International Journal of Artificial Organs最新文献

After the initiation of veno-arterial extracorporeal membrane oxygenation (V-A ECMO) for hemodynamic support, patients often require vasopressor and inotropic medications to support their blood pressure and cardiac contractility. The vasoactive-inotropic score (VIS) is a standardized calculation of vasopressor and inotrope equivalence, which uses coefficients for each medication to calculate a total value. This study evaluated the association between the 30-day survival of patients receiving V-A ECMO support and the VIS calculated 24 h after ECMO cannulation (VIS24). This was a single-center, retrospective, observational cohort study. The median VIS24 of the entire cohort was 6.0, and was determined as a cutoff for comparison. Patients with a VIS24 < 6.0 were assigned to a group, and those with a VIS24 ≥ 6.0 were assigned to a second group. Patients with a VIS24 < 6.0 had higher 30-day survival than those with a VIS24 ≥ 6.0 (54.5% vs 41.4%; p = 0.03). The group with a VIS24 < 6.0 also had significantly improved survival to decannulation of ECMO support; however, there was no difference in the survival to hospital discharge. We conducted a secondary analysis of quartiles and determined that individuals with a VIS24 > 11.4 had the lowest survival in the cohort. This finding may help identify patients with the lowest probability of 30-day survival in those receiving V-A ECMO for hemodynamic support.

The ratio of blood volume to extracellular volume is approximately one to three under physiological conditions and also in stable chronic hemodialysis patients. Recently, it was found that this ratio remains unchanged during hemodialysis despite ultrafiltration. This would signify that the higher the ratio, the lower the refilling and vice versa. To test this hypothesis, treatment data of a previous study were re-analyzed. In 79 stable chronic hemodialysis patients, the refilling fraction was 0.749 ± 0.094. There was a significant negative correlation (r = -0.412; p < 0.001) between the blood volume to extracellular volume ratio and the refilling fraction. The blood volume to extracellular volume relationship seems to be a significant determinant of vascular refilling: the higher the ratio, the lower the refilling, and vice versa.

The mechanisms underlying vascular stenosis formation in the arteriovenous fistula (AVF) for hemodialysis (HD) remain mostly unknown. Several computational fluid dynamics (CFD) studies have suggested a potential role for unsteady flow in inducing intimal hyperplasia and AVF stenosis, but the majority of these observations have been limited to a single time point after surgical creation. The aim of the present study was to investigate the relation between hemodynamic conditions and AVF vascular remodeling through a CFD longitudinal study. Non contrast-enhanced MR images and Doppler Ultrasound (US) examinations were acquired at 3 days, 40 days, 6 months, 1 year, and 1.5 years after surgery in a 72-year male referred for native radio-cephalic AVF. Three-dimensional AVF models were generated and high fidelity CFD simulations were performed using pimpleFoam, setting patient-specific boundary conditions derived from US. Morphological and hemodynamic changes over time were then analyzed. Analysis of vessel morphology and hemodynamics during follow-up showed that the AVF had a successful maturation process, characterized by a massive arterial and venous dilatation within the 6 months after surgery, a corresponding increase in blood flow volume and important flow instabilities. Between 6 months and 1 year, a stenosis developed in the juxta-anastomotic vein and caused AVF failure at 1.5 years. The development of stenosis was paralleled by the regularization of blood flow velocity pattern and consequent decrease in the near-wall disturbed flow metrics. These results suggest that development of intimal hyperplasia and vessel stenosis, triggered by unsteady flow, could be the result of vascular inward remodeling toward regularization of turbulent-like flow.

