bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Taylor Vortices in Hemocompatibility Investigations
Authors: Körfer S. , Klaus S. , Mottaghy K. 
Published: January 2018

Background Artificial organs, implants and extracorporeal circulation affect the physiological flow characteristics of blood as a liquid organ. These artificial systems consist of a wide variety of biomaterials with different geometries and, therefore, with their own flow properties. Secondary flow also occurs in extra – as well as in intracorporeal circulation. Methods In order to investigate the influence of vortical flow conditions a modified Taylor-Couette system was introduced. It consisted of two coaxial cylinders whose surfaces were the target of investigation. The annular gap was filled with donor blood shear and secondary flows were produced by rotating the inner cylinder. Platelet activation and protein adsorption were investigated as markers for thrombogenicity. Results At shear rates high enough to establish stable Taylor vortices (G ≥ 550 s −1) significant differences between vortical Taylor flow and steady laminar flow were detected. At shear rates of G ≥ 550 s −1 laminar flow caused a significantly higher platelet drop and PF4 release when compared to Taylor vortex flow. Also protein adsorption per square unit was significantly higher for laminar flow. Conclusions Based on the present data we conclude that vortical flow patterns lead to an accumulation of platelets and plasma proteins in the vortex center and therefore to a decreased probability of contact between platelets and material surfaces. It can be concluded that a preactivation of the platelets circulating in extracorporeal circuits can be manifested downstream in other geometrical configurations and flow conditions.
Treatment Strategies for Postinfarction Left Ventricular Free Wall Rupture: Stabilization with Peri-operative IABP and off-pump Repair
Authors: Nappi G. , De Santo L. S. , Torella M. , Della Corte A. , Maresca L. , Romano G. , Cotrufo M. 
Published: January 2018

Background Perioperative management of post-infarction left ventricular free wall rupture (LVFWR) is not clearly standardized and surgical repair is the only therapeutic option. Role of off-pump surgery and stabilization with perioperative intraaortic balloon pumping (IABP) were here analysed. Methods Seven patients underwent surgery for LVFWR between 1990 and 2002. Clinical picture included electromechanical dissociation (3 patients) and sudden hypotension (4 patients). Except in one patient who was reanimated through femoro-femoral cardiopulmonary bypass, off-pump repair through on-lay patching technique was always performed. IABP was employed in the immediate postoperative period in five cases. Results A satisfactory hemodynamic state was restored in all cases and there were no reoperations for bleeding or rerupture. Hospital survival was 100%. One patient underwent successful surgical myocardial revascularization two months after LVFWR. Two patients died at follow-up. The survivors present with good NYHA and CCS functional classes. Conclusions When the anatomy of the LVFWR is favourable, off-pump external patching repair proves a good choice. Postoperative IABP provides satisfactory hemodynamic support.
Recovery of Organ Dysfunction during Bridging to Heart Transplantation in Children and Adolescents
Authors: Reiss N. , Ei-Banayosy A. , Arusoglu L. , Kleikamp G. , Minami K. , Körfer R. 
Published: January 2018

The beneficial effects of ventricular assist devices on organ dysfunction during bridging to heart transplantation have been widely reported in the adult population. In contrast, the use of ventricular assist devices used as bridge-to-transplant in children is limited. To evaluate organ recovery during ventricular support in pediatric transplant candidate, respiratory, renal and hepatic function were reviewed retrospectively. The Thoratec device (stroke volume 65 ml) and the HIA-Medos-system (stroke volume 25/10 ml) were used as bridge-to transplant in 11 children and adolescents who were in low-output-syndrome despite maximal pharmacological support. Prior to implantation five patients were mechanically ventilated, six patients underwent cardiopulmonary resuscitation, eight patients had anuria (one treated by hemofiltration), three patients had liver dysfunction and four patients had signs of severe infection. At the time of implantation one patient was supported by the intraaortic balloon pump and one by the femorofemoral bypass for rapid hemodynamic stabilization. Eight patients were treated using the Thoratec device (one of these by Nova cor on the left side), three by the HIA-Medos system. The support time ranged between seven and 140 days. Seven patients could be extubated within three days. Renal function recovered in all pts. Liver enzymes decreased in all pts without reaching normal values. Bilirubin values also decreased in survivors but increased to 9.3 mg/dL in non-survivors. At least seven patients underwent successful heart transplantation, three patients died because of multiorgan failure after extended transfusion and one patient because of technical failure. In our experience the hemodynamic situation was sufficient in all bridging to transplant candidates. In all patients who underwent successful transplantation, transplantability was associated with rapid organ recovery within seven days after initiating mechanical assistance. Extended blood tranfusions, combined failure of three organs and increasing bilirubin values during support seem to be predictors of poor outcome.
ß2-Microglobulin Clearance with Super High Flux Hemodialysis: an Ex Vivo Study
Authors: Lee W.C.R. , Uchino S. , Fealy N. , Baldwin I. , Panagiotopoulos S. , Goehl H. , Morgera S. , Neumayer H.-H. , Bellomo R. 
Published: January 2018

