Intravascular fluid catheter with minimal internal fluid volume

Abstract

A catheter-based/intravascular ablation (denervation) system includes a multiplicity of needles which expand open around a central axis to engage the wall of a blood vessel, or the wall of the left atrium, allowing the injection of a cytotoxic or/or neurotoxic solution for ablating conducting tissue, or nerve fibers around the ostium of the pulmonary vein, or circumferentially in or just beyond the outer layer of the renal artery. The expandable needle delivery system is formed with self-expanding materials and include structures, near the end portion of the needles, or using separate guide tubes. The system also includes means to limit and/or adjust the depth of penetration of the ablative fluid into the tissue of the wall of the targeted blood vessel. The preferred embodiment of the catheter delivered through the vascular system of a patient includes a multiplicity of expandable guide tubes that engage the wall of a blood vessel. Injection needles having injection egress at or near their sharpened distal end are then advanced through the guide tubes to penetrate the wall of the blood vessel to a prescribed depth. The ability to provide PeriVascular injection so as to only affect the outer layer(s) of a blood vessel without affecting the media has particular application for PeriVascular Renal Denervation (PVRD) of the sympathetic nerves which lie in the adventitia or outside the adventitia of the renal artery.

1 - 72 . (canceled) 
     
     
         73 . A method comprising:
 providing a system comprising a catheter body, a first guide tube, a second guide tube, a first injection needle, and a second injection needle, the first injection needle disposed within a lumen of the first guide tube, the second injection needle disposed within a lumen of the second guide tube;   advancing the first guide tube and the second guide tube toward a wall of a target vessel;   advancing the first injection needle and the second injection needle through the first guide tube and the second guide tube, respectively, to penetrate an internal elastic lamina of the target vessel; and   delivering an ablative fluid through the first injection needle and the second injection needle to deliver an ablative fluid at or deep to an adventitial plane of the target vessel.   
     
     
         74 . The method of  claim 73 , wherein the ablative fluid fills a layer containing sympathetic nerves. 
     
     
         75 . The method of  claim 73 , wherein the ablative fluid flows circumferentially around the target vessel. 
     
     
         76 . The method of  claim 73 , wherein the ablative fluid comprises ethanol. 
     
     
         77 . The method of  claim 73 , wherein the target vessel is a renal artery. 
     
     
         78 . The method of  claim 73 , wherein the first injection needle and the second injection needle advance a preset depth. 
     
     
         79 . The method of  claim 73 , wherein the first injection needle advances at least 0.5 mm beyond the internal elastic lamina. 
     
     
         80 . The method of  claim 73 , wherein the first injection needle advances between 0.5 mm and 4 mm beyond the internal elastic lamina. 
     
     
         81 . The method of  claim 73 , wherein the first injection needle comprises an injection egress between 1 mm and 2 mm beyond a distal end of the first guide tube. 
     
     
         82 . The method of  claim 73 , wherein between 0.1 ml and 5 ml of the ablative fluid is delivered. 
     
     
         83 . A method comprising:
 providing a system comprising a catheter body, a first guide tube, a second guide tube, a first injection needle, and a second injection needle, the first injection needle disposed within a lumen of the first guide tube, the second injection needle disposed within a lumen of the second guide tube;   advancing the first guide tube and the second guide tube toward a wall of a target vessel;   advancing the first injection needle and the second injection needle through the first guide tube and the second guide tube, respectively, to penetrate the wall of the target vessel; and   delivering an ablative fluid through the first injection needle and the second injection needle for ablation applied beyond an intimal surface of the target vessel to selectively target a layer of the target vessel.   
     
     
         84 . The method of  claim 83 , wherein the ablative fluid is delivered around an entire circumference of the target vessel. 
     
     
         85 . The method of  claim 83 , wherein the ablative fluid ablates nerves that run along an adventitial plane of the target vessel. 
     
     
         86 . The method of  claim 83 , wherein the ablative fluid ablates nerves in an adventitial or peri-adventitial layer of the target vessel while minimizing intimal and medial injury. 
     
     
         87 . The method of  claim 83 , wherein the first injection needle and the second injection needle only penetrate into tissue to a preset distance. 
     
     
         88 . A method comprising:
 providing a system comprising a catheter body, a first guide tube, a second guide tube, a third guide tube, a first injection needle, a second injection needle, and a third injection needle, the first injection needle disposed within a lumen of the first guide tube, the second injection needle disposed within a lumen of the second guide tube, the third injection needle disposed within a lumen of the third guide tube;   advancing the first guide tube, the second guide tube, and the third guide tube toward a wall of a target vessel;   advancing the first injection needle, the second injection needle, and the third injection needle through the first guide tube, the second guide tube, and the third guide tube, respectively, to penetrate the wall of the target vessel; and   delivering an ablative fluid through the first injection needle and the second injection needle for circumferential filling of a space outside of an adventitial layer of the target vessel.   
     
     
         89 . The method of  claim 88 , wherein the ablative fluid penetrates circumferentially into a ring segment of the target vessel. 
     
     
         90 . The method of  claim 88 , wherein the ablative fluid ablates sympathetic nerve fibers of the adventitial layer. 
     
     
         91 . The method of  claim 88 , wherein a depth setting for penetration of the first injection needle, the second injection needle, and the third injection needle is known prior to advancing the first injection needle, the second injection needle, and the third injection needle. 
     
     
         92 . The method of  claim 88 , wherein delivering the ablative fluid comprises at least three points of simultaneous injection.