Journal of Artificial Organs最新文献

The St. Jude Medical Epic Supra valve is a porcine bioprosthesis designed for complete supraannular implantation. No report has shown the hemodynamic performance and clinical outcomes of aortic valve replacement with the Epic Supra valve for severe aortic stenosis in a Japanese cohort. We retrospectively evaluated 65 patients who underwent aortic valve replacement using the Epic Supra valve for aortic stenosis at our department between May, 2011 and October, 2016. The mean follow-up period was 68.7 ± 32.7 months, and the follow-up rate was 89.2%. The mean age was 76.8 ± 5.3 years. The 1-, 5-, and 8-year survival rates were 96.9%, 79.4%, and 60.3%, respectively. The rates of freedom from valve-related events were 96.6% and 81.9% at 5 and 8 years, respectively. Four patients were diagnosed with structural valve deterioration (SVD), and reintervention was performed in two patients. The rates of freedom from SVD were 98.2% and 83.3% at 5 and 8 years, respectively, and the mean time to diagnosis of SVD was 72.5 ± 25.3 months. The mean pressure gradient (MPG) was 16.8 ± 6.0 mmHg postoperatively, 17.5 ± 9.4 mmHg at 5 years, and 21.2 ± 12.4 mmHg at 8 years (p = 0.08). The effective orifice area index (EOAI) was 0.95 ± 0.2 cm2/m2 immediately after surgery, 0.96 ± 0.27 cm2/m2 at 5 years, and 0.84 ± 0.2 cm2/m2 at 8 years (p = 0.10). An increase in MPG and decrease in EOAI were also observed, which may be associated with SVD. Follow-up after 5 years is important to determine if there is an increase.

The evolution of hemodialysis membranes (dialyzer, artificial kidney) was remarkable, since Dow Chemical began manufacturing hollow fiber hemodialyzers in 1968, especially because it involved industrial chemistry, including polymer synthesis and membrane manufacturing process. The development of hemodialysis membranes has brought about the field of medical devices as a major industry. In addition to conventional electron microscopy, scanning probe microscopy (SPM), represented by atomic force microscopy (AFM), has been used in membrane science research on porous membranes for hemodialysis, and membrane science contributes greatly to the hemodialyzer industry. Practical studies of membrane porous structure-function relationship have evolved, and methods for analyzing membrane cross-sectional morphology were developed, such as the ion milling method, which was capable of cutting membrane cross sections on the order of molecular size to obtain smooth surface structures. Recently, following the global pandemic of SARS-CoV-2 infection, many studies on new membranes for extracorporeal membrane oxygenator have been promptly reported, which also utilize membrane science researches. Membrane science is playing a prominent role in membrane-based technologies such as separation and fabrication, for hemodialysis, membrane oxygenator, lithium ion battery separators, lithium recycling, and seawater desalination. These practical studies contribute to the global medical devices industry.

The utilization of a minimally invasively placed catheter-mounted intravascular micro-axial flow blood pump (IMFBP) is increasing in the population with advanced heart failure. The current development of IMFBPs dates back around the 1990s, namely the Hemopump with a wire-drive system and the Valvopump with a direct-drive system. The wire-drive IMFBPs can use a brushless motor in an external console unit to transmit rotational force through the drive wire rotating the impeller inside the body. The direct-drive IMFBPs require an ultra-miniature and high-power brushless motor. Additionally, the direct-drive system necessitates a mechanism to protect against blood immersion into the motor. Therefore, the direct-drive IMFBPs can be categorized into two types of devices: those with seal mechanisms or those with sealless mechanisms using magnetically coupling. The IMFBPs can be classified into two groups depending on their purpose. One group is for cardiogenic shock following a heart attack or for use in high-risk percutaneous coronary intervention (PCI), and the other group serves the purpose of acute decompensated heart failure. Both direct-drive IMFBPs and wire-drive IMFBPs have their own advantages and disadvantages, and efforts are being made to develop and improve, and clinically implement them, leveraging their own strengths. In addition, there is a possibility that innovative new devices may be invented. For researchers in the field of artificial heart development, IMFBPs offer a new area of research and development, providing a novel treatment option for severe heart failure.

Impella is a mechanical circulatory support device of a catheter-based intravascular microaxial pump for left ventricular support and unloading. However, nonclinical studies assessing the effects of the extended duration of left ventricular unloading on cardiac recovery are lacking. An animal model using Impella implanted with a less invasive procedure to enable long-term support is required. This study aimed to evaluate the feasibility of an animal model for long-term support with Impella 5.5 implanted through carotid artery access in sheep.

