Abstract: Heart valve leaflet selection methods and apparatuses which subject individual leaflets to loads and measure the resulting deflection to more reliably group leaflets of similar physical characteristics for later assembly in prosthetic heart valves. The deflection testing may be accomplished using a variety of test set ups which are designed to impart a load on the leaflet which simulates the actual loading within a heart valve. The results from a number of deflection tests are used to categorize individual leaflets, which data can be combined with other data regarding the characteristics of the leaflet to better select leaflets for assembly into a multi-leaflet heart valve. In one embodiment, the deflection test is combined with an intrinsic load test, and leaflets having similar deflection and intrinsic load values used in the same heart valve.

Abstract: An assembly for holding a substantially flexible suture guide of predetermined length in a substantially taut position used to achieve a suture line having a dimension equal to the length of the suture guide, such as the circumference about a heart valve annulus. The assembly includes a rigid suture guide holder having a surface against which the length of suture guide is releasably positioned. The guide holder can have a shape or geometry, such as a circumference or circumferential segment, equivalent to the shape or geometry of the intended suture line. The shape of the guide holder can therefore be selected to hold the suture guide in the shape most advantageous to placing the desired suture line.

Abstract: An assembly for holding a substantially flexible suture guide of predetermined length in a substantially taut position used to achieve a suture line having a dimension equal to the length of the suture guide, such as the circumference about a heart valve annulus. The assembly includes a rigid suture guide holder having a surface against which the length of suture guide is releasably positioned. The guide holder can have a shape or geometry, such as a circumference or circumferential segment, equivalent to the shape or geometry of the intended suture line. The shape of the guide holder can therefore be selected to hold the suture guide in the shape most advantageous to placing the desired suture line.

Abstract: A ventricular assist device includes a pair of valved conduits and a pumping portion connected by these conduits into the circulatory system of a host patient. The pumping portion and valved conduits are constructed and configured to minimize the number of material-surface transitions which blood must cross in flowing through the device. Also, the valved conduits include porcine xenograft valves, which are externally supported by stenting structure located outside of the blood-contacting flow path of the device. A flexible shape-retaining inner wall member of the valved conduits is impervious to blood, but defines a porous inner surface on which a stable biological interface may form. Also, this inner wall member is shaped with sinuses which do not replicate either the porcine sinuses from which the xenograft valves were taken, or human aortic sinuses.

Abstract: Heart valve leaflet selection methods and apparatuses which subject individual leaflets to loads and measure the resulting deflection to more reliably group leaflets of similar physical characteristics for later assembly in prosthetic heart valves. The deflection testing may be accomplished using a variety of test set ups which are designed to impart a load on the leaflet which simulates the actual loading within a heart valve. The results from a number of deflection tests are used to categorize individual leaflets, which data can be combined with other data regarding the characteristics of the leaflet to better select leaflets for assembly into a multi-leaflet heart valve. In one embodiment, the deflection test is combined with an intrinsic load test, and leaflets having similar deflection and intrinsic load values used in the same heart valve.

Abstract: An infra-annular annuloplasty prosthesis is disclosed including a flexibly semi-rigid frame, a portion of which is shaped to conform to the scalloped configuration of the normal circumference of an arterial heart valve annulus. Axially projecting legs spaced circumferentially to correspond to the location of tissue adjacent to the valve commissures are provided for support and anchoring of the annulus-conforming portion to the dense fibrous tissues adjacent each commissure. The prosthesis includes a one-or two-part frame having scalloped upper and lower edges defining peaks and valleys. The upper edge is shaped to follow the contour of the tissue underneath the valve leaflets, and thus supports the leaflets and aortic wall from below. The lower edge is similarly scallop-shaped, but with less pronounced peaks and valleys than the upper edge, and is thus shaped to conform to the aortic annulus shape and provide support directly thereto.

