Peelable PTFE sheaths and methods for manufacture of same

Abstract

The present invention provides improved medical introducer devices which incorporate a single or multi-layer PTFE peelable sheath. Devices of the present invention are suitable for use in inserting an ancilliary medical device, e.g., a catheter, guide wire and the like, into a patient. Methods of the present invention also are disclosed which employ a precision sintering process in order to produce sheaths having excellent tear properties and optimal peelability.

What is claimed is:  
     
         1 . A medical introducer device comprising: 
 (a) a single-layer, peelable PTFE sheath having a bore extending therethrough and that does not include mechanically produced skiving for longitudinal splitting of the sheath, the sheath thermally cured to provide a peel strength of at least about 0.5 lbs with a standard deviation of no greater than about 0.40; and    (b) a hub unit attached at a proximal end of the peelable sheath which facilitates splitting of the peelable sheath upon application of an effective shearing force thereon.    
     
     
         2 . The device of  claim 1  wherein the sheath has a peel strength of at least about 0.70.  
     
     
         3 . The device of  claim 1  wherein the sheath has a peel strength of at least about 1.0.  
     
     
         4 . The device of  claim 1  wherein the sheath has a peel strength standard deviation of no more than about 0.30.  
     
     
         5 . The device of  claim 1  wherein the sheath has a peel strength standard deviation of no more than about 0.20.  
     
     
         6 . The device of  claim 1  further comprising a plurality of wing portions attached to the hub unit on opposing sides for grasping the hub unit.  
     
     
         7 . The device of  claim 1  wherein the peelable sheath comprises a detectable material capable of external visualization.  
     
     
         8 . The device of  claim 1  further comprising a needle or dilator assembly extending longitudinally within the bore of the peelable sheath  
     
     
         9 . A medical introducer device comprising: 
 (a) a multi-layer, peelable PTFE sheath having a bore extending therethrough, and that does not include mechanically produced skiving for longitudinal splitting of the sheath, the sheath thermally cured to provide a peel strength of at least about 0.5 lbs with a standard deviation of no greater than about 0.40; and    (b) a hub unit attached at a proximal end of the peelable sheath which facilitates splitting of the peelable sheath upon application of an effective shearing force thereon.    
     
     
         10 . The device of  claim 9  wherein the sheath has a peel strength of at least about 0.70.  
     
     
         11 . The device of  claim 9  wherein the sheath has a peel strength of at least about 1.0.  
     
     
         12 . The device of  claim 9  wherein the sheath has a peel strength standard deviation of no more than about 0.30.  
     
     
         13 . The device of  claim 9  wherein the sheath has a peel strength standard deviation of no more than about 0.20.  
     
     
         14 . The device of  claim 9  further comprising a plurality of wing portions attached to the hub unit on opposing sides for grasping the hub unit.  
     
     
         15 . The device of  claim 9  further comprising a needle or dilator assembly extending longitudinally within the bore of the peelable sheath  
     
     
         16 . The device of  claim 9  wherein the multi-layer, peelable sheath comprises a thermally stable outer layer and at least one inner layer.  
     
     
         17 . The device of  claim 16  wherein the inner layer comprises a detectable material capable of external visualization.  
     
     
         18 . The device of  claim 16  wherein the thermally stable outer layer of the peelable sheath comprises a pigment.  
     
     
         19 . The device of  claim 18  wherein the outer layer and inner layer of the peelable sheath each comprise visibly distinct pigments.  
     
     
         20 . A method of manufacturing a single-layer, peelable PTFE sheath that does not include mechanically produced skiving for longitudinal splitting of the sheath, the method comprising: 
 (a) providing a PTFE preform material;    (b) extruding the preform material into tubing;    (c) drying the tubing; and    (d) curing the tubing to provide a peel strength of at least about 0.5 lbs with a standard deviation of no greater than about 0.40.    
     
     
         21 . The method of  claim 20  further comprising adding a detectable material to the preform blend in an amount sufficient to facilitate external visualization by X-ray or fluoroscopic procedures.  
     
     
         22 . The method of  claim 20  further comprising: 
 (a) affixing a hub unit onto a proximal end of the peelable sheath;  
 (b) attaching a plurality of wing portions to opposing sides of the hub unit; and  
 (c) tipping the peelable sheath at a distal end thereof.  
 
     
     
         23 . The method of  claim 22  wherein the tipping comprises thermally treating the sheath.  
     
     
         24 . A method of manufacturing a multi-layer, PTFE peelable sheath that does not include mechanically produced skiving for longitudinal splitting of the sheath, comprising: 
 (a) preparing a first preform PTFE material for forming the inner layer of the peelable sheath;    (b) preparing a second preform PTFE material for forming the outer layer of the peelable sheath;    (c) combining the first preform material and second preform material blend into a two layer preform;    (d) extruding the two layer preform into tubing;    (e) drying the tubing; and    (f) curing the tubing using a precision sintering process.    
     
     
         25 . The method of  claim 24  further comprising equilibrating the first preform material and second preform material prior to their combination.  
     
     
         26 . The method of  claim 24  further comprising adding a detectable material to the first preform blend in an amount sufficient to facilitate external visualization.  
     
     
         27 . The method of  claim 24  further comprising adding a colored pigment to at least one of the first preform material and the second preform material.  
     
     
         28 . The method of  claim 24  further comprising: 
 (a) affixing a hub unit onto a proximal end of the peelable sheath;  
 (b) attaching a plurality of wing portions to opposing sides of the hub unit; and  
 (c) tipping the peelable sheath at a distal end thereof.  
 
     
     
         29 . The method of  claim 28  wherein tipping the peelable sheath comprises using a thermal process.  
     
     
         30 . A method of introducing a catheter or guide wire into a patient comprising: 
 (a) providing a medical introducer device of  claim 1;     (b) piercing and dilating the vasculature of the patient using the needle or dilator assembly;    (c) inserting the catheter or guidewire through the bore of the peelable sheath into vasculature of the patient;    (d) applying cooperating forces to the wing portions of the hub unit to axially shear the peelable sheath; and    (e) removing the peelable sheath from the vasculature of the patient.    
     
     
         31 . A method of introducing a catheter or guide wire into a patient comprising: 
 (a) providing a medical introducer device of  claim 9;     (b) piercing and dilating the vasculature of the patient using the needle or dilator assembly;    (c) inserting the catheter or guidewire through the bore of the peelable sheath into vasculature of the patient;    (d) applying cooperating forces to the wing portions of the hub unit to axially shear the peelable sheath; and    (e) removing the peelable sheath from the vasculature of the patient.