Journal of Artificial Organs最新文献

Heart transplantation is considered to be the best treatment for severe heart failure refractory to medical therapy, improving patients' survival and quality of life (QOL). However, the number of donors is smaller than the number of registered applicants for heart transplantation, which increases every year, and the waiting period for heart transplantation has been extended to more than 1700 days by 2022. Since 2011, reimbursement for the implantable left ventricular assist device (iLVAD) was established. The numbers of the iLVAD patients have been increasing year by year. Patients are managed at home with an iLVAD and can live with their families and even return to work, depending on the situation. On the other hand, self-management at home, including caregivers, is important for a safe life. Home management beyond 5 years is becoming more common due to long waiting time for transplant. This article outlines the important aspects of patient management for long-term support. 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. 62-66), with some modifications.

We report a case in which excessive negative pressure may have been applied to the proximal side hole of a drainage cannula during venovenous extracorporeal membrane oxygenation (V-V ECMO), resulting in abnormal stenosis of the drainage cannula. V-V ECMO was introduced in a 71-year-old male patient who was transferred from another hospital for severe respiratory failure associated with varicella pneumonia and acute respiratory distress syndrome. Drainage was performed using a PCKC-V™ 24Fr (MERA, Japan) cannula via the right femoral vein with the tip of the cannula near the level of the diaphragm under fluoroscopy. Reinfusion was performed via the right internal jugular vein. Due to poor systemic oxygenation, the drainage cannula was withdrawn caudally and refixed to reduce the effect of recirculation. Two days later, drainage pressure dropped rapidly, and frequent ECMO flow interruption occurred due to poor drainage. An abdominal X-ray revealed abnormal stenosis of the proximal side hole site of the drainage cannula. We diagnosed that the drainage cannula was damaged, and it was replaced with another, namely a Medtronic Bio-Medicus™ 25 Fr (GETINGE, Sweden) cannula. However, the removed drainage cannula was not damaged, suggesting that the cannula was temporarily stenosed by momentary excessive negative pressure. In a multi-stage drainage cannula, the main drainage site is the proximal side hole, with little negative pressure applied at the apical foramen in a mock experimental ex vivo drainage test in a water tank. Hence, improvement of a multi-stage drainage cannula is recommended, such as adequate reinforcement of the side hole site with a wire.

Purpose: Hemi-resurfacing arthroplasty (Hemi) and metal-on-metal hip resurfacing arthroplasty (HR) were proposed as alternatives to conventional total hip arthroplasty (THA) for patients with osteonecrosis of the femoral head (ONFH). Long-term results were evaluated.

Methods: Twenty-three hips with ONFH were treated, using Hemi in 12 and HR in 11. Mean follow-up was 15 years in the Hemi group and 10 years in the HR group. Long-term outcomes were reviewed retrospectively.

Results: In the Hemi group, 8 hips showed acetabular protrusion and were revised to THA. One of the 8 hips showed femoral loosening. In the HR group, pseudotumor was detected in 4 hips (36%), and 1 hip was revised due to symptomatic pseudotumor. No evidence of any femoral or acetabular loosening was seen in the HR group. Ten-year survival rates were 64.2% and 90.9% in the Hemi and HR groups, respectively. Survival rate in the Hemi group dropped to 22.9% at 15 years.

Conclusions: Long-term results of Hemi for patients with ONFH were very poor, and Hemi should not continue to be used. Although HR had a concern of pseudotumor, it could offer attractive indications for 10 years.

Models of urea kinetics facilitate a mechanistic understanding of urea transfer and provide a tool for optimizing dialysis efficacy. Dual-compartment models have largely replaced single-compartment models as they are able to accommodate the urea rebound on the cessation of dialysis. Modeling the kinetics of urea and other molecular species is frequently regarded as a rarefied academic exercise with little relevance at the bedside. We demonstrate the utility of System Dynamics in creating multi-compartment models of urea kinetics by developing a dual-compartment model that is efficient, intuitive, and widely accessible to a range of practitioners. Notwithstanding its simplicity, we show that the System Dynamics model compares favorably with the performance of a more complex volume-average model in terms of calibration to clinical data and parameter estimation. Its intuitive nature, ease of development/modification, and excellent performance with real-world data may make System Dynamics an invaluable tool in widening the accessibility of hemodialysis modeling.