Background ß2m accumulation induces disease in patients with end-stage renal failure (ESRF). Thus, its removal from patients with ESRF appears desirable. Current dialysis technology, however, has limited effectiveness. Aims To measure ß2m clearance with a novel super high flux membrane. Design Ex vivo experimental study. Setting Intensive Care Laboratory of Tertiary institution. Subjects Six volunteers. Measurements and Results At a blood flow of 300 ml/min, the clearance of ß2-MG increased from 113.5 ± 38.5 ml/min with a dialysate flow rate of 200 ml/min to 184.8 ± 61.1 ml/min with a flow rate of 300 ml/min and 195.0 ± 60.0 ml/min with a 500 ml/min flow rate. The clearance of albumin was 4.5 ml/min with a dialysate flow rate of 200 ml/min, 5.2 ml/min for a flow rate of 300 ml/min and 5.8 ml/min for a flow rate of 500 ml/min. Conclusions High levels of ß2m clearance can be achieved with a super high flux membrane while albumin losses remain limited
Pilot Study on Prevention of Lung Injury during Surgery for Type a Acute Aortic Dissection: No Evident Improvements with Celsior Flushing through the Pulmonary Artery
Authors: De Santo L.S. , Romano G. , Amarelli C. , Corte A. Della , Onorati F. , Torella M. , De Feo M. , Nappi G.A. , Cotrufo M. 
Published: January 2018

Objective Postoperative respiratory failure is a frequent and serious complication in patients with type A acute aortic dissection. Experimental evidence suggests that pulmonary artery perfusion using hypothermic protective solutions helps prevent lung injury. The aim of this pilot prospective study was to evaluate the effect of pulmonary artery flushing during selective cerebral perfusion (SCP) on lung function. Methods Twenty patients referred for acute type A aortic dissection, who were free from preoperative respiratory dysfunction, were assigned prospectively and alternately to two treatment groups. Pulmonary flushing was performed during SCP in group P (10 patients), while conventional Kazui technique was applied in group N (10 patients). Lung perfusion consisted of single-shot hypothermic pulmonary artery flush with Celsior. Lung function was evaluated by intubation time, scoring of chest radiograms at 12 hours after CPB, and PaO2/FiO2 assessed from immediately before surgery to 72 hours after termination of cardiopulmonary bypass. Results Incidence of pre, intra and post operative determinants of lung dysfunction proved homogeneous in both groups. Lung oxygenation function showed a marked post operative decline followed by a slow improvement in both groups. Analysis of respiratory ratios did not disclose significant differences even though the flushed group had a better performance in all study patients. The incidence of prolonged ventilator support (longer than 72 hours) (30% vs 20%, p=NS) and severity of x-ray pulmonary infiltrate score were comparable (mean score 1.7±0.71 vs 1.6±0.68, p=NS). Conclusions Pulmonary artery flushing with Celsior solution does not seem to provide an effective preservation of lung function.
The Ex-Vivo-Shunt-Model: Novel Approach for Assessing the Thrombogenicity of Vascular Implants
Authors: Wilhelmi M.H. , Gratz K.F. , Mischke R. , Von Depka M. , Noske D. , Francis T. , Haverich A. , Mertsching H. 
Published: January 2018

