Journal of Artificial Organs最新文献

Since the COVID-19 pandemic of 2020-2023, extracorporeal membrane oxygenator (ECMO) has attracted considerable attention worldwide. It is expected that ECMO with long-term durability is put into practical use in order to prepare for next emerging infectious diseases and to facilitate manufacturing for novel medical devices. Polypropylene (PP) and polymethylpentene (PMP) capillary membranes are currently the mainstream for gas exchange membrane for ECMO. ECMO support days for COVID-19-related acute hypoxemic respiratory failure have been reported to be on average for 14 or 24 days. It is necessary to improve opposing functions such that promoting the permeation of oxygen and carbon dioxide and inhibiting the permeation of water vapor or plasma to develop sufficient durability for long-term use. For this purpose, accurately controlling the anisotropy of the pore structure of the entire cross section and functions of capillary membrane is significant. In this study, we focused on the cross-sectional ion-milling (CSIM) method, to precisely clarify the pore structure of the entire cross section of capillary membrane for ECMO, because there is less physical stress on the porous structure applied during the preparation of cross-sectional samples of porous capillary membranes. We attempted to observe the cross sections of commercially available PMP membranes using the CSIM method. As a result, we succeeded in fabricating fine-scale flat cross-sectional samples of PMP capillary membranes. The pore structures and the degree of anisotropy of the cross sections are quantitatively clarified. The achievements and the approaches of this study are being applied to the development of next-generation gas exchange membranes.

Human body constitutes unique biological system containing specific fluid mechanics and biomechanics. Traditional cell culture techniques of 2D and 3D do not recapitulate these specific natures of the human system. In addition, they lack the spatiotemporal conditions of representing the cells. Moreover, they do not enable the study of cell-cell interactions in multiple cell culture platforms. Therefore, establishing biological system of dynamic cell culture was of great interest. Organs on chips systems were fabricated proving their concept to mimic specific organs functions. Therefore, it paves the way for validating new drugs and establishes mechanisms of emerging diseases. It has played a key role in validating suitable vaccines for Coronavirus disease (COVID-19). Herein, the concept of organs on chips, fabrication methodology and their applications are discussed.

Bleeding complications are frequently observed in patients undergoing extracorporeal membrane oxygenation and are associated with increased mortality. Due to the complex mechanisms, managing bleeding during ECMO remains a challenge. Acquired von Willebrand syndrome (AVWS) in ECMO highlights a potentially reduced affinity of von Willebrand factor (vWF) for binding to platelets and collagen in response to vascular damage, thus contributing to increased bleeding in ECMO patients. Conventional coagulation parameters are incomplete predictors for bleeding in ECMO patients, whereas AVWS is often overlooked due to the absence of vWF evaluation in the coagulation profile. Therefore, clinical physicians should evaluate AVWS in patients experiencing bleeding complications during ECMO support.

We examined the number of patients abandoning cardiac replacement therapy due to the inability to secure a designated caregiver. At Osaka University Hospital Heart Center, when we receive a consultation for a patient with severe heart failure from another hospital, a heart failure team makes a visit to the referring hospital as soon as possible. We retrospectively analyzed this hospital-visit database. We received 199 severe heart failure consultations from 2016-2023. Issues identified during hospital visits included age ≥ 65 years (8%), inability to confirm the patient's intention (8.5%), and explicit refusal of therapy (2.5%). Medical problems included multiple organ failure (18.1%), obesity (13.1%), diabetes (9.5%), malignancy (5.5%), chronic dialysis (1.0%), and other systemic diseases (12.6%). Adherence problems included poor medication compliance (3.5%), history of heavy drinking (2.5%), and smoking (2.0%). Social problems included inadequate family support in 16.1% of patients. Of the 199 patients, 95 (48.0%) proceeded to a heart transplant and LVAD indication review meeting at Osaka University Hospital. The remaining 104 patients (52.0%) did not proceed to the meeting. Reasons included improvement of heart failure with conservative treatment in 37 cases (35.6%), death before discussion in 21 cases (20.2%), medical contraindications in 18 cases (18.3%), lack of caregivers in 18 cases (18.3%; 9.5% of 199 cases), and patient refusal in 5 cases (4.8%). Approximately 10% of patients consulted at Osaka University Hospital Heart Center for severe heart failure abandoned cardiac replacement therapy due to the lack of caregivers.

