Journal of Artificial Organs最新文献

This study aimed to demonstrate whether impregnating the graft bone with platelet-rich plasma (PRP) accelerates graft bone catabolism in lateral lumbar interbody fusion (LLIF). Consecutive patients who underwent LLIF were assessed. Of the two spaces for bone grafts in the intervertebral cage, one space was filled with graft bone impregnated with PRP, and the other was filled with graft bone without PRP, which divided the graft bones into PRP and non-PRP groups. The mean Hounsfield units (HU) of the graft bone at the center of the cage space in the coronal and axial slices were measured using computed tomography (CT) images 1 week and 6 months after surgery. The delta value of HU from 1 week to 6 months after surgery was calculated for the PRP and non-PRP groups. We compared the delta values of the HU between the two groups. The PRP and non-PRP groups comprised 16 bone grafts. In the coronal slices, the HU value in the PRP group (delta value: 526.1 ± 352.2) tended to have a greater decrease at 6 months after surgery compared with that in the non-PRP group (delta value: 217.6 ± 240.4) (p = 0.065). In the axial slices, the HU value in the PRP group (delta value: 501.3 ± 319.6) was significantly decreased at 6 months after surgery compared with that in the non-PRP group (delta value: 159.2 ± 215.3) (p = 0.028). Impregnating the graft-bone with PRP accelerated graft bone catabolism in LLIF within 6 months after surgery.

In April 2021, destination therapy (DT) was finally approved in Japan. Since DT does not aim at heart transplantation (HT), our goal is to have a patient safely remain on an implantable ventricular assist device (VAD) for the rest of his/her life. To achieve this goal, similarly to bridge-to-transplant (BTT) patients, the authors believe the following six aspects are even more crucial in DT patients: (1) to appropriately assess risks before implantation, (2) to carefully determine the ability to manage the device by multidisciplinary discussions, (3) to prevent complications by improving the quality of care, (4) to expand the number of facilities that can take care of DT patients by improving collaboration among the facilities, (5) to reduce the burden of caregivers by utilizing social resources, and (6) to establish a home palliative care system based on advance care planning. In addition, for elderly DT patients to live happy and long lives, it is essential to help them to find a purpose of life and to keep activities of daily living, such as employment, schooling, and participation in social activities, just like the general elderly population. Our goals are not only to do our best for the patients just in front of us, but also to establish a system to follow up our DT cohort, same as BTT one, by all-Japan manner. In the present review, we discuss the current state of DT in Japan and what we need to focus on to maintain or improve its long-term performance.

A 31-year-old man with a HeartMate 3 was admitted with a "Driveline Communication Fault" alarm due to liquid infiltration. Eleven months earlier, the connector between the modular and pump cables had gotten wet when he was taking a shower. The cable connector was dried immediately, and no alarm had been observed during follow-up. Subsequently, the modular cable and system controller were replaced, with corrosion found on the modular cable connector. The "Communication Fault" alarm recurred, and complete damage to the communication cables was discovered. The pump was replaced, and the removed pump cable connector showed corrosion as well. If the driveline connector gets wet, the multidisciplinary team should discuss if it should be immediately disconnected and dried, averting the need for future pump replacements due to corrosion.

The mortality rate in patients with heart failure complicated by cardiogenic shock following acute myocardial infarction (AMI) remains high, prompting research on mechanical circulatory support. Improved mortality rates have been reported with the early introduction of EcMELLA (Impella combined with extracorporeal membrane oxygenation, ECMO). However, clear indications for this treatment have not been established, given the associated risks and limitations related to access routes. Left ventricular thrombosis is traditionally considered a contraindication for Impella use. A 74-year-old man without specific medical history or coronary risk factors was diagnosed with Forrester IV heart failure due to cardiogenic shock complicated by AMI and left ventricular thrombosis. The patient underwent emergency coronary artery bypass surgery, intracardiac thrombus removal, and Dor surgery. Following cardiopulmonary bypass, ongoing heart failure was observed, necessitating the implementation of EcMELLA for circulatory support. Preoperative computed tomography showed that the bilateral subclavian arteries were too narrow (< 7 mm) and anatomically unsuitable for traditional access methods. Thus, we introduced a single-access EcMELLA 5.5, through which the Impella was introduced and veno-arterial-ECMO blood was delivered from a single artificial vessel anastomosed to the brachiocephalic artery. The patient was weaned off veno-arterial-ECMO and extubated on postoperative day 3. By postoperative day 14, improved cardiac function allowed for Impella removal. The patient was discharged on postoperative day 31 with improved ambulation; thereafter, the patient returned to work. Thus, the single-access EcMELLA5.5 treatment strategy combined with Dor procedure was effective in left ventricular thrombosis in patients with heart failure with cardiogenic shock complicated by AMI.

Hemolysis is the most important issue to consider in the design and optimization of blood-contacting devices. Although the use of Computational Fluid Dynamics (CFD) in hemolysis prediction studies provides convenience and has promising potential, it is an extremely challenging process. Hemolysis predictions with CFD depend on the mesh, implementation method, coefficient set, and scalar-shear-stress model. To this end, an attempt was made to find the combination that would provide the most accurate result in hemolysis prediction with the commonly cited power-law based hemolysis model. In the hemolysis predictions conducted using CFD on the Food and Drug Administration (FDA) benchmark blood pump, 3 different scalar-shear-stress models, and 5 different coefficient sets with the power-law based hemolysis model were used. Also, a mesh independence test based on hemolysis and pressure head was performed. The pressure head results of CFD simulations were compared with published pressure head of the FDA benchmark blood pump and a good agreement was observed. In addition, results of CFD-hemolysis predictions which are conducted with scalar-shear-stress model and coefficient set combinations were compared with experimental hemolysis data at three operating conditions such as 6-7 L/min flow rates at 3500 rpm rotational speeds and 6 L/min at 2500 rpm. One of the combinations of the scalar-shear-stress model and the coefficient set was found to be within the error limits of the experimental measurements, while all other combinations overestimated hemolysis.

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.