bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of a Multiple Disk Centrifugal Pump as an Artificial Ventricle
Authors: Miller G.E. , Sidhu A. , Fink R. , Etter B.D.
Published: July 2010

Abstract: A multiple‐disk centrifugal pump based on the Tesla Turbine design has been modified for potential use as an artificial ventricle or ventricular assist device. The pump consists of a series of interconnected parallel disks placed within a spiral volute housing. This pump normally operates as a continuous flow device; however, a controller circuit has been developed to also allow for pulsatile operation. Frequency, systolic duration, systolic rise time, and diastolic decay time can be independently controlled to produce a wide range of pulsatile pressures and flows. This pumping system was tested in vitro on a mock circulatory system using a blood analogue. Inlet and outlet pressures, outlet flow, and motor rotations per minute were continually monitored over a wide range of physiologic operating conditions. The disk pump output was compared with that of other artificial ventricles and produced favorable results. Direct experimental comparisons were made with a Harvard Apparatus pulsatile piston pump. Unlike the Harvard pump, the disk pump does not use valves. Rather, a slight forward rotation of the disks is used to offset the adverse diastolic pressure gradient, which avoids backflow through the device.
A Straight Path Centrifugal Blood Pump Concept in the Capiox Centrifugal Pump
Authors: Kijima Toshihiko , Oshiyama Hiroaki , Horiuchi Kunio , Nogawa Atuhiko , Hamasaki Hiroaki , Amano Nobuhiko , Nojiri Chisato , Fukasawa Hiromichi , Akutsu Tetuzo
Published: July 2010

Abstract: This article describes comparative studies of a newly developed “straight path” centrifugal pump (Capiox centrifugal pump) targeted for open‐heart surgery and circulatory support. A unique straight path design of the rotor was very effective in reducing the pump's rotational speed and prime volume. This pump was evaluated for hydraulics, hemolysis, depriming characteristics, cavitation, and heat generation. Two commercially available centrifugal pumps, the Biomedicus cone‐type pump and the Sarns 3M impeller‐type pump, were used as controls. The new pump required the lowest pump speed to produce the same flow rates under the same pressure loads and demonstrated the lowest hemolysis and the lowest temperature rise with the outlet clamped. The air volume required to deprime the new pump was one‐third to one‐half that for the other pumps, and no sign of cavitation was observed even if a small amount of air was introduced to the pump inlet under a negative pressure of 200 mm Hg.
Clinical Experience of Assisted Circulation with a Centrifugal Pump at Tokyo Women's Medical College
Authors: Nishida Hiroshi , Koyanagi Hitoshi , Hashimoto Akimasa , Endo Masahiro , Aomi Shigeyuki , Koyanagi Toshiya , Hirota Jun , Tagusari Osamu , Yamaki Fumitaka
Published: July 2010

Abstract:In postpericardiotomy patients, the use of pulsatile pumps is limited in a semielective fashion to patients whose postoperative marginal hemodynamics are expected preoperatively. Since 1989, 25 patients have under‐gone assisted circulation with a centrifugal pump: 15 (60%) were weaned from the pump, and 7 (28%) survived. In 1988, we heparin‐coated the Bio‐Pump using the Carmeda technique and developed a totally heparin‐coated left heart bypass system together with heparin‐coated cannulas and tubing. Four postpericardiotomy patients underwent left heart bypass with this system without heparin for 2 to 9 days. No thrombus was detected in the system. Left heart bypass with a centrifugal pump has been used as a supportive method in surgical repair of thoracic or thoracoabdominal aortic aneurysm. To over‐come intraoperative hypothermia and hypoxia, we used a small membrane oxygenator with a heat exchanger in 11 patients, and postoperative recovery dramatically improved. We also developed a preassembled percutaneous cardiopulmonary support (PCPS) system with an automatic priming function using Terumo's straight path centrifugal pump and small membrane oxygenator in cooperation with the Terumo Corporation. This system was used in a patient with cardiogenic shock after acute myocardial infarction. The setup and priming took only 5 min, and 2.5‐3.5 L/min of flow was obtained.
Lipid Apheresis by Hemoperfusion: In Vitro Efficacy and Ex Vivo Biocompatibility of a New Low‐Density Lipoprotein Adsorber Compatible with Human Whole Blood
Authors: Bosch T. , Schmidt B. , Blumenstein M. , Gurland H.‐J.
Published: July 2010

Abstract: To date, selective extracorporeal low‐density lipoprotein (LDL) removal can only be performed from plasma; that is, a plasma‐cell separation step using a centrifuge or a plasma membrane separator is necessary initially. This article characterizes a new polyacrylate‐based LDL adsorber directly applicable to whole blood. In vitro single‐pass hemoperfusion tests using pooled donor blood showed quantitative adsorption of atherogenic LDL‐cholesterol (LDL‐C) and complete recovery of protective high‐density lipoprotein C. Fibrinogen, another independent risk factor of atherosclerosis, was also adsorbed to a lesser extent. Single‐pass ex vivo biocompatibility using fresh donor blood on‐line was excellent and resulted in minimal cell loss. Neither signs of hemolysis nor activation of monocytes (interleukin‐l production) were detected. Only slight activation of leukocytes (elastase release) and thrombocytes (platelet factor 4 secretion) as well as of coagulation (thrombin‐antithrombin complex formation) and complement (C3a, C5a generation) was observed. Under the experimental conditions used, the optimal anticoagulation regimen was 0.5 IU heparin plus 0.375 mg citratelml blood. Priming the column with a buffer of pH 7.4 containing heparin, citrate, and Ca2+ is recommended. In conclusion, this new adsorber exhibited selective LDLC adsorption in vitro combined with excellent ex vivo biocompatibility and thus holds great promise for a successful clinical application in a closed‐loop system in patients.
Chronic Biofiltration Therapy
Authors: Djordjević Vidojko , Kostić Svetislav , Stefanović Vladisav
Published: July 2010