Abstract: An expandable annuloplasty ring which may either expand spontaneously, in situ, as the patient grows or be expanded by surgical intervention by balloon dilatation. The distensible annuloplasty ring of the invention may be usable in pediatric patients whose growth, subsequent to surgical implantation of the ring, will necessitate subsequent enlargement of the ring to accommodate growth of the annulus. The ring may include relatively expandable segments to enable the enlargement thereof. The ring segments may include engaging teeth which cooperate with notches or slots formed in the tubes to provide some resistance to ring distention, while preventing collapse of the ring in the opposite direction. The teeth may be of different sizes or shapes to regulate the amount of force needed to expand the ring at different stages of the patient's growth.

Abstract: An assembly for holding a substantially flexible suture guide of predetermined length in a substantially taut position used to achieve a suture line having a dimension equal to the length of the suture guide, such as the circumference about a heart valve annulus. The assembly includes a rigid suture guide holder having a surface against which the length of suture guide is releasably positioned. The guide holder can have a shape or geometry, such as a circumference or circumferential segment, equivalent to the shape or geometry of the intended suture line. The shape of the guide holder can therefore be selected to hold the suture guide in the shape most advantageous to placing the desired suture line.

Abstract: A ventricular assist device includes a pair of valved conduits and a pumping portion connected by these conduits into the circulatory system of a host patient. The pumping portion and valved conduits are constructed and configured to minimize the number of material-surface transitions which blood must cross in flowing through the device. Also, the valved conduits include porcine xenograft valves, which are externally supported by stenting structure located outside of the blood-contacting flow path of the device. A flexible shape-retaining inner wall member of the valved conduits is impervious to blood, but defines a porous inner surface on which a stable biological interface may form. Also, this inner wall member is shaped with sinuses which do not replicate either the porcine sinuses from which the xenograft valves were taken, or human aortic sinuses.

Abstract: Improved, adaptable tissue-type heart valves and methods for their manufacture are disclosed wherein a dimensionally stable, pre-aligned tissue leaflet subassembly is formed and its peripheral edge clamped between and attached to an upper shaped wireform and a lower support stent. A variety of adaptable structural interfaces including suture rings, flanges, and conduits may be attached to the support stent with or without an outlet conduit disposed about the wireform to provide a tissue-type heart valve adaptable for use in either a natural heart or in mechanical pumping devices. The methods include forming individual leaflets with a template and using the template to attach the leaflets together to form a tissue leaflet subassembly. The template and leaflets include a straight edge terminating in oppositely directed tabs, and a curvilinear cusp edge extending opposite the straight edge.

Abstract: Heart valve leaflet selection methods and apparatuses which subject individual leaflets to loads and measure the resulting deflection to more reliably group leaflets of similar physical characteristics for later assembly in prosthetic heart valves. The deflection testing may be accomplished using a variety of test set ups which are designed to impart a load on the leaflet which simulates the actual loading within a heart valve. The results from a number of deflection tests are used to categorize individual leaflets, which data can be combined with other data regarding the characteristics of the leaflet to better select leaflets for assembly into a multi-leaflet heart valve. In one embodiment, the deflection test is combined with an intrinsic load test, and leaflets having similar deflection and intrinsic load values used in the same heart valve.

Abstract: Improved, adaptable tissue-type heart valves and methods for their manufacture are disclosed wherein a dimensionally stable, pre-aligned tissue leaflet subassembly is formed and its peripheral edge clamped between and attached to an upper shaped wireform and a lower support stent. A variety of adaptable structural interfaces including suture rings, flanges, and conduits may be attached to the support stent with or without an outlet conduit disposed about the wireform to provide a tissue-type heart valve adaptable for use in either a natural heart or in mechanical pumping devices.

Abstract: To continuously produce and separate high purity p-xylene from a C.sub.8 aromatic hydrocarbon charge, successive use is made in combination of (1) a stage of separating low-purity p-xylene (75 to 98%) by simulated moving bed adsorption chromatography; (2) a stage of purifying and washing the low-purity p-xylene by recrystallization (-25 to +10.degree. C.); (3) a stage of catalytic isomerization of the charge which has been p-xylene-depleted by the separating stage (1); and recovering an isomerate which is then recycled to the charge. The solvent for desorption in stage (1) and washing in stage (2) is advantageously toluene.

