Gene correction and overexpression of TNNI3 improve impaired relaxation in engineered heart tissue model of pediatric restrictive cardiomyopathy.

Research on cardiomyopathy models using engineered heart tissue (EHT) created from disease-specific induced pluripotent stem cells (iPSCs) is advancing rapidly. However, the study of restrictive cardiomyopathy (RCM), a rare and intractable cardiomyopathy, remains at the experimental stage because there is currently no established method to replicate the hallmark phenotype of RCM, particularly diastolic dysfunction, in vitro. In this study, we generated iPSCs from a patient with early childhood-onset RCM harboring the TNNI3 R170W mutation (R170W-iPSCs). The properties of R170W-iPSC-derived cardiomyocytes (CMs) and EHTs were evaluated and compared with an isogenic iPSC line in which the mutation was corrected. Our results indicated altered calcium kinetics in R170W-iPSC-CMs, including prolonged tau, and an increased ratio of relaxation force to contractile force in R170W-EHTs. These properties were reversed in the isogenic line, suggesting that our model recapitulates impaired relaxation of RCM, i.e., diastolic dysfunction in clinical practice. Furthermore, overexpression of wild-type TNNI3 in R170W-iPSC-CMs and -EHTs effectively rescued impaired relaxation. These results highlight the potential efficacy of EHT, a modality that can accurately recapitulate diastolic dysfunction in vitro, to elucidate the pathophysiology of RCM, as well as the possible benefits of gene therapies for patients with RCM.

Left ventricular assist device temporary explantation as a strategy for infection control in a pediatric patient.

We report a case of temporary Berlin Heart EXCOR® explantation in a pediatric patient with idiopathic dilated cardiomyopathy who suffered an uncontrollable inflow cannulation site infection while on bridge-to-transplantation. Despite failure to thrive and catheter-related infections, once free of the device, the patient was cured of infection using systemic antibiotics and surgical debridement. The patient underwent EXCOR® reimplantation after four months, and is awaiting heart transplantation in stable condition. A life-threatening ventricular assist device-related infection may require device explantation under conditions that may not fulfill conventional explantation criteria despite risks. Temporary explantation can be an effective strategy if isolated systolic dysfunction is managed carefully.

Trans-subclavian approach for Impella CP implantation using the chimney graft in a pediatric patient with fulminant myocarditis during extracorporeal support.

Impella is a device effective for the treatment of cardiogenic shock. However, among small children, its application has limitations due to left ventricle size and vasculature and the turning diameter of the aortic arch. Herein, we report an 11-year-old girl with fulminant myocarditis who was successfully managed with Impella CP implantation via the right subclavian artery using a polyethylene terephthalate chimney graft. Compared with insertion via the femoral artery, this method has several advantages. That is, it can address limitations in aortic arch diameter and facilitate equable fixation of the Impella device in small pediatric patients.

Public attitudes in the clinical application of genome editing on human embryos in Japan: a cross-sectional survey across multiple stakeholders.

Recent advances in genome editing technology are accompanied by increasing public expectations on its potential clinical application, but there are still scientific, ethical, and social considerations that require resolution. In Japan, discussions pertaining to the clinical use of genome editing in human embryos are underway. However, understanding of the public's sentiment and attitude towards this technology is limited which is important to help guide the debate for prioritizing policies and regulatory necessities. Thus, we conducted a cross-sectional study and administered an online questionnaire across three stakeholder groups: the general public, patients and their families, and health care providers. We received responses from a total of 3,511 individuals, and the attitudes were summarized and compared among the stakeholders. Based on the distribution of responses, health care providers tended to be cautious and reluctant about the clinical use of genome editing, while patients and families appeared supportive and positive. The majority of the participants were against the use of genome editing for enhancement purposes. Participants expressed the view that clinical use may be acceptable when genome editing is the fundamental treatment, the risks are negligible, and the safety of the technology is demonstrated in human embryos. Our findings suggest differences in attitudes toward the clinical use of genome editing across stakeholder groups. Taking into account the diversity of the public's awareness and incorporating the opinion of the population is important. Further information dissemination and educational efforts are needed to support the formation of the public's opinion.

Risk factors of gynecological bleeding in female patients with left-ventricular assist device.

