I've heard of stents getting blocