Hypoxia stabilizes the H2 O2 -producing oxidase Nox4 in cardiomyocytes via suppressing autophagy-related lysosomal degradation.

The hydrogen peroxide (H2 O2 )-producing NADPH oxidase Nox4, forming a heterodimer with p22phox , is expressed in a variety of cells including those in the heart to mediate adaptive responses to cellular stresses such as hypoxia. Since Nox4 is constitutively active, H2 O2 production is controlled by its protein abundance. Hypoxia-induced Nox4 expression is observed in various types of cells and generally thought to be regulated at the transcriptional level. Here we show that hypoxia upregulates the Nox4 protein level and Nox4-catalyzed H2 O2 production without increasing the Nox4 mRNA in rat H9c2 cardiomyocytes. In these cells, the Nox4 protein is stabilized under hypoxic conditions in a manner dependent on the presence of p22phox . Cell treatment with the proteasome inhibitor MG132 results in a marked decrease of the Nox4 protein under both normoxic and hypoxic conditions, indicating that the proteasome pathway does not play a major role in Nox4 degradation. The decrease is partially restored by the autophagy inhibitor 3-methyladenine. Furthermore, the Nox4 protein level is upregulated by the lysosome inhibitors bafilomycin A1 and chloroquine. Thus, in cardiomyocytes, Nox4 appears to be degraded via an autophagy-related pathway, and its suppression by hypoxia likely stabilizes Nox4, leading to upregulation of Nox4-catalyzed H2 O2 production.

Acute Dapagliflozin Administration Ameliorates Cardiac Surgery-Associated Acute Kidney Injury in a Rabbit Model.

BACKGROUND: Several studies have shown that sodium-glucose cotransporter-2 inhibitors have a renoprotective effect on acute kidney injury (AKI), but their effect on cardiac surgery-associated AKI is unknown.Methods and Results: AKI was induced in 25 rabbits without diabetes mellitus by cardiopulmonary bypass (CPB) for 2 h and they were divided into 5 groups: sham; dapagliflozin-treated sham; CPB; dapagliflozin-treated CPB; and furosemide-treated CPB (n=5 in each group). Dapagliflozin was administered via the femoral vein before initiating CPB. Kidney tissue and urine and blood samples were collected after the surgical procedure. There were no differences in the hemodynamic variables of each group. Dapagliflozin reduced serum creatinine and blood urea nitrogen concentrations, and increased overall urine output (all P<0.05). Hematoxylin and eosin staining showed that the tubular injury score was improved after dapagliflozin administration (P<0.01). Dapagliflozin administration mitigated reactive oxygen species and kidney injury molecule-1 as assessed by immunohistochemistry (both P<0.0001). Protein expression analysis showed improvement of inflammatory cytokines and apoptosis, and antioxidant enzyme expression was elevated (all P<0.05) through activation of the nuclear factor erythroid 2-related factor 2 pathway (P<0.01) by dapagliflozin. CONCLUSIONS: Acute intravenous administration of dapagliflozin protects against CPB-induced AKI. Dapagliflozin may have direct renoprotective effects in renal tubular cells.

Efficacy of Sac Coil Embolization in Endovascular Aortic Repair for Sac Shrinkage in Patients at a High Risk of Type II Endoleak from Lumbar Arteries.

BACKGROUND: In endovascular aortic repair (EVAR), preemptive embolization of sac branch vessels is effective in preventing postoperative type II endoleak (T2EL). However, this technique has not been widely adopted especially for lumbar arteries (LAs) because of technical difficulties and time constraints. This study aimed to investigate the efficacy of nonselective sac coil embolization, which is a simpler surgical method, in postoperative sac shrinkage for patients at a high risk of T2EL from LAs. METHODS: We retrospectively assessed 76 patients who underwent elective EVAR for abdominal aortic aneurysm with 4 or more patent LAs or at least 1 patent LA of ≥2 mm at our hospital between January 2014 and December 2022. The patients who underwent sac coil embolization were included in Group Ⅰ (n = 20), and the others were divided into 2 groups: those with an inferior mesenteric artery that was originally occluded or embolized by coils or stent graft bodies (Group Ⅱ, n = 21), and those without that (Group Ⅲ, n = 35). In Group Ⅰ, 0.035-inch coils were inserted into the sac after complete stent graft deployment. The cumulative incidence of sac shrinkage (≥5 mm) was compared between the groups. Further, univariable and multivariable Cox regression analyses were used to determine the predictors of sac shrinkage. RESULTS: Sac shrinkage (≥5 mm) was observed more frequently in Group Ⅰ (50%) than in Group Ⅱ (19%) and Group Ⅲ (17%) (P = 0.052 and 0.043, respectively). The cumulative incidence of sac shrinkage was significantly higher in Group Ⅰ than in Group Ⅱ (log-rank P = 0.039) and Group Ⅲ (log-rank P = 0.024). Multivariable Cox regression analyses revealed that sac embolization was a significant predictor of sac shrinkage (hazard ratio, 4.23; 95% confidence interval, 1.66-10.8; P = 0.003). CONCLUSIONS: Nonselective sac coil embolization in EVAR is potentially effective for sac shrinkage in the early postoperative phase in patients at high risk of T2EL from LAs. This simple procedure may improve prognosis after EVAR.

Open Versus Zone 0/1 Endovascular Aortic Repair for Arch Aneurysm: A Propensity Score-Matched Study from the National Clinical Database in Japan.

BACKGROUND: Although open surgical repair (OSR) is the gold standard for treating arch aneurysms, thoracic endovascular aortic repair (TEVAR) may be a less invasive alternative. However, it remains unclear which of the 2 methods yields better outcomes. In this study, we compared the perioperative outcomes of both procedures for arch aneurysms using a nationwide surgical database. METHODS: Data of patients who underwent elective aortic repair for true arch aneurysms were extracted from the National Clinical Database of Japan. Patients who underwent OSR and Zone 0/1 TEVAR were matched in a 1:1 ratio using propensity scores and their mortality and morbidity rates were compared. RESULTS: A total of 2,815 and 1,125 patients underwent OSR and Zone 0/1 TEVAR, respectively. After propensity score matching, 1,058 patients were included in both groups. Compared with OSR, Zone 0/1 TEVAR was associated with a significantly higher incidence of stroke (5.8 vs. 10.0%, P < 0.001) and paraplegia/paraparesis (1.6 vs. 4.4%, P < 0.001). However, there were no significant differences in the 30-day and operative mortality rates between the 2 groups (2.2 vs. 2.7% and 4.5 vs. 5.4%, respectively). In the Zone 0/1 TEVAR group, postoperative computed tomography was performed in 92.4% of patients, and types I and III endoleaks were identified in 6.4% and 1.1% of patients, respectively. CONCLUSIONS: Zone 0/1 TEVAR has higher incidences of stroke and paraplegia/paraparesis than OSR, with a risk of postoperative endoleaks. Resolving these problems is the key for expanding the application of Zone 0/1 TEVAR and in the meantime OSR remains the gold standard for surgically fit patients.

"Kyushu-style" collaboration between the implantable ventricular assist device implantation and management centers: a republication of the article published in Japanese journal of artificial organs.

Collaboration between the implantation centers, management centers, and regional core hospitals is a key factor in securing long-term implantable ventricular assist device (VAD) management. In Kyushu, a management system for patients with implantable VADs has been established at the prefectural and regional levels. Presently, six implantable VAD implantation centers and seven management centers exists in the eight prefectures of Kyushu and Okinawa, with at least one specialized VAD centers in each prefecture. This collaborative management system allows patients with VADs to receive seamless treatment based on the same management concept wherever they live. In fact, approximately half of the present outpatients treated at our center reside outside the prefecture and are managed in collaboration with management centers and regional core hospitals. Among our patients, there were no significant differences in survival or rehospitalization-free rates between patients with VADs in and out of the prefecture, suggesting that the place of residence did not affect the outcome. With the increase in the number of patients with VADs and the diversification of patients, patient management has become more complex. Mutual collaboration between the implantation centers, management centers, and regional core hospitals, is essential to improve the quality of VAD management. This review was created based on a translation of the Japanese review written in the Japanese Journal of Artificial Organs in 2023 (Vol. 52, No. 1, pp. 85-88), with some modifications.

Prevalence of bleeding events in real-world Japanese registry for Percutaneous Ventricular Assist Device.

PURPOSE: Bleeding complication is a critical risk factor for outcomes of acute heart failure patients requiring mechanical circulatory support (MCS), including percutaneous catheter-type heart pumps (Impella). The Japanese registry for Percutaneous Ventricular Assist Device (J-PVAD) is an ongoing, large-scale, real-world registry to characterize Japanese patients requiring Impella. Here we analyzed bleeding complication profiles in patients who received Impella. METHODS: All consecutive Japanese patients who received Impella from October 2017 to January 2020 were enrolled. The 30-day survival and bleeding complications were analyzed. RESULTS: A total of 1344 patients were included: 653 patients received Impella alone, 685 patients received a combination of veno-arterial extracorporeal membrane oxygenation and Impella (ECPELLA), and 6 patients had failed Impella delivery. Overall 30-day survival was 67.0%, with Impella alone at 81.9% and ECPELLA at 52.7%. Overall bleeding/hematoma adverse events with a relation or not-excluded relation to Impella was 6.92%. Among them, the rates of hematoma and bleeding from medical device access sites were 1.41% and 4.09%, respectively. There was no difference between etiologies for these events. CONCLUSION: This study represents the first 3-year survival and the safety profile focused on bleeding adverse events from the J-PVAD registry. The results show that the real-world frequency of bleeding adverse events for patients who received Impella was an expected range from previous reports, and future real-world studies should aim to expand this data set to improve outcomes and adverse events.

Short-Term Outcomes of Impella Support in Japanese Patients With Cardiogenic Shock Due to Acute Myocardial Infarction　- Japanese Registry for Percutaneous Ventricular Assist Device (J-PVAD).

BACKGROUND: The Impella®percutaneous left ventricular assist device has been available in Japan since 2017. This is the first large-scale registry study to analyze the efficacy and safety of Impella in Japanese patients with acute myocardial infarction with cardiogenic shock (AMICS).Methods and Results: The Japanese registry for Percutaneous Ventricular Assist Device (J-PVAD) has registered all consecutive Japanese patients treated with Impella. We extracted data for 593 AMICS patients from J-PVAD and analyzed 30-day survival and safety profiles. Overall 30-day survival was 63.1%. The 30-day survival of the Impella alone and Impella plus venoarterial extracorporeal membrane oxygenation (ECPELLA) groups was 80.9% and 45.7%, respectively. The Impella alone group was older and had a lower rate of cardiac arrest, milder consciousness disturbance, less inotrope use, lower serum lactate concentrations, higher B-type natriuretic peptide concentrations, and higher left ventricular ejection fraction (LVEF) than the ECPELLA group. Cox regression analysis revealed that older age and comorbid renal disturbance were common risk factors affecting 30-day mortality in both groups. Major adverse events were hemolysis (10.8%), hemorrhage/hematoma (7.6%), peripheral ischemia (4.4%), stroke (1.3%), and thrombosis (0.7%). LVEF improved in both groups during support. CONCLUSIONS: AMICS treatment with Impella showed favorable 30-day survival and safety profiles. The survival rate of patients treated with Impella alone was particularly high. Further studies are needed to improve outcomes of patients with ECPELLA support.

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.

Safety and Performance of the Micra VR Leadless Pacemaker in a Japanese Cohort　- Comparison With Global Studies.

BACKGROUND: The Micra leadless pacemaker has demonstrated favorable outcomes in global trials, but its real-world performance and safety in a Japan-specific population is unknown.Methods and Results: Micra Acute Performance (MAP) Japan enrolled 300 patients undergoing Micra VR leadless pacemaker implantation in 15 centers. The primary endpoint was the acute (30-day) major complication rate. The 30-day and 6-month major complication rates were compared to global Micra studies. All patients underwent successful implantation with an average follow-up of 7.23±2.83 months. Compared with previous Micra studies, Japanese patients were older, smaller, more frequently female, and had a higher pericardial effusion risk score. 11 acute major complications were reported in 10 patients for an acute complication rate of 3.33% (95% confidence interval: 1.61-6.04%), which was in line with global Micra trials. Pericardial effusion occurred in 4 patients (1.33%; 3 major, 1 minor). No procedure or device-related deaths occurred. Frailty significantly improved from baseline to follow-up as assessed by Japan Cardiovascular Health Study criteria. CONCLUSIONS: In a Japanese cohort, implantation of the Micra leadless pacemaker had a high success rate and low major complication rate. Despite the Japan cohort being older, smaller, and at higher risk, the safety and performance was in line with global Micra trials.

Necrostatin-1 Attenuates Delayed Paraplegia after Transient Spinal Cord Ischemia in Rabbits by Inhibiting the Upregulation of Receptor-Interacting Protein Kinase 1 and 3.

BACKGROUND: Delayed-onset paraplegia is a disastrous complication after thoracoabdominal aortic open surgery and thoracic endovascular aortic repair. Studies have revealed that transient spinal cord ischemia caused by temporary occlusion of the aorta induces delayed motor neuron death owing to apoptosis and necroptosis. Recently, necrostatin-1 (Nec-1), a necroptosis inhibitor, has been reported to reduce cerebral and myocardial infarction in rats or pigs. In this study, we investigated the efficacy of Nec-1 in delayed paraplegia after transient spinal cord ischemia in rabbits and assessed the expression of necroptosis- and apoptosis-related proteins in motor neurons. METHODS: This study used rabbit transient spinal cord ischemia models using a balloon catheter. They were divided into a vehicle-treated group (n = 24), Nec-1-treated group (n = 24), and sham-controls (n = 6). In the Nec-1-treated group, 1 mg/kg of Nec-1 was intravascularly administered immediately before ischemia induction. Neurological function was assessed using the modified Tarlov score, and the spinal cord was removed 8 hr and 1, 2, and 7 days after reperfusion. Morphological changes were examined using hematoxylin and eosin staining. The expression levels of necroptosis-related proteins (receptor-interacting protein kinase [RIP] 1 and 3) and apoptosis-related proteins (Bax and caspase-8) were assessed using western blotting and histochemical analysis. We also performed double-fluorescence immunohistochemical studies of RIP1, RIP3, Bax, and caspase-8. RESULTS: Neurological function significantly improved in the Nec-1-treated group compared with that in the vehicle-treated group 7 days after reperfusion (median 3 and 0, P = 0.025). Motor neurons observed 7 days after reperfusion were significantly decreased in both groups compared with the sham group (vehicle-treated, P < 0.001; Nec-1-treated, P < 0.001). However, significantly more motor neurons survived in the Nec-1-treated group than in the vehicle-treated group (P < 0.001). Western blot analysis revealed RIP1, RIP3, Bax, and caspase-8 upregulation 8 hr after reperfusion in the vehicle-treated group (RIP1, P = 0.001; RIP3, P = 0.045; Bax, P = 0.042; caspase-8, P = 0.047). In the Nec-1-treated group, the upregulation of RIP1 and RIP3 was not observed at any time point, whereas that of Bax and caspase-8 was observed 8 hr after reperfusion (Bax, P = 0.029; caspase-8, P = 0.021). Immunohistochemical study revealed the immunoreactivity of these proteins in motor neurons. Double-fluorescence immunohistochemistry revealed the induction of RIP1 and RIP3, and that of Bax and caspase-8, in the same motor neurons. CONCLUSIONS: These data suggest that Nec-1 reduces delayed motor neuron death and attenuates delayed paraplegia after transient spinal cord ischemia in rabbits by selectively inhibiting necroptosis of motor neurons with minimal effect on their apoptosis.

A case of mediastinal abscess and infected aortic aneurysm caused by dissemination of Mycobacterium abscessus subsp. massiliense pulmonary disease.

An 81-year-old man was admitted to our hospital because of fever and malaise that had persisted for 3 months. The patient had undergone two aortic valve replacements, 10 and 5 years previously, because of aortic valve regurgitation and infectious endocarditis. He also had had asymptomatic Mycobacterium abscessus complex (MABC) pulmonary disease for the two previous years. Contrast-enhanced computed tomography showed a mediastinal abscess and an ascending aortic aneurysm. Mycobacterium abscessus subsp. massiliense was cultured from his blood, suggesting the aortic aneurysm was secondary to infection of an implanted device. After enlargement over only a few days, a leakage of contrast medium to the mediastinal abscess was found on computed tomography. The patient was diagnosed with rupture of an infectious aortic aneurysm, and emergency aortic replacement and drainage of the mediastinal abscess were successful. The patient was treated with several antibiotics, including meropenem, amikacin, and clarithromycin, and his general condition improved. Cultures from both the mediastinal abscess and a pericardial patch that was placed at the time of surgery 5 years previously revealed MABC. In our case, the infected aortic aneurysm most likely resulted from MABC pulmonary disease rather than from previous intraoperative contamination. This route of infection is rare. Physicians should be aware of the possibility of dissemination and subsequent infection of implants related to MABC pulmonary disease.

Veno-venous extracorporeal membrane oxygenation support of pulmonary insufficiency using Avalon Elite® cannula in pediatric patients.

The "Avalon Elite®" cannula is a double-lumen cannula used to establish veno-venous extracorporeal membrane oxygenation support. The reported advantages are that extracorporeal circulation can be established by cannulating through the right internal jugular vein only, and there is less re-circulation than with a two-cannula technique. It is available in a wide range of cannula sizes and can be used in a variety of patients, from children to adults. We herein report three pediatric cases in which an Avalon Elite® cannula was useful. The first was a case of acute mitral regurgitation due to idiopathic chordal rupture for postoperative severe lung injury and atelectasis due to cardiogenic pulmonary edema. The second was a case of end-stage radiation pneumonitis for safe transfer to facility of lung transplantation. The third was a convalescent case of fulminant myocarditis with severe atelectasis due to cardiogenic pulmonary edema. In each case, veno-venous extracorporeal membrane oxygenation using an Avalon Elite® cannula was established, the expected sufficient support was secured, and a good clinical course was obtained without major complications associated with an Avalon Elite® cannula.

Three-year experience of catheter-based micro-axial left ventricular assist device, Impella, in Japanese patients: the first interim analysis of Japan registry for percutaneous ventricular assist device (J-PVAD).

Catheter-based micro-axial ventricular assist device Impella® (Abiomed, Danvers, MA) has been used in Japanese patients with drug-refractory acute heart failure (AHF) since 2017. This is the first interim analysis of the ongoing Japan Registry for Percutaneous Ventricular Assist Device (J-PVAD) to investigate the safety and efficacy of Impella support. Between October 2017 and January 2020, 823 Japanese patients, who were treated with the Impella 2.5, CP, or 5.0 pump, were enrolled. The primary endpoints were safety profiles and cumulative 30-day survival. Among them, 44.8% of patients were acute myocardial infarction with cardiogenic shock. The Impella pumps were unable to implant in 4 patients. The Impella 2.5, CP, and 5.0 pumps were used in 72.4%, 6.2%, and 16.6%, respectively, and mean support duration was 8.1 ± 10.2 days. Combination use of Impella and venoarterial extracorporeal membrane oxygenation (VA-ECMO) was applied for 387 patients (47.3%). Pump stop occurred 22 patients (2.7%). Major adverse events included hemolysis (11.2%), hemorrhage/hematoma (6.1%), peripheral ischemia (1.6%), and stroke (1.6%). The overall 30-day survival was 62.2%. Survival of patients with single Impella support was significantly higher than patients with Impella combined with VA-ECMO support (81.1% vs 49.6%; p < 0.01), who had lower blood pressure, lower left ventricular ejection fraction, and higher degree of inotropic support. Results suggest that short-term outcome of Impella support for Japanese patients was favorable with acceptable safety profiles.