Women with implantable left-ventricular assist devices (LVADs) experience gynecological bleeding (GYN-bleeding). However, a few studies have investigated female-specific problems. Therefore, this study aimed to identify the risk factors for adverse GYN-bleeding after LVAD implantation. We retrospectively analyzed 59 women (mean age: 41 ± 15 years) with long-term implantable LVAD support (≥ 6 months) at our institution between 2005 and 2018. The history of GYN-bleeding before implantation was defined as abnormal utero-ovarian bleeding, excessive menstruation, uterine fibroids, and endometrial lesions. GYN-bleeding after implantation was defined as a requirement of emergency outpatient visits and/or hospitalization, blood transfusions, hormonal therapy, and/or surgery. Additionally, risk factors for GYN-bleeding were identified using the Cox regression model. Twenty-four GYN-bleeding cases were seen in 15 patients (two times: five patients, three times: two patients, 0.18 events per patient-year). The 1- and 2-year GYN-bleeding-free rates were 84% and 73%, respectively. Twelve patients (17 events) required RBC ≥ 4 units, and five patients (7 events) required FFP ≥ 4 units. Seven patients required pseudomenopausal treatment after blood transfusion, and four patients required surgical treatment. Fifteen patients with GYN-bleeding after implantation were significantly younger than the remaining 44 patients without GYN-bleeding (34 ± 12 years vs. 43 ± 16 years, P = 0.02). Multivariable risk analysis showed a history of GYN-bleeding before implantation was a significant risk factor (hazard ratio 3.7 [1.2-10.6], P = 0.004). Patients with a history of GYN-bleeding before LVAD implantation have a high risk of developing GYN-bleeding after implantation. We should identify the high-risk population and prepare for the management of GYN-bleeding.

[Clinical Outcome of Heart Transplantation in Osaka University].

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.

Cardiac Fibroblasts Play Pathogenic Roles in Idiopathic Restrictive Cardiomyopathy.

BACKGROUND: Restrictive cardiomyopathy (RCM) is characterized by impaired ventricular relaxation. Although several mutations were reported in some patients, no mutations were identified in cardiomyocyte expressing genes of other patients, indicating that pathological mechanisms underlying RCM could not be determined by cardiomyocytes only. Cardiac fibroblasts (CFs) are a major cell population in the heart; however, the pathological roles of CFs in cardiomyopathy are not fully understood.Methods and Results:This study established 4 primary culture lines of CFs from RCM patients and analyzed their cellular physiology, the effects on the contraction and relaxation ability of healthy cardiomyocytes under co-culture with CFs, and RNA sequencing. Three of four patients hadTNNI3mutations. There were no significant alterations in cell proliferation, apoptosis, migration, activation, and attachment. However, when CFs from RCM patients were co-cultured with healthy cardiomyocytes, the relaxation velocity of cardiomyocytes was significantly impaired both under direct and indirect co-culture conditions. RNA sequencing revealed that gene expression profiles of CFs in RCM were clearly distinct from healthy CFs. The differential expression gene analysis identified that several extracellular matrix components and cytokine expressions were dysregulated in CFs from RCM patients. CONCLUSIONS: The comprehensive gene expression patterns were altered in RCM-derived CFs, which deteriorated the relaxation ability of cardiomyocytes. The specific changes in extracellular matrix composition and cytokine secretion from CFs might affect pathological behavior of cardiomyocytes in RCM.

External compression due to seroma of ventricular assist device outflow graft.

A 45-year-old woman with repaired complex congenital heart disease, who underwent placement of Jarvik 2000, a ventricular assist device (VAD) for 4 years, experienced abdominal pain due to outflow graft compression caused by seroma formation between the outflow graft and ringed Gore-Tex graft. We exchanged the pump of Jarvik 2000 and punched several small holes in the new ringed Gore-Tex graft. Seroma formation between the two grafts should be considered as a cause of outflow graft obstruction in patients with the long-term support of VAD, and additional surgical interventions to the ringed Gore-Tex graft may prevent this complication.

Pediatric patient with restrictive cardiomyopathy on staged biventricular assist device support with Berlin Heart EXCOR® underwent heart transplantation successfully: the first case in Japan.

Pure restrictive cardiomyopathy is a strong risk factor for poor outcomes in children with cardiomyopathy on ventricular assist devices. Owing to concomitant right heart failure, children with end-staged restrictive cardiomyopathy who are supported with a ventricular assist device often require a biventricular assist device, which is another risk factor for waitlist mortality in heart transplantation candidates. Herein, we report the case of a 3-year-old boy with pure restrictive cardiomyopathy who successfully underwent heart transplantation after 12 months of support with staged biventricular assist devices. Owing to the progression of diastolic dysfunction, the left ventricular assist device could not provide adequate circulation support. Despite the provision of biventricular assist device support, the patient required a complex management strategy that involved balancing the left and right ventricular assist device supports. We were able to stabilize the patient by careful synchronization of the supports and proceeded to heart transplantation. TRIAL REGISTRATION: Clinical Registration No.: Institutional Review Board of Osaka University Hospital, approval no. 16105.

