sleep apnea syndrome at age 10. Adenotonsillectomy and continuous positive airway pressure support therapy were indicated. At age 13, long-term, lowdose CAM administration was started following mycoplasma infection. In all three cases, the levels of calcineurin inhibitors (cyclosporine and tacrolimus) and everolimus were kept in the optimal range with careful drug monitoring. Longterm, low-dose macrolide administration effectively prevents and treats respiratory complications in pediatric HTx patients as long as attention is paid to potential drug interactions.

[Diagnosis of rejection after heart transplantation].

By the development of immunosuppressants since the clinical use of cyclosporine in 1980s, the combination of various immunosuppressants such as cyclosporine or tacrolimus, azathioprine or mycophenolate mofetil, and steroid has been tried for the prevention of rejection. Acute rejection, however, has been still the second highest cause of death in the early stage post-tansplantation. Endomyocardial biopsy provides the diagnosis of acute cellular rejection, and its classification was recently revised; 0 (no rejection), 1R (mild rejection), 2R (moderate rejection), and 3R (severe rejection). Echocardiography has also provided helpful information not only for detecting acute rejection but also judgment of the recovery from it especially in pediatric patients. Cardiac allograft vasculopathy, that is, chronic rejection has been a main cause of death in the late stage post-tansplantation. As this involves entire coronary arteries from epicardial to distal portion in the myocardium, the diagnosis only by coronary angiogram is not sufficient, and the measurement of coronary flow reserve and/or intravascular ultrasound provide diagnostic information. m-TOR inhibitors such as sirolimus or everolimus are being used with increasing frequency following heart transplantation due to their potent immunosuppressive and antiproliferative effects. In clinical trials in de novo and maintenance heart transplant recipients, m-TOR inhibitors are associated with a reduced incidence of cardiac allograft vasculopathy when compared with alternative immunosuppressive regimens.