Abstract: Long‐term follow‐up evaluation of biofiltration treatment in 7 patients is presented. These patients experienced frequent episodes of hypotension during acetate hemodialysis. A 3‐year biofiltration treatment reduced by 43% episodes of symptomatic hypotension and produced a significant increase in the pretreatment pH and plasma bicarbonate levels. The β2‐microglobulin level was significantly reduced during biofiltration therapy. The mean systolic and diastolic blood pressures slightly increased during biofiltration. Uremic polyneuropathy, as demonstrated by an increase in motor nerve conduction velocity, slightly improved. The patients reported increased comfort during biofiltration therapy.
Clinical Experience and Model Analysis on Beta‐2‐Microglobulin Kinetics in High‐Flux Hemodialysis
Authors: Da Lian Jong , Cheng Chi Hung , Chagn Yen Lin , Hsiong Cheng Hwae , Lee †Chau Jen
Published: July 2010

Abstract: Beta‐2‐microglobulin (β2M) is associated with amyloidosis. The study of β2M kinetics can provide information on the elimination of this uremic toxin. A β2M kinetic model modified from Gotch, considering the volume changes between intracellular, interstitial, and intravascular compartments and the generation stimulation and inhibition during hemodialysis is proposed. The clinical experiments on 8 stable hemodialysis patients treated with polysulfone (F80) and polymethyl methacrylate (PMMA, BK2.1p) 3 times a week were conducted. There was an 18% decrease of β2M clearance in the period from 30 to 180 min with a time‐averaged β2M clearance of 48 ml/min using polysulfone dialyzers (F80). In PMMA dialyzers, there was a 64% decrease of β2M clearance from 30 to 180 min with a time‐averaged clearance of 56.3 ml/min. During hemodialysis, the generation rate was 0.379 mg/min in polysulfone and 0.828 mg/min in PMMA dialyzers. There was a stimulation generation of 0.309 mg/min in polysulfone and 0.749 mg/min in PMMA during hemodialysis. In conclusion, we provide a β2M kinetic model including volume changes, polymerization, generation stimulation, and inhibition that is similar to the human physiological condition. This model can be used for further clinical study.
The Effect of Interdialytic Weight Gain on Predialysis Blood Pressure
Authors: Sherman Richard A. , Daniel Amir , Cody Ronald P.
Published: July 2010

Abstract: Interdialytic weight gain is believed to influence predialysis blood pressure. Since interdialytic weight gains vary among treatments for individual patients, blood pressure and weight gain data could be examined to determine how weight variations correlate with differences in blood pressure. Therefore, the quantitative effect on prehemodialysis blood pressure of typical interdialytic weight gains was prospectively studied in 19 nondiabetic patients on chronic hemodialysis. Over a mean of 23.6 treatments (range 17–25), the slope of each patient's prehemodialysis blood pressure versus excess weight (prehemodialysis weight minus baseline dry weight) was determined. The mean slope of the prehemodialysis mean blood pressure/excess weight regression line was 1.2 mm Hg/lb excess weight. No significant correlation was found between individual prehemodialysis blood pressure/excess weight slopes and patient age (r = 0.20), months on dialysis (r = 0.33), dry weight (r = 0.05), or mean excess weight (r = 0.19). Slopes did not differ for 3‐day versus 2‐day interdialytic intervals, hypertension‐treated versus untreated patients, or men versus women. In 5 patients, individual prehemodialysis mean blood pressure/excess weight slopes were significantly greater than 0, averaging 2.4 mm Hg/lb excess weight (vs. 0.8 mm Hg/lb in the remaining patients). These 5 volume‐responsive patients did not differ clinically from the 14 volume‐resistant patients. The weight gains commonly observed in patients undergoing chronic hemodialysis have only a modest effect on prehemodialysis blood pressure in the majority of patients.
A New Device for Endothelial Cell Seeding of a Small‐Caliber Vascular Prosthesis
Authors: Mazzucotelli Jean Philippe , Roudière Jean Louis , Bernex Florence , Bertrand Patrick , Léandri Jacqueline , Loisance Daniel
Published: July 2010

Abstract: A device permitting homogeneous endothelial cell seeding of a small‐calíber arteríal prosthesís has been developed. The prosthesis is maintained firmly attached to a rotative scaffolding device. This device is activated by an electrical motor at constant and adjustable speed. The whole system is maintained at 37°C in a cell culture incubator. The 4 mm internal diameter polytetrafluoroethylene (PTFE) prosthesis was coated with biological glue and seeded with human saphenous vein endothelial cells obtained by mechanical detachment. Cell seeding density was 2.104 cells/cm2 (Group A, n = 6) or 105 cells/cm2 (Group B, n = 6). Rotation speed was 8 revolutions per hour (rph) during 90 min. Analysis of the homogeneity of cell seeding was permitted by cell counts on five different segments of the prosthesis. Each longitudinal segment was analyzed at three different subsegments of the circumference. The average adhesion was 43 ± 4% in Group A and 38%± in Group B of seeded cells. No difference could be observed between the different segments and subsegments. In the two groups, cells were spread, and in Group B, a complete endothelial cell layer was obtained on the graft surface. This study permits validation of the device to allow homogeneous cell seeding in an arterial prosthesis.
Reoperations on Prosthetic Heart Valves: An Analysis of Outcome
Authors: Otaki Masaki , Kitamura Nobuo
Published: July 2010

