Catheters and dilators for trans-septal procedures and methods for making and using them

Abstract

Devices and methods are provided for performing a medical procedure using a trans-septal approach. The device includes a dilator including a proximal end, a distal end terminating in a distal tip, and a lumen extending between the dilator proximal and distal ends, and a needle device including a proximal end, a distal end sized for introduction into the dilator lumen and terminating in a sharpened distal tip. The needle is movable relative to the dilator to selectively expose the needle device distal tip distally from the dilator lumen and advance the dilator relative to the needle device. The dilator may have a complex tapered shape on its distal tip, e.g., including first and second tapered regions. The needle device may include an inner needle including the sharpened distal tip and an outer tube including a substantially blunt distal end that slidably receives the inner needle.

1 . An access device for performing a medical procedure using a trans-septal approach, comprising:
 a dilator comprising a proximal end, a distal end sized for introduction into a patient's body and terminating in a tapered distal tip, and a lumen extending between the dilator proximal and distal ends;   an outer tube comprising a proximal end, a distal end sized for introduction into the dilator lumen and terminating in a substantially blunt distal tip, and a lumen extending between the outer tube proximal and distal ends; and   a needle comprising a proximal end, a distal end sized for introduction into the outer tube lumen and terminating in a sharpened distal tip, wherein the needle is movable relative to the outer tube to selectively expose the needle distal tip distally from the outer tube lumen and retract the needle distal tip into the outer tube lumen, and wherein the dilator is movable relative to the outer tube for advancing the dilator distal tip relative to the outer tube.   
     
     
         2 . The device of  claim 1 , wherein the outer tube comprises a stainless steel hypotube extending between the proximal and distal ends. 
     
     
         3 . The device of  claim 2 , wherein the distal tip of the outer tube comprises a polymeric material. 
     
     
         4 . The device of  claim 1 , wherein the needle comprises stainless steel. 
     
     
         5 . The device of  claim 1 , wherein the distal tip of the dilator has a complex tapered shape. 
     
     
         6 . The device of  claim 5 , wherein the dilator distal tip comprises a distal-most region have a first linear taper defining a first angle relative to a longitudinal axis of the dilator, and a second region adjacent the distal-most region having a second liner taper defining a second angle relative to the longitudinal axis, the second angle being smaller than the first angle. 
     
     
         7 . The device of  claim 6 , wherein the distal-most region has a first length and the second region has a second length longer than the first length. 
     
     
         8 . The device of  claim 6 , the distal-most region has a length L 1  and transitions from a first diameter D 1  to an intermediate diameter D 2 , and the second region has a length L 2  and transitions from the intermediate diameter D 2  to an outer diameter D 3  of the dilator, and wherein the regions are configured such that (D 2 -D 1 )/L 1  is greater than (D 3 -D 2 )/L 2 . 
     
     
         9 . The device of  claim 1 , wherein the dilator comprises an inner layer defining an inner surface of the dilator lumen and an outer layer surrounding the inner layer, the inner layer having a greater hardness than the outer layer. 
     
     
         10 . The device of  claim 9 , wherein inner layer has a smaller thickness than the outer layer. 
     
     
         11 - 20 . (canceled) 
     
     
         21 . A method for performing a medical procedure within a patient's body, comprising:
 introducing a distal end of a tubular sheath into a first body lumen;   advancing a distal end of a needle device from the distal end of the sheath through a tissue wall into a second body lumen;   advancing a distal end of a dilator over the needle device through the tissue wall, thereby dilating tissue surrounding the puncture using a complex shaped tapered distal tip of the dilator; and   advancing the sheath distal end over the dilator through the dilated puncture into the second body lumen.   
     
     
         22 . An access device for performing a medical procedure using a trans-septal approach, comprising:
 a dilator comprising a proximal end, a distal end sized for introduction into a patient's body and terminating in a tapered distal tip, and a lumen extending between the dilator proximal and distal ends;   an outer tube comprising a proximal end, a distal end sized for introduction into the dilator lumen and terminating in a substantially blunt distal tip, and a lumen extending between the outer tube proximal and distal ends; and   a needle comprising a proximal end, a distal end sized for introduction into the outer tube lumen and terminating in a sharpened distal tip, wherein the needle is movable relative to the outer tube to selectively expose the needle distal tip distally from the outer tube lumen and retract the needle distal tip into the outer tube lumen, and wherein the dilator is movable relative to the outer tube for advancing the dilator distal tip relative to the outer tube,   wherein the dilator comprises an inner layer surrounding the lumen formed from abrasion resistant material, and an outer layer surrounding the inner layer formed from material that is relatively soft relative to the inner layer.