International Journal of Artificial Organs最新文献

The collagen-based soft tissue substitutes are popularly used instead of autogenous connective tissue grafts (CTG). However, it has some drawbacks, such as rapid degradation and compromised volume stability. The novel bifunctional and volume-stable soft tissue substitute (BVSS), based on polyvinyl alcohol (PVA), biphasic calcium phosphate (BCP), and fish collagen was developed to overcome those mentioned problems. The physicochemical and mechanical properties were characterized and compared using scanning electron microscopy (SEM), degradation and swelling behavior, Fourier transform infrared spectroscopy(FT-IR), differential scanning calorimetry (DSC), and tensile testing, respectively. The biocompatibility was evaluated with fibroblast and osteoblast cells. The SEM images showed a rough and porous surface with interconnected porous structures. The 3% PVA-based scaffolds showed a suitable degradation rate in collagenase (40%-50%), more than 5% PVA (20%-30%) in 8 weeks. All prepared BVSS presented high water absorption rates. The 5% PVA-based scaffolds showed higher tensile strength than the 3% PVA-based scaffolds. The 3% 8:2 and 5% 8:2 demonstrated good cell proliferation and adhesion of both fibroblast and osteoblast cells on the scaffold. The prepared BVSS is compatible with hard and soft tissues and maintains a volume-stable character, making it ideal as a bifunctional peri-implant tissue scaffold.

High shear stress and turbulence in a miniature axial blood pump are affected by the pump's blade structure. which impacts the pump's hemodynamics and hemocompatibility performance. This study designed blades for a miniature axial blood pump via computational fluid dynamics (CFD). The optimal blade angle distribution must improve hemodynamic and hemocompatibility performance under the designed operating conditions (45,000 rpm rotational speed and 3 L/min flow rate). First, the blade inlet angles β1 were varied from -100° to -220°. Second, using the optimal β1, the blade angle distribution was changed by setting different curvatures at different curvature positions. Finally, the relationships among blade angle distribution parameters and hemodynamic, hemolysis, and thrombosis risk were analyzed. The results indicated that angle distribution should avoid positive curvature, and that "the absolute value of negative curvature percentage should increase progressively with the increasing of curvature position." Compared with the original impeller, the CFD and experimental results revealed an optimized impeller with a 17.4% increase in pressure head, a 2.1% increase in hydraulic efficiency, an 8.4% decrease in hemolysis index, and a 5.3% decrease in volume-averaged scaled activated platelet concentration. CFD-guided blade angle optimization can improve the hemodynamic and hemocompatibility performance of miniature axial blood pumps.

Purpose: Patients on veno-venous extracorporeal membrane oxygenation (VV ECMO) have shown to have higher intravenous (IV) sedation requirements and prolonged mechanical ventilation (MV) time. Literature suggests that early extubation and mobility improve survival; however, inability to wean IV analgosedation is a barrier. A strategy to decrease IV sedation is the use of adjunct enteral sedative, anxiolytic, and analgesic agents, although there is limited supportive data. The objective of this study was to assess the impact of early versus late (⩽72 h vs >72 h from time of cannulation) addition of enteral adjunct agents on continuous sedation/analgesic requirements in VV ECMO patients.

Major findings: The study included 61 patients in the early group and 59 patients in the late. There was no difference in the primary outcome of time to ⩽1 continuous infusion analgosedation agent from ECMO cannulation. Incidence of adverse drug events were not shown to be increased between groups. No difference was seen in MV duration; however, early initiation of adjuncts resulted in a shorter intensive care unit length of stay.

Conclusion: While early adjunct use did not impact weaning of IV sedation, the lack of major safety events and potential benefits seen may support adjunct use in this patient population.

Purpose: The assessment of dialysis adequacy is of great clinical importance. However, it depends on the nonlinear effects of numerous confounding factors and is therefore difficult to predict using traditional statistical methods. In this study, we used Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Least Absolute Shrinkage and Selection Operator Regression (LASSO) to assess dialysis adequacy.

Methods: A training set (70%) and a test set (30%) were randomly selected from the 264 dialysis patient case records collected for this study. We compared the machine learning models with statistical logistic regression prediction models. In addition, we performed fivefold cross internal validation and external validation.