Abstract: To evaluate risks and complications of reoperations on prosthetic heart valves, we reviewed data on 70 patients who underwent reoperations because of prosthetic valve malfunction. Overall hospital mortality was 13% (9/70 patients). The common cause of death was low cardiac output syndrome following surgery (4 patients). Respiratory failure and mediastinal infection accounted for 2 deaths each, and neurological complication for 1 death. However, hospital mortality was different according to the risk factors; reoperations for prosthetic valve endocarditis (18%, p < 0.05), advanced New York Heart Association (NYHA) class (50%, p < 0.001), and emergency operation (33%, p < 0.005) were the significant risk factors. In contrast, advanced age, female sex, type of prosthesis, valve position, and diagnosis (leak, structural deterioration, or valve thrombosis) did not appear to be significant risk factors. There were 7 late deaths (4 valve‐related, 2 cardiac, and 1 noncardiac). Inasmuch as emergency operation, advanced NYHA class, and prosthetic valve endocarditis affected hospital mortality, these factors contributed to late death. Actuarial survival rate and freedom from valve‐related mortality at 10 years were 75.8 ± 2.8% and 87.2 ±2.3%, respectively. There were 8 valve‐related complications, and freedom from valve‐related complications at 10 years was 73.5 ± 3.5%. As judged by these data, hospital mortality and late survival can be improved if hemodynamic conditions leading to myocardial damage can be prevented.
A Fluid Dynamic Analysis of a Rotary Blood Pump for Design Improvement
Authors: Treichler J. , Rosenow S. E. , Damm G. , Naito K. , Ohara Y. , Mizuguchi K. , Makinouchi K. , Takatani S. , Nosé Y.
Published: July 2010

Abstract: The proper design of a left ventricular assist device (LVAD) requires an understanding of the pump's fluid dynamic and biocompatible properties. A hydraulically efficient system minimizes the power required for pumping. Biocompatibility refers to the ability to pump blood with minimal hemolysis and thrombus formation. Typically, shear stresses below a threshold level will not damage blood significantly. A fluid dynamic analysis of a prototype centrifugal pump designed for use as an LVAD was performed to establish flow characteristics. A flow visualization technique using Amberlite particles suspended in a glycerin/water blood analogue was used. The system was illuminated with a 1 mm planar beam strobed helium‐neon laser, and the results were recorded photographically. An analysis of photographs revealed laminar and turbulent flows with vortices within an illuminated plane in both the inlet and outlet port areas. From these data, velocity and shear stress profiles were generated that showed possible areas of improvement. It was concluded that the outlet port design could be improved by changing its angle and the continuity of its expansion. The inlet port could also be improved by smoothing the transition area between the inlet tube and the pump body to allow for gradual acceleration of the entering fluid.
Dialysis Treatment Using an Ethylene Vinyl Alcohol Membrane and No Anticoagulation for Chronic Uremic Patients
Authors: Cicchetti T. , Senatore R.P. , Frandina F. , Ferrari S. , Striano U. , Milei M. , Cosentino S.
Published: July 2010

Abstract: Anticoagulation used in hemodialysis treatment brings with it the risk of hemorrhagic complications and the possible consequences associated with chronic heparin administration. These problems have not been satisfactorily addressed to date. This study examined a new dialysis method that does not require the administration of anticoagulants. Dialysis is performed for 3 h with a continuous infusion of 750 ml of physiological saline solution in predilution mode and using filters made of ethylene vinyl alcohol copolymer membranes. Eleven patients with chronic uremia underwent more than 2,000 dialysis treatments performed with 9 episodes of coagulation of the dialyzer or blood tubings (0.43%). An evaluation of individual treatments revealed a high degree of biocompatibility and only a scanty activation of coagulation. Blood depuration efficacy was very good as evaluated from pretreatment and posttreatment routine blood chemistries. The technique described here represents a simple and effective method for performing regular dialysis treatment and does not require anticoagulant therapy.
Catastrophic Vasoconstriction after Protamine Reversal of Heparin Anticoagulation in the Goat
Authors: Tominaga Ryuji , Smith William A. , Harasaki Hiroaki , Golding Leonard A.R.
Published: July 2010

Abstract: Catastrophic pulmonary vasoconstriction after protamine reversal of heparin anticoagulation was observed frequently in goats that underwent centrifugal biventricular bypass pump implant. Care should be taken when protamine is used to reverse heparin anticoagulation in goats.
A Long‐Term Culture System for the Expansion of Hematopoietic Stem Cells from Embryonic Yolk Sac with the Capacity to Seed Erythroid and Lymphoid Development In Vitro and to Reconstitute the Lymphoid Compartment in Severe Combined Immunodeficient Mice
Authors: Ji Hong , Yu Xian‐Zhong , Wagner Thomas E.
Published: July 2010

Abstract: We have established a long‐term culture system under which hematopoietic stem cells derived from the embryonic yolk sac may be maintained for long periods. Evidence for the persistence of stem cells in this culture is provided by three experimental observations. First, erythroid progenitors, as evidenced by morphological, functional, and phenotypical analysis, may be generated from these yolk sac cultures after more than 7 months in culture. The yolk sac derived erythroid progenitors are distinct from those of bone marrow derived cells both qualitatively and quantitatively. This is evidenced by the high colony plating efficiency, large colony size, different growth factor requirements, increased sensitivity to Epo and other cytokines, as well as significant and prolonged expansion capability, suggesting that the yolk sac derived progenitors are both more proliferative and more primitive than their bone marrow derived analogs. Second, under different conditions, lymphoid progenitors may also be derived from these long term yolk sac cultures in the presence of the appropriate cytokines. Third, preliminary data suggest the engraftment of these yolk sac cells and reconstitution of at least some compartments of the hematopoietic system of host animals. This long‐term culture system will provide a useful model for the study of early embryonic hematopoiesis, and the cells derived from this culture system may also have the potential of serving as donor cells for hematopoietic cell transplantation.
Prolongation of Rat Liver Graft Survival by Splenectomy Combined with Low Dose FK506 Therapy
Authors: Kashu Yasuaki , Abe Yasuhito , Miyauchi Katsutoshi , Watanabe Yuji , Sato Motomichi , Sato Naoshi , Kimura Shigeru
Published: July 2010