Heparin resistance (HR) is observed before cardiopulmonary bypass (CPB), despite with normal antithrombin III (AT-III) levels. The relationships between preoperative AT-III activity and activated clotting time (ACT) after the first heparin dose should be clarified. We retrospectively analyzed the data of 818 patients who underwent CPB surgery, with the initial heparin of 300, 400, and 500 IU/kg, between 2017 and 2021. We defined HR as the failure to achieve ACT after the initial heparin dose (Post ACT) of > 480 s.There were no significant correlations between the AT-III activity and Post ACT in all patients, including 143 patients with AT-III activity < 80% and 675 patients with AT-III activity of ≥ 80%. Also, there were no significant correlations between the AT-III activity and Post ACT in 74 patients who received heparin of 300 IU/kg, in 186 patients with 400 IU/kg, and in 339 patients with 500 IU/kg. After identifying smoking, HR, activated partial thromboplastin time, fibrinogen degradation products (FDP), and ACT as influencing factors, multiple comparisons using the Steel-Dwass test showed significant difference in FDP and HR among the patients who received heparin of 300 IU/kg, 400 IU/kg, and 500 IU/kg. There is no association between preoperative AT-III activity and ACT after the first heparin administration for CPB, even in different dose of heparin. Rather, the higher the initial UFH dose is, the higher ACT may be, regardless of the AT-III activity.

The present systematic review and meta-analysis aims to compare the effect of bicarbonate hemodialysis and HDF on quality of life (QoL), fatigue, and time to recovery in end-stage renal disease (ESRD) patients. Searches were run on January 2024 and updated on 3 March 2024 in the following databases: Ovid MEDLINE (1985 to present); Ovid EMBASE (1985 to present); Cochrane Library (Wiley); PubMed (1985 to present). Ten articles were fully assessed for eligibility and included in the investigation. Compared to HD, online HDF had a pooled MD of the mental component score (MCS) of the SF-36 of 0.98 (95% CI − 0.92, 2.87; P = 0.31). and of the physical component score (PCS) of 0.08 (95% CI − 1.32, 1.48; P = 0.91). No significant heterogeneity was observed (Chi² = 4.85; I² = 38%; P = 0.18 and Chi² = 3.85; I² = 22%; P = 0.28, respectively). Studies that compared the QoL assessed through the Kidney Disease Questionnaire or KDQOL-SF and show that HDF does not improve QoL when compared with HD, in most studies. In five out of seven studies, HDF was not significantly more effective than HD in improving fatigue. The length of the recovery time resulted in similar in patients receiving HDF and HD in all studies included in the present review. HDF is not more effective than HD in improving QoL and fatigue and in reducing the length of time of recovery after dialysis.

Ventricular-assist device therapy for small patients with congenital heart disease is challenging due to its complex anatomy and hemodynamics. We describe a 3-year-old patient with heart failure with truncus arteriosus in the palliative stage. The patient underwent palliative right ventricular outflow tract reconstruction following bilateral pulmonary artery banding. At 6 months of age, the patient developed severe truncal valve regurgitation and left ventricular dysfunction. Emergent truncal valve replacement with a mechanical valve was performed, but left ventricular dysfunction persisted. At 3 years of age, the patient developed acute progression of heart failure triggered by influenza infection. The patient was intubated and transferred to our center to determine the indication for heart transplantation. On the second day after admission, signs of multiorgan failure appeared. Emergent ventricular-assist device implantation for both ventricles was performed with truncal valve closure, ventricular septal defect closure, atrial septal defect closure, and re-right ventricular outflow tract reconstruction. The right ventricular-assist device was successfully removed on the seventh postoperative day. Due to the small pulmonary arteries, severe pulmonary stenosis persisted after ventricular-assist device implantation, but it gradually improved with multiple pulmonary angioplasties. The patient was registered in the Japanese organ transplant network and is awaiting a donor organ in a stable condition.

