Bioabsorbable stent that modulates plaque geometric morphology and chemical composition

Abstract

Methods of treating a diseased blood vessel exhibiting stenosis with a bioabsorable stent are disclosed. The implanted stent supports the section of the vessel at an increased diameter for a period of time to allow the vessel to heal. The stent loses radial strength sufficient to support the section of the vessel in less than 6 months after implantation, loses mechanical integrity, and then erodes away from the section. The biodegradable stent results in changes in properties of plaque with time as the stent degrades. The time-dependent properties include the luminal area of the plaque and plaque geometric morphology parameters.

1 . (canceled) 
     
     
         2 . A method of treating a diseased section of a blood vessel, comprising:
 implanting a bioabsorbable polymeric stent comprising a scaffolding composed of a pattern of struts at a diseased section of a blood vessel to form a stented segment comprising the stent and a vessel wall at the diseased section,   wherein implanting comprises deploying the stent from a crimped diameter to a diameter of 3 mm,   wherein a reference vessel diameter is 3 mm and a diameter stenosis of the diseased section of the blood vessel pre-implantation is greater than 50%,   wherein the vessel wall comprises a plaque region including a necrotic core component and a fibrous component, wherein at pre-implantation and immediately following implantation of the stent the necrotic core component is in contact the lumen.   
     
     
         3 . The method of  claim 2 , wherein as the stent degrades the fibrous component becomes positioned between the necrotic core component and the lumen so that the necrotic core component is no longer in contact with the lumen. 
     
     
         4 . The method of  claim 2 , wherein the scaffolding is made from PLLA. 
     
     
         5 . The method of  claim 2 , wherein the scaffolding polymer has a degree of crystallinity between 25-50%, a Tg between 10 and 30° C. above human body temperature, induced circumferential polymer chain orientation to provide the sufficient radial strength and to inhibit failure of the scaffolding as it supports the vessel wall. 
     
     
         6 . A method of treating a diseased section of a blood vessel, comprising:
 implanting a bioabsorbable polymeric stent comprising a scaffolding composed of a pattern of struts at a diseased section of a blood vessel to form a stented segment comprising the stent and a vessel wall at the diseased section,   wherein implanting comprises deploying the stent from a crimped diameter to a diameter of 3 mm,   wherein a reference vessel diameter is 3 mm and a diameter stenosis of the diseased section of the blood vessel pre-implantation is greater than 50%,   wherein the vessel wall comprises a plaque region including a necrotic core component, and   wherein as the stent degrades the area of the necrotic core component as a percentage of a total area of the plaque region decreases.   
     
     
         7 . The method of  claim 6 , wherein when the stent is completely degraded away, the area of the necrotic core component as a percentage of the total plaque area is less than the percentage post-stenting. 
     
     
         8 . The method of  claim 6 , wherein the scaffolding is made from PLLA. 
     
     
         9 . A method of treating a diseased section of a blood vessel, comprising:
 implanting a bioabsorbable polymeric stent comprising a scaffolding composed of a pattern of struts at a diseased section of a blood vessel to form a stented segment comprising the stent and a vessel wall at the diseased section,   wherein implanting comprises deploying the stent from a crimped diameter to a diameter of 3 mm,   wherein a reference vessel diameter is 3 mm and a diameter stenosis of the diseased section of the blood vessel pre-implantation is greater than 50%,   wherein the vessel wall comprises plaque including a necrotic core component and a fibrous component,   wherein between post-implantation and when the stent is completely or substantially degraded away the necrotic core component as a percentage of the plaque decreases and the fibrous component as a percentage of the plaque increases.   
     
     
         10 . The method of  claim 9 , wherein the scaffolding is made from PLLA with a crystallinity between 25-50%. 
     
     
         11 . The method of  claim 9 , wherein the stent is completely and substantially degraded away in at least two years. 
     
     
         12 . The method of  claim 9 , wherein when the stent is completely and substantially degraded away, the stented section exhibits vasomotion.