Abstract: The effects of low dose FK506 therapy (0.1 mg/kg/day × 1 day) on graft survivals were analyzed, and the feasibility of splenectomy was assessed. ACI strain liver grafts were orthotopically implanted into LEW male rat recipients. In the control group, the survival period was 10.4 ± 1.4 days. In the group treated with splenectomy, the survival period was 13.4 ± 2.0 days. In the groups with low dose FK506 therapy, the survival periods were 22.7 ± 6.7 and 39.7 ± 6.3 days with or without splenectomy, respectively. Rats in the group with average dose FK.506 (1.0 mg/kg/day × 7 days) survived more than 100 days. In summary, the effect of low dose FK506 therapy was relatively limited. Splenectomy by itself was marginally effective; however, this effect was enhanced when combined with low dose FK.506 therapy.
Study of the Changes of Serum Hyaluronic Acid During Porcine Liver Transplantation: Influence of Warm Ischemia
Authors: Nakajima Yasuaki , Kimura Jun , Isai Hideya , Tamura Motoshi , Ito Koji , Kon Hirofumi , Kamachi Hirofumi , Koike Masahiro , Kusumoto Kenju , Uchino Junichi
Published: July 2010

Abstract: Twelve porcine liver transplantations were performed to investigate whether serum hyaluronic acid (HA) serves as a marker of warm ischemic injury. Group 1 was a control without warm ischemia (n = 7), and pigs in Group 2 were sacrificed by intracardiac KC1 injection 60 min before harvesting (n = 5). All pigs survived more than 4 days in Group 1. In Group 2, all died within 2 days due to graft failure. Arterial and hepatic venous glutamic‐oxaloacetic transaminase (GOT) in Group 2 were higher after revascularization. However, there were no differences between the 2 groups in arterial and hepatic venous HA levels. HA clearance by the graft also showed no differences between the groups. Although GOT reflected the degree of warm ischemia, HA and its hepatic clearance were not influenced by warm ischemic damage. In conclusion, HA was not thought to serve as a marker of liver injury when the graft suffered from warm ischemia.
Immunosuppressive Treatment of Primary Cadaveric Renal Transplant Patients Receiving Kidneys from Non‐Heart Beating Donors
Authors: Ohshima Shinichi , Fujita Tamio , Ono Yoshinari , Kinukawa Tsuneo , Katoh Norio , Matsuura Osamu
Published: July 2010

Abstract: Since November 1982, 276 primary cadaveric kidney transplants have been performed using kidneys from non‐heart beating donors. Between November 1982 and December 1986, 49 transplant patients were treated with cyclosporine and steroid immunosuppressive therapy (CSA regimen). Twenty‐seven patients were treated with low dose cyclosporine (initial dosage, 4 mg/kg/day), steroid therapy, and a 21‐day course of 500 mg/day anti‐lymphocyte globulin (ALG 1 regimen) between January 1987 and December 1987. Seventy‐nine patients were treated with low dose cyclosporine (initial dosage, 6 mg/ kg/day), steroid therapy, and a 14‐day course of 1,000 mg/day antilymphocyte globulin (ALG 2 regimen) between January 1988 and June 1990, and 85 patients were treated with low dose cyclosporine (initial dosage, 6 mg/ kg/day), steroid therapy, and a 14‐day course of 1,000 mg/day antilymphocyte globulin followed by 2 mg/kg/day mizoribine (ALG 3 regimen) between July 1990 and May 1995. Ten patients, who showed hypersensitivity to antilymphocyte globulin therapy, were treated with low dose cyclosporine, steroid therapy, and mizoribine. Finally, 26 patients were treated with FK506 and steroid therapy (FK.506 regimen) between June 1990 and February 1992. Graft survival was 78% at 1 year, 69% at 3 years, 63% at 5 years, and 51% at 10 years in the CSA regimen group and 67% at 1 year, 52% at 3 years, and 48% at 5 years in the ALG 1 regimen group. It was 85% at 1 year, 70% at 3 years, and 62% at 5 years in the ALG 2 regimen group and 87% at 1 year and 67% at 3 years in the ALG 3 regimen group. In the FK506 regimen group, graft survival was 92% at 1 year and 80% at 3–5 years. Never‐functioning grafts were observed in 3 CSA patients (6%), I ALG 1 patient (4%), 3 ALG 2 patients (4%), 3 ALG 3 patients (4%), and I FK506 patient (4%). These results indicate that low dose cyclosporine (initial dosage, 6 mg/kg/day), steroid therapy, and a 14 day course of antilymphocyte globulin therapy is beneficial for cadaveric renal transplant patients receiving kidneys from non‐heart beating donors; FK506 and steroid therapy might be more effective than cyclosporine based immunosuppressive therapies even in such patients.
Development of Low Potassium Solution (EP4 Solution) for Long‐Term Preservation of a Lung Transplant: Evaluation in Primate and Murine Lung Transplant Model
Authors: Fujimura Shigefumi , Kondo Takashi , Handa Masashi , Ohura Hiroyuki , Saito Ryo , Sugita Makoto , Suzuki Satoshi
Published: July 2010