Results: The test dataset showed sensitivity values of 0.86 (95% CI = 0.75-0.96), 0.81 (95% CI = 0.69-0.93), and 0.72 (95% CI = 0.58-0.85) for the RF, XGBoost, and LASSO models, respectively. The matched specificity was 0.73 (95% CI = 0.58-0.87), 0.81 (95% CI = 0.67-0.93), and 0.83 (95% CI = 0.71-0.95). Accuracy was 0.80 (95% CI = 0.71-0.89), 0.81 (95% CI = 0.72-0.90), and 0.77 (95% CI = 0.68-0.86). F1 scores were 0.83 (95% CI = 0.72-0.90), 0.82 (95% CI = 0.73-0.91), and 0.78 (95% CI = 0.67-0.87). The receiver operating characteristic curves (AUROC) were 0.88 (p < 0.05, 95% CI = 0.70-0.88), 0.86 (p = 0.12, 95% CI = 0.72-0.90), and 0.88 (p < 0.05, 95% CI = 0.69-0.86). The mean absolute errors (MAE) of the calibration curves were 0.15, 0.11, and 0.07. In addition, the decision curve analysis (DCA) showed wide intervals of net clinical benefit for the models.

Conclusion: Machine learning can be used to predict dialysis adequacy for optimal RF performance.

Background: Ongoing donor-organ shortage has limited transplantation making LVADs an effective alternative therapy for patients with end-stage heart failure. When LVAD-associated complications arise device exchange is a feasible and safe alternative. This study addresses the factors that impact survival post-LVAD exchange.

Methods: Our decoded database was constructed retrospectively. Surgical details, device features, and re-intervention information were studied. The primary outcome was mortality. Kaplan-Meier estimators were used for post-pump exchange survival analysis. Pairwise log-rank tests compare the survivals between different groups within each variable. p-Value <0.05 was considered significant. Backward-stepwise regression was used to construct the multivariable model using a subset of variables, retaining only variables with a p-value <0.1. Hazard ratios, their 95% confidence intervals, and p-values of the significant variables were reported.

Results: Analysis of factors impacting survival post-pump exchange study showed a poor survival probability of only primary midline-sternotomy/redo (p = 0.005). Multivariable analysis showed that bridging with ECMO was protective with a hazard ratio of 0.16 (0.03-0.86, p = 0.03).

Conclusions: The overall survival probability is 50% at 4 years post-pump exchange. This study highlights the differences in post-exchange outcomes depending on the device types and surgical approaches used. LVAD exchange for device-related complications can be performed in high-risk patients as a viable alternative to heart transplantation in the setting of the current heart allocation prioritization systems.

Background: Normothermic machine for liver perfusion (NMP) has emerged as a promising technique for dynamic preservation and functional assessment of liver grafts. However, red blood cell hemolysis is a frequently underestimated complication that may impair the interpretation of viability metrics. This study aims to determine the impact of rising free hemoglobin levels (fHb) on hepatic perfusion during NMP.

Materials and methods: Fifteen healthy female porcine livers were perfused for 18 hours using a NMP circuit primed with autologous whole blood. Hourly measurements included fHb levels, total hepatic, portal, and arterial flows, as well as biochemical parameters. Correlations between fHb and perfusion parameters were evaluated using Spearman's rank test.

Results: All livers were successfully perfused for 18 h. Free hemoglobin levels progressively increased over time. Significant inverse correlations were observed between fHb and portal vein flow (ρ = -0.772) and total hepatic flow (ρ = -0.650). Among biochemical markers, only GGT and CK showed positive correlations with fHb.

Conclusion: Progressive hemolysis during NMP is associated with impaired hepatic perfusion, affecting the portal system, and correlates with selective biochemical injury markers. These findings highlight the need for systematic monitoring of fHb in NMP protocols to ensure viability assessment and optimize graft preservation.

Background: Patients receiving left ventricular assist device (LVAD) implantation can experience significant psychological stress that negatively impacts quality of life and treatment outcomes. Assessment of LVAD stress is critical for providing targeted interventions and advancing the relevant literature. The goal of this study was to establish a new measure of LVAD-specific patient stress, the LVAD Stress Questionnaire (LSQ).