Impact of Long-Term Support with Berlin Heart EXCOR® in Pediatric Patients with Severe Heart Failure.

Berlin Heart EXCOR® (BHE) ventricular assist device (VAD) (Berlin Heart, Berlin Heart AG, Berlin, Germany) implantation is prevalent in patients with severe heart failure. However, clinical outcomes of pediatric patients on long-term BHE support remain mainly unknown. This study aimed to report our clinical experience with long-term support of pediatric patients with severe heart failure supported by BHE VAD. Clinical outcomes of 11 patients (median age 8.4 months; two male), who underwent LVAD implantation of the Berlin Heart EXCO® (BHE) VAD (Berlin Heart, Berlin Heart AG, Berlin, Germany) between 2013 and 2017 at our institution were reviewed. The median support period was 312 (range 45-661) days and five patients were supported for more than 1 year. The longest support duration was 661 days. No mortality occurred, and six patients were successfully bridged to heart transplantation, while three patients were successfully weaned off the device. Two patients are currently on BHE support while they await heart transplantation. Four patients had cerebral bleeding or infarction, but only one case of persistent neurological deficit occurred. No fatal device-related infection occurred during LVAD support. BHE VAD can provide long-term support for pediatric patients with severe heart failure with acceptable mortality and morbidity rates with long-term support.

Clinical Predictors of Right Ventricular Myocardial Fibrosis in Patients With Repaired Tetralogy of Fallot.

BACKGROUND: This study aimed to identify the clinical predictors of the degree of right ventricular (RV) myocardial fibrosis in patients with repaired tetralogy of Fallot (TOF) with special focus on the RV pressure load.Methods and Results:From April 2004 to March 2017, 30 patients with repaired TOF underwent pulmonary valve replacement and concomitant RV myocardial biopsy. The stroke volume ratio (RV stroke volume/left ventricular stroke volume), RV end-diastolic volume index, and right-to-left ventricular systolic pressure ratio were evaluated with respect to their prognostic value for the degree of RV myocardial fibrosis. Significant positive linear correlations were detected between the stroke volume ratio and the degree of RV myocardial fibrosis (P=0.003, r=0.52). Patients with a right-to-left ventricular systolic pressure ratio >0.45 showed a significantly greater degree of RV myocardial fibrosis under an equivalent stroke volume ratio. CONCLUSIONS: Under conditions of RV volume overload, a right-to-left ventricular systolic pressure ratio >0.45 was a predisposing factor for progression of RV myocardial fibrosis in patients with repaired TOF.

Application of a Fresh Decellularized Pulmonary Allograft for Pulmonary Valve Replacement in Japan.

BACKGROUND: Tissue engineering has advanced the technique of decellularization of the heart valve. The valve is reseeded with the patient's own cells after implantation with suppression of immunologic reactions. The same advantage has been reported for fresh decellularized heart valves, and more than 10 years of excellent outcomes have been achieved. We began performing such heart valve implantations in 2013 as part of a clinical study at Osaka University. We report our evaluation of the safety and efficacy of heart valve implantation.Methods and Results:Human pulmonary valves from the German Society for Tissue Transplantation (n=2) or from Japanese heart transplant recipient heart (n=4) were used to make decellularized heart valves; the decellularization process was the same as that used in Europe. Valves were implanted in 5 adults with pulmonary valve insufficiency after tetralogy of Fallot repair and in 1 infant with a double-outlet right ventricle with pulmonary stenosis. Postoperative echocardiography and cardiac magnetic resonance imaging revealed that the valve and ventricular function were significantly improved and maintained postoperatively. CONCLUSIONS: Decellularized heart valves could be the new material used as artificial heart valves. Pulmonary allografts derived from the hearts of heart transplant recipients are considered to be useful material for decellularized heart valves. The application of this valve to Japanese clinical circumstances and using the hearts of heart transplant recipients is considered to be very significant.

Overview of the 82nd Annual Scientific Meeting of the Japanese Circulation Society　- Futurability: Pioneering the Future of Circulatory Medicine.

The 82nd Annual Scientific Meeting of the Japanese Circulation Society was held in Osaka, Japan, on March 23-25, 2018, when the cherry blossoms were just opening everywhere around the venue. This was the 5th Annual Scientific Meeting of JCS in which a cardiovascular surgeon served as Congress Chairperson. The main theme of this meeting was "Futurability: Pioneering the Future of Circulatory Medicine". The word, futurability, is a neologism of future ability, because we now have to contemplate what constitutes the essence of cardiovascular medicine, how it should develop as medicine for future generations, and how its ability should be displayed. The meeting was favored by splendid weather and the number of participants was recorded as being higher than 18,700. There were heated and profound discussions about the "futurability" of cardiology, cardiovascular surgery, and heart team medical care as well, in every session. The meeting was successfully completed and we sincerely appreciate the great cooperation and support from all affiliates.