Impella 5.5 was implanted in four sheep through the proximal region of the left carotid artery without a thoracotomy, and myocardial injuries were induced by coronary microembolization. Support by Impella 5.5 was maintained for 4 weeks, and the animals were observed. The position of Impella 5.5 and cardiac function was evaluated using cardiac computer tomography at 2 and 4 weeks after implantation.

All four animals completed the 4-week study without major complications. The discrepancy in the Impella 5.5 flow rate between the conscious and anesthetized states was observed depending on the device’s position. Animals in whom the inflow was above the left ventricular papillary muscle had a relatively high flow rate under the maximum performance level without a suction alarm during the conscious state. Pathological changes in the aortic valve were observed. Cardiac function under the minimum performance level was observed with no remarkable deterioration.

The animal model with myocardial injuries supported for 4 weeks by Impella 5.5 implanted through carotid artery access in sheep was feasible.

Advance care planning (ACP) is essential in managing serious and chronic illnesses to ensure that patients receive care aligned with their personal values, goals, and preferences. This review focuses on integrating ACP in the treatment of patients receiving implantable left ventricular assist devices (VADs). The heart failure palliative care team developed a unique advance directive form and pamphlet to facilitate ACP discussions, emphasizing not only medical treatment preferences but also patients’ values and life goals.

The study highlights the distinction between bridge to transplantation (BTT) and destination therapy (DT) in VAD patients, with different goals and considerations for ACP. The use of decision aids developed especially for DT candidates as a communication tool helps in sharing patients’ wishes and facilitates shared decision-making, particularly in the complex decisions surrounding DT therapy.

Challenges in implementing ACP, such as time constraints due to urgent medical conditions, difficulties in patient communication, and the recent COVID-19 pandemic, are addressed. The need for a comprehensive healthcare system capable of supporting patients’ ACP wishes, especially in the community setting, is also pointed out.

Future directions include not only developing materials to ease ACP discussions and ensuring that ACP content is shared among healthcare providers to foster collaborative and detailed planning, but also a call for widespread adoption of ACP in Japan.

This is a translation of a paper written in Japanese Journal of Artificial Organs (Vol. 52, No. 1, pp. 89–92) with additions and corrections.

Since 2011, implantable ventricular assist devices have been a standard treatment for severe heart failure alongside heart transplantation in Japan. However, the limited availability of donors has led to a prolonged wait for transplants, now averaging 1719 days, intensifying the issue of aortic insufficiency in patients with continuous flow ventricular assist devices. These devices limit the opening of the aortic valve, leading to sustained closure and increased shear stress, which accelerates valve degradation. Risk factors for aortic insufficiency include having a smaller body surface area, being of advanced age, and the presence of mild aortic insufficiency prior to device implantation. In patients presenting with mild or moderate aortic regurgitation at the time of ventricular assist device implantation, interventions such as aortic valve repair or bioprosthetic valve replacement are performed with the aim of halting its progression. The choice of surgical procedure should be tailored to each patient’s individual condition. The management of de novo aortic insufficiency in patients with continuous flow ventricular assist devices remains challenging, with no clear consensus on when to intervene. Interventions for significant aortic insufficiency typically consider the patient’s symptoms and aortic insufficiency severity. De novo aortic insufficiency progression in continuous flow ventricular assist devices patients necessitates careful monitoring and intervention based on individual patient assessments and valve condition. 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. 77–80), with some modifications.

Abstract

Critically ill pediatric patients supported on ventricular assist devices (VADs) are increasingly being anticoagulated on bivalirudin, but with difficulty monitoring anticoagulation. Activated partial thromboplastin time (aPTT) has recently been shown to poorly correlate with bivalirudin plasma concentrations, while dTT had excellent correlation. However, aPTT is the more common monitoring test and dTT testing is rarely used. In addition, effects of frequent clinical VAD scenarios (such as inflammation) on the accuracy of aPTT and dTT testing remains uncertain. We reviewed the effects of clinical scenarios (infection/inflammation, chylothorax, and steroids administration) on anticoagulation monitoring in 10 pediatric VAD patients less than 3 years at Cincinnati Children's Hospital Medical Center from 10/27/2020 to 5/6/2022 using bivalirudin for anticoagulation. There were 16 inflammation/infection, 3 chylothorax, and 6 steroids events. Correlation between dTT and aPTT was significantly lower after infection/inflammation, with dTT increasing prior to inflammation/infection while aPTT remained unchanged. In addition, steroids are administered to VAD patients to reduce inflammation and thus additionally stabilize anticoagulation. However, this anticoagulation stabilization effect was reflected more accurately by dTT compared to aPTT. In children requiring VAD support utilizing bivalirudin anticoagulation, inflammation/infection is a common occurrence resulting in anticoagulation changes that may be more accurately reflected by dTT as opposed to aPTT.