Abstract: The results of recent studies on long‐term preservation using low potassium flush solution, which was originally produced in our department, are presented and discussed. In the primate model, a lung preserved for 24 h with EP4 solution retained sufficient function in single lung allotransplantation. In the murine experiments, we have evaluated the ion transport properties across alveolar epithelial cells in the transplanted lung using the tools of alveolar fluid clearance tests. The alveolar fluid clearance rate, which can be inhibited by 10‐3M ouabain, is also well preserved for the first 24 h, indicating that the alveolar epithelial Na‐K‐ATPase is still functioning and that the 72 h preservation decreases those function of Na‐K‐ATPase in a time‐dependent manner. In conclusion, because 24 h hypothermic preservation with EP4 solution did not show any obvious disadvantage on primate lung allografts and the cellular and molecular viability of the preserved lung flushed with EP4 solution could be retained for 24 h, this kind of solution with extracellular electrolyte composition can be applicable in the clinical settings.
Effect of Surface Roughness on Hemolysis in a Pivot Bearing Supported Gyro Centrifugal Pump (C1E3)
Authors: Takami Yoshiyuki , Makinouchi Kenzo , Nakazawa Tadashi , Glueck Julie , Benkowski Robert , Nose Yukihiko
Published: July 2010

Abstract: The blood contacting surface quality is an important pump parameter for blood compatibility and cell damage. This study investigates the surface roughness and the effect it has on hemolysis in a centrifugal blood pump. In vitro hemolysis tests were performed with a pivot bearing supported Gyro centrifugal pump (C1E3) simulating cardiopulmonary bypass (CPB; 5 L/min, 350 mm Hg) and left ventricular assist device (LVAD; 5 L/min, 100 mm Hg) conditions. To produce 4 different grades of surface roughness, the impellers and housings were subjected to vapor polishing, sand papering, fine sand blasting, or coarse sand blasting. Seven pumps were assembled with different impeller and housing surfaces. These surfaces were then examined by a surface profile instrument and a scanning electron microscope. The results of this study are as follows. First, the effect of surface roughness on hemolysis was significantly greater in the CPB condition than in the LVAD condition. Second, surface roughness, regardless of whether it is the impeller or pump housing, had little effect on hemolysis in the LVAD condition. Third, in the CPB condition, the surface roughness of the pump housing has a greater effect on hemolysis than does that of the impeller. From a hemolytic point of view, an extremely smooth pump housing is required for use of an impeller type centrifugal pump as a CPB device. In contrast, it is conceivable that a smooth surface is not always essential for an impeller type centrifugal pump that is used as an LVAD.
Clinical Use of CarboMedics and St. Jude Medical Valves
Authors: Wang Shoei‐Shen , Chu Shu‐Hsun , Tsai Chang‐Her , Lin Fang‐Yue
Published: July 2010

Abstract: Three hundred and twenty‐six patients underwent CarboMedics valve implantation (CM) in the aortic (119 patients), mitral (148 patients) or aortic and mitral (59 patients) positions while 371 patients underwent St. Jude Medical valve implantation (SJ) in the aortic (113 patients), mitral (184 patients), or aortic and mitral (74 patients) positions at National Taiwan University Hospital from August 1991 through 1995. All patients received warfarin (Coumadin) anticoagulation with the target international normalized ratio around 1.5. The hospital mortality was 3.7% in the CM group and 4.3% in the SJ group. In the CM group at 5 years, the actuarial freedom from thromboembolism, valve thrombosis, and anticoagulant‐related hemorrhage was 89.91 ± 2.66%, 95.23 ± 1.50%, and 99.62 ± 0.37%, respectively, and the actuarial: survival rate was 90.4 ± 1.6%. In the SJ group at 5 years, the actuarial freedom from thromboembolism, valve thrombosis, and anticoagulant‐related hemorrhage was 94.79 ± 1.70%, 98.80 ± 0.72%, and 99.68 ± 0.31%, respectively, and the actuarial survival rate was 91.3 ± I 1.7%. We therefore concluded that a similar survival rate was noted in the CM and SJ groups. With low dose anticoagulation, the complications of thromboembolism, I valve thrombosis, and anticoagulant‐related hemorrhage were low in the SJ group.
Pulsatile Augmentation Device for Extracorporeal Circulation
Authors: Doty Donald B. , Wang Nai‐dong , Chiang Bang‐yu , Mohammad S. Fazal
Published: July 2010

Abstract: A device has been designed, constructed, and tested to provide pulsatile pressure/flow to a standard extracorporeal bypass circuit. The pulsatile augmentation device is pneumatically driven similar to an artificial heart ventricle except that there are no valves. It is constructed of polyurethane by vacuum forming and high frequency welding. Drivers used are a modified Arrow‐Kontron in‐traaortic balloon pump or the Utah artificial heart driver. In vitro testing with fresh bovine blood demonstrated acceptable blood compatibility and hemodynamic function. In vivo testing for 4 h in a right and left heart extracorporeal bypass circuit showed good pulse augmentation in pulmonary and systemic bypass circuits. The device shows promise for adding pulse to standard cardiopulmonary bypass and to extracorporeal right heart circulatory assist circuits.
The Pulsatile Impeller Pump for Left Ventricular Assist
Authors: Wang Shoei‐Shen , Chu Shu‐Hsun , Chou Nai‐Kuan , Qian Kun‐Xi
Published: July 2010

