Self-Expanding Medical Occlusion Device

Abstract

A self-expanding medical occlusion device treats a heart defect in a patient and is erted into the body in minimally invasive fashion using a catheter system, and includes raiding of thin threads which exhibits a first preliminarily definable shape as the clusion device is being inserted into the patient's body and a second preliminarily finable shape in the implanted state, whereby the occlusion device is in a collapsed te in the first shape of the braiding and in an expanded state in the second shape of braiding. The threads of braiding are composed of a shape memory polymer mposite such that braiding deforms from a temporary shape to a permanent shape in nsequence of an external stimulus, whereby the temporary shape is given in a first ofile form of the braiding and the permanent shape is given in a second profile form of braiding.

1 . A method for implanting a medical occlusion device comprising a degradable material for treating defects in a patient, in particular closing abnormal openings in tissue, comprising:
 positioning a catheter in the body of the patient such that a distal end of the catheter is positioned at the site to be treated,   collapsing the occlusion device in a first preliminarily definable shape,   inserting the occlusion device into the catheter,   pushing the occlusion device through the catheter such that the occlusion device exits at said distal end,   expanding the occlusion device from the first shape to a second preliminarily definable shape in the implanted state of the occlusion device, and wherein the occlusion device in the first shape is in a collapsed state and the occlusion device in the second shape is in an expanded state, and whereby the occlusion device will degrade after a given interval of time.   
   
   
       2 . The method for implanting a medical occlusion device according to  claim 1 , wherein said degradable material is a polymer composite. 
   
   
       3 . The method for implanting a medical occlusion device according to  claim 2 , wherein said polymer composite is a shape memory polymer composite. 
   
   
       4 . The method for implanting a medical occlusion device according to  claim 3 , wherein the occlusion device comprise a braiding of thin threads of the shape memory polymer composite, whereby the braiding will deform from a temporary shape to a permanent shape by means of an external stimulus; and wherein the temporary shape is given in the first shape of braiding and the permanent shape is given in the second shape of braiding. 
   
   
       5 . The method for implanting a medical occlusion device according to  claim 1 , wherein the degrading of the occlusion device is controlled at a variable speed. 
   
   
       6 . The method for implanting a medical occlusion device according to  claim 1 , wherein the degrading of the occlusion device comprises removal of the degradable material from the body due to natural metabolism. 
   
   
       7 . The method for implanting a medical occlusion device according to  claim 2 , wherein the polymer composite exhibits a hydrolytically degradable polymer, in particular poly(hydroxy carboxylic acids) or the corresponding copolymers. 
   
   
       8 . The method for implanting a medical occlusion device according to  claim 2 , wherein the polymer composite exhibits enzymatically degradable polymers. 
   
   
       9 . The method for implanting a medical occlusion device according to  claim 2 , wherein the polymer composite exhibits a biodegradable thermoplastic amorphous polyurethane-copolyester polymer network. 
   
   
       10 . The method for implanting a medical occlusion device according to  claim 2 , wherein the polymer composite exhibits biodegradable elastic polymer network, obtained from crosslinking of oligomer diols with diisocyanate. 
   
   
       11 . The occlusion device in accordance with  claim 2 , wherein the polymer composite is formed as covalent networks based on oligo(.epsilon.-caprolactone)dimethacrylate and butylacrylate. 
   
   
       12 . The method for implanting a medical occlusion device according to  claim 4 , wherein said external stimulus is a definable switching temperature. 
   
   
       13 . The method for implanting a medical occlusion device according to  claim 12 , wherein the switching temperature is within a range of between room temperature and the patient's body temperature. 
   
   
       14 . The method for implanting a medical occlusion device according to  claim 12 , wherein the polymer composite comprises polymer switching elements; and wherein the temporary shape of said braiding is stabilized below the definable switching temperature based on the characteristic phase transitions of polymer switching elements. 
   
   
       15 . The method for implanting a medical occlusion device according to  claim 14 , wherein the polymer composite exhibits a crystalline or semi-crystalline polymer network having crystalline switching segments; wherein the temporary shape to said braiding is fixed and stabilized by freezing the crystalline switching segments at crystallization transition; and wherein the switching temperature is a function of the crystallization temperature, of the switching temperature of the crystalline switching segments respectively. 
   
   
       16 . The method for implanting a medical occlusion device according to  claim 14 , wherein the polymer composite exhibits an amorphous polymer network having amorphous switching segments; and wherein the temporary shape to said braiding is fixed and stabilized by freezing of the amorphous switching segments at the switching segment glass transition; whereby the switching temperature is a function of the glass transition temperature of the amorphous switching segments. 
   
