bluuebunny/crossref_metadata_2025 huggingface dataset:
An Outbreak of Pyrogenic Reactions in Chronic Hemodialysis Patients Associated with Hemodialyzer Reuse
Authors: Rudnick Judith R. , Arduino Matthew J. , Bland Lee A. , Cusick Lucy , McAllister Sigrid K. , Aguero Sonia M. , Jarvis William R.
Published: November 2008

Abstract: In February 1992, 22 patients undergoing chronic hemodialysis at an outpatient dialysis center experienced pyrogenic reactions (PR). The PR rate was significantly greater (p < 0.001) during the epidemic (February 3–5) than the pre‐epidemic period (November 1, 1992‐February 1, 1992). All patients with PR used dialyz‐ers that had been manually reprocessed either on February 1 or 3. These dialyzers contained up to 120.8 EU/ml of endotoxin in the blood compartment. The only dialyzer reprocessed before February 1 that was available for analysis was found to contain no detectable endotoxin, while dialyzers reprocessed during the epidemic period contained a median endotoxin concentration of 52.8 EU/ ml. The bioburden of water used to prepare dialysate was in excess of the Association for the Advancement of Medical Instrumentation (AAMI) standard for water, ≤200 colony forming units (CFU)/ml. Samples of treated water collected in the reuse area were within AAMI standards at the time of the investigation (February 11 and February 26), but before the investigation, water samples were assayed with a culture method that could not detect micro‐bial concentrations below 103 CFU/ml. In addition, the treated water feed line to the disinfectant container may never have been disinfected. However, no samples were collected from this line during the investigation. This outbreak emphasizes the need to use water that meets the AAMI bacteriologic and endotoxin standards of ≤200 CFU/ml and/or 5 EU/ml, respectively, for reprocessing hemodialyzers and to ensure that appropriate culture techniques are used for treated water and dialysate.
Diffusive and Convective Solute Transport in Peritoneal Dialysis with Glucose as an Osmotic Agent
Authors: Waniewski Jacek , Heimbürger Olof , Werynski Andrzej , Park Min Sun , Lindholm Bengt
Published: November 2008

Abstract: To investigate possible effects of glucose concentration, dwell time, and peritoneal reabsorption on the combined diffusive and convective peritoneal solute transport, dialysate to plasma concentration ratios (D/P) and solute clearances were evaluated for 6‐h peritoneal dwell studies with 1.36, 2.27, and 3.86% glucose solutions. The diffusive mass transport coefficient, KBD, and sieving coefficient, S, were estimated using the Babb‐Randerson‐Farrell model of peritoneal transport. Dialysate volumes over time and peritoneal reabsorption rates, KR, were assessed using radiolabeled iodinated serum albumin (RISA). The transport parameters were estimated with and without peritoneal reabsorption of solutes taken into account. To test the stability of the transport parameters throughout a single peritoneal dwell, KBD and S values were estimated for the initial 3–120 min, the final 120–360 min, and the entire 3–360 min dwell period for dialysis with 3.86% glucose solution. The transport parameters did not differ between the three dialysis fluids although clearances of small solutes were higher with the 3.86% solution. Values of KBD, but not S, were dependent on the correction for peritoneal reabsorption of solutes. Computer simulations showed that S could be estimated even with the 1.36% glucose solution. A significant change of the transport parameters, with increased values of KBD during the initial period of the dwell, was found for urea, potassium, sodium, and total protein during dialysis with the 3.86% solution. S values for urea and potassium were close to 1 during the initial period whereas unphysical (higher than 1) S values were found for the whole dwell period. The transient increase of KBD during the initial part of the dwell may reflect changes in the peritoneal barrier possibly induced by fresh dialysis fluid. In conclusion, the transport parameters KBD and S are not influenced by the concentration of glucose in the dialysis fluid. Moreover, the estimation of KBD but not of 5 is dependent on the assumed rate of peritoneal reabsorption. Finally, the current results challenge the assumption that KBD and S are constant throughout a peritoneal dialysis exchange.
Apheresis Technologies: An International Perspective
Authors: Malchesky Paul S. , Bambauer Rolf , Horiuchi Takashi , Kaplan DAndre , Sakurada Yutaka , Samuelsson Gustav
Published: November 2008

Abstract: The developments in apheresis techniques and their clinical applications world‐wide are technologically driven. In the past, apheresis survey statistics have highlighted both the differences by region in clinical practice and in the types of technologies utilized. Such differences have provided a basis for the scientific and clinical assessments of these apheresis technologies and their clinical outcomes and have stimulated the marketing and business development of new technologies world‐wide. A review of the regional practices and technologies utilized provides a perspective on the future role of apheresis and its developments in clinical practice. While technology is a driving force for the development of new techniques for clinical practice, it is not the only market force. For technology introduction, several other important issues need to be considered. Regulations at the local and, most importantly, the federal level impact the timing for new technology introduction. Reimbursement by healthcare payers is critically important from the initiation of the development of a technology through its clinical use. Clinical trials are critically important to show the safety and clinical‐ and cost‐effectiveness of the technology in order for payers to provide reimbursement for its use, but these trials are sometimes long and costly. Research funding availability at the governmental and commercial levels critically impacts new technology investigation and its introduction. Apheresis technology developments offer new hopes and promises for the clinical team; however, their development, introduction, and utilization will be influenced by the prevailing market forces.
Oxygenator with Built‐in Hemoconcentrator: A New Concept
Authors: Nishida Hiroshi , Endo Masahiro , Koyanagi Hitoshi , Suzuki S. , Katsuyuki Kuwana , Hikaru Nakanishi
Published: November 2008

