Methods and devices for puncturing tissue

A method of accessing a chamber of a patient's heart using a superior access approach, the method using a dilator with an ancillary device to access a tissue of the patient's heart, the ancillary device comprising a steerable device having a curvature-imparting region operable to guide the dilator by directing the dilator along a curve, the dilator comprising a passive dilator comprising a substantially rigid distal end region, and a substantially flexible intermediate region terminating at the distal end region, the passive dilator substantially lacking a curve, the method comprising the steps of:

• (a) advancing the steerable device through a patient's vasculature, from a superior approach access site into the patient's heart, the steerable device defining a lumen and containing the passive dilator within the lumen, where a location of the substantially flexible intermediate region of the dilator corresponds to a location-of the curvature-imparting region of the ancillary device;
• (b) articulating the steerable device to manipulate the flexible intermediate region of the dilator to position the rigid distal end region of the dilator substantially adjacent the tissue of the patient's heart, wherein the lack of the curve, in conjunction with the substantially flexible intermediate region, ensures that the dilator does not substantially interfere with the curvature of the ancillary device enabling the ancillary device to attain the desired curvature to position the dilator distal end portion at the puncture site via the superior access approach;
• and
• (c) advancing the substantially rigid distal end region of the dilator through a puncture in the tissue.

A kit for accessing a puncture site within a patient's heart by a superior access approach, the kit comprising:

• a passive dilator comprising a substantially flexible intermediate region terminating at a substantially rigid distal end region;
• the passive dilator substantially lacking a curve;
• a steerable sheath comprising a deflectable region and defining a lumen for receiving the dilator therethrough;
• the sheath and dilator being configured to co-operate such that, in use, the dilator is positionable within the sheath such that a location of the substantially flexible intermediate region of the dilator within the lumen corresponds to a location of the deflectable region of the sheath;
• and
• Wherein the lack of the curve, in conjunction with the substantially flexible intermediate region, minimizes resistance of the dilator to deflection of the deflectable region of the steerable sheath enabling the steerable sheath to position the dilator distal end portion at the puncture site via the superior access approach.

A sheath assembly for accessing a puncture site within a patient's heart by a superior access approach, the sheath assembly comprising:

• a steerable sheath defining a lumen therethrough and defining a deflectable region;
• a passive dilator comprising a substantially flexible intermediate region terminating at a substantially rigid distal end region, the passive dilator substantially lacking a curve;
• the dilator being configured to extend through said lumen such that the deflectable region of the sheath is aligned with the flexible intermediate region of the dilator, the flexible intermediate region having sufficient flexibility to adopt a curvature of the deflectable region upon deflection;
• and
• the rigid distal end region having sufficient rigidity to allow the dilator to be advanced across the puncture site for dilating the tissue at the puncture while preventing deformation of the rigid distal end region during advancement;
• Wherein the lack of the curve, in conjunction with the substantially flexible intermediate region, ensures that the dilator does not substantially interfere with the curvature of the ancillary device enabling the ancillary device to attain the desired curvature to position the dilator distal end portion at the puncture site via the superior access approach.

A method of using a steerable sheath assembly to access a puncture site within a patient's heart by a superior access approach, the method comprising the steps of:

• advancing a steerable sheath through vasculature through the superior approach to the puncture site within the patient's heart, the steerable sheath comprising a deflectable region;
• positioning a dilator within a lumen of the steerable sheath, wherein the passive dilator substantially lacks a curve, said dilator comprising a substantially flexible intermediate region and a substantially rigid distal end region, such that the flexible intermediate region is located within the sheath lumen at a position substantially aligned with the deflectable region of the steerable sheath;
• actuating the steerable sheath to deflect the steerable sheath to a desired deflection angle thereby deflecting the flexible intermediate region of the dilator for enabling positioning of the dilator distal end region at a desired tissue site within said region of tissue, wherein the passive dilator is configured such the lack of a curve and the flexible intermediate region substantially do not affect the deflection of the steerable sheath while substantially adopting the desired deflection angle;
• and
• advancing a portion of the dilator including the distal end region through said desired tissue site, said dilator distal end region having sufficient rigidity to enable advancement of the distal end region through the desired tissue site for dilating said tissue site while preventing deformation of the distal end region.