Support-frame-centered catheter for chemical ablation

A method comprising:

• introducing a catheter into a vasculature of a patient and advancing a distal portion of the catheter to a target treatment site;
• deploying a support frame of a neuromodulation assembly at the distal portion of the catheter from a contracted configuration to an expanded configuration, wherein the neuromodulation assembly comprises:
• one or more fluid-delivery needles configured to extend radially outward from a central longitudinal axis of the catheter at a distal portion of the catheter;
• and
• the support frame, wherein, while in the expanded configuration, a longitudinally central portion of an exterior surface of the support frame is configured to contact and apply pressure to a vessel wall of a vessel of the patient to approximately radially center the distal portion of the catheter within the vessel, and wherein the one or more fluid delivery needles are configured to extend radially outward through longitudinal positions within the central portion of the exterior surface of the support frame, such that the exterior surface of the support frame distributes the applied pressure both proximal and distal to the longitudinal positions;
• deploying the one or more fluid-delivery needles through the central portion of the support frame to pierce the vessel wall;
• and
• introducing a chemical agent into a perivasculature of the patient via the one or more fluid-delivery needles.