Abstract: A hemoconcentrator is an instrument essential for open heart surgery without blood transfusion. In order to simplify the extracorporeal blood circuit and to facilitate handling of cardiopulmonary bypass, we have combined a hollow fiber unit for gas exchange and that for hemofiltration into one component and developed a new membrane oxygenator with the function of a hemoconcentrator. The cylindrical device consists of a hollow fiber for hemofiltration with another fiber for gas exchange provided outside. Both of them adopt the blood outside perfusion system. Blood enters and flows through the central hole for hemofiltration and then flows into the oxygenator. By applying the flow mode to the device, blood is allowed to flow from the center of the core toward the hollow fiber around it. Therefore, even distribution of blood flow to the entire fiber is realized, and the performance of the device is improved. The oxygen transfer rate was 317 ml/min at a flow rate of 6 L/min, and the ultrafiltration rate was 7 L/h at a flow rate of 4 L/tnin with a hematocrit of 25%. The combined structure of the two units has not caused any adverse effects. In conclusion, by combining an oxygenator and a hemoconcentrator, excellent and simplified hemoconcentration is made available as the blood outside flow mode is adopted, which is one of the unique aspects of this device.
Theoretical Description of Mass Transport in Medical Membrane Devices
Authors: Werynski Andrzej , Waniewski Jacek
Published: November 2008

Abstract: The application of the one‐dimensional theory of mass transport to the derivation of mathematical formulas for clearances of a variety of membrane mass exchangers, namely hemodialyzers, hemofilters, plasma separators, and the cascade filtration procedure, has been reviewed. The applied theory predicts that clearances depend approximately on fluid inlet flow rates but not on concentrations, and with constant fluid flow rates, clearances are constant. Also, the application of device clearance in kinetic modeling has been discussed.
From Wooden Limbs to Biomaterial Organs: The Ethics of Organ Replacement and Artificial Organs
Authors: Kielstein Rita , Sass Hans‐Martin
Published: November 2008

Abstract: This paper discussed issues of ethical assessment and moral concern associated with organ replacement and physical enhancement: research, allocation, organ donation, artificial organs, xenografts, biomaterials, and neuromaterials. While emphasizing the medical and moral benefits over associated risks, it calls for a better integration of moral assessment into technology assessment and for the establishment of a cross‐cultural and interdisciplinary International Ethics Committee for Organ Replacement Therapy.
Total Erythrocyte Destruction Time: The New Index for the Hemolytic Performance of Rotary Blood Pumps
Authors: Shimono Takatsugu , Makinouchi Kenzo , Nosé Yukihiko
Published: November 2008

Abstract: To date an index of hemolysis is the only parameter to evaluate in vitro the hemolytic properties of blood pumps. However, this index does not reflect the sublethal conditions of erythrocytes. In this paper, a new concept, the total destruction of erythrocytes, to indicate traumatic features on erythrocytes is proposed. Five paired long duration in vitro hemolysis tests were conducted using the BioMedicus pump; BP80, and the Nikkiso pump, HMS12. The pumps ran until either a sudden change in blood color to dark red was noted or the pumps ran for over 24 h. At a certain point, the plasma‐free hemoglobin levels suddenly and dramatically increased in each experiment except one Nikkiso case. At a certain point in time, the destruction of most erythrocytes suddenly and simultaneously occurred. We call this phenomenon total destruction of erythrocytes and define the pumping duration required to raise the level of the plasma‐free hemoglobin to 50% of the total hemoglobin as total destruction time. Although there is no statistical difference in the normalized index of hemolysis between the two pumps, the total destruction time of the BioMedicus pump is significantly shorter than that of the Nikkiso pump. It appears that an accumulation of sublethal damage on erythrocytes resulted in the decrease of the hemolytic threshold of the entire erythrocyte and also resulted in a sudden entire destruction of erythrocytes.
Flow Visualization Study on Centrifugal Blood Pump Using a High Speed Video Camera
Authors: Sakuma Ichiro , Tadokoro Hiroyuki , Fukui Yasuhiro , Dohi Takeyoshi
Published: November 2008

Abstract: Flow visualization is widely applied to evaluate rotary blood pumps; however, it is very difficult to visualize flow near the vanes of centrifugal blood pumps because the rotational speed of the impeller is usually several thousand rpm. In this study, a tracer method with a high speed video camera that can take more than 2,000 frames/s was utilized for flow visualization together with computer‐assisted image measurement. This method visualized the complex secondary flow pattern near the vanes of the impeller, such as the vortex and recircula‐tion. It also visualized the enhanced washout effect by the secondary washout vanes on the backside of the impeller. The proposed method was effective to analyze the flow pattern in the centrifugal blood pump by providing useful information for better design of the pump hemolysis and thrombus formation.
An Improved Left Ventricular Cannula for Chronic Dynamic Blood Pump Support
Authors: Antaki James F. , Dennis Tammy J. , Konishi Hiroaki , Brown Michael E. , Maher Timothy R. , Tomczak John P. , Kerrigan John P. , Kormos Robert L.
Published: November 2008

