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.

Consensus Report on Destination Therapy in Japan　- From the DT Committee of the Council for Clinical Use of Ventricular Assist Device Related Academic Societies.

Destination therapy (DT) is the indication to implant a left ventricular assist device (LVAD) in a patient with stage D heart failure who is not a candidate for heart transplantation. The implantable LVAD has been utilized in Japan since 2011 under the indication of bridge to transplant (BTT). After almost 10 year lag, DT has finally been approved and reimbursed in May 2021 in Japan. To initiate the DT program in Japan, revision of the LVAD indication from BTT is necessary. Also, in-depth discussion of caregiver issues as well as end-of-life care is indispensable. For that purpose, we assembled a DT committee of multidisciplinary members in August 2020, and started monthly discussions via web-based communication during the COVID-19 pandemic. This is a summary of the consensus reached after 6 months' discussion, and we have included as many relevant topics as possible. Clinical application of DT has just started, and we are willing to revise this consensus to meet the forthcoming issues raised during real-world clinical experience.

Survival of Heart Transplant Candidates in Japan.

BACKGROUND: In Japan, there are more patients waiting for heart transplants (HTXs) than available organs. Methods and Results: Since July 2010, 68 pediatric and 366 adult patients aged <60 years applied for HTX candidacy with the Japanese Circulation Society's HTX Committee. No significant differences in freedom from death or HTX were observed between pediatric Status 1 and Status 2 patients. More adult Status 1 patients reached the endpoint of death or HTX than adult Status 2 patients. Pediatric patients (Status 1 and 2) did not have better survival than adult Status 1 or Status 2 patients. CONCLUSIONS: Pediatric patients should be prioritized over adult patients for HTX.

Impact of pretransplant antibodies on outcomes after heart transplantation.

PURPOSE OF REVIEW: Since the discovery of human leukocyte antigen (HLA) in the 1950s, there has been great interest in the role of antibodies in posttransplant rejection. The development of the lymphocyte toxicity test by Terasaki et al. in the 1960s was the first step toward understanding the role of antibodies in posttransplant rejection. RECENT FINDINGS: Subsequently, various organs have been transplanted and improving posttransplant outcomes have become a focus of research. In particular, methods to measure antibodies that affect posttransplant outcomes, including anti-HLA antibodies, and methods to desensitize patients from specific antibodies have been explored. One recent method for measuring antibodies is called the solid-phase assay, which uses purified HLA fixed to microbeads. This assay does not use donor lymphocytes and allows clinicians to test the reactivity of patient serum against a panel of antibodies. It has also enabled the identification of specific anti-HLA antibodies using a single HLA. SUMMARY: In addition to advances in methods to measure and analyze anti-HLA antibodies, the clinical impact of non-HLA antibodies has also received much attention recently.

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.

Genetic background of Japanese patients with pediatric hypertrophic and restrictive cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) and restrictive cardiomyopathy (RCM) present a high risk for sudden cardiac death in pediatric patients. The aim of this study was to identify disease-associated genetic variants in Japanese patients with pediatric HCM and RCM. We analyzed 67 cardiomyopathy-associated genes in 46 HCM and 7 RCM patients diagnosed before 16 years of age using a next-generation sequencing system. We found that 78% of HCM and 71% of RCM patients carried disease-associated genetic variants. Disease-associated genetic variants were identified in 80% of HCM patients with a family history and in 77% of HCM patients with no apparent family history (NFH). MYH7 and/or MYBPC3 variants comprised 76% of HCM-associated variants, whereas troponin complex-encoding genes comprised 75% of the RCM-associated variants. In addition, 91% of HCM patients with implantable cardioverter-defibrillators and infant cases had NFH, and the 88% of HCM patients carrying disease-associated genetic variants were males who carried MYH7 or MYBPC3 variants. Moreover, two disease-associated LAMP2, one DES and one FHOD3 variants, were identified in HCM patients. In this study, pediatric HCM and RCM patients were found to carry disease-associated genetic variants at a high rate. Most of the variants were in MYH7 or MYPBC3 for HCM and TNNT2 or TNNI3 for RCM.

Impact of Recurrent Ventricular Tachyarrhythmia on Outcome in Japanese Heart Transplant Candidates With a Left Ventricular Assist Device.

BACKGROUND: Recurrent ventricular tachyarrhythmias (VTA) are "A factor" modifiers in the Interagency Registry for Mechanically Assisted Circulatory Support profile. The effect of recurrent VTA on clinical outcome, however, is controversial. We evaluated the impact of recurrent VTA on outcome in Japanese heart transplant candidates with a left ventricular assist device (LVAD). Methods and Results: Sixty-six adult patients with advanced heart failure who were listed for heart transplantation between January 2005 and October 2017 were enrolled in the study. Recurrent VTA (modifier A status) was defined as a sustained ventricular tachycardia or fibrillation that required implantable cardioverter defibrillator shocks or an external defibrillator more than twice weekly. The primary outcome was death from any cause. The secondary outcomes were the first occurrence of VTA and recurrent VTA after LVAD implantation. Sixteen patients (24%) met the criteria for modifier A status, and 15 patients had an LVAD implanted. During a median follow-up of 1,124 days, 21 of 60 patients with an LVAD died. There was a significantly higher mortality rate in LVAD patients with modifier A status than in those who did not meet the modifier A criteria. On multivariate analysis, patients with modifier A status had an increased risk of mortality (HR, 3.43; 95% CI: 1.30-8.61, P=0.001). CONCLUSIONS: Recurrent VTA might be a marker for worse outcome in Japanese heart transplant candidates with an LVAD.

