Journal of Artificial Organs最新文献

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.

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.

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.

Purpose: A narrow terminal aorta is a risk factor for endograft occlusion after endovascular aneurysm repair. To minimize limb complications, we used Gore Excluder legs positioned side-by-side at the terminal aorta. We investigated the outcomes of our strategy for endovascular aneurysm repair in patients with a narrow terminal aorta.

Methods: We enrolled 61 patients who underwent endovascular aneurysm repair with a narrow terminal aorta (defined as < 18 mm in diameter) from April 2013 to October 2021. The standard procedure involves complete treatment with the Gore Excluder device. When other types of main body endografts were used, they were deployed proximal to the terminal aorta, and we used the Gore Excluder leg device in the bilateral limbs. Postoperatively, the intraluminal diameter of the legs at the terminal aorta was measured to assess the configuration.

Results: During the follow-up period (mean: 2.7 ± 2.0 years), there were no aorta-related deaths, endograft occlusions, or leg-related re-interventions. There were no significant differences between the pre- and postoperative ankle-brachial pressure index values in the dominant and non-dominant legs (p = 0.44 and p = 0.17, respectively). Postoperatively, the mean difference rate (defined as [dominant leg diameter-non-dominant leg diameter]/terminal aorta diameter) was 7.5 ± 7.1%. The difference rate was not significantly correlated with the terminal aortic diameter, calcification thickness, or circumferential calcification (r = 0.16, p = 0.22; r = 0.07, p = 0.59; and r = - 0.07, p = 0.61, respectively).

Conclusions: Side-by-side deployment of Gore Excluder legs produces acceptable outcomes for endovascular aneurysm repair with a narrow terminal aorta. The endograft expansion at the terminal aorta is tolerable without influencing calcification distribution.

In veno-arterial extracorporeal membrane oxygenation (VA-ECMO) treatment, the mixing zone is a key hemodynamic factor that determines the efficacy of the treatment. This study aimed to evaluate the applicability of a novel ultrasound technique called vector flow imaging (VFI) for visualizing complex flow patterns in an aorta phantom under VA-ECMO settings. VFI experiments were performed to image aortic hemodynamics under VA-ECMO treatment simulated in an anthropomorphic thoracic aorta phantom using a pulsatile pump (cardiac output: 2.7 L/min) and an ECMO pump with two different flow rates, 0.35 L/min and 1.0 L/min. The cardiac cycle of hemodynamics in the ascending aorta, aortic arch, and descending aorta was visualized, and the spatio-temporal dynamics of flow vectors were analyzed. VFI successfully visualized dynamic flow patterns in the aorta phantom. When the flow rate of the ECMO pump increased, ECMO flow was more dominant than cardiac output in the diastole phase, and the speed of cardiac output was suppressed in the systole phase. Vortex flow patterns were also detected in the ascending aorta and the arch under both ECMO flow rate conditions. The VFI technique may provide new insights into aortic hemodynamics and facilitates effective and safe VA-ECMO treatment.

During continuous-flow left ventricular assist device (CF-LVAD) support, hemodynamic shear stress causes a burden on aortic valve (AV) leaflets, leading to de novo aortic insufficiency (AI). This study investigated the influence of preoperative hemodynamic parameters on de novo AI in CF-LVAD recipients. We reviewed 125 patients who underwent CF-LVAD implantation without concomitant AV surgery between 2005 and 2018. De novo AI was defined as moderate or severe AI in those with none or trivial preoperative AI. During mean 30 ± 16 months of CF-LVAD support, de novo AI-free rate was 86% and 67% at 1 and 2 years, respectively. Multivariable analysis showed that higher right ventricular stroke work index (RVSWI) (hazard ratio, 1.12 /g/m²/beat; 95% confidence interval, 1.00-1.20; p = 0.047) and trivial grade AI (hazard ratio, 2.8; 95% confidence interval, 1.2-6.4; p = 0.020) were independent preoperative risk factors for de novo AI. The longitudinal analysis using generalized mixed effects model showed that higher RVSWI was associated with continuous AV closure after LVAD implantation (Odd ratio, 1.20/g/m²/beat; 95% confidence interval, 1.00-1.43 /g/m²/beat; p = 0.047). Right heart catheterization revealed that preoperative RVSWI was positively correlated with postoperative pump flow index in patients with continuously closed AV (r = 0.44, p = 0.04, n = 22). Preoperative higher RVSWI was a significant risk factor for de novo AI following CF-LVAD implantation. In patients with preserved right ventricular function, postoperative higher pump flow may affect AI development via hemodynamic stress on the AV.

ExtraCorporeal Liver Support (ECLS) systems were developed with the aim of supporting the liver in its detoxification function by clearing the blood from hepatic toxic molecules. We conducted a retrospective comparative analysis on patients presenting with liver failure who were treated with different extracorporeal techniques in our intensive care unit to evaluate and compare their detoxification abilities. To verify the effectiveness of the techniques, mass balance (MB) and adsorption per hour were calculated for total bilirubin (TB), direct bilirubin (DB), and bile acids (BA) from the concentrations measured. MB represents the total amount (mg or mcMol) of a molecule removed from a solution and is the only representative parameter to verify the purification effectiveness of one system as it is not affected by the continuous production of the molecules, released in the circulation from the tissues, as it is the case for the reduction rate (RR). The total adsorption per hour is calculated by the ratio between MB and the time duration and shows the adsorption ability in an hour. Our comparative study shows the superior adsorption capability of CytoSorb system regarding TB, DB, and BA, evaluated through the MB and adsorption per hour, in comparison with CPFA, MARS, Prometheus, and PAP. In conclusion, as extracorporeal purification in liver failure could be considered useful for therapeutic purposes, Cytosorb, being more performing than other systems considered, could represent the device of first choice.

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.