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

A system for performing a medical procedure using a trans-septal approach, comprising:

• a tubular sheath comprising a proximal end, a distal end sized for introduction into a patient's body, and a lumen extending between the sheath proximal and distal ends;
• a dilator comprising a proximal end, a distal end sized for introduction into the sheath lumen 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 puncturing 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 and the sheath for advancing the dilator distal tip relative to the outer tube.

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 an outer tube from the distal end of the sheath within the first body lumen;
• pressing the outer tube distal end against a tissue wall within the first body lumen;
• with an inner needle positioned within the outer tube such that a sharpened distal tip of the needle is positioned adjacent the outer tube distal end and the tissue wall, retracting the outer tube, thereby impaling the tissue wall on the sharpened distal tip and directing the sharpened distal tip through the tissue wall into a second body lumen and creating a puncture through the tissue wall;
• and
• advancing the outer tube distal end over the needle through the puncture and into the second body lumen.

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.