Partially coated stents

Abstract

A medical product comprises a biodegradable filament and a non-biodegradeable coating. The biodegradable filament forms a stent body having a first end portion, a middle portion, and a second end portion opposite the first end portion. The middle portion extends between the first and second end portions. The non-biodegradeable coating encapsulates the at least one biodegradable filament along the middle portion of the stent body. The non-biodegradeable coating forms a barrier such that the non-biodegradeable coating prevents degradation of the at least one biodegradable filament along the middle portion. The first and second end portions are uncoated. After implantation, the end portions of the stent may biodegrade. The middle portion will not biodegrade due to its encapsulation by the non-biodegradeable coating.

What is claimed is: 
     
         1 . A stent comprising:
 at least one biodegradable filament forming a stent body, the stent body having a first end portion, a middle portion, and a second end portion opposite the first end portion, the middle portion extending between the first and second end portions; and   a non-biodegradeable coating, the non-biodegradeable coating encapsulating the at least one biodegradable filament along the middle portion of the stent body and forming a barrier such that the non-biodegradeable coating prevents degradation of the at least one biodegradable filament along the middle portion, wherein the first and second end portions are uncoated and biodegradeable.   
     
     
         2 . The stent of  claim 1 , wherein the at least one biodegradable filament is a monofilament. 
     
     
         3 . The stent of  claim 1  further comprising a retrieval loop. 
     
     
         4 . The stent of  claim 3 , wherein at least a portion of the retrieval loop is routed through at least a portion of the middle portion. 
     
     
         5 . The stent of  claim 1 , wherein the stent has an unexpanded configuration and an expanded configuration; in the expanded configuration, at least one of the first end portion and second end portion has a cross-sectional area greater than the cross-sectional area of at least a portion of the middle portion. 
     
     
         6 . The stent of  claim 5 , wherein, in the expanded configuration, at least a portion of the first end portion and at least a portion of the second end portion has a cross-sectional area greater than at least a portion of the cross-sectional area of the middle portion. 
     
     
         7 . The stent of  claim 1 , wherein the at least one biodegradable filament is formed from poly(lactic-co-glycolic) acid (PLGA), polylactic acid (PLA), polyglycolic acid (PGA), poly(ortho ester) (POE), poly(epsilon-caprolactone) (PCL), and polyhydroxybutyrate-valerate (PHBV), or polydioxanone (PDO). 
     
     
         8 . The stent of  claim 1 , wherein the non-biodegradeable coating is formed from a silicone polymer, silicone copolymer, polyurethane, polystyrene-polyethylene/butylene-polystyrene (SEBS) copolymer, acrylate polymer, acrylate copolymer, methacrylate polymer, methacrylate copolymer, fluorinated polymer, (modified) ethylene-tetrafluoroethylene copolymer (ETFE) polymer, polytetrafluoroethylene (PTFE), poly(tetrafluoroethylene-co-hexafluoropropene) (FEP), polyvinylidene fluoride (PVDF), and combinations thereof. 
     
     
         9 . The stent of  claim 1  further comprising a plurality of retrieval loops. 
     
     
         10 . The stent of  claim 1 , wherein the at least one biodegradable filament is braided to form the stent body. 
     
     
         11 . The stent of  claim 1  further being an esophageal stent. 
     
     
         12 . The stent of  claim 1 , wherein the stent body comprises a first flared portion, a portion of the first flared portion being coated with the non-biodegradeable coating and a portion of the flared portion being uncoated. 
     
     
         13 . The stent of  claim 12 , wherein the stent body comprises a second flared portion, a portion of the second flared portion being coated with the non-biodegradeable coating and a portion of the second flared portion being uncoated. 
     
     
         14 . A stent comprising:
 at least one biodegradable filament forming a braided stent body, the braided stent body having a first end portion, a middle portion, and a second end portion opposite the first end portion, the middle portion extending between the first and second end portions;   a non-biodegradeable coating, the non-biodegradeable coating encapsulating the at least one biodegradable filament along the middle portion of the braided stent body and forming a barrier such that the non-biodegradeable coating prevents degradation of the at least one biodegradable filament along the middle portion, wherein the first and second end portions are uncoated and biodegradeable; and   at least one retrieval loop threaded through at least a portion of the middle portion of the braided stent body.   
     
     
         15 . The stent of  claim 14 , wherein the at least one retrieval loop comprises a first retrieval loop and a second retrieval loop, the second retrieval loop threaded through at least a portion of the middle portion, the second retrieval loop being longitudinally offset from the first retrieval loop. 
     
     
         16 . The stent of  claim 14 , wherein the stent has an unexpanded configuration and an expanded configuration; in the expanded configuration, at least one of the first end portion and second end portion has a cross-sectional area greater than the cross-sectional area of at least a portion of the middle portion. 
     
     
         17 . The stent of  claim 16 , wherein, in the expanded configuration, at least a portion of the first end portion and at least a portion of the second end portion has a cross-sectional area greater than the cross-sectional area of at least a portion of the middle portion. 
     
     
         18 . The stent of  claim 14 , wherein the at least one biodegradable filament is formed from poly(lactic-co-glycolic) acid (PLGA), polylactic acid (PLA), polyglycolic acid (PGA), poly(ortho ester) (POE), poly(epsilon-caprolactone) (PCL), and polyhydroxybutyrate-valerate (PHBV), or polydioxanone (PDO). 
     
     
         19 . The stent of  claim 18 , wherein the non-biodegradeable coating is formed from a silicone polymer, silicone copolymer, polyurethane, polystyrene-polyethylene/butylene-polystyrene (SEBS) copolymer, acrylate polymer, acrylate copolymer, methacrylate polymer, methacrylate copolymer, fluorinated polymer, (modified) ethylene-tetrafluoroethylene copolymer (ETFE) polymer, polytetrafluoroethylene (PTFE), poly(tetrafluoroethylene-co-hexafluoropropene) (FEP), polyvinylidene fluoride (PVDF), and combinations thereof. 
     
     
         20 . The stent of  claim 19 , wherein the stent body defines a plurality of interstices, the interstices being covered by the non-biodegradeable coating along the middle portion of the stent body, thereby preventing tissue ingrowth therealong.