Objective Disadvantages associated with commercially available vascular implants necessitate alternative strategies to develop new vascular prostheses. Although many tissue characterizing strategies have been defined, no valid test for thrombogenicity exists. Here we introduce a novel concept for thrombogenicity testing of vascular implants Methods Silastic tubes were implanted into the carotid arteries of 12 sheep. After placing these shunts, tc99m-labeled platelets were administered and test-vessels were put in between the shunts. Native autologous (n=6), as well as native / acellularized allogeneic (n=6/n=6), and xenogeneic (n=6/n=6) carotid arteries and allogeneic (n=6/n=6) and xenogeneic (n=6/n=6) carotid arteries re-seeded with allogeneic endothelial-cells, fibroblasts and myocytes were evaluated. Number and time course of intra-operatively deposited platelets were evaluated with a Geiger-counter; certain areas of platelet deposition located, envisioned and characterized by a γ-camera and scanning electron-microscopy afterwards. Results Counter results revealed no significant different platelet depositions when comparing silastic tubes with either autologous or allogeneic native carotid arteries. However, starting 5 minutes after placement, acellularized/reseeded allogeneic (p=0.001/p=0.00004), and xenogeneic (p=0.0001/p=0.01) carotid arteries showed significantly more platelet depositions than native autologous carotides. Moreover, it was possible to show that almost no platelets adhere to native vessels or silastic tubes, thus proving the test method itself. Conclusion The Ex-Vivo-Shunt-Model is a valid method to measure and envision the intrinsic thrombogenicity of vascular implants.
Reverse Transcriptase/Polymerase Chain Reaction Analyses of Hemodialysis Ultrafiltrates and Sera of Hepatitis C Virus Positive Patients
Authors: Simjanovska L.J. , Porcu K. , Amitov V. , Efremov G.D. , Polenakovic M. 
Published: January 2018

The hepatitis C virus is a highly prevalent infection among chronic dialysis patients and represents one of the major problems of hemodialysis units. Hepatitis C virus transmission occurs either by blood transfusion or nosocomially. One of the proposed pathways of nosocomial transmission of the hepatitis C virus is cross-contamination through the dialysis procedure. In an effort to elucidate whether the hepatitis C virus may pass across the hemodialysis membrane, we have performed analyses of ultrafiltrates collected in different stages of hemodialysis treatments, using different types of hemodialysis membranes and different types of dialysis machines. Samples collected from the dialysis compartment during the rinsing of the blood compartment at the end of the hemodialysis treatment were also analyzed. The hepatitis C virus was found in 17 out of 58 ultrafiltrate samples taken at different times of the hemodialysis treatment. Moreover, the hepatitis C virus was present in 15 out of 17 samples collected from the dialysate compartment during the saline solution rinsing step of the blood compartment. The presence of the hepatitis C virus had no strict correlation with the type of dialysis membrane or with the type of dialysis machine. Although the results suggest that the passage of the hepatitis C virus during the hemodialysis treatment is multi-factorial and case- specific, the most critical point is when the blood is flushed out with physiological saline.
Retrospective Comparison of 5 different Methods for Long-Term LDL-Apheresis in 20 Patients between 1986 and 2001
Authors: Krebs A. , Krebs K. , Keller F. 
Published: January 2018

Purpose To compare long-term efficacy and biocompatibility of the 5 most commonly applied LDL-apheresis techniques using a specifically modified calculation method of the area under the curve (AUC) for laboratory parameters. Design Retrospective long-term analysis of 20 patients with homozygous or severe heterozygous familial hypercholesterolemia. Procedures The following 5 extra-corporeal LDL-apheresis methods were compared: IMAL (Immuno Adsorption of Lipoproteins), DSA (Dextran Sulphate Adsorption), HELP (Heparin Induced Extra-corporeal LDL Precipitation), DALI (Direct Adsorption of Lipoproteins), MDF (Membrane Differential Filtration). Main outcome measures AUC derived plasma concentrations (CAUC) of lipoproteins between two apheresis procedures and their long-term course. Comparison of biocompatibility and efficacy concerning the LDL-C target of < 2.6 mmol/L of 5 apheresis techniques. Progression of atherosclerosis in patients with severe hypercholesterolemia. Main findings The means of AUC derived average plasma concentrations (CAUC) of all treatment intervals were for LDL-C and the LDL/HDL ratio as follows: IMAL (5.59 mmol/L; ratio 4.1), DSA (3.03 mmol/L; ratio 2.0), HELP (4.06 mmol/L; ratio 2.2), DALI (3.83 mmol/L; ratio 3.3), MDF (3.26 mmol/L; ratio 3.2). Coronary heart disease and cardiac events (myocardial infarction, PTCA/ stent implantation, CABG) progressed in only 2 patients whereas atherosclerosis manifestations (sclerosis abdominal aorta, carotid artery stenosis, peripheral vascular disease) worsened in 13 patients. Mean ergometric capacity improved from 112 to 118 Watt. Conclusions All 5 apheresis methods (IMAL, DSA, HELP, DALI, MDF) proved to be safe and suitable for long-term treatment in patients with severe hypercholesterolemia. The introduction of the CAUC revealed that the target of LDL-C < 2.6 mmol/L was not achieved with regard to the time averaged concentration (CAUC).
Numerical Simulation of the Hepatic Circulation
Authors: Van Der Plaats A. , 'tHart N.A. , Verkerke G.J. , Leuvenink H.G.D. , Verdonck P. , Ploeg R.J. , Rakhorst G. 
Published: January 2018

