Expandable trans-septal sheath

Abstract

Disclosed is an expandable transluminal sheath, for introduction into the body while in a first, low cross-sectional area configuration, and subsequent expansion of at least a part of the distal end of the sheath to a second, enlarged cross-sectional configuration. The sheath is configured for use in the vascular system. The access route is through the inferior vena cava to the right atrium, where a trans-septal puncture, followed by advancement of the catheter is completed. The distal end of the sheath is maintained in the first, low cross-sectional configuration during advancement through the atrial septum into the left atrium. The distal end of the sheath is expanded using a radial dilator. In one application, the sheath is utilized to provide access for a diagnostic or therapeutic procedure such as electrophysiological mapping of the heart, radio-frequency ablation of left atrial tissue, placement of atrial implants, valve repair, or the like.

1 . An expandable endovascular access sheath for providing minimally invasive access to a left atrium, comprising: 
 an axially elongate sheath tube with a proximal end, a distal end, and a central through lumen, the sheath having a distal region which is expandable in circumference in response to outward pressure applied therein;    a hub coupled to the proximal end of the sheath tube, the hub configured to facilitate the passage of instrumentation;    an obturator that extend through the central lumen and which is configured to occlude the central lumen of the sheath during insertion, the obturator comprising an obturator hub that is releasably couples to the hub of the sheath; and    a guidewire lumen within the obturator;    wherein. the obturator is a balloon dilator capable of expanding the distal region of the sheath from a collapsed configuration to an expanded configuration.    
   
   
       2 . The endovascular access sheath of  claim 1  where the sheath tube comprises a reinforcing layer embedded within a membrane layer fabricated from polymeric materials.  
   
   
       3 . The endovascular access sheath of  claim 1  wherein the sheath tube comprises: an outer layer, an inner layer, and a reinforcing layer, the outer layer and the inner layer comprising polymeric materials.  
   
   
       4 . The endovascular access sheath of  claim 3  wherein the reinforcing layer is a coil of metal.  
   
   
       5 . The endovascular access sheath of  claim 3  wherein the reinforcing layer is a braid.  
   
   
       6 . The endovascular access sheath of  claim 3  wherein the inner and outer layer are fabricated from different polymers.  
   
   
       7 . The endovascular access sheath of  claim 1  wherein the length of the sheath is between 50 and 250 cm.  
   
   
       8 . The endovascular access sheath of  claim 2  wherein the inner lumen of the sheath ranges between 6 and 30 French when the distal region is fully expanded.  
   
   
       9 . A method of instrumenting a left atrium of a patient comprising the steps of: 
 routing a guidewire into the right atrium from a peripheral vein,    inserting a sheath with a collapsed distal region and a pre-inserted dilator into the patient over the guidewire;    advancing the sheath to a treatment or diagnostic site within the right atrium of the heart;    performing a trans-septal puncture between the right and left atrium and advancing the collapsed distal region through the puncture into the left atrium;    dilating the distal region of the sheath so that the distal region of the sheath is expanded;    collapsing the dilator;    removing the dilator from the sheath,    inserting instrumentation through the lumen of the sheath into the left atrium,    performing therapy or diagnosis with the instrumentation, and    removing the sheath from the patient.    
   
   
       10 . The method of  claim 9  wherein dilating the distal region comprises inflating a balloon on the dilator.  
   
   
       11 . The method of  claim 9  wherein dilating the distal region comprises attaching a liquid-filled inflation device to a balloon inflation port at the distal end of the dilator and infusing liquid under pressure into the dilator.  
   
   
       12 . The method of  claim 11  wherein collapsing the dilator comprises withdrawing a plunger on the inflation device to withdraw liquid from the dilator.  
   
   
       13 . The method of  claim 9  wherein performing therapy or diagnosis with the instrumentation comprises electrophysiology energy delivery.  
   
   
       14 . The method of  claim 9  wherein inserting instrumentation through the lumen of the sheath comprises inserting two or more catheters through the sheath to perform the therapy.  
   
   
       15 . The method of  claim 9  wherein performing therapy or diagnosis with the instrumentation comprises delivering an implant into the left atrium.  
   
   
       16 . The method of  claim 9  wherein dilating the distal region also comprises dilating anchors within the atria.  
   
   
       17 . The method of  claim 9  wherein the full-size lumen created in the expandable region by the dilator is substantially larger than the lumen of the proximal non-expandable tubing.  
   
   
       18 . A sheath adapted for insertion into the right or left atrium of the heart comprising: 
 a diametrically collapsed distal end;    means for tracking the sheath over an already placed guidewire to a target treatment site in the right or left atrium of the heart,    means for articulating the distal end of the sheath,,    means for dilating at least a portion of the distal end of the sheath, and    means for removal of the sheath from the patient.    
   
   
       19 . The sheath of  claim 18  further comprising means for performing instrumentation, infusion of material into the atria of the heart, or withdrawal of material from the atria of the heart.  
   
   
       20 . The sheath of  claim 18  further comprising means for readily visualizing, positioning, and orienting said sheath using visualization techniques employing X-rays.  
   
   
       21 . The sheath of  claim 18  further comprising means for infusion of antithrombogenic fluid into the central lumen of the sheath.  
   
   
       22 . The sheath of  claim 18  further comprising means for infusion of antithrombogenic fluid into the guidewire lumen of the dilator.