Abstract: Ventricular unloading with dynamic blood pumps can be markedly affected by the geometry of the cannula tip within the ventricular chamber. Due to the ability of these pumps to develop significant negative inflow pressure, existing cannula tips designed for passively filling blood pumps can be predisposed to inflow occlusion by intraventricular anatomic structures. A novel “trumpet” mouth cannula was constructed to overcome this limiting problem. This design was based on two criteria: to provide additional stenting to the ventricular apex, and to assure placement of the tip opening relative to the endocardial surface. This prototype cannula was evaluated in vivo against conventional caged, blunt, and tapered designs to assess anatomic and hemodynamic interaction within the ventricular apex. Post mortem examination revealed the inflow tract to be devoid of myocar‐dial obstruction in all cases. These initial studies indicate that a trumpet mouth cannula can provide satisfactory hemodynamic performance required by dynamic blood pumps.
Preliminary Design and Optimization of an ECC Blood Pump by Means of a Parametric Approach
Authors: Montevecchi F.M. , Inzoli F. , Redaelli A. , Mammana M.
Published: November 2008

Abstract: This study concerns the development of an analytical parametric model of a centrifugal disk pump. The advantage of this kind of approach is to have an adaptable tool as a first step for the design of a pump device. The method allows the evaluation of the velocity profiles and the shear stresses within the impeller disks in the flow domain along with the performance of the device in terms of torque, mechanical power, power loss, head‐flow performance, pump efficiency, and hemolytic index. Some simplifying hypotheses are assumed: steady state condition, laminar flow, Newtonian and incompressible fluid. The radial velocity profiles are assumed to be uniform and the flow cross‐sectional area is assumed to be constant along the radius. The influence of the housing and secondary flows caused by recirculation are neglected. To test the approach reliability, the model was used to simulate a pump with the following characteristics: an external and internal radius of 50 mm and 5 mm, respectively, and a channel height of 2.5‐0.25 mm (h) from inlet to outlet section. The angular velocity ω was varied in the range 500‐3,000 rpm. The flow rate has been varied from 1 to 5 L/min. The results show that when the flow rate is increased, head performances obtained using this pump model vary from 411 to 100 mm Hg, and its efficiency varies from 48 to 15%. A parallel simulation has been carried out by means of a Finite Element Method model with an angular velocity equal to 2,000 rpm. The resulting comparison shows a good agreement between the results of these approaches. This occurrence indicates that the analytical approach is a valid and simple tool in defining pump design.
New Version of Flow‐Transformed Pulsatile Total Artificial Heart with No Electrical Switching Valve
Authors: Isoyama Takashi , Imachi Kou , Abe Yuusuke , Chinzei Tsuneo , Imanishi Kaoru , Mabuchi Kunihiko , Matsuura Hiroyuki , Fujimasa Iwao
Published: November 2008

Abstract: The flow‐transformed pulsatile total artificial heart (FTPTAH) is a new pulsatile total artificial heart that consists of a single continuous flow rotary blood pump and blood flow switching valves. It can perfuse the pulmonary and the systemic circulation alternately with pulsatile flow. A new version of the FTPTAH, which consists of one undulation pump (UP), 4 jellyfish valves, and a compensatory chamber, has been proposed. The UP is a reversible continuous flow blood pump, and flow transformation is caused by switching the direction of the motor rotation so that no electrical flow switching valve is needed. A prototype model could perfuse alternately pulmonary and systemic circulation with 3.0 L/min in a mock circulation. Unoxygenated blood in the UP at the end of pulmonary circulation will be stored in the compensatory chamber by shifting a flexible membrane to the direction of the left atrium (LA); therefore, the blood is not sent to the systemic circulation.
Development of a New Apparatus to Observe Microcirculation Chronically in Continuous Flow Blood Pump Research
Authors: Imachi Kou , Chinzei T. , Abe Y. , Isoyama T. , Mabuchi K. , Ono T. , Kouno A. , Imanishi K. , Kusakabe M. , Onuma M. , Atsumi K. , Fujimasa I.
Published: November 2008

Abstract: To observe microcirculation chronically is an important key to the successful evaluation of the continuous flow blood pump. In this study, we succeeded in developing a new apparatus by which microcirculation could be observed chronically without a microscope in a conscious animal. The apparatus utilizes a charge coupled device (CCD). A thin living tissue, such as mesentery, is put directly on a highly integrated CCD and is lit up through the tissue with a light‐emitting diode (LED). The vascular nets in the tissue are projected onto the CCD like a contact photograph, which is then sent to a television screen and which can be used to analyze their motion and function. A 0.5‐inch CCD having 250,000 pixels was used in this study. The cover glass of the CCD was removed, and a fiber optic plate was fixed onto the surface of the CCD for the tissue to be able to contact with the apparatus surface without clearance. The CCD as well as the LED were molded with epoxy resin for electrical insulation. The apparatus was 35 mm wide and 12 mm high with a micro stand for an LED, which can be easily implanted into an animal. The apparatus was implanted into a rabbit for 12 h. The configuration of arterioles and venules, tens of micrometers in diameter, and their motions in subcutaneous tissue could be observed.
New Methods for the Investigation of Blood‐Biomaterial Interaction
Authors: Schütt W. , Thomaneck U. , Grümmer G. , Kraeft S.‐K. , Reinholz F. , Cornell U. Waldschläger
Published: November 2008

Abstract: Quantitative microscopy with integrated image processing is a useful tool for investigation of the interaction of blood components with biomaterials. We have developed new automated measuring devices suitable for simultaneously characterizing biological cells (size, shape, localization, migration, electrophoresis), synthetic particles (electrophoretic fingerprinting), and dialysis membranes (morphology, electric charge). These techniques are useful for the investigation of cell adherence on biomaterials, localization of cells in membrane filters (Chemotaxis), characterization of the protein adsorption on model systems, detection of cytokines (produced after lymphocyte‐biomaterial contact), and estimation of morphological properties and charge distribution in dialysis membranes.
A High Selectivity Cascade Filtration Technique for LDL–Cholesterol and Lp(a) Removal
Authors: Legallais Cécile , Moriniere Philippe , Wojcicki Jan M. , Lalau Jean–Daniel , Fournier Albert , Jaffrin Michel Y.
Published: November 2008