Availability of donor livers and the relatively short preservation time limit the success of liver transplantation. The use of hypothermic machine perfusion could pave the way for expansion of the donor pool. To better define optimal settings of such a device, the feasibility of using a numerical simulation model of the hepatic circulation is determined. Hemodynamics in the hepatic arterial, portal venous and hepatic venous compartments of the hepatic vascular tree was modelled using an electrical analogue. Calculated pressure and flow profiles throughout the liver were in accordance with physiologic profiles in the total circulatory system. Comparison of calculated flow values with normal control values showed a discrepancy that was explained by inaccurate diameter input data. Until more precise methods for determining vascular dimensions become available, redefining vessel diameter makes the simulation model perfectly suitable for predicting influences of temperature and/or viscosity on hepatic hemodynamics and is thereby an excellent tool in defining optimal settings for our hypothermic liver perfusion system.
Effect of Left Ventricular Assist Device on Circulatory Autonomic Nervous Activity
Authors: Tsutsui T. , Takiya R. , Jikuya T. , Shigeta O. , Sakakibara Y. , Sankai Y. 
Published: January 2018

Purpose For evaluation of the autonomic nervous system (ANS) activity of patients with mechanical circulatory support including LVAD, IABP and PCPS, arterial pressure variability (APV) was examined. APV is the power density values of pressure signals. High frequency (0.15 to 0.4 Hz) and low frequency (0.04 to 0.15 Hz) components of APV are regarded as a function of the autonomic nervous system. Methods Arterial pressure signals were acquired every 2 hours at 100 Hz for 6 minutes. Power spectral analysis was carried out, and APV was observed in 18 patients with IABP and/or PCPS. APV was also observed in 3 patients with LVADs (Xemex, Zeon Medical, Japan) before their discharge from ICU for transfer to another hospital for cardiac transplantation. Results Although the value gradually increased in 18 patients with IABP and/or PCPS, sustained low values of LFAnorm of APV in 6 patients were related to prolonged mechanical support, and 4 patients among them died consequently. The normalized power spectral component with low frequency (LFAnorm) was maintained at relatively high values in 3 patients with LVADs. Conclusion The study results suggest that power spectral analysis of systemic arterial pressure offers a reasonable means for the evaluation of the severity of patient cardiovascular condition and for the prediction of clinical outcome. It also suggested that LVAD support exerts a favorable effect on ANS in patients with severe heart failure before cardiac transplantation.
Influence of Differences in Body Weight and Volume Management on Experimental Results in Porcine Models
Authors: Schnoor J. , Schreck R. , Baumert J.H. , Grosse-Siestrup C. , Rossaint R. , Unger J.K. 
Published: January 2018