Infectious complications are common during extracorporeal membrane oxygenation (ECMO) and may negatively impact outcomes. However, there is considerable variation in the reported rates of incidence, which hampers the use of infections as a quality benchmark for ECMO centers. To assess the contributing role of poor interrater agreement, three independent raters reviewed medical records from all intensive care unit (ICU) patients who received ECMO for >24 h in our tertiary center between October 2019 and October 2021 for suspected episodes of infection, which were rated based on their date of onset and presumed site/diagnosis. To establish a gold standard, any discrepancies were resolved using an expert panel consisting of two intensivists/infectious disease specialists. During 83 ECMO-runs in 77 patients, we observed a total of 62 adjudicated infectious episodes (incidence rate 62, 95% CI: 48-80, per 1000 days at risk). Among 81 episodes suspected by at least one observer, 66 (81%) were identified by two, and only 44 (54%) by all three raters, resulting in Fleiss' kappa of 0.10 (95% CI: 0.00-0.19; slight agreement). However, if raters concurred regarding infection onset, subsequent agreement on infection site was good (concordance 89%; kappa 0.85, 95% CI: 0.72-0.98; near perfect agreement). In conclusion, adjudication of infectious episodes during ECMO is associated with poor interrater agreement regarding occurrence-but not site-of infection. This finding might partially explain the significant disparities observed in reported infection rates during ECMO, emphasizing the need for caution when interpreting infection data in this particular population due to the potential for inherent measurement error.

More than 50% of heart failure (HF) patients require diuretic therapy after left ventricular assist device (LVAD). Although few data related to diuretic response (DR) exist in stage D patients, tubular sodium reabsorption may be clinically prognostic independent of estimated glomerular filtration rate (eGFR) and proteinuria within this cohort. We aimed to characterize DR serially before and after LVAD implantation in a stage D population. We conducted a prospective, observational cohort study of HF patients receiving diuretics with plans to undergo LVAD implantation. We measured urine sodium (U_Na) and creatinine (U_Cr) at three points after diuretic therapy: pre-LVAD, post-LVAD prior to discharge, and as an outpatient. Prior to LVAD, patients (N = 19) had an average eGFR of 54.0 ± 18.0 mL/min/1.73 m², spot U_Na of 74.8 ± 28.0 mmol/L, and fractional excretion of sodium (FE_Na) of 3.1 ± 2.7%. Pre-LVAD, eGFR did not correlate with spot U_Na nor FE_Na (p > 0.05 for both). LVAD implantation did not improve DR post-LVAD (mean change FE_Na per 40 mg IV furosemide 0.5 ± 1.0%; p = 0.84), and 90% of patients required loop diuretics at 90 days post-surgery. Improved hemodynamics following LVAD may not improve DR or tubular function; larger studies are needed to confirm our results and assess the utility of DR to predict post-LVAD outcomes.

Objective: To investigate the effects of low-calcium and standard-calcium dialysate in patients with chronic kidney disease on peritoneal dialysis, and find out which dialysate has less vascular calcification effect.

Methods: A total of 141 patients who had undergone peritoneal dialysis (PD) for 2 years in the PD centre from January 2012 to December 2017 were included and divided into two groups according to the calcium concentration of the PD fluid used. There were 79 cases in the low-calcium group, with a dialysate calcium concentration of 1.25 mmol/L and 62 cases in the standard-calcium group, with a dialysate calcium concentration of 1.75 mmol/L. The demographic characteristics and clinical information before initiation of PD were collected and compared between the two groups. Information on the serum calcium, phosphorus and PTH, systolic and diastolic blood pressures and the use of antihypertensive and phosphate-lowering drugs in the second year of dialysis was also collected and compared between the two groups. Vascular calcification was assessed in patients on PD treatment.

Results: The mean serum calcium concentrations before initiation of PD in the low- and standard-calcium groups were 1.94 ± 0.27 and 1.89 ± 0.28 mmol/L, respectively. The serum calcium concentrations after PD were 2.30 ± 0.21 and 2.41 ± 0.23 mmol/L, respectively. After PD, the serum calcium concentration in both groups was significantly increased (p < 0.05). The serum calcium concentration in the low-calcium group after PD treatment was lower than that in the standard-calcium group, and the difference was statistically significant (p < 0.05). Compared with the standard-calcium group, patients in the low-calcium group had significantly higher parathyroid hormone concentrations (p < 0.05). More types of phosphate-lowering drugs were used (59.49%) in the low-calcium group than that in the standard-calcium group (35.48%; p < 0.05). The number of antihypertensive drug usage were also higher in the low-calcium group, and the difference was statistically significant (p < 0.05). As for the vascular calcification effect, the two groups have shown no statistical difference in abdominal aortic calcification rate, carotid arteriosclerosis rate and aortic arch calcification rate (p < 0.05).