Pulmonary Valve Replacement With Fresh Decellularized Pulmonary Allograft for Pulmonary Regurgitation After Tetralogy of Fallot Repair　- First Case Report in Japan.

BACKGROUND: Pulmonary valve replacement (PVR) is a common reoperation, typically required approximately 10 years following right ventricular outflow tract reconstruction and especially true in cases of tetralogy of Fallot. However, an improved prosthetic valve is required. METHODS AND RESULTS: A fresh decellularized pulmonary allograft was used for PVR to correct pulmonary valve regurgitation in a 35-year-old man 33 years following tetralogy of Fallot repair. The postoperative course and short-term valve function were excellent. This is the first case of a decellularized pulmonary allograft in Japan. CONCLUSIONS: Fresh decellularized pulmonary allografts have the potential to become a new source of material for PVR in patients who have undergone right ventricular outflow tract reconstruction.

The usefulness of staged extra-anatomic bypass for coarctation of the aorta with arch hypoplasia, from premature neonate to adult.

Various surgical techniques have been developed for coarctation of the aorta. However, coarctation repair in neonates with arch hypoplasia remains challenging. We herein report a case in which a premature neonate under 1500 g with coarctation of the aorta and arch hypoplasia underwent an extra-anatomical bypass at 18 days old. A second extra-anatomical bypass was performed at 3 years of age, and a third extra-anatomic bypass for recurrent coarctation was performed in adulthood. By increasing the size of the graft as the patient grows, extra-anatomic bypass can be a useful surgical option for premature neonates with coarctation and arch hypoplasia.

Restrictive annuloplasty or replacement on reverse remodeling for nonischemic dilated cardiomyopathy.

BACKGROUND: For patients with nonischemic dilated cardiomyopathy (NIDCM), the indications for and results of mitral surgery remain controversial. We reviewed a strategy of mitral repair and replacement for clinically relevant secondary mitral regurgitation (MR) in patients with NIDCM. METHODS: We retrospectively reviewed 65 patients with advanced NIDCM (LVEF < 40%) who underwent mitral surgery. Of them, 47 (72%) underwent mitral annuloplasty and 18 (28%) replacement for secondary MR. The primary endpoint was postoperative reduction in indexed LV end-systolic volume (LVESVI). RESULTS: At baseline, there was no intergroup difference in LVESVI (123 ± 47 vs. 147 ± 37 ml/m2, P = 0.055), LVEF (27 ± 8% vs. 25 ± 6%, P = 0.41), incidence of severe MR (57% (27/47) vs. 72% (13/18), P = 0.40), or EuroSCORE II score (6.2% vs. 7.6%, P = 0.90). At 6 months, the annuloplasty group reduced LVESVI to a greater degree than the replacement group (P < 0.001), yielding significantly smaller postoperative LVESVI (96 ± 59 vs. 154 ± 61 ml/m2, P < 0.001) and better LVEF (P < 0.001). The rates of moderate/severe recurrent MR were 17% (8/47) and 0%, respectively. Multivariable analysis demonstrated that mitral annuloplasty (OR 6.10, 95% CI 1.14-32.8, P = 0.035) was significantly associated with postoperative LV reverse remodeling. Cumulative survival was not different between the groups (P = 0.26). CONCLUSIONS: In patients with NIDCM, mitral annuloplasty reduced LV volume to a greater degree than did mitral replacement. These findings may assist with surgical options for secondary MR associated with NIDCM.

Impaired Relaxation in Induced Pluripotent Stem Cell-Derived Cardiomyocytes with Pathogenic TNNI3 Mutation of Pediatric Restrictive Cardiomyopathy.