Acute respiratory distress syndrome (ARDS) is a serious complication following cardiac surgery mainly associated with the use of cardiopulmonary bypass (CPB), which could increase the risk of mortality and morbidity. This study investigated the association of regional oxygen saturation (rSO₂) during CPB with postoperative outcomes, including respiratory function. Patients who underwent cardiac surgery with CPB from 2015 to 2019 were included. Near-infrared spectroscopy was used to monitor rSO₂ at the forehead, abdomen, and thighs throughout the surgery. Postoperative markers associated with CPB were assessed for correlations with PaO₂/FiO₂ (P/F) ratios at intensive care unit (ICU) admission. Postoperative lung injury (LI) was defined as moderate or severe ARDS based on the Berlin criteria, and its incidence was 29.9% (20/67). On multiple regression analysis, the following were associated with P/F ratios at ICU admission: vasoactive-inotropic scores at CPB induction (P = 0.03), thigh rSO₂ values during CPB (P = 0.04), and body surface area (P < 0.001). A thigh rSO₂ of 71% during CPB was significantly predictive of postoperative LI with an area under the curve of 0.71 (P = 0.03), sensitivity of 0.70, and specificity of 0.68. Patients with postoperative LI had longer ventilation time and ICU stays. Thigh rSO₂ values during CPB were a potential predictor of postoperative pulmonary outcomes.

Online hemodiafiltration (OL-HDF) is a treatment modality using diffusion and ultrafiltration. There are two types of dilution methods in OL-HDF: pre-dilution, which is commonly provided in Japan, and post-dilution, which is commonly provided in Europe. The optimal OL-HDF method for individual patients is not well studied. In this study, we compared the clinical symptoms, laboratory data, spent dialysate, and adverse events of pre- and post-dilution OL-HDF. We conducted a prospective study of 20 patients who underwent OL-HDF between January 1, 2019 and October 30, 2019. Their clinical symptoms and dialysis efficacy were evaluated. All patients underwent OL-HDF every 3 months in the following sequence: first pre-dilution, post-dilution, and second pre-dilution. We evaluated 18 patients for the clinical study and 6 for the spent dialysate study. No significant differences in spent dialysates regarding small and large solutes, blood pressure, recovery time, and clinical symptoms were observed between the pre- and post-dilution methods. However, the serum α1-microglobulin level in post-dilution OL-HDF was lower than that in pre-dilution OL-HDF (first pre-dilution: 124.8 ± 14.3 mg/L; post-dilution: 116.6 ± 13.9 mg/L; second pre-dilution: 125.8 ± 13.0 mg/L; first pre-dilution vs. post-dilution, post-dilution vs. second pre-dilution, and first pre-dilution vs. second pre-dilution: p = 0.001, p < 0.001, and p = 1.000, respectively). The most common adverse event was an increase in transmembrane pressure in the post-dilution period. Compared to pre-dilution, the post-dilution method decreased the α1-microglobulin level; however, there were no significant differences in clinical symptoms or laboratory data.

Diabetic ketoacidosis (DKA) is a life-threatening complication of pediatric diabetes mellitus (DM). A bedside closed-loop artificial pancreas (AP) (STG-55; NIKKISO, Tokyo, Japan) maintains the blood glucose (BG) levels within the target range via automatic infusion of insulin and glucose. We report the application of the closed-loop AP to safely control the BG levels of a pediatric patient with DKA. A 12-year-old child with an unremarkable medical history presented with fever and restlessness. The patient was diagnosed with DKA secondary to fulminant type 1 DM and was treated with insulin infusion. He presented with Glasgow Coma Scale of E2V3M4. Arterial blood gas analysis revealed metabolic acidosis and BG levels of 489 mg/dL. His urine test was positive for ketones. Along with infusion therapy, automatic BG control using a closed-loop AP was initiated after ICU admission. This was adjusted to maintain BG levels within 100 mg/dL/6 h or less. After 24 h in the ICU, the patient regained consciousness and recovered from the metabolic acidosis. His general condition improved, and he was prescribed a diet treatment. The treatment was shifted to continuous insulin infusion, and he was transferred to the general ward, and was discharged on the 33rd day of hospitalization. The closed-loop AP prevented repetitive blood extractions, achieved prompt glycemic control, and prevented cerebral edema in a pediatric patient with DKA. This is the first report of successful treatment of DKA using a bedside closed-loop AP.