Abstract: This work proposes an improvement of the cascade filtration technique in the treatment of familial hypercholesterolemia. A model of the whole process permitted the definition of the parameters that could influence the selectivity of the fractionation: the pore size, the sieving coefficients of both fractionation and plasmapheresis membrane, and the final retentate flow rate. In vivo studies have shown that the dead–end mode for the secondary filter was not always practical because of severe membrane plugging except when a pulsatile pump was included in the extracorporeal circuit. This pump generated hydrodynamic instabilities which decreased membrane fouling and retarded the build up of the polarization concentration layer. Optimization of these specific operating conditions permitted increase in the selectivity index from 1. 15 to 2. 24. The performances of cascade filtration were then comparable to those of adsorption on dextran sulfate columns.
Dialyzer Reuse: Interaction Between Dialyzer Membrane, Disinfectant (Formalin), and Blood During Dialyzer Reprocessing
Authors: Ng Yee‐Yung , Yang An‐Hang , Wong Kai‐Cheng , Lan Hui‐Yao , Hung Tsai‐Lu , Kerr Peter G. , Huang Tung‐Po
Published: November 2008

Abstract: The growing practice of dialyzer reuse in recent years is mainly based on medical and economic considerations. However, adverse reactions such as immunohemolytic anemia due to anti‐Nfrom antibody associated with dialyzer reuse have been reported. In this study, scanning electron microscopy and cytologic staining were used to evaluate the interaction between blood components and the reprocessed synthetic dialyzer membrane (polysulfone) after disinfectant (formaldehyde) treatment. The results showed that various blood components such as fibrin and blood cells still adhered to the dialyzer membrane after reprocessing. The study also demonstrated that the adhered denatured blood components could be detached by sonication andlor simulated hemodialysis and then gain access into the circulation. The re‐entry of the denatured blood components to the patients exposed to reused dialyzers may result in an enhanced imrnunological response which may contribute to antibody formation (such as anti‐Nfrom antibody) with a reused hemodialyzer.
Functional Stability of Porcine Hepatocyte Spheroids in Various Culture Systems Under 100% Porcine and Human Plasma Conditions
Authors: Sakai Yasuyuki , Naruse Katsutoshi , Nagashima Ikuo , Muto Tetsuichiro , Suzuki Motoyuki
Published: November 2008

Abstract: To select an immobilization method suitable for bioartificial liver (BAL) modules utilizing porcine hepatocyte spheroids, functional activities were compared in various systems in 100% porcine and human plasma together with a synthesized medium. The spheroids, continuously suspended in rotating dishes or entrapped in collagen (CN) gel, expressed approximately two times higher ammonium detoxification abilities over conventional monolayers during 8 days of direct contact with 100% human or porcine plasma with a standardized inoculum cell number. No significant deterioration was observed in the abilities as compared with that in a synthesized medium. Although the cell number gradually decreased in rotational culture, the abilities per cells remaining on Day 10 were two times higher than in the CN‐gel entrapped spheroids in all the media examined, presumably due to the diffusion limitation by the gel. Thus, in utilizing porcine hepatocyte spheroids in BAL modules, immobilization allowing direct contact of spheroids with perfused patient plasma was concluded to be possible and suitable.
Cytokine Generation in Rabbits During Extracorporeal Lung Assist with a Mini Hollow Fiber Lung
Authors: Yanagi Fumiharu , Terasaki Hidenori , Matsukawa Akihiro , Ohkawara Susumu , Morioka Tohru , Yoshinaga Masaru
Published: November 2008

Abstract: To examine host responses to extracorporeal lung assist (ECLA) in small animals, we developed a mini hollow fiber lung of nonmicroporous polyolefin and an extracorporeal bypass circuit with a priming volume of 25 ml. This circuit allowed ECLA of up to 72 h without blood transfusion in 20 rabbits. The ECLA procedure induced the appearance of tumor necrosis factor‐a (TNF‐a) and interleukin‐1 (IL‐1) receptor antagonist (IL‐IRa) in plasma, but not IL‐ip. However, these changes were observed only at the initial stage of ECLA, and the levels returned to pre‐ECLA levels within 24 h. Although leukocytes adhering to the hollow fibers were immunohisto‐chemically positive for IL‐ip and IL‐IRa, the plasma levels of these cytokines in response to ECLA were not different from those observed in rabbits given anesthesia and subjected to minor surgery but without ECLA. Thus, ECLA itself is a minor factor in the production of these cytokines.
Effects of Right Ventricular Failure on Renal Function During Pneumatic Left Ventricular Assist
Authors: Akamatsu Hideki , Arai Hirokuni , Sakamoto Tohru , Suzuki Akio
Published: November 2008

Abstract: In an experimental dog model of acute biventricular failure, the effects of left ventricular (LV) assist on renal hemodynamics and function were evaluated. After the induction of severe cardiac failure by multiple ligation of the coronary arteries, LV assist with a 40 ml pneumatic pulsatile pump was initiated, and the aortic flow was maintained at control values. The right atrial pressure (RAP) rose to 21.3 mm Hg with the appearance of profound right ventricular (RV) failure. Renal arterial blood flow (RAF) decreased to about 60% of the control value after 2 h of LV assist. The urine volume decreased and renal function deteriorated progressively. RV assist decreased the RAP to 4.8 mm Hg, and the reduced RAF recovered. After 3 h of RV assist, the RAF returned to initial values and the urine volume increased, but renal function did not recover. Advanced biventricular failure with elevated RAP during LV assist reduced renal perfusion and impaired renal function and may be an indication for early RV assist
Advantage of Monitoring Skin Vibration as an Index of Arteriovenous Fistular Blood Flow
Authors: Aoki Takeshi , Shinzato Toru , Itani Hisahiro , Kato Tatsunori , Miwa Masatniki , Nakai Shigeru , Maeda Kenji
Published: November 2008