Abstract: A ventricular assist device includes a pair of valved conduits and a pumping portion connected by these conduits into the circulatory system of a host patient. The pumping portion and valved conduits are constructed and configured to minimize the number of material-surface transitions which blood must cross in flowing through the device. Also, the valved conduits include porcine xenograft valves, which are externally supported by stenting structure located outside of the blood-contacting flow path of the device. A flexible shape-retaining inner wall member of the valved conduits is impervious to blood, but defines a porous inner surface on which a stable biological interface may form. Also, this inner wall member is shaped with sinuses which do not replicate either the porcine sinuses from which the xenograft valves were taken, or human aortic sinuses.

Abstract: An apparatus for sodding onto the inner lumenal surface of a synthetic graft of harvested and concentrated microvessel endothelial cells from liposuctioned fat tissues, which harvested cells are formed into a "pellet" of isolated endothelial cells in loose aggregations, includes a sodding tube having a single rigid outer wall bounding a sodding chamber. A filter pack assembly is provided to communicate the pellet of cells from a processing vessel to the graft. This filter pack assembly includes a series of successively finer filter members cooperatively defining a series of turbulent-flow chambers in which aggregations of cells too large to pass through a particular filter are exposed to liquid flow turbulence which is effective to break up the aggregations.

Abstract: An assembly for holding a substantially flexible suture guide of predetermined length in a substantially taut position used to achieve a suture line having a dimension equal to the length of the suture guide, such as the circumference about a heart valve annulus. The assembly includes a rigid suture guide holder having a surface against which the length of suture guide is releasably positioned. The guide holder can have a shape or geometry, such as a circumference or circumferential segment, equivalent to the shape or geometry of the intended suture line. The shape of the guide holder can therefore be selected to hold the suture guide in the shape most advantageous to placing the desired suture line.

Abstract: To continuously produce and separate high purity p-xylene from a C.sub.8 aromatic hydrocarbon charge, successive use is made in combination of (1) a stage of separating low-purity p-xylene (75 to 98%) by simulated moving bed adsorption chromatography, with a ratio for the solvent to charge flow rates of 1.2 to 2.5; (2) a stage of purifying and washing the low-purity p-xylene by recrystallization (-25.degree. to +10.degree. C.); (3) a stage of catalytic isomerization of the charge which has been p-xylene-depleted by the separating stage (1); and recovering an isomerate which is then recycled to the charge. The solvent for desorption in stage (1) and washing in stage (2) is advantageously toluene.

Abstract: An assembly for holding a substantially flexible suture guide of predetermined length in a substantially taut position used to achieve a suture line having a dimension equal to the length of the suture guide, such as the circumference about a heart valve annulus. The assembly includes a rigid suture guide holder having a surface against which the length of suture guide is releasably positioned. The guide holder can have a shape or geometry, such as a circumference or circumferential segment, equivalent to the shape or geometry of the intended suture line. The shape of the guide holder can therefore be selected to hold the suture guide in the shape most advantageous to placing the desired suture line.

Abstract: A processing vessel for isolating microvessel endothelial cells from liposuctioned fat tissues includes a fat-receiving basket defined by polyester screen material. Fat tissue removed from a patient by liposuction is received into the basket and is rinsed and digested with an enzymatic solution. The freed microvessel endothelial cells from the fat tissues are separated from the fat cells, and from blood cells and other materials which may be present in the basket by centrifuging. A bottom chamber of the processing vessel is configured to define a "pellet" of isolated endothelial cells which may be removed from the processing vessel for deposition on the inner lumenal surface of a synthetic graft which the fat-donor patient is to receive.

Abstract: To continuously produce and separate high purity p-xylene from a C.sub.8 aromatic hydrocarbon charge, successive use is made in combination of (1) a stage of separating low-purity p-xylene (75 to 98%) by simulated moving bed adsorption chromatography, with a ratio of the solvent to charge flow rates of 1.2 to 2.5; (2) a stage of purifying and washing the low-purity p-xylene by recrystallization (-25 to +10.degree. C.); (3) a stage of catalytic isomerization of the charge which has been p-xylene-depleted by the separating stage (1); and recovering an isomerate which is then recycled to the charge. The solvent for desorption in stage (1) and washing in stage (2) is advantageously toluene.