Abstract: Because of severe hemolysis, especially on producing pulsatile flow by changing the rotating speed of the impellers, the traditional centrifugal pump was rarely used for long‐term support of the failing heart. We therefore developed a motor driven pulsatile implantable impeller pump. The pulsatility was achieved by changing the rotating speed via introducing a square waveform voltage into the motor coil. The impeller vane was designed to have both radial and axial curves according to the stream surface and stream lines to reduce the thrombosis and hemolysis. Nine calves weighing 80 to 100 kg were used. With the calves under endotracheal general anesthesia, left posterolateral thoracotomy was performed to connect the inflow tube with the left atrial appendage and to anastomose the outflow tube with the descending aorta. The calves usually awoke and stood up within hours after discontinuation of anesthetics. Within 7 days, continuous monitoring of electrocardiogram, systemic and pulmonary arterial pressures, and central venous pressure were performed to adjust the pump flow to 40% to 50% of the cardiac output. During the survival of 4 to 54 days (mean 16.3 ± 19.3 days with two calves surviving longer than 1 month), no significant deterioration of liver or renal function was noted. Because of bleeding, hemoglobin reduced from 11.4 ± 1.8 to 9.0 ± 1.3 g/dl, and the hematocrit decreased from 34.5 ± 4.7 to 26.7 ± 4.6%. No significant changes of free hemoglobin were noted. In our results, the device revealed competent pulsatile function without severe blood damage or organ dysfunction.
In Vitro Evaluation of Linear Motor‐Driven Total Artificial Heart
Authors: Kobayashi Manabu , Wakiwaka Hiroyuki , Watanabe Mitsuaki , Mizuno Hiroshi , Karita Mitsuji , Maeda Minoru , Matsuura Yuichiro , Fukunaga Shintaro , Yamada Hajime
Published: July 2010

Abstract: This paper deals with the in vitro evaluation of a newly developed linear motor‐driven total artificial heart (linear TAH). The linear TAHs have been developed and evaluated in mock testing and acute animal experiments. The new linear TAH was made based on experience with acute animal experiments. The maximum static thrust of the new linear pulse motor is 146 N with exciting current of 1.69 A. The weight and the volume of this linear TAH are 1.9 kg and 560 ml, respectively. The linear TAH has a kinetic thrust of 85 to 43 N and provides the maximum flow rate of 6.8 L/min in mock circulatory testing.
Cytoplasmic Calcium Levels and Membrane Fluidity of Platelets in Contact with Polyether‐Polyamide Multiblock‐Copolymer Surfaces
Authors: Yui Nobuhiko , Okano Teruo , Sakurai Yasuhisa , Kora Shinichi , Ishikawa Kenji , Hiranuma Takaaki , Yamashita Shuzo
Published: July 2010

Abstract: Cytoplasmic calcium levels and the membrane fluidity of rabbit platelets stored in mini blood bags of crystalline‐amorphous microstructured polymers (polyether‐polyamide multiblock‐copolymers) were studied. Fluorescent dye (Fura 2 or l,6‐diphenyl‐l,3,5‐hexa‐triene)‐loaded platelet suspensions were stored at 37oC for 1 h in the blood bags, and metabolic changes in the platelets during storage were evaluated by the fluorescent spectroscopic technique. The surfaces of poly(vinyl chloride) and polyolefin elastomers, which are used for commercially available blood bags, enhanced the progress of platelet metabolism; i.e., there was a dramatic decrease in membrane fluidity and an increase in [Ca2+]i. Furthermore, the decrease in membrane fluidity was observed prior to the increase in [Ca2+]i. These results suggest that the decrease in membrane fluidity of platelets in contact with polymer surfaces can be the dominant stage in the activation of these platelets. In contrast, the surfaces of polyether‐polyamide multiblock‐copolymers exhibited few changes in either membrane fluidity or [Ca2+]i levels. These results suggest that the platelets in contact with the crystalline‐amorphous microstructured copolymer surfaces can be inert and inactivated in terms of the prevention of a decrease in membrane fluidity.
Evaluation of Intramyocardial Coronary Blood Flow Waveform During Intraaortic Balloon Pumping in the Absence or Presence of Coronary Stenosis
Authors: Toyota Eiji , Songfang Lu , Kimura Akihiro , Hiramatsu Osamu , Tachibana Hiroyuki , Chiba Yoko , Goto Masami , Ogasawara Yasuo , Tsujioka Katsuhiko , Kajiya Fumihiko
Published: July 2010

Abstract: Our aim was to evaluate the effects of intraaortic balloon pumping (IABP) on the blood velocity waveform in the absence or presence of coronary artery stenosis. Using anesthetized open‐chest dogs, the septal arterial blood flow velocities were measured with a 20 MHz 80‐channel ultrasound pulsed Doppler velocimeter in the absence (n = 5) or presence (n = 3) of left main coronary artery stenosis. The blood velocity waveform was analyzed by calculating the systolic retrograde velocity integral (SR) and the diastolic antegrade velocity integral (DA). A slosh ratio was defined as SR/DA. The left anterior descending arterial flow (CBF), aortic pressure (AoP), and poststenotic distal coronary pressure (DiP) were also measured simultaneously. We compared the effect of IABP on the velocity waveforms in the absence and in the presence of coronary artery stenosis. In the absence of stenosis, IABP increased DiP during diastole and augmented DA while it also increased SR. IABP augmented the net CBF because of the greater increase in DA than SR. In the presence of stenosis, however, IABP did not increase DiP and resulted in no significant effect on the net CBF.
Development of a Bioartificial Liver with Sandwiched‐Cultured Hepatocytes Between Two Collagen Gel Layers
Authors: Taguchi Koichi , Matsushita Michiaki , Takahashi Manabu , Uchino Junichi
Published: July 2010

Abstract: We have been developing a multiplate type of bioartificial liver (BAL) using primary cultured hepatocyte monolayers since 1987. This BAL has been shown to prolong the survival time of anhepatic dogs and rabbits. Initially, hepatocytes were cultivated on collagen‐coated plates. To increase the multiplated BAL function, a sandwich cultivation method was employed in which rat hepatocytes were cultured between two collagen gel layers and were then evaluated in both stationary and perfusion cultures. In the stationary culture, the sandwich method showed a higher activity in urea synthesis than in the other culture methods (culture on a collagen coating, culture on a collagen gel, and culture between a collagen coating and a collagen gel) for 14 days. In the perfusion culture, a BAL housing cultured hepatocytes (6.5 times 10 cells) in the sandwich system showed urea synthesis activity ranging from 17.5 to 22.6 μg/2 times 106 cells/90 min. This activity was maintained for 5 days in the perfusion culture. The sandwich type of cultivation is applicable to the multiplated BAL.
New Method to Calculate Creatinine Generation Rate Using Pre‐ and Postdialysis Creatinine Concentra tions
Authors: Shinzato Toru , Nakai Shigeru , Miwa Masamiki , Iwayama Norihisa , Takai Ichiro , Matsumoto Yoshihiro , Morita Hiroyuki , Maeda Kenji
Published: July 2010