Methods: The LSQ is an 18-item measure developed by researchers with extensive clinical experience providing psychological assessment and care for LVAD candidates and recipients. In this study, the LSQ was evaluated with a sample of 73 participants post-LVAD implant.

Results: Results of factor analysis supported the use of an LSQ full-scale score, also yielding five subscales of distinct areas of stress. Cronbach's alpha indicated that the full scale and subscales had reasonable to good internal consistency. The LSQ full scale score and four of the subscale scores were positively associated with depression and anxiety. Younger age, female gender, and being unpartnered were associated with higher LVAD stress based on one or more subscale scores.

Conclusions: The LSQ is a useful tool that treatment teams can utilize to ascertain whether and in which area an LVAD causes stress, thereby informing interventions to maximize patient outcomes.

Background: Despite veno-venous extracorporeal membrane oxygenation (VV-ECMO) support, hypoxemia may persist due to venous shunting past the ECMO circuit into diseased lungs. Heart rate (HR) control therapy in patients with elevated cardiac output (CO) is one strategy to improve the ratio of ECMO flow to CO and reduce shunting.

Methods: This retrospective study examined VV-ECMO patients between June 2019 and June 2023 that received ⩾1 HR control agent within 10 days post-cannulation. Efficacy outcomes included trends in hemodynamics, oxygenation, and ventilator and ECMO parameters within 72 h after HR control initiation. Safety outcomes included incidence of hypotension or bradycardia requiring intervention.

Results: Thirty-nine patients were included. The most common HR control strategy was initiation of esmolol infusion with transition to an oral beta-blocker after a median overlap of 6 days. Patients experienced reductions in HR and CO; however, there were no substantial changes in oxygenation parameters. Adverse events were minimal, with only two cases of hypotension requiring intervention.

Conclusions: While HR control therapy was well tolerated and effectively reduced HR, it did not seem to improve oxygenation. Larger prospective studies should be designed to ascertain the role of HR control strategies in VV-ECMO patients with elevated CO experiencing refractory hypoxemia.

Severe rhabdomyolysis, characterized by extensive muscle breakdown and release of myoglobin and creatine kinase (CK), is a life-threatening condition often complicated by acute kidney injury (AKI) and multi-organ failure (MOF). Even when conventional treatments such as fluid resuscitation and renal replacement therapy (RRT) are timely applied, severe cases remain challenging to manage. Among therapies available in this setting, hemadsorption with CytoSorb has the potential not only to treat rhabdomyolysis through removal of circulating molecules but also to limit or even prevent rhabdomyolysis-related renal failure and MOF. In this case series we present a preliminary experience with a novel use CytoSorb hemoadsorption therapy, which encompassed the use of two CytoSorb cartridges running in parallel, to enhance myoglobin and cytokine clearance. Clinical data from the three patients with severe rhabdomyolysis treated with dual concomitant CytoSorb treatments highlighted marked improvements in CK, renal, hepatic, and inflammatory markers, with possible remarkable impact in containing rhabdomyolysis-related organ failure and death. Further investigation is warranted to establish the opportunity of tailored protocols for critically ill patients.

When the cardiac function is minimal, LVAD patients' intraventricular blood flow occurs entirely through the LVAD, the aortic valve is continuously closed, this condition significantly alters intraventricular haemodynamics and increases the risk of intraventricular thrombosis. The aim of this study was to analyse intraventricular blood flow patterns in continuous aortic closure, during axial flow pump support. In vitro flow visualization experiments inside a 3D-printed silicone LV model were conducted to emulate the intraventricular hemodynamic parameters inside the LV during LAP31 axial blood pump support, including the distribution of velocity, vorticity and the standard deviation of velocity. The results showed that the intraventricular blood flows directly from the mitral valve to the blood pump inlet at the three instants of the cardiac cycle when the aortic valve is continuously closed, and the standard deviation of the blood flow velocity in the examined cross-section was uniform. Meanwhile, the strong vorticity was observed in the ventricular wall near the blood pump inlet and below the aorta throughout the cardiac cycle, and the location of the strong vorticity region does not change over time. This phenomenon causes intraventricular blood stagnation in the left ventricular outflow tract and the ventricular wall near the blood pump inlet, which increases the risk of thrombus formation in the heart.