Background In contrast to humans, young pigs naturally have a low COPpl (12–16 mmHg versus 22–26 mmHg in young humans). Thus, behavior occurring when volume management is performed similar to human medicine might be different. Potentially underestimated intra- to extravascular fluid and solute shifts could influence time course of variables investigated. That is why we studied whether differences in the basic protocol for infusion therapy and different levels of COP - according to age or body weight, respectively - impair reproducibility and reliability of experimental results. Methods Group A [n=6, lower body weight (LBW < 22 kg)] was treated with unrestricted infusion rates (UIR) adjusted to maintain a constant blood pressure; group B [n=6, higher body weight (HBW > 28 kg)] was treated with a restricted continuous infusion rate for fluid balance (RIR); group C (n=6) combined HBW and UIR protocol. Blood pressure, plasma solutes, diuresis, and peritoneal fluid were analysed. Statistical analysis was performed using Kruskal-Wallis test and Wilcoxon test. Results UIR-treated pigs with LBW (group A) developed ascites and demonstrated time dependent decreases of plasma solute concentrations whereas in pigs of group C mainly diuresis was increased and subcutaneous edema occurred. None of the protocols enabled constant blood pressure. Discussion In young pigs (LBW), an adaptive volume substitution using crystalloids to standardize blood pressure may induce fluid extravasation; in turn data may not show statistical significance, stable hemodynamics may not be achieved and changes in plasma solute concentrations may lead to false interpretations. RIR-strategy provided reproducible, plausible results and thus should be recommended in combination with pigs >29 kg BW for the use of porcine models.
Morphological and Functional Alterations in Glycerol Preserved Rat Aortic Allografts
Authors: Fahner P.J. , Idu M.M. , Legemate D.A. , Vanbavel E. , Borstlap J. , Pfaffendorf M. , Van Marle J. , Van Gulik T.M. 
Published: January 2018

Glycerol preservation is an effective method for long-term preservation of skin allografts and has a potential use in preserving arterial allografts. We evaluated the effect of glycerol concentration and incubation period on vessel-wall integrity of rat aortic allografts. No significant differences were measured in breaking strength (2.3 ± 0.3 N) and bursting pressure (223 ± 32 kPa) between standard glycerolized and control segments (1.7 ± 0.3 N, 226 ± 17 kPa). Isometric tension measurements showed complete lack of functional contraction and relaxation capacity in allograft segments prepared according to all preservation protocols. Morphologically, thickness of the vessel-wall media diminished after preservation using low (30/50/75 %) or high (70/85/98%) concentrations of glycerol, as compared to control segments (i.e. 81 ± 2.4 μm, 95 ± 5.6 μm and 125 ± 3.5 μm, respectively). Confocal microscopy and Fourier analysis demonstrated that vascular collagen and elastin bundle orientation had remained unaltered. Electron microscopy showed defragmentation of luminal endothelial cells. In conclusion, glycerol preservation of rat aorta resulted in an acellular tissue matrix, which maintained biomechanical integrity and extracellular matrix characteristics. The next step in the investigation will be to test the concept of glycerol preservation of arterial allografts in a vascular transplantation model.
Theoretical Morphological Approach to Simple Peritoneal Sclerosis
Authors: Di Paolo N. , Gaggiotti E. 
Published: January 2018

The term peritoneal sclerosis can be applied to a vast range of peritoneal alterations. At one end of the range we have the slight peritoneal sclerosis constantly associated with peritoneal dialysis, which may be defined as simple sclerosis. Its clinical impact is slight. The role of glucose in determining peritoneal sclerosis is supported by morphological studies and therefore backed by much biochemical and immunological data.
Histological and Functional Characteristics of Peritoneal Membrane in Peritoneal Sclerosis of Pd Patients
Authors: Bertoli S.V. , Buzzi L. , Ciurlino D. , Maccario M. , Traversi L. , Martino S. , Procaccio M. 
Published: January 2018

Background Function and structure of peritoneal membrane (PM) are impaired on peritoneal dialysis (PD). Peritoneal sclerosis is a common finding in peritoneal biopsies (PB) of PD patients. The aim of this study was to examine the impact of peritoneal sclerosis on peritoneal function and clinical parameters in PD patients submitted to peritoneal biopsy. Methods A PB was performed on 31 PD patients during catheter removal due to malfunction or after drop-out from treatment. For each patient PM transport was evaluated by the last peritoneal equilibration test before PB. Each daily glucose load was calculated. Tissue was formalin-embedded and stained for histological and immunohistochemical studies. Results Patients with submesothelial sclerosis and those with impairment of submesothelial basement membrane and subendothelial vascular membrane were submitted to a larger daily glucose load. Peritoneal sclerosis > 50 microns was more frequent in high transporters, who were exposed to larger daily glucose load compared to medium-high transporters. Mesothelial loss is correlated to peritoneal sclerosis and vascular injuries. Conclusions Peritoneal sclerosis is not constant in PD patients: it is related to the loss of mesothelium integrity, to the daily glucose load of PD treatment and to vascular injuries, but apparently not to the presence of inflammatory infiltrate. It remains a matter of debate how much the peritoneal sclerosis modifies the function of PM and how new more biocompatible PD solutions could reduce PM injury.