   
       17 . The method for implanting a medical occlusion device according to  claim 12 , wherein the polymer composite comprises a linear, phase-segregated multi-block copolymer network which can exhibit at least two different phases; and wherein the first phase is a hard segment-forming phase in which a plurality of hard segment-forming blocks are formed in the polymer which serve the physical crosslinking of the polymer structure and define and stabilize the permanent shape to said braiding; and wherein the second phase is a switching segment-forming phase in which a plurality of switching segment forming blocks are formed in the polymer which serve to fix the temporary shape of said braiding; and wherein the transition temperature from the switching segment-forming phase to the hard segment-forming phase is the switching temperature; and wherein conventional methods such as injection molding or extrusion processes can be used to set the profile form to said braiding above the transition temperature of the hard segment-forming phase. 
   
   
       18 . The method for implanting a medical occlusion device according to  claim 17 , wherein the polymer composite exhibits thermoplastic polyurethane elastomers of a multi-block structure; and wherein the hard segment forming phase is formed by conversion of diisocyanates, in particular methylene-bis(4-phenylisocyanate) or hexamethylene diisocyanate, with diols, in particular 1,4-Butandiol; and wherein the switching segment-forming phase yields from oligomeric polyether/poly-esterdiols, in particular based on OH-terminated oly(tetrahydrofuran), poly(.epsilon.-caprolactone), poly(ethylene adipate), poly(ethylene glyocol) or poly(propylenglycol). 
   
   
       19 . The method for implanting a medical occlusion device according to  claim 17 , wherein the phase-segregated di-block copolymers of the polymer composite exhibit an amorphous A-block and a semi-crystallized B-block; and wherein the glass transition of the amorphous A-block constitutes the hard segment forming phase; and wherein the melting temperature of the semi-crystalline B-block serves as the switching temperature for the thermal shape memory effect. 
   
   
       20 . The method for implanting a medical occlusion device according to  claim 19 , wherein the polymer composite has polystyrol as the amorphous A-block and poly(1,4-butadiene) as the semi-crystalline B-block. 
   
   
       21 . The method for implanting a medical occlusion device according to  claim 17 , wherein the polymer composite exhibits a phase-segregated tri-block copolymer having a semi-crystalline central B-block and two amorphous terminal A-blocks; wherein the A-blocks constitute the hard segment and the B-block establishes the switching temperature. 
   
   
       22 . The method for implanting a medical occlusion device according to  claim 21 , wherein the polymer composite exhibits semi-crystalline poly-(tetrahydrofuran) as the central B-block and amorphous poly(2-methyloxazolin) as terminal A-blocks. 
   
   
       23 . The method for implanting a medical occlusion device according to  claim 3 , wherein the polymer composite comprises polynorbornene, polyethylene/nylon-6-graft copolymers and/or crosslinked poly(ethylene-covinyl acetate) copolymers. 
   
   
       24 . The method for implanting a medical occlusion device according to  claim 3 , wherein the polymer composite exhibits a covalent crosslinked polymer network which is formed by polymerization, polycondensation and/or polyaddition of difunctional monomers or macromers with additive of tri or higher functional crosslinking; and wherein given an appropriate selection of the monomers, their functionality and ratio of crosslinkers, the chemical, thermal and mechanical properties of the polymer network as formed can be specifically and selectively set. 
   
   
       25 . The method for implanting a medical occlusion device according to  claim 24 , wherein the polymer composite is a covalent polymer network which comprises a crosslinker by crosslinking copolymerization of stearylacrylate and methacrylic acid with N,N′-methylenebisacrylamide, whereby the shape memory effect of the polymer composite is based on crystallizing stearyl-side chains. 
   
   
       26 . The method for implanting a medical occlusion device according to  claim 2 , wherein the polymer composite exhibits a covalent crosslinked polymer network which is formed by subsequent crosslinking of linear or branched polymers. 
   
   
       27 . The method for implanting a medical occlusion device according to  claim 3 , wherein a shape memory polymer network is synthesized from a combination of physical or covalent shape memory polymer networks having biodegradable polymer segments. 
   
   
       28 . The method for implanting a medical occlusion device according to  claim 27 , wherein said shape memory polymer network is used as a matrix for a controlled release of an active substance. 
   
   
       29 . The method for implanting a medical occlusion device according to  claims 9  and  14 , wherein the amorphous polyurethane-copolyester polymer network having segments in biodegradable poly(p-diaxanone)-polyurethane (P DO) multi-block copolymers in combination with poly(lacti-co-glycolid) (PDLG) and poly(epsilon-caprolactone) PCL switching segments. 
   
   
       30 . The method for implanting a medical occlusion device according to  claim 9 , wherein the amorphous polyurethane-copolyester polymer network is formed by synthesizing biodegradable star-shaped copolyester polyols based on dilactile DL (cyclic lactic acid dimer), diglyocolide DG (cyclic glycol acid dimer) and trimethylolpropane TP (F=3) or pentaerythrit PE (F=4) and crosslinking with trimethylhexa methylene diisocyanate TMDI.