Implantable ventricular assist device (VAD) has enabled patients with severe heart failure to be discharged from the hospital and to continue their care at home. The presence of caregivers is essential to maintain home care of patients with VAD. The caregivers are mainly the family members who live with the patient with VAD. The caregivers need to be trained (1) VAD device management, (2) disinfection of driveline skin punctures, (3) medication management, and (4) responding to sudden changes. The caregivers' lifestyle is also forced to change. In this article, we discuss the role of caregivers in the VAD era, where long-term support beyond 5 years is now possible. 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. 81-84), with some modifications.

Periprosthetic joint infection (PJI) is a catastrophic complication after total hip arthroplasty. A new drug-loaded carbon fiber-reinforced polymer (CFRP) prosthesis with a sustained drug-release mechanism is being developed for one-stage surgery. We aimed to examine the diffusion dynamics of vancomycin from vancomycin paste-loaded CFRP implants. The differences in the in vitro diffusion dynamics of vancomycin paste were investigated using the elution test by varying parameters. These included the mixing ratio of vancomycin and distilled water (1:0.8, 1:1.2, and 1:1.4) for vancomycin paste, and hole diameter (1 mm and 2 mm) on the container. The in vivo diffusion dynamics were investigated using a rabbit model with vancomycin-loaded CFRP implants placed subcutaneously. The in vitro experiments showed that the diffusion effect of vancomycin was highest in the parameters of vancomycin paste with distilled water mixed in a ratio of 1:1.4, and with a 2 mm hole diameter. The in vivo experiments revealed diffusion dynamics similar to those observed in the in vitro study. The drug diffusion effect tended to be high for vancomycin paste with a large water ratio, and a large diameter of holes. These results indicate that the drug diffusion dynamics from a CFRP implant with holes can be adjusted by varying the water ratio of the vancomycin paste, and the hole size on the CFRP implant.

Presepsin, which is used as a biomarker for sepsis, is thought to be removed by dialysis, but the actual removal properties of dialysis are unknown. We investigated the presepsin removal properties of continuous hemodiafiltration using the high concentration of presepsin from human plasma drained by plasma exchange. Each solution in plasma exchange was connected to a continuous hemodiafiltration blood circuit and circulated at 4 conditions. The results show that presepsin was confirmed to be removed more efficiently in hemofiltration than in hemodialysis. In addition, when using a polymethylmethacrylate hemofilter for continuous hemodiafiltration, the lowest presepsin concentration is on the filtrate side, suggesting that the main removal mechanism is adsorption. Since presepsin has a molecular weight of 13,000, its removal efficiency is high by hemofiltration as per principle. In addition, since the main adsorption principle of polymethylmethacrylate hemofilter is hydrophobic bond, presepsin is considered to be adsorbed. Since presepsin is metabolized in the kidney, it is elevated in renal failure. In this paper, we confirmed that presepsin is eliminated by continuous hemodiafiltration not only in the kidney. Depending on the timing of presepsin measurement, there is a risk of missing the diagnosis of sepsis. Kidney function and continuous hemodiafiltration should be checked when measuring presepsin.

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.

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.

This study aimed to modify a laser Doppler flowmeter designed and assembled at our institute. After measuring sensitivity evaluation in ex vivo experiments, we confirmed the efficacy of this new device for monitoring real-time esophageal mucosal blood flow changes after thoracic stent graft implantation by simulating various clinical situations in an animal model. Thoracic stent graft implantation was performed in a swine model (n = 8). Esophageal mucosal blood flow decreased significantly from baseline (34.1 ± 18.8 ml/min/100 g vs. 16.7 ± 6.6 ml/min/100 g, P < 0.05) in the lower esophagus (Th6-Th8) where the stent graft covered the aorta. In the hemorrhagic shock model (shock index ≥ 1.0), esophageal mucosal blood flow showed a remarkable change from baseline in the upper esophagus (Th1-Th3), where the stent graft did not cover the aorta (20.8 ± 9.8 ml/min/100 g vs. 12.9 ± 8.6 ml/min/100 g, P < 0.01); however, it returned to the baseline value within a 30-min period. Mucosal blood flow remained stable in the esophagus, where the stent graft did not cover the aorta. After elevating the mean blood pressure to > 70 mmHg with continuous intravenous noradrenaline infusion, esophageal mucosal blood flow increased significantly in both regions; however, the reaction was different between the two regions. Our newly developed laser Doppler flowmeter could measure real-time esophageal mucosal blood flow changes in various clinical situations during thoracic stent graft implantation in a swine model. Hence, this device can be applied in many medical fields by downsizing it.