Catheter systems with biasing rails and methods for forming fistulas

A method of forming a fistula between a first blood vessel and a second blood vessel, comprising:

• advancing a first catheter into the first blood vessel, wherein the first catheter comprises:
• a first catheter body, an electrode, one or more arrays of magnets, and a first plurality of biasing rails, wherein:
• the electrode is configured to project from a working site of the first catheter and define an active side of the first catheter;
• the one or more arrays of magnets are arranged longitudinally along the first catheter body;
• the first plurality of biasing rails longitudinally extend along a length of the first catheter body and are configured to radially arch away from the first catheter body between a proximal point positioned proximal a first end of at least one array of the one or more arrays of magnets and a distal point positioned distal to a second end of the at least one array of the one or more arrays of magnets so as to longitudinally span the at least one array of the one or more arrays of magnets;
• and
• the first plurality of biasing rails extend from a non-active side of the first catheter body such that the first plurality of biasing rails are configured to bias the working site and the one or more arrays of magnets against a first blood vessel wall;
• and
• ablating tissue with the electrode to form the fistula.

A system for forming a fistula between two blood vessels, comprising:

• a first catheter comprising a catheter body, an electrode, one or more arrays of magnets, and a plurality of biasing rails, wherein:
• the electrode is configured to project from a working site of the first catheter and define an active side of the first catheter;
• the one or more arrays of magnets are arranged longitudinally along the catheter body;
• the plurality of biasing rails longitudinally extend along a length of the catheter body;
• the plurality of biasing rails are configured to radially arch away from the catheter body between a proximal point positioned proximal a first end of at least one array of the one or more arrays of magnets and a distal point positioned distal to a second end of the at least one array of the one or more arrays of magnets so as to longitudinally span the at least one array of the one or more arrays of magnets;
• the plurality of biasing rails extend from a non-active side of the catheter body such that the plurality of biasing rails are configured to bias the working site and the one or more arrays of magnets against a first blood vessel wall;
• the plurality of biasing rails are joined by a connecting rail that laterally extends between the plurality of biasing rails at a point between the proximal point and the distal point;
• and
• the plurality of biasing rails comprise a proximal portion extending through a lumen of the catheter body, wherein:
• the proximal portion may be advanced in the lumen to transition the plurality of biasing rails to an extended configuration, wherein the plurality of biasing rails radially arch away from the catheter body;
• and
• the proximal portion may be retracted in the lumen to transition the plurality of biasing rails to a low-profile configuration, wherein a maximum distance of radial deflection of the plurality of biasing rails is less than a maximum distance of radial deflection of the plurality of biasing rails in the extended configuration.