Patent ID: 7955319

Claim:
A method of delivering a therapeutic substance to a delivery site in a patient, comprising the steps of: pumping said therapeutic substance under pressure from a reservoir of an implantable medical device implanted at a first location of a patient through a catheter fluidly coupled to said reservoir, said catheter having a proximal end coupled to the implantable medical device, a delivery region and a first lumen extending between said proximal end and said delivery region, said delivery region of said catheter placed in proximity to said delivery site in said patient, wherein the delivery site is removed from the first location of the patient; detecting a pressure of said therapeutic substance in said first lumen; detecting a reference pressure in the patient in proximity to the delivery region of said catheter; comparing the pressure in said first lumen to the reference pressure to obtain a relative pressure in said first lumen; and taking an action in response to said relative pressure in said lumen.