Patent 7947031 was granted and assigned to Boston Scientific on May, 2011 by the United States Patent and Trademark Office.
A catheter includes a wall surrounding a lumen. The wall has an inner portion forming an outer surface of the lumen and an outer portion surrounding at least a portion of an outer surface of the inner portion. A first diffusion rate of materials from the lumen through the inner portion is different from a second diffusion rate through the outer portion. A durometer hardness of the inner portion is lower than a durometer hardness of the outer portion.