System and method for plaque serration

Abstract

A device and method for intravascular treatment of atherosclerotic plaque prior to balloon angioplasty which microperforates the plaque with small sharp spikes acting as serrations for forming cleavage lines or planes in the plaque. The spikes may also be used to transport medication into the plaque. The plaque preparation treatment enables subsequent angioplasty to be performed at low balloon pressures of about 4 atmospheres or less, reduces dissections, and avoids injury to the arterial wall. The subsequent angioplasty may be performed with a drug-eluting balloon (DEB) or drug-coated balloon (DCB). The pre-angioplasty perforation procedure enables more drug to be absorbed during DEB or DCB angioplasty, and makes the need for a stent less likely. Alternatively, any local incidence of plaque dissection after balloon angioplasty may be treated by applying a thin, ring-shaped tack at the dissection site only, rather than applying a stent over the overall plaque site.

1 . An intravascular device for perforation and serration of atherosclerotic plaque prior to balloon angioplasty, comprising a carrier carrying lines or patterns of small sharp spikes, and an expansion apparatus for pressing the spikes to pierce a luminal surface of the plaque with lines or patterns of microperforations which act as serrations for forming cleavage lines or planes in the plaque. 
     
     
         2 . An intravascular device according to  claim 1 , wherein the spikes and carrier are drug-coated. 
     
     
         3 . An intravascular device according to  claim 1 , wherein the spikes each have an internal drug-containing reservoir so that it behaves like a syringe. 
     
     
         4 . An intravascular device according to  claim 1 , wherein the spikes are detachable from the carrier and are medication-eluting or bearing so that they are detached and left in place after perforation of the plaque. 
     
     
         5 . An intravascular device according to  claim 4 , wherein the spikes are made of bio-degrading or bio-absorbable material, so that over time the left-behind spikes are degraded or absorbed and leave behind only the perforation holes. 
     
     
         6 . An intravascular device according to  claim 1 , wherein the expansion apparatus is an expansion balloon. 
     
     
         7 . An intravascular device according to  claim 6 , wherein a balloon-restricting mesh is provided over the expansion balloon for restricting its maximum expansion diameter so that it is equal to or less than the blood vessel diameter. 
     
     
         8 . An intravascular device according to  claim 6 , wherein a balloon-restricting mesh is provided over the expansion balloon for restricting a tendency to balloon out at its ends extending beyond the plaque site. 
     
     
         9 . An intravascular device according to  claim 1 , wherein the spikes have a length for piercing into the plaque to a selected depth, and a spacing between spikes selected to create desired cleavage lines or planes in the plaque. 
     
     
         10 . An intravascular device according to  claim 9 , wherein the ratio of spacing between spikes to their depth is about 1:1 or greater. 
     
     
         11 . A method for treating atherosclerotic plaque intravascularly prior to balloon angioplasty comprising:
 perforating and serrating the plaque by forming microperforations with lines or patterns of small sharp spikes pressed by expansion to pierce a luminal surface of the plaque, wherein the microperforations act as serrations for forming cleavage lines or planes in the plaque that facilitate expansion of the lumen at the plaque site.   
     
     
         12 . A method according to  claim 11 , which is followed by performing balloon angioplasty to compress the perforation-prepared plaque and enlarge the lumen at a site of atherosclerotic disease, wherein the perforation preparation enables the balloon angioplasty to be performed with less potential for dissection and a smoother surface. 
     
     
         13 . A method according to  claim 11 , wherein the expansion for pressing the spikes into the plaque is obtained by expansion of a balloon at a low pressure of about 4 atmospheres or less. 
     
     
         14 . A method according to  claim 13 , wherein the expansion of pressing the spikes is obtained by expansion of the balloon at a very low pressure of 2 atmospheres or less. 
     
     
         15 . A method according to  claim 12 , wherein the subsequent balloon angioplasty is performed with a drug-eluting balloon (DEB) or drug-coated balloon (DCB), and the preparation perforation results in increasing the surface area of the plaque for contact with drug applied during DEB or DCB angioplasty. 
     
     
         16 . A method according to  claim 12 , wherein the subsequent balloon angioplasty is performed at low expansion pressure of 4 atmospheres or less. 
     
     
         17 . A method according to  claim 11 , wherein the spikes and the delivery system are also used to transport medication into the plaque and onto its surface. 
     
     
         18 . A method according to  claim 17 , wherein the spikes are arranged in one of the following ways consisting of: (i) the spikes have drug-coated tips; (ii) the spikes each have an internal drug-containing reservoir so that it behaves like a syringe; and (iii) the spikes are detachable from the carrier and are medication-eluting or bearing so that they are detached and left in place after perforation of the plaque. 
     
     
         19 . A method according to  claim 12 , wherein following the balloon angioplasty, any local incidence of post-angioplasty dissection is treated by applying a thin, ring-shaped tack to retain the plaque at only the location of the dissection site, rather than applying a stent over the overall plaque site. 
     
     
         20 . A method according to  claim 12 , wherein following the balloon angioplasty, any incidence of post-angioplasty dissection is avoided due to the pre-angioplasty preparation of the plaque by perforation to form cleavage lines or planes in the plaque and to performing the balloon angioplasty at a low pressure of about 4 atmospheres or less, thereby avoiding any need for applying a stent over the plaque site.