Abstract: The creatinine (Cr) generation rate reflects the muscle mass, a possible indicator of protein nutritional status. Thus, in this study, we developed equations for calculating the Cr generation rate. Depner and Daugirdas recently developed a method for determining the protein catabolic rate (PCR) from the pre‐ and postdialysis blood urea nitrogen concentrations. We modified their method to develop equations for calculating the total Cr generation rate from the measured predialysis Cr concentration and estimated postrebound concentration. The total Cr generation rate is defined as the sum of the intrinsic Cr generation rate and the extrinsic Cr generation rate (i.e., the generation rate of Cr derived from food). In the pre sent study, the postrebound Cr concentration was estimated on the basis of postdialysis Cr concentration and the KN for Cr. The intrinsic Cr generation rate was obtained by subtracting the extrinsic Cr generation rate, which was estimated on the basis of the PCR, from the total Cr generation rate calculated. The intrinsic Cr generation rate determined with this method was virtually the same as that obtained using the postrebound Cr concentration, the concentration immediately before the next hemodialysis (HD) session, and the PCR. The intrinsic Cr generation rate determined with the present method did not vary with changes in the HD prescription (i.e., with an increase in blood flow rate, a prolongation of the HD duration time, or a change in dialyzer membrane area). The present study also indicated that the intrinsic Cr generation rate de creased with age in both males and females.
Hernodynamic Performance of the St. Jude Medical Hemodynamic Plus Valve
Authors: Hayashida Nobuhiko , Isomura Tadashi , Hisatomi Kouichi , Sato Tohru , Maruyama Hiroshi , Kosuga Kenichi , Aoyagi Shigeaki
Published: July 2010

Abstract: The hemodynamic performance of the St. Jude Medical Hemodynamic Plus valve (HP) for a small aortic annulus was compared to that of the standard St. Jude Medical valve (SJM). Doppler echocardiographic parameters were evaluated in patients undergoing aortic valve replacement with either a 19 mm HP (HP19, n = 71, a 21 mm HP (HP21, n = S), a 19 mm SJM (SJM19, n = 16), or a 21 mm SJM (SJM21, n = 34). The peak and mean pres sure gradients and peak flow velocity were significantly (p < 0.05) lower in both patients with the HP21 and those with the HP19 than patients with the SJM21 and those with the SJM19, respectively. The echocardiographic parameters of the patients with the HP19 corresponded closely to those of patients with the SJM21. The left ventricular mass index regressed markedly in patients with the HP19 during the late postoperative period. The results suggested that the hemodynamic performances of certain sizes of the HP were superior to those of the same sue SJMs and were considered to be equivalent to those of the next size larger SJM.
Material of the Double Pivot Bearing System in the Gyro C1E3 Centrifugal Pump
Authors: Takami Yoshiyuki , Nakazawa Tadashi , Makinouchi Kenzo , Benkowski Robert , Glueck Julie , Nosé Yukihiko
Published: July 2010

Abstract: A double pivot bearing system is adopted for the Gyro C1E3 centrifugal blood pump to achieve a completely sealless structure that prevents blood leakage and thrombus formation around the shaft. The double pivot bearing system is also a critical factor for blood trauma and durability of the C1E3 pump. This study focuses on the double pivot bearing material. The pump with the male ceramic and female polyethylene pivots (PE) was compared with the pump with the male ceramic and female ceramic pivots (CRM), pertaining to stability of the impeller spinning motion, hemolysis, and durability. At first, the wear rate of the pivots was recorded after operating the pumps in various rotational speeds. As for hemolysis, in vitro tests were carried out using fresh bovine blood in 2 conditions (5 L/min, 350 mm Hg and 5 L/min, 100 mm Hg). Then, stability of the spinning motion was investigated by evaluating the vibration of the pump. The two pumps with different female pivots were operated identically at 2,700 rpm, and the vibration signals were measured using an accelerometer that was mounted on the top of the pump housing. The following findings were obtained in this study. The wear sites were different between the PE and CRM. Most of the wear occurred at the top female polyethylene pivot in the PE. In contrast, most of the wear occurred at the top male ceramic pivot in the CRM. In addition, the amount of the initial wear was less and the wear rate was lower in the PE than in the CRM. The hemolysis caused by the PE was less than the hemolysis caused by the CRM. The vibration signals of the PE had less amplitude and a narrower range of frequency than the vibration signals of the CRM. In conclusion, the combination of materials male ceramic‐female polyethylene are superior to the male ceramic‐female ceramic for the double pivot bearing system of the Gyro C1E3 centrifugal pump because of less vibration, less hemolysis, and less wear.
Hot‐Knife Dissection of the Latissimus Dorsi Muscle for Dynamic Cardiomyoplasty
Authors: Takahashi Masao , Tomita Shigeyuki , Ohtake Hiroshi , Tanaka Nobuyuki , Kawasuji Michio , Watanabe Yoh
Published: July 2010