[Cardiovascular Surgery for Patients Under Immunosuppressive Therapy].

Immunosuppressive agents including steroids are generally given to patients with collagen disease or organ transplant recipients. Cardiovascular surgery for these patients can potentially associate with increased rate of postoperative infection or wound healing complications. Here, some key points for perioperative management in patients under immunosuppressive therapy are reviewed. Before an elective surgery, steroids need to be tapered down as much as possible, because even small amount of steroid can lead to adverse postoperative outcomes. Withholding Biologic disease-modifying antirheumatic drugs (bDMARDs) and Janus kinase (JAK) inhibitors is recommended for stable collagen disease patients. Current guidelines for perioperative management of antirheumatic medication are summarized in Table 1. Perioperative Glucocorticoid management is also required for patients exposed to steroid therapy. Intra-and postoperative steroid cover regimen is shown in Table 2. On the other hand, immunosuppressive therapy should not be discontinued for those after organ transplant and patients with severely active collagen disease. Our experience of kidney transplant recipients who underwent cardiovascular surgery is shown in Table 3. Close monitoring of blood Tacrolimus level is highly important, because it tends to fluctuate after operation and high Tacrolimus level possibly leads to deterioration in renal function. In conclusion, careful perioperative management in cooperation with transplant surgeons and rheumatologists is vital in this clinical setting.

Effect of Diabetes Mellitus on Outcomes in Patients With Left Ventricular Assist Device　- Analysis of Data From a Japanese National Database.

BACKGROUND: The objective of this study is to investigate the effect of preoperative diabetes on all-cause mortality and major postoperative complications among patients with continuous-flow left ventricular assist device (LVAD) by using data from a national database.Methods and Results: The 545 study patients who underwent primary HeartMateII implantation between 2013 and 2019 were divided into 2 groups according to their diabetes mellitus (DM) status; patients with DM (n=116) and patients without DM (n=429). First, the on-device survival and incidence of adverse events were evaluated. Second, after adjusting for patients' backgrounds, the change of laboratory data in the 2 groups were compared. Overall, on-device survival at 1, 2, and 3 years was almost equivalent between the 2 groups; it was 95%, 94%, and 91% in patients without DM, and 93%, 91%m and 91% in patients with DM (P=0.468) The incidence of adverse events was similar between 2 groups of patients, except for driveline exit site infection in the adjusted cohort. Cox proportional hazards regression analysis revealed younger age (HR: 0.98 (95% confidence interval (CI): 0.97-0.99, P=0.001) and presence of DM (HR: 1.83 (95% CI: 1.14-2.88), P=0.016) as significant predictors of driveline infection. Laboratory findings revealed no differences between groups throughout the periods. CONCLUSIONS: The clinical results after LVAD implantation in DM patients were comparable with those in non-DM patients, except for the driveline exit site infection.

Successful Total Management of Multi-Causative Sleep-Disordered Breathing Complicated with Patient with Adult Congenital Heart Disease.

Sleep-disordered breathing is one of the complications commonly seen in patients with adult congenital heart disease (ACHD) due to multiple causes including complex underlying cardiac defects, cardiomegaly, previous thoracotomies, obesity, scoliosis, and paralysis of the diaphragm. It is often hard to determine its main cause and predict the efficacy of each treatment in its management. We herein report a 30-year-old woman after biventricular repair of pulmonary atresia with intact ventricular septum diagnosed as sleep-related hypoventilation disorder. Simultaneous treatment targeting obesity, paralysis of the diaphragm, and cardiomegaly followed by respiratory muscle reinforcement through non-invasive ventilation resolved her sleep-related hypoventilation disorder. Such management for each factor responsible for the hypoventilation is expected to provide synergetic therapeutic efficacy and increase daily activity in a patient with ACHD.

