A dilator system for insertion of a catheter or other elongate device into a body of a patient includes a catheter having a lumen that initially defines a first inner diameter. The catheter includes a swellable material that swells after insertion into the body. A dilator includes an elongate body that is initially disposed in the catheter lumen and a tapered head extending from a distal end of the catheter lumen. The dilator head defines an outer diameter that is larger than the first inner diameter of the catheter lumen. After insertion of the dilator head and a distal portion of the catheter into the body, the catheter swells such that the lumen defines a second inner diameter that is larger than the outer diameter of the dilator head. This enables the dilator to be proximally removed from the body via the catheter lumen defining the second diameter.