Abstract: Monitoring of the skin vibration is disturbed little by environmental noise. Therefore, the skin vibration is more relevant than bruit on the skin by means of monitoring the fistular blood flow. Frequency analysis of the skin vibration generated by an internal arteriovenous fistula indicated two peaks of power spectral density (PSD), one in the frequency range of 4–10 Hz and the other from 100–300 Hz. The analysis of the skin vibration generated by an external fistula, however, showed only one peak in the range of 4–10 Hz and a moderate flat PSD level in the range of 100–300 Hz. The PSD level in the range of 100–300 Hz decreased dramatically or disappeared when the fistular blood flow diminished or ceased. Therefore, the optimal frequency for monitoring skin vibration may be the range of 100–300 Hz.
Drug Therapy of Severe Hypercholesterolemia in Patients with Coronary Artery Disease
Authors: Parhofer Klaus G. , Richter Werner O. , Schwandt Peter
Published: November 2008

Abstract: The beneficial effect of cholesterol–lowering therapy for secondary prevention in patients with coronary artery disease (CAD) is well established. The therapeutic goal in this situation is a low–density lipoprotein (LDL) cholesterol level of 100 mg/dl. Cholesterol–lowering therapy will not only lead to a reduction in the progression of lesions but also and probably more importantly will reduce lesion activation and rupture and improve endothelial vasomotor function. Depending on the underlying hyperlipoproteinemia, the first choice for single drug therapy is a bile acid–binding resin or a hepatic hydroxymethyl glutaryl coenzyme A (HMG–CoA) reductase inhibitor in isolated LDL hypercholesterolemia, and nicotinic acid, a fibric acid, or a HMG–CoA reductase inhibitor in combined hyperlipidemia. Combination therapy usually consists of a bile acid–binding resin with either an HMG–CoA reductase inhibitor, a fibric acid, or nicotinic acid in LDL hypercholesterolemia and nicotinic acid with a fibric acid in combined hyperlipidemia.
H.E.L.P. Apheresis Therapy in the Treatment of Severe Hypercholesterolemia: 10 Years of Clinical Experience
Authors: Seidel Dietrich
Published: November 2008

Abstract: In collaboration with B. Braun Melsungen AG, Germany, we were able to develop the heparin–mediated extracorporeal low–density lipoprotein (LDL) fibrinogen precipitation (H.E.L.P.) system and to introduce it into clinical use. The H.E.L.P. apheresis system is the most potent technique to reduce at the same time LDL, lipoprotein (a) (Lp[a]), and fibrinogen plasma concentrations if the physiological clearing mechanisms are insufficient and if diet and drugs fail to achieve a target concentration of 100 mg/dl LDL–cholesterol or lower, required for secondary prevention of coronary heart disease. The H.E.L.P. LDL apheresis system also improves plasma viscosity and microcirculation efficiently. The clinical experience with the H.E.L.P. system has proved its clinical utility; regression of coronary heart disease occurs, a decrease in events of coronary heart disease takes place, and acute as well as chronic impairment of microcirculation shows a remarkable improvement with H.E.L.P. therapy. For the future, the availability of this safe and efficient apheresis technique may help many patients who previously could not be treated adequately
Heparin–Induced Extracorporeal Low–Density Lipoprotein Precipitation and Low–Density Lipoprotein Chemoadsorption onto Dextran Sulfate: A Comparison
Authors: Bosch Thomas
Published: November 2008

Abstract: Both heparin–induced extracorporeal low–density lipoprotein precipitation (HELP) and dextran sulfate (DS) apheresis are potent tools for acute and long–term risk factor reduction in the secondary prevention treatment of coronary patients suffering from recalcitrant hypercholesterolemia. They combine high efficacy and selectivity of risk factor removal. Whereas LDL cholesterol and lipoprotein (a) adsorption onto DS offers the advantage of an unlimited treatable plasma volume and somewhat easier handling, HELP reduces fibrinogen more effectively and does not interfere with angiotension converting enzyme (ACE) inhibitors. Both systems can improve blood rheology and induce regression or stabilize coronary lesions. In an uncontrolled trial, HELP reduced the incidence of myocardial infarction. To date, no controlled prospective trials have been performed comparing the two systems with respect to their long–term risk factor reduction and their effect on coronary lesions, morbidity, and mortality.
Treatment of Severe Hyperlipidemia: Six Years' Experience with Low–Density Lipoprotein Apheresis
Authors: Bambauer Rolf , Schiel Ralf , Latza Reinhard , Klinkmann Jens
Published: November 2008