Neuron-specific-enolase is used as a marker of neurological prognosis after cardiopulmonary resuscitation. It is also present in red blood cells and platelets. It is not known whether hemolysis increases the values of neuron-specific-enolase enough to clinically affect its interpretation in critically ill patients who are to be introduced to veno-arterial extracorporeal oxygenation. In this study, we examined the relationships among neuron-specific-enolase and hemolysis indicators such as free hemoglobin and lactate dehydrogenase after the introduction of veno-arterial extracorporeal oxygenation. Of the 91 patients who underwent veno-arterial extracorporeal membrane oxygenation in our hospital from January 1, 2018, to February 24, 2021, 68 patients survived for more than 24 h. Of these, 14 patients who were categorized into the better cerebral performance categories (1-3) and 19 patients who were categorized into the poor neurological prognosis category (4) were included. After the introduction of veno-arterial extracorporeal membrane oxygenation, neuron-specific-enolase was markedly higher in the poor neurological prognosis group than in the good neurological prognosis group (41.6 vs. 92.0, p = 0.04). A significant positive correlation was revealed between neuron-specific-enolase and free hemoglobin in the good neurological prognosis group (rs = 0.643, p = 0.0131). A similar relationship was observed for lactate dehydrogenase and neuron-specific-enolase in both the conscious (rs = 0.737, p = 0.00263) and non-conscious groups (rs = 0.544, p = 0.0176). When neuron-specific-enolase is used as a marker for neuroprognostic evaluation, an abnormally high value is likely to indicate the lack of consciousness, whereas a lower elevation should be interpreted with caution, taking into account the effects of hemolysis.

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is a rescue therapy for severe respiratory failure in which conventional mechanical ventilation therapy is unsuccessful. Hemolysis during VV-ECMO support arises from multiple factors associated with organ damage and poor outcomes. Therefore, close and prompt monitoring is needed. Hemolytic uremic syndrome (HUS) is characterized by hemolysis, acute renal failure, and thrombocytopenia. Hemolytic features of the disease may complicate VV-ECMO management. A 26-year-old man with a history of cerebral palsy underwent VV-ECMO for acute respiratory distress syndrome (ARDS) due to septic shock caused by bacterial translocation during treatment for HUS. He showed features of hemolysis, with elevated lactate dehydrogenase (LDH), fragmented red blood cells, and low haptoglobin levels. Plasma free hemoglobin was measured daily throughout the whole course of ECMO with levels higher than 10 mg/dL but not exceeding 50 mg/dL. The extracorporeal membrane oxygenation (ECMO) circuit pressures were carefully monitored to ensure the pump generated no excessive negative pressure. The patient was weaned off ECMO on the eleventh day. There have been several cases of VA-ECMO in patients with HUS; however, there is limited literature on VV-ECMO. As the days on VV-ECMO tend to be longer than those on VA-ECMO, features of hemolysis may complicate management. Although HUS did not directly influence the clinical course in the present case, features of hemolysis were continuously observed. This case highlighted the importance of standard ECMO monitoring, especially daily measurement of plasma free hemoglobin.

Biological valves are becoming more frequently used in aortic valve replacement. While several reports have evaluated the performance of biological valves, echocardiography studies during exercise stress remain scarce. Furthermore, no current reports compare rate changes in the aortic valve area of biological valves under increased exercise load. Here, we performed exercise stress echocardiography in patients after AVR with Trifecta or Inspiris valves and compared the rates of change in aortic valve areas (AVA). In addition, hydrodynamic analysis at rest was conducted with four-dimensional flow magnetic resonance imaging (4D-flow MRI). Exercise stress echocardiography was performed in seven Trifecta and seven Inspiris patients who underwent AVR at our hospital while 4D flow MRI was performed in all but two Trifecta cases. Comparing the percentage change in AVA when loaded to 25 W versus at rest, Trifecta was greater than Inspiris (28.7 ± 36.0 vs - 0.8 ± 12.4%). The smaller AVA at rest was considered causative for this. Meanwhile, Trifecta systolic energy loss in the prosthetic valve segment on 4D-flow MRI (97.5 ± 35.9 vs 52.7 ± 25.3 mW) was higher than Inspiris. The opening of the Trifecta valve was considered to be restricted at rest and this may reflect the current reports of early valve degradation requiring reoperation. Taken together, we observed that the Trifecta design may promote faster wear due to higher valve stress.