[Heart Transplantation for Older Patients].

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.

[Extracorporeal Ventricular Assist Device for Acute Cardiogenic Shock].

Various diseases cause acute cardiogenic shocks, such as fulminant myocarditis and acute myocardial infarction, but if medical treatment as an induction therapy is not effective, mechanical circulatory support (MCS) should be promptly converted. Intraaortic balloon pumping (IABP) and peripheral veno-arterial extracorporeal membrance oxygenation( V-A ECMO)[percutaneous cardiopulmonary support (PCPS)] are generally used as MCS that can be easily introduced via the groin. Still, there are some cases in which recovery of cardiac function cannot be achieved even after the acute phase therapies. This article will explain the extracorporeal ventricular assist device as a more powerful MCS after IABP or V-A ECMO as induction therapy.

[The Trend of Minimally Invasive Cardiac Surgery:Where Robot-assisted Cardiac Surgery in Japan is Now].

The trend in cardiac surgery is moving toward minimally invasive procedures worldwide. In Japan, robot-assisted cardiac surgery has started simultaneously with the insurance coverage of minimally invasive cardiac surgery in April 2018. Technology innovations such as the miniaturization of the robot arm, the development of various type of instruments have improved operability and has contributed to the spread of robot-assisted cardiac surgery. On the other hand, there are several issues that may be barriers to its widespread use. The number of facilities for robot-assisted cardiac surgery has not increased as expected probably due to the current insurance system, that is still being developed, the requirement for implementation, and the cost. The current status and issues of robot-assisted cardiac surgery in Japan will be discussed.

[Robot-assisted Cardiac Surgery Council and Current Status and Future Prospect of Robotic Mitral Valve Surgery in Japan].

The Robot-assisted Cardiac Surgery Council (RACSC) was established in 2015, and consists of the members of three closely related surgical societies and associations. The RACSC conducts the review and approval of applicant surgeons and institutions. A registry system has also been established through the Japan Cardiovascular Surgery Database-National Clinical Database( JCVSD-NCD). For the last five years, including the time when robotic mitral valve surgery was first approved as a procedure covered by the Japanese social insurance system in 2018, a total of 1,161 patients were enrolled in the JCVSDNCD, with an increase of nearly 500 cases per year. These cases underwent operations in 25 approved hospitals. The mean patient age was 59±13 years( range:20-90 years), and the male to female patient ratio was 1.8 male dominant. The most common procedure was mitral valve reconstruction, and 79% of all patients underwent annuloplasty. The mean operative time was 238±100 min, the mean cardiopulmonary bypass (CPB) time was 158±69 min, and the mean aortic cross-clamp (AXC) time was 102±49 min. When these results were compared with those of the Cleveland Clinic, which treated more than 1,000 cases as an initial institutional experience, both CPB and AXC times were nearly the same. It is believed that 200 cases are needed to stabilize the CPB and AXC time. Currently in Japan, only 3 or 4 out of the 25 approved hospitals have performed more than 200 cases over the past 5 years. The 30-day hospital mortality and redo operation rate for persisting mitral regurgitation was 0.3% and 0.6%, respectively, almost equivalent to that of the Cleveland Clinic. We believe that the 5-year result for robotic mitral surgery in Japan is acceptable. It is of note, however, that the length of hospital stay was 10.8±7.6 days, much longer than that of patients at the Cleveland Clinic( 5.2±2.8 days), and the homologous blood transfusion rate was 40.3%, twofold higher than that of the Cleveland Clinic( 20.5%). Therefore, the full benefits of less invasive robotic mitral repair surgery have not yet been achieved. Further improvements in results are both essential and anticipated.