As the initial stage of development of implantable left ventricular assist system (VAS), the blood pump system was designed to be positioned in the left abdominal wall. The pump is a pneumatic and diaphragm-type modified from NCVC VAS made of Japanese-made segmented polyether polyurethane. Inflow cannula was reinforced at the distal portion. The pump was connected by inflow and outflow cannulae between the left ventricular apex and the descending aorta, and was connected to the external console by a percutaneous tube. In animal experiments using goats, this system showed easy applicability and stable hemodynamics over three weeks. There was no signs of infection around the pocket of pump. In conclusion, this blood pump system is safely applicable to long-term left ventricular assist.

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A newly synthesized serine protease inhibitor 4-sulfamoyl phenyl-4-guanidinobenzoate methansulfonate (SPGM) (ONO-3307, Ono Pharmaceutical Co.) competitively inhibites trypsin, thrombin and plasmin, and their Ki values were 0.048, 0.18 and 0.31μM, respectively. We tested whether SPGM can make heparin-free hemodialysis (HD) possible in uremic patients (Pts). Continuous infusion of 40-100 mg/h SPGM at the inlet of dialyzer elongated activated partial thromboplastin time (aPTT) of extracorporeal blood, but showed no effect on aPTT of corporeal blood during HD. Prothrombin time of extracorporeal blood did not differ from that of corporeal blood. Activated coagulation time did not change significantly during HD with SPGM. HD was successfully done with minimum clotting in drip chamber and dialyzer in 30 HD patients. No hemorrhagic complications were observed in 5 uremic Pts during HD with SPGM after surgery. We conclude that non-heparin hemodialysis with SPGM should be considered in patients with hemorrhagic disorders.

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We investigated the change in the renal functions in 4 total artificial heat (TAH) animals (goats) in order to study the influence of TAH circulation on renal functions. In every case, renal plasma flow, renal blood flow, and glomerular filtration rate showed significant decreases after TAH implantation, though no significant abnormality of blood biochemical data was observed. Concerning to hemodynamics, significant elevation in right atrial pressure (RAP) was observed in all cases, which corresponded to the renal dysfunction. To study the influence of the wave form of blood flow and that of blood pressure on renal functions under TAH circulation, we analysed the renal functions of an experimental goat model, whose circulations of upper and lower body were perfused by her natural heart and artificial heart, respectively. In this case, RAP showed no elevation, and renal functions rather elevated which corresponded to increase in the output of the artificial heart. These results suggest that renal dysfunction in TAH animals is principally due to elevation in RAP, and the wave form of blood flow or pressure by artificial heart has little influence on renal functions.

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Immunoadsorption utilizing silica beads enbedded with blood type A or B antigen expressing-trisaccharides as the adsorbent was performed for a purpose of removal of anti-A or anti-B antibody from the blood of the kidney transplantation candidates of ABO incompatible couples. However, 4 of 27 patients scheduled developed hypotension, chest pain, nausea, vomiting etc. during the adsorption procedures. Evidence of complements activation and white blood cell count changes suggest that a similar anaphylactoid reaction as observed in hemodialysis patients, so-called first use syndrome or reaction, occurred in those specially hypersensitive patients to the adsorbent material. Instead, anti-A and/or anti-B antibodies were removed by double filtration plasmapheresis and kidney transplantations succeeded in those patients.

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This paper reports in vivo protein adsorption on polymers including Biomer (B), PEO grafted Biomer (B-PEO4 K) and HEMA-styrene block copolymer (HEMA-St). Vascular graft (6mm ID, 7cm in length) was fabricated with Biomer, modified on its luminal surface with test polymers, and implanted in the abdominal aorta of dogs. After 1-3 months, the graft was retrieved and processed for transmission and scanning electron microscopy (TEM/SEM). Surface protein layer thickness stained with a 1%OsO₄ solution was measured by TEM. Visualization of adsorbed plasma proteins (albumin, IgG and fibrinogen) was performed with TEM/SEM using an immunogold double antibody method. B and B-PEO4 K grafts occluded within 1 month, while HEMA-St grafts were patent for over 3 months. B and B-PEO4 K showed thick multilayers of adsorbed proteins (1, 000-2, 000Å) with high concentration of fibrinogen and IgG, and less albumin. In contrast, HEMA-St showed a thin protein layer thickness (<200Å) even after 3 months, and displayed a monolayer-like adsorbed protein patterns with high concentration of albumin and IgG, and relatively less fibrinogen. In terms of antithrombogenicity, thin monolayer-like pattern showed improved properties over multilayered proteins.

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