Molecular basis for clinical heterogeneity in inherited cardiomyopathies due to myopalladin mutations.

Abnormalities in Z-disc proteins cause hypertrophic (HCM), dilated (DCM) and/or restrictive cardiomyopathy (RCM), but disease-causing mechanisms are not fully understood. Myopalladin (MYPN) is a Z-disc protein expressed in striated muscle and functions as a structural, signaling and gene expression regulating molecule in response to muscle stress. MYPN was genetically screened in 900 patients with HCM, DCM and RCM, and disease-causing mechanisms were investigated using comparative immunohistochemical analysis of the patient myocardium and neonatal rat cardiomyocytes expressing mutant MYPN. Cardiac-restricted transgenic (Tg) mice were generated and protein-protein interactions were evaluated. Two nonsense and 13 missense MYPN variants were identified in subjects with DCM, HCM and RCM with the average cardiomyopathy prevalence of 1.66%. Functional studies were performed on two variants (Q529X and Y20C) associated with variable clinical phenotypes. Humans carrying the Y20C-MYPN variant developed HCM or DCM, whereas Q529X-MYPN was found in familial RCM. Disturbed myofibrillogenesis with disruption of α-actinin2, desmin and cardiac ankyrin repeat protein (CARP) was evident in rat cardiomyocytes expressing MYPN(Q529X). Cardiac-restricted MYPN(Y20C) Tg mice developed HCM and disrupted intercalated discs, with disturbed expression of desmin, desmoplakin, connexin43 and vinculin being evident. Failed nuclear translocation and reduced binding of Y20C-MYPN to CARP were demonstrated using in vitro and in vivo systems. MYPN mutations cause various forms of cardiomyopathy via different protein-protein interactions. Q529X-MYPN causes RCM via disturbed myofibrillogenesis, whereas Y20C-MYPN perturbs MYPN nuclear shuttling and leads to abnormal assembly of terminal Z-disc within the cardiac transitional junction and intercalated disc.

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.

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.

Clinical Validation of a Neointima-Inducing Inflow Cannula in a Continuous Flow Left Ventricular Assist Device.

Wedge thrombus formation around the inflow cannula of a continuous left ventricular assist device (LVAD) is a source of systemic thromboemboli. We previously reported the potential advantages of a new inflow cannula wrapped with titanium mesh (GU30) over the standard smooth surface oblique cut cannula (GU10). The objective of the present study was to clinically validate this new cannula. A retrospective cohort analysis of patients with implanted LVAD (EVAHEART) comparing the GU10 to the GU30 was conducted. Clinical outcomes, including survival, the incidence of thromboembolism, and bleeding events, were compared. Gross and histopathological analyses of explanted GU30 cannula were conducted following transplant or patient death. No significant differences in the survival rate, severe emboli, or cerebral bleeding were observed during the LVAD implantation. However, severe emboli occurred earlier after LVAD implantation when using the GU30 cannula compared with the GU10. In cases of long LVAD support, the neointima fully covered the inflow of the GU30 cannulae without wedge thrombus formation. The titanium mesh-wrapped inflow cannulae did not reduce the overall incidence of neurological events significantly. However, the titanium mesh-wrapped inflow cannula induced autologous neointimal growth over the cannula and prevented wedge thrombus formation in late-phase LVAD implantation.

Prevalence and distribution of sarcomeric gene mutations in Japanese patients with familial hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM), which is inherited as an autosomal dominant trait, is the most prevalent hereditary cardiac disease. Although there are several reports on the systematic screening of mutations in the disease-causing genes in European and American populations, only limited information is available for Asian populations, including Japanese. METHODS AND RESULTS: Genetic screening of disease-associated mutations in 8 genes for sarcomeric proteins, MYH7, MYBPC3, MYL2, MYL3, TNNT2, TNNI3, TPM1, and ACTC, was performed by direct sequencing in 112 unrelated Japanese proband patients with familial HCM; 37 different mutations, including 13 novel ones in 5 genes, MYH7, MYBPC3, TNNT2, TNNI3, and TPM1, were identified in 49 (43.8%) patients. Among them, 3 carried compound heterozygous mutations in MYBPC3 or TNNT2. The frequency of patients carrying the MYBPC3, MYH7, and TNNT2 mutations were 19.6%, 10.7%, and 8.9%, respectively, and the most frequently affected genes in the northeastern and southwestern parts of Japan were MYBPC3 and MYH7, respectively. Several mutations were found in multiple unrelated proband patients, for which the geographic distribution suggested founder effects of the mutations. CONCLUSIONS: This study demonstrated the frequency and distribution of mutations in a large cohort of familial HCM in Japan.

