Journal of Artificial Organs最新文献

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.

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.

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.

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.

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.

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.

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.