DEVELOPMENT OF BIOMECHANICAL PUMP SYSTEM USING SKELETAL MUSCLE: EXAMINATION OF COMPONENTS

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We designed a totally implantable circulatory assist device consisting of a hybrid artificial ventricle composed of a skeletal muscle ventricle lined with a hybrid artificial endocardium. This hybrid artificial endocardium consist of a structural matrix made of a polyurethane porous membrane, fragment blood vessel, and collagen gel.To clarify the ability of skeletal muscle as energy source, the effect of cardiomyoplasty on ventricular function was evaluated. The experiment was performed with the left latissimus dorsi muscle (LDM) in 4 normal heart goats. After electrically conditioned for 6 to 8 weeks, the pedicled LDM were sutured around the ventricle clockwise and stimulated synchronously with our compact electrical stimulator. To evaluated the ventricular function,systolic pulmonary arterial pressure (sPAP), right ventricular ejection fraction (RVEF), cardiac output (CO), systolic left ventricular pressure ; and maximal end-systolic volume-elactance (Ees) with and without stimulatio … More n were measured. Although no significant changes were observed in these data, sPAP RVEF, and CO showed a tendency to increase.We prepared the polyurethane porous membrane by solvent cocasting with salt powder. We used collagen gel with fragmented goat carotid vein to perform in vitro construction of the hybrid artificial endocardium. For in vivo construction of the hybrid artificial endocardium, we used a modified version of the tissue fragment method for vascular prostheses. We prepared suspensions of tissue fragments using collagen gel with fragmented goat carotid vein. We used a highly porous fabric vascular prosthesis as a structural matrix; tissue fragments were entrapped on the outer surface of the prosthesis, and the prostheses then was implanted into the carotid artery of four adult goats.In specimens 1 and 3 months postimplantation, cells from the fragmented tissue regenerated an endothelium-like monolayer sheet on the inner suface of the prosthese. Output of a prototype bioaritifical ventricle reached 920 ml/min at an afterload of 80 mmHg and a preload of 20 mmHg.Based on these data, the authors concluded the bioartificial ventricle cound play an important part to improve the right ventricular function and is promising as an implantable device with excellent antithrombogenicity. Less