Conclusion: We found that low-calcium PD fluid may increase the PTH level and the proportion of CKD patients using antihypertensive drug and phosphorus-lowering drug, but the vascular calcification effect of the low and standard calcium PD fluid needs further exploration. This paper provides new evidence for the choice of dialysate for PD, low-calcium dialysate has no outstanding advantages for long term dialysis.

Objective: We aimed to elucidate the effects of the micro-structure of the pyrolytic carbon for artificial heart valves on its hydrodynamic performance.

Methods: Bileaflet mechanical valves of GKS 23 and 29 A were randomly selected. According to ISO5840, mean transvalvular pressure (MPG), regurgitation fraction (RF), and effective orifice area (EOA) of valve were assessed. Then, parallel-groove pattern was constructed by laser etching on leaflet surface, and the valves were subjected again to the same test.

Results: Compared with before patterning at 2, 3.5, 5, and 7 L/min, the MPG of the valves in two specifications were higher, the EOA was larger in 23 A, but smaller in 29 A, and the RF was contrary to EOA. At 5 L/min, the RF in both specifications was lower after etching at 45 bpm. At 70 bpm however, the RF in 23 A decreased, in 29 A increased.

Conclusion: The parallel-groove pattern on leaflet surface affected the hemodynamic performance of the valve prostheses.

The use of dabigatran in patients with non-valvular atrial fibrillation (AF) has widely increased in the last decades, due to its positive effects in terms of safety/efficacy. However, because of the risk of major bleeding, a great degree of attention has been suggested in elderly patients with multiple comorbidities. Notably, dabigatran mainly undergoes renal elimination and dose adjustment is recommended in patients with Chronic Kidney Disease (CKD). In this regard, the onset of an abrupt decrease of kidney function may further affect dabigatran pharmacokinetic profile, increasing the risk of acute intoxication. Idarucizumab is the approved antagonist in the case of dabigatran-associated major bleeding or concomitant need of urgent surgery, but its clinical use is limited by the lack of data in patients with Acute Kidney Injury (AKI). Thus, the early start of Extracorporeal Kidney Replacement Therapy (EKRT) could be indicated to remove the drug and to reverse the associated excess anticoagulation. Sustained Low-Efficiency Dialysis (SLED) could represent an effective therapeutic option to reduce the dabigatran plasma levels rapidly while avoiding post-treatment rebound. We present here a case series of three AKI patients with acute dabigatran intoxication, effectively and safely resolved with a single SLED session.

Hemodialysis is the commonest kidney replacement therapy (KRT) globally and rapidly growing in developing countries, while in developed countries it is reaching a plateau. The penetration of hemodialysis (HD) varies widely among countries and is largely influenced by socioeconomics, healthcare financing, particularly by government, local infrastructure, healthcare workforce, health system characteristics, and affordability of the population. Biomedical equipment, consumables, disposables, and labor are major cost drivers of KRT. Implementing strategies to balance cost and quality of care is an arduous task for health care planning, delivery, and patient care in low- and middle-income countries. In this context, the cost of dialyzers which form a significant component of the recurring cost of HD can be reduced by reuse after appropriate reprocessing. But this practice is largely abandoned in developed countries because of concerns of safety. However, the evidence against the reuse of modern dialyzers is not robust and certainly not based on well-designed randomized trials. The industrialization of dialysis delivery, the interests of equipment manufacturers and the nature of dialysis delivery have propelled single use of dialyzers. In this context, developing countries needing to expand HD services access at low cost are caught at crossroads. Process improvements are needed to standardize reprocessing that prioritizes safety while maintaining effectiveness. Recent advances in mobile and internet technologies could make this an achievable reality. We propose such an approach that would ensure treatment effectiveness, patient and healthcare provider safety, efficient resource utilization, and cost control.