Abstract: In total, 30 patients suffering from familial hypercholesterolemia, resistant to diet and lipid–lowering drugs, were treated for up to 6 years (3.6 ± 1.6; range, 0.2–6.8 years) with low–density lipoprotein (LDL) apheresis. Three different systems were used; the dextran sulfate adsorption system (Kaneka) for 27 of 30 patients, the immunoadsorption system from Baxter for 2 of 30 patients, and the immunoadsorption system with special li–poprotein(a) (Lp[a]) columns from Lipopak for one patient. Prior to the LDL apheresis, 23 of 30 patients suffered from coronary heart disease. Twenty of 23 patients suffered intermittently from symptoms of angina, excertional dyspnea, and claudication. With LDL apheresis, reductions of 47% for total cholesterol, 49% for LDL, 26% for Lp(a), and 40% for triglycerides were reached. Severe side effects such as shock or allergic reactions were very rare (0.55%). In the course of treatment with LDL apheresis, an improvement in general well–being and increased performance were experienced in 27 of 30 patients. A reduction of nitrate medication between 60 and 100% was observed in 17 of 23 patients. The present data clearly demonstrate that treatment with LDL apheresis in patients suffering from severe familial hyperlipidemia, resistant to maximum conservative therapy, is very effective and safe even over long periods of time.
Low–Density Lipoprotein Apheresis in the Treatment of Two Patients with Coronary Heart Disease and Extremely Elevated Lipoprotein (a) Levels
Authors: Bambauer Rolf , Schiel Ralf , Keller Hans Erich , Klinkmann Jens , Latza Reinhard
Published: November 2008

Abstract: Hyperlipidemia and elevated lipoprotein (a) (Lp[a]) levels have been linked to the development and progression of premature atherosclerosis. Our study concerned 2 white male patients (aged 36 and 42 years) with heterozygous familial hypercholesterolemia and extremely elevated Lp(a) concentrations that were resistant to diet regimens and lipid–lowering drugs. The patients were treated with low–density lipoprotein (LDL) apheresis for 59 months (Liposorber system, Kaneka, Japan) and 19 months (immunoadsorption system, special Lp(a) columns; Lipopak; Pocard, Russia), respectively. The concentration of Lp(a) decreased on average by 50%, total cholesterol by 27%, LDL cholesterol by 41%, triglycerides by 43%, and fibrinogen by 16%. High–density lipoprotein (HDL) cholesterol increased by approximately 4%. Before treatment with LDL apheresis, each patient had suffered 3 myocardial infarctions, and had had 4 and 6 coronary angiographies with 2 and 4 percutaneous transluminal angioplasties (PTCAs), respectively. Since treatment with LDL apheresis, no myocardial infarctions or cardiac complaints were observed. In the course of treatment, both patients reported an increased performance. Available data suggest that LDL apheresis may be effective in the treatment of patients, the only risk factor for premature atherosclerosis being extremely elevated Lp(a) concentrations.
A Ferrofluidic Seal Specially Designed for Rotary Blood Pumps
Authors: Mitamura Yoshinori , Fujiyoshi Masayoshi , Yoshida Toshiobu , Yozu Ryohei , Okamoto Eiji , Tanaka Takashi , Kawada Shiaki
Published: November 2008

Abstract One of the key technologies required for rotary blood pumps is sealing of the motor shaft. A ferrofluidic seal was developed for an axial flow pump. The seal body was composed of a plastic magnet and two pole pieces. This seal was formed by injecting ferrofluid into the gap between the pole pieces and the motor shaft. To contain the ferrofluid in the seal and to minimize the possibility of ferrofluid making contact with blood, a shield with a small cavity was provided on the pole piece. Sealing pressure of the seal was measured. The sealing pressure was maintained at more than 23.3 kPa (175 mm Hg) for a motor speed up to 11,000 rpm. The specially designed ferrofluidic seal for sealing out liquids is useful for axial flow blood pumps.
Comparative Hemolysis Study of Clinically Available Centrifugal Pumps
Authors: Naito Kozo , Suenaga Etsuro , Cao Zhi‐Li , Suda Hisao , Ueno Tetsuya , Natsuaki Masafumi , Itoh Tsuyoshi
Published: November 2008

Abstract

Centrifugal pumps have become important devices for cardiopulmonary bypass and circulatory assistance. Five types of centrifugal pumps are clinically available in Japan. To evaluate the blood trauma caused by centrifugal pumps, a comparative hemolysis study was performed under identical conditions. In vitro hemolysis test circuits were constructed to operate the BioMedicus BP‐80 (Medtronic, BioMedicus), Sams Delphin (Sarns/3M Healthcare), Isoflow (St. Jude Medical [SJM]), HPM‐15 (Nikkiso), and Capiox CX‐SP45 (Terumo). The hemolysis test loop consisted of two 1.5 m lengths of polyvinyl chloride tubing with a 3/8 ‐inch internal diameter, a reservoir with a sampling port, and a pump head. All pumps were set to flow at 6 L/min against the total pressure head of 120 mm Hg. Experiments were conducted simultaneously for 6 h at room temperature (21oC) with fresh bovine blood. Blood samples for plasma‐free hemoglobin testing were taken, and the change in temperature at the pump outlet port was measured during the experiment. The mean pump rotational speeds were 1,570, 1,374, 1,438, 1,944, and 1,296 rpm, and the normalized indexes of hemolysis were 0.00070, 0.00745, 0.00096, 0.00066, 0.00090 g/100 L for the BP‐80, Sarns, SJM, Nikkiso, and Terumo pumps, respectively. The change in temperature at the pump outlet port was the least for the Nikkiso pump (1.8oC) and the most with the SJM pump (3.8oC). This study showed that there is no relationship between the pump rotational speed (rpm) and the normalized index of hemolysis in 5 types of centrifugal pumps. The pump design and number of impellers could be more notable factors in blood damage.
New Method of Evaluating Sublethal Damage to Erythrocytes by Blood Pumps
Authors: Shimono Takatsugu , Makinouchi Kenzo , Yada Isao , Nose Yukihiko
Published: November 2008