Abstract: The overall purpose of circulatory assistance utilizing skeletal muscle is the most efficient application of muscle power. From the histological viewpoint, hot‐knife dissection of the latissimus dorsi muscle (LDM) is presented to preserve muscle tissue. The shaw hemostatic scalpel could be used similarly to standard surgical blades, and its hemostatic performance was efficient in sealing collateral vessels from the thoracic wall. Muscular and nervous twitching was never observed throughout dissecting the LDM. Histological findings revealed that muscle fibers could be preserved by hot‐knife dissection rather than by electrocautery. This technique may reduce the inconvenience of the operators, and, therefore, shorten the operation time in dynamic cardiomyoplasty and other experiments.
LDL Apheresis with Dextran Sulfate and Angiotensin Receptor Antagonist (Losartan)
Authors: Elicio Nicola , Bertolini Stefano , Garbarini Roberta , Nardiello Giovanni , Elicio Alessandro
Published: July 2010

Abstract:Anaphylactoid reactions during low‐density li‐poprotein (LDL) apheresis with dextran sulphate adsorption have been reported in patients taking angiotensin converting enzyme (ACE) inhibitors.
Nonsymmetric Leaflet Motion of St. Jude Medical Mitral Valves Simulated with a Computer‐Controlled Hydraulic Mock Circulator
Authors: Ohta Yuji , Okamoto Kazutoshi , Sonderegger Marcel , Dohi Takeyoshi , Matsumoto Hiroshi , Horiuchi Takashi
Published: July 2010

Abstract: Since the introduction of high‐performance prosthetic heart valves, particularly bileaflet valves and monoleaflet valves with larger opening angles, we have observed in vivo complex leaflet motion which has not seen experimentally confirmed yet. We developed a computer‐controlled hydraulic mock circulator to study the motion of in vivo leaflets. A high speed CCD camera recorded the valve movement. In the mitral position, a standard St. Jude Medical valve was tilted to be horizontal or vertical. The test valve was driven with single‐ or double‐peaked flow. The flow rate was set to 5.0 Umin at 70 bpm with a systole/diastole ratio of 0.3. We found the following results: independent of valve orientation, the valve showed a nonsymmetric leaflet motion; the valve showed unpredictable leaflet position during decreasing flow or absence of flow; and the disc closed temporarily at the lower inflow rate between the 2 flow peaks.
Adsorption of Hepatitis C Virus Particles Onto the Dialyzer Membrane
Authors: Hayashi Haruyuki , Okuda Kunio , Yokosuka Osamu , Kobayashi Susumu , Yokozeki Kazuo , Ohtake Yoshio , Irie Yasubumi
Published: July 2010

Abstract: It was recently found that the blood level of hepatitis C virus (HCV) RNA is significantly reduced after each dialysis procedure in patients on chronic hemodialysis. This study was designed to elucidate the mechanism for this phenomenon. In two patients with high serum levels of HCV RNA, the filtrate through the dialyzer (TF‐α, Teijin Co., Tokyo, Japan) was analyzed for viral RNA using the polymerase chain reaction. At the end of dialysis, the filter was washed with saline, and during the saline washing, aliquots were taken for quantification of RNA by the branched DNA method. The HCV core antigen was quantified as a measure of viral particles, and hemoglobin was also measured for correcting for blood contamination. After the clearance of the blood, the filter was washed with guanidinium isothiocyanate, and the recovery of RNA was measured. The filtrate did not contain detectable RNA.

The saline washing of the filter after dialysis contained a significant amount of RNA. Washing with guanidinium isothiocyanate of the thoroughly saline washed filter also recovered a significant amount of RNA. During saline dashing, the recovery of RNA in the washing was much delayed behind that of hemoglobin, suggesting the adsorption of the former onto the filter membrane. There was a discordant recovery of RNA and HCV core antigen in the washing, the recovery of the former being delayed behind that of the latter. These results indicate that viral particles are adsorbed onto the inner surface of the filter membrane during dialysis. Some of these adsorbed viral particles are perhaps destroyed by hydraulic pressure applied to blood for dialysis.
LDL Hemoperfusion‐A New Procedure for LDL Apheresis: Biocompatibility Results from a First Pilot Study in Hypercholesterolemic Atherosclerosis Patients
Authors: Bosch T. , Schmidt B. , Kleophas W. , Otto V. , Samtleben W.
Published: July 2010

Abstract: Current lipid apheresis techniques can remove atherogenic lipoproteins only from plasma. The initial mandatory separation of plasma and blood cells renders the extracorporeal circuit complex. We recently described the first clinical application of a new lipid adsorber that adsorbs low‐density lipoprotein (LDL) and lipoprotein (a) (Lp[a]) directly from whole blood. In continuation of our work, this paper describes the clinical biocompatibility of this new LDL hemoperfusion system. In a 2 center phase II clinical trial, 12 hypercholesterolemic patients suffering from overt coronary or peripheral artery disease were treated once with LDL hemoperfusion. The new LDL adsorber (DALI, Fresenius, St. Wendel, Germany) contained 480 ml of polyacrylate coated polyacrylamide gel. The anticoagulation protocol consisted of an initial heparin bolus followed by an acid citrate dextrose‐A (ACD‐A) infusion during the treatment. One patient blood volume was treated per session. All sessions were clinically un eventful. No signs of hemolysis or extracorporeal clot formation could be detected, and cell counts remained virtually constant. In a subgroup of patients (n = 4–6), further biocompatibility parameters were studied. Activation of leukocytes (elastase release), thrombocytes (β‐thrombo‐globulin [β‐TG] extrusion), and monocytes (interleukin (IL)‐1β and IL‐6) were minimal. Complement activation (C3a and C5a generation) was negligible. The chosen anticoagulation protocol was both safe (constant ionized calcium levels) and effective (low thrombin‐antithrombin formation). In summary, within the scope of a first pilot study. this new LDL hemoperfusion procedure combined the features of excellent clinical tolerance, good biocompatibility, and ease of handling. Phase III clinical trials will have to show whether these encouraging preliminary results can be corroborated in a larger patient population.