Team-based learning, a learning strategy for clinical reasoning, in students with problem-based learning tutorial experiences.

Acquiring clinical reasoning skills in lectures may be difficult, but it can be learnt through problem-solving in the context of clinical practice. Problem finding and solving are skills required for clinical reasoning; however, students who underwent problem-based learning (PBL) still have difficulty in acquiring clinical reasoning skills. We hypothesized that team-based learning (TBL), a learning strategy that provides the opportunity to solve problems by repeatedly taking tests, can enhance the clinical reasoning ability in medical students with PBL experiences during the pre-clinical years. TBL courses were designed for 4(th) year students in a 6-year program in 2008, 2009, and 2010. TBL individual scores, consisting of a combination of individual and group tests, were compared with scores of several examinations including computer-based testing (CBT), an original examination assessing clinical reasoning ability (problem-solving ability test; P-SAT), term examinations, and Objective Structured Clinical Examination (OSCE). CBT, OSCE and P-SAT scores were compared with those of students who learned clinical reasoning only through PBL tutorials in 2005, 2006, and 2007 (non-TBL students). Individual TBL scores of students did not correlate with scores of any other examination. Assessments on clinical reasoning ability, such as CBT, OSCE, and P-SAT scores, were significantly higher in TBL students compared with non-TBL students. Students found TBL to be effective, particularly in areas of problem solving by both individuals and teams, and feedback from specialists. In conclusion, TBL for clinical reasoning is useful in improving clinical reasoning ability in students with PBL experiences with limited clinical exposure.

13N-ammonia positron emission tomography-derived left-ventricular strain in patients after heart transplantation validated using cardiovascular magnetic resonance feature tracking as reference.

OBJECTIVE: Heart transplant rejection leads to cardiac allograft vasculopathy (CAV). 13N-ammonia positron emission tomography (PET) can be useful in detecting CAV, as it can evaluate both epicardial vessels and microvasculature. In this study, we evaluated the regional wall motion in heart transplant patients using our PET-specific feature-tracking (FT) algorithm for myocardial strain calculation and validated it using a cardiovascular magnetic resonance (CMR) FT strain as a reference. METHODS: A total of 15 heart transplant patients who underwent both 13N-ammonia PET and CMR within 3 months were retrospectively enrolled. The same slice position of short-axis cine images of the middle slice of left ventricle (LV) and the same slice position of horizontal long-axis cine images were selected for the two modalities to measure the circumferential strain (CS) and longitudinal strain (LS), respectively. Based on the FT technique, time-strain curves were calculated by semi-automatic tracking of the endocardial contour on cine images throughout a cardiac cycle. The peak value in the time-strain curve was defined as the representative value. Correlations of CS and LS between PET and CMR were analyzed using Pearson correlation coefficients. The inter-modality error of strain measurements was evaluated using intraclass correlation coefficients (ICCs) with two-way random single measures. RESULTS: Excellent correlations of CS and LS between PET and CMR were observed (CS: r = 0.80; p < 0.01; LS: r = 0.87; p < 0.01). Excellent ICCs were observed (0.89 and 0.85) in CS and LS derived from PET. CONCLUSIONS: We propose the first PET strain showing an excellent agreement with the CMR strain and high reproducibility in measurement.

Stratification of Destination Therapy Candidates by J-HeartMate Risk Score Among Elderly Non-Responders to Cardiac Resynchronization Therapy.

Background: For elderly patients with refractory heart failure (HF), destination therapy (DT) with a continuous-flow left ventricular assist device (LVAD) is a possible treatment. The aim of DT is for long-term, satisfying quality of life on LVAD support. Previously, elderly non-responders to cardiac resynchronization therapy (CRT) were primarily destined for palliative care, but DT has been available in Japan since April 30, 2021. This study investigated the prognosis of elderly CRT non-responders and assessed the feasibility of DT in these patients based on the J-HeartMate Risk Score (J-HMRS). Methods and Results: Of the 559 patients who underwent CRT at Tokyo Women's Medical University between 2000 and 2018, 198 were aged 65-75 years. Among these, 76 were identified as non-responders based on echocardiographic data, and were included in this study. We calculated patients' J-HMRS and investigated associations between the J-HMRS and cardiac events after CRT. Patients were divided into 3 groups according to the J-HMRS: low (n=23), medium (n=29), and high (n=24) risk. Patients in the low-risk group experienced as many HF rehospitalizations and ventricular arrhythmia events as those in the other groups. However, survival analysis revealed that, after CRT, survival was higher for patients in the low- compared with high-risk group (P=0.04). Conclusions: The J-HMRS classified 30% of elderly CRT non-responders as low risk and as suitable candidates for DT in Japan.

Acute myocardial infarction and sudden cardiac arrest caused by anomalous left coronary artery arising from the noncoronary cusp.

Anomalous left coronary artery arising from the noncoronary cusp (LCANCC) is a rare congenital disorder. We herein describe a 17-year-old female patient with sudden cardiac arrest followed by refractory cardiogenic shock. LCANCC-induced acute myocardial infarction with left main coronary artery involvement was subsequently diagnosed, and the patient required a durable left ventricular assist device. .