Abstract We recently proposed a new concept, the total destruction time of erythrocytes, to indicate sublethal damage to erythrocytes by blood pumps. In this article, results of additional experiments concerning this new concept are reported. Five paired in vitro hemolysis tests with bovine blood were conducted using a cone‐type centrifugal pump (Group A) and an impeller‐type pump (Group B). A total pressure head of 100 mm Hg was applied. The factors evaluated were the normalized index of hemolysis and the total destruction time, or the pumping duration, required to raise the level of the plasma‐free hemoglobin to 50% of the total hemoglobin. The morphologic change of the erythrocytes also was analyzed. The percentage of crenated cells was calculated from blood smear specimens 1 min after starting the pumps and 2 h before the total destruction time of Group A in each experiment. Although there was no statistical difference in the normalized index of hemolysis between the two groups, the total destruction time of Group A erythrocytes was significantly shorter than that of Group B (18.9 ± 4.5 h and 33.7 ± 9.9 h in Group A and group B, respectively; p < 2). The rate of crenated erythrocytes was higher in Group A than in Group B at a point 2 h before the total destruction time of Group A. The total destruction time values seem to define a good method for establishing sublethal traumatic damage to erythrocytes in blood pumps.
Prototype Continuous Flow Ventricular Assist Device Supported on Magnetic Bearings
Authors: Allaire P.E. , Kim H.C. , Maslen E.H. , Olsen D.B. , Bearnson G.B.
Published: November 2008

Abstract This article describes a prototype continuous flow pump (CFVAD2) fully supported in magnetic bearings. The pump performance was measured in a simulated adult human circulation system. The pump delivered 6 L/min of flow at 100 mm Hg of differential pressure head operating at 2,400 rpm in water. The pump is totally supported in 4 magnetic bearings: 2 radial and 2 thrust. Magnetic bearings offer the advantages of no required lubrication and large operating clearances. The geometry and other properties of the bearings are described. Bearing parameters such as load capacity and current gains are discussed. Bearing coil currents were measured during operation in air and water. The rotor was operated in various orientations to determine the actuator current gains. These values were then used to estimate the radial and thrust forces acting on the rotor in both air and water. Much lower levels of force were found than were expected, allowing for a very significant reduction in the size of the next prototype. Hemolysis levels were measured in the prototype pump and found not to indicate damage to the blood cells.
Fluctuations of the Hemodynamic Derivatives During Left Ventricular Assistance Using Oscillated Blood Flow
Authors: Yambe Tomoyuki , Kobayashi Shinichi , Nanka Shunsuke , Naganuma Shigeru , Nitta Shinichi , Matsuki Hidetoshi , Abe Ken‐ichi , Yoshizawa Makoto , Fukuju Takeo , Tabayashi Kou‐ichi , Takeda Hiroshi , Hashimoto Hiroyuki
Published: November 2008

Abstract: To analyze the autonomic nervous system during left heart bypass with a vibrating flow pump (VFP), fluctuations in hemodynamic derivatives were evaluated by the spectral analysis method using fast fourier transform methodology. After the left pleural cavity was opened through the fourth intercostal space under general anesthesia, a VFP was implanted as the left heart bypass device in chronic animal experiments using 3 healthy adult goats. Hemodynamic parameters with and without VFP assistance were recorded on magnetic tape in awake animals and were analyzed by computer through an analog to digital convertor. Power spectral analysis was performed on a beat‐to‐beat basis for the evaluation of the fluctuations. During left heart bypass with the VFP, Mayer wave fluctuations were decreased significantly although respiratory waves were not changed significantly. These results suggest that sympathetic nervous system modulation was changed under the influences of the left heart bypass with VFP. By using this analysis methodology, truly physiologic ventricular assistance may be achieved.
Subchronic Use of the St. Jude Centrifugal Pump as a Mechanical Assist Device in Calves
Authors: Curtis Jack , Wagner‐Mann Colette , Mann Fred , Demmy Todd , Walls Joseph , Turk James
Published: November 2008

Abstract: The purpose of this experiment was to study the effects of the St. Jude Lifestream centrifugal pump on hemodynamic and hematologic parameters and the incidence of postmortem findings in a subchronic ex vivo left ventricular assist animal model. Five calves were implanted with the pump as a left ventricular assist device (left atrial to thoracic aorta bypass) and studied for 96 h of continuous pumping under identical conditions. Heparin (100 IU/kg) was administered only in the initial saline pump prime. Throughout the protocol, mean arterial and central venous pressures averaged 102.1 ± 4.6 and 3.4 ± 2.2 mm Hg, respectively. Pump flow was 47.8 ± 8.4 ml/kg/min at a mean pump speed of 1,676.3 ± 106.1 rpm. No clinical abnormalities or mechanical malfunctions attributable to the pump were detected during the 96 h of continuous pumping for each calf. Mean plasma‐free hemoglobin after 96 h was 3.9 ± 3.7 u, mol/L (p = 0.337 compared to baseline). At post mortem, renal infarctions were detected in 1 calf. No other pump‐associated lesions were detected in any of the other calves. We have concluded that the St. Jude Lifestream centrifugal pump functions reliably during 96 h of continuous left heart bypass in a calf model.
Subchronic Centrifugal Mechanical Assist in an Unheparinized Calf Model
Authors: Wagner‐Mann Colette , Curtis Jack , Mann Fred A. , Turk James , Demmy Todd , Turpin Timothy
Published: November 2008

Abstract. The purpose of this study was to determine whether the major centrifugal pumps currently in use in the United States (Medtronic, BioMedicus BioPump and Carmeda‐coated BioPump, Sams 3M centrifugal pump, and St. Jude Medical Lifestream) could function as left mechanical assist devices in the subchronic (72 h) unheparinized calf model. Calves were instrumented for left atrial to aorta ex vivo assist, and the pump flow was set at 3.5 ± 0.4 L/min. Two calves (Sarns 3M and St. Jude) survived 72 h of pumping without clinical complications. The other 2 calves died at 62 and 66 h (Medtronic Bio‐Pump and Carmeda‐coated BioPump, respectively); both had pelvic limb paralysis. The seal of the Sarns 3M pump head ruptured after approximately 36 h of pumping and required replacement. On postmortem examination, pump‐associated thromboembolic lesions were detected in 3 of the 4 calves in one or more of the following organs: kidney, pancreas, abomasum, duodenum, ileum, spleen, and lumbar spinal cord. The calf with the Sarns 3M pump had no discernable lesions. Because of the clinical abnormalities and postmortem lesions in the unheparinized calf model, it was suggested that anticoagulation is necessary for conducting centrifugal mechanical assist studies in calves using presently available technology.
Clinical Use of Centrifugal Pumps and the Roller Pump in Open Heart Surgery: A Comparative Evaluation
Authors: Yoshikai Masaru , Hamada Masakatsu , Takarabe Kyoumi , Okazaki Yukio , Yoshika Masaru
Published: November 2008

Abstract: Centrifugal pumps have been used widely as the main pump in open heart surgery to reduce damage to blood elements and to reduce the activation of the coagulation system. The purpose of this study was the evaluation and comparison of the effects of two types of centrifugal pumps and of one type of roller pump on blood elements, the coagulation system, complements, and immunoglobulins. Two types of centrifugal pumps (Lifestream; St. Jude Medical, Chelmsford, Massachusetts; and BP‐80; Medtronic, BioMedicus, Inc., Eden Prairie, Minnesota, U.S.A.) and one roller pump (Mera Co.) were used separately as the main pump for cardio‐pulmonary bypass (CPB) in 29 patients. Platelet counts, lactate dehydrogenase, antithrombin III, thrombin‐antithrombin complex (TAT), complements (C3, C4, and CH50) and immunoglobulins G, A, and M values were measured before and after CPB and compared. Values, except those for TAT, showed no significant difference among the three groups. The TAT values increased less in each of the centrifugal pump groups than in the roller pump group. This finding suggests that thrombin synthesis might be suppressed by the use of a centrifugal pump.
Clinical Experience with the Nikkiso Centrifugal Pump
Authors: Shomura Yu , Shimono Takatsugu , Onoda Koji , Hioki Iwao , Tenpaku Hironori , Maze Yasumi , Mizumoto Torn , Tani Kazuhiro , Tanaka Kuniyoshi , Shimpo Hideto , Yuasa Hiroshi , Yada Isao
Published: November 2008

Abstract: The Nikkiso HPM‐15 is a minimally sized centrifugal pump. Preliminary results regarding clinical use of this pump for cardiopulmonary bypass (CPB) procedures have been reported previously. Recently, we have managed some additional cases using a newly developed controller. This article reports our clinical experiences with the use of this pump. We have managed 23 cases with a Nikkiso centrifugal pump. Twenty‐two patients underwent CPB and 1 patient with fulminant viral myocarditis underwent percutaneous cardiopulmonary support (PCPS). With this pump, the circuit was extremely easy to prepare and deaeration was achieved readily. Hemodynamics during CPB and PCPS were stable in all cases. The increase in serum‐free hemoglobin levels during CPB with this pump was as low as that seen in preliminary tests. A decrease in the platelet count was observed after the initiation of CPB with this pump; however, platelet counts returned to preoperative values 7 days after surgery. Moreover, urine output during CPB with this pump was as high as that seen in preliminary tests. No abnormalities in renal or liver function occurred during CPB. It appears that this new centrifugal pump is safe and easy to operate, and we conclude that it is useful for CPB and PCPS.
Soluble TNFα Receptors Are Increased in Chronic Renal Insufficiency and Hemodialysis and Inhibit Neutrophil Priming by TNFα
Authors: Ward Richard A. , McLeish Kenneth R.
Published: November 2008

Abstract: The oxidative burst of neutrophils from azotemic patients is refractory to priming by tumor necrosis factor‐α (TNFα). Soluble TNFα binding proteins (TNFR) accumulate in the plasma of azotemic patients. To test the hypothesis that these increased sTNFR concentrations inhibit TNFa priming of oxidative burst activity, we measured plasma sTNFR concentrations in nondialyzed azotemic patients, hemodialysis patients, and normal subjects, and determined TNFa priming of fMet‐Leu‐Phe‐stimulated superoxide production in neutrophils incubated in plasma with differing levels of sTNFR. These sTNFR concentrations increased significantly as creatinine clearance decreased and were significantly greater in hemodialysis patients than could be accounted for by loss of renal function alone. TNFα primed superoxide production by normal neutrophils in normal plasma, but this effect was significantly reduced in plasma with increased concentrations of sTNFR. Neutrophils from azotemic and hemodialysis patients were refractory to priming by TNFα in autologous plasma, and incubation in normal plasma only partially corrected this defect. We conclude that sTNFR accumulate as a result of the loss of renal function and hemodialysis and inhibit TNFα priming of neutrophils in azotemic and hemodialysis patients, but that these cells also have an intrinsic functional defect.