BACKGROUND: Restrictive cardiomyopathy (RCM) is characterized by impaired diastolic function with preserved ventricular contraction. Several pathogenic variants in sarcomere genes, including TNNI3, are reported to cause Ca2+ hypersensitivity in cardiomyocytes in overexpression models; however, the pathophysiology of induced pluripotent stem cell (iPSC)-derived cardiomyocytes specific to a patient with RCM remains unknown. METHODS AND RESULTS: We established an iPSC line from a pediatric patient with RCM and a heterozygous TNNI3 missense variant, c.508C>T (p.Arg170Trp; R170W). We conducted genome editing via CRISPR/Cas9 technology to establish an isogenic correction line harboring wild type TNNI3 as well as a homozygous TNNI3-R170W. iPSCs were then differentiated to cardiomyocytes to compare their cellular physiological, structural, and transcriptomic features. Cardiomyocytes differentiated from heterozygous and homozygous TNNI3-R170W iPSC lines demonstrated impaired diastolic function in cell motion analyses as compared with that in cardiomyocytes derived from isogenic-corrected iPSCs and 3 independent healthy iPSC lines. The intracellular Ca2+ oscillation and immunocytochemistry of troponin I were not significantly affected in RCM-cardiomyocytes with either heterozygous or homozygous TNNI3-R170W. Electron microscopy showed that the myofibril and mitochondrial structures appeared to be unaffected. RNA sequencing revealed that pathways associated with cardiac muscle development and contraction, extracellular matrix-receptor interaction, and transforming growth factor-ß were altered in RCM-iPSC-derived cardiomyocytes. CONCLUSIONS: Patient-specific iPSC-derived cardiomyocytes could effectively represent the diastolic dysfunction of RCM. Myofibril structures including troponin I remained unaffected in the monolayer culture system, although gene expression profiles associated with cardiac muscle functions were altered.

Novel surgical technique for anomalous origin of a left coronary artery from the right sinus of Valsalva with a single coronary orifice.

Anomalous origin of a left coronary artery from the right sinus of Valsalva with a single coronary orifice is a rare congenital anomaly, which has been associated with myocardial ischemia and sudden death. Surgical repair is recommended upon its detection. A 14-year-old boy was diagnosed with anomalous origin of a left coronary artery from the right sinus of valsalva with a single coronary orifice after a syncope attack. The patient underwent relocation of the left coronary orifice. The postoperative course was uneventful, with no ventricular arrhythmia or syncope. The patient did not develop cardiac ischemia or infarction on exercise Tc-99 m myocardial scintigraphy 8 months after the procedure.

Univentricular Conversion for Acquired Severe Right Ventricular Failure.

In a 14-year-old boy, prolonged right ventricular (RV) dysfunction due to postmyocarditis cardiomyopathy developed, whereas left ventricular function recovered with conservative treatment. On catheterization, the RV end-diastolic volume index was 184 mL/m2, and mean pulmonary artery pressure was 16 mm Hg. Despite one-and-a-half ventricle repair, RV dilation continued to worsen; therefore, 3 years after the operation, RV exclusion and extracardiac total cavopulmonary connection were performed. Postoperatively, left ventricular function was maintained, and no further RV dilation was observed. Univentricular conversion may be an effective procedure for the treatment of acquired severe isolated right-sided heart failure.

Three-step surgical management algorithm for annular rupture in transcatheter aortic valve replacement.

Objective: Whereas transcatheter aortic valve replacement is widely implemented, annular rupture is a devastating complication and could be highly mortal. However, owing to its rare incidence, the optimal treatment algorithm has not been established. Thus, we evaluated the feasibility and effectiveness of a 3-step algorithm to treat annulus rupture. Methods: From 2009 to 2022, 8 patients of 1083 transcatheter aortic valve implantation (0.8%) developed annulus rupture and were treated with the three-step algorithm. The algorithm was composed of a first step (pericardial drainage and protamine neutralization with blood pressure control), second step (manual hemostatic compression via full/partial sternotomy), and a third step (conservative treatment or radical surgical correction). Results: The median age at the procedure was 85 (78-88) years and 7 female patients were included in this study. Two (25%) patients had end-stage renal failure under hemodialysis, and median Society of Thoracic Surgeons score was 8.9% (2.1%-23.2%). The implanted transcatheter heart valves (THVs) were 7 balloon-expandable THVs and 1 self-expandable THV with balloon postdilatation. Under this strategy, 8 (100%) patients underwent pericardial drainage as first step and 5 patients achieved hemostasis. Of these, patient 1 demonstrated bleeding from left sinus of Valsalva and required a Bentall procedure. Although the etiology of this phenomenon was not investigated by contrast-enhanced computed tomography, it might be derived from pseudoaneurysm rupture or delayed annular rupture. In 2 patients, the second step treatment was needed for hemostasis. Third-step treatment was conducted in 1 patient. Postoperatively, 6 patients could be discharged without critical complications whereas 2 patients died during the hospitalization. There were no other complications during the followed-up (584 [7-1614]) days. Conclusions: In accordance with the three-step algorithm, 6 patients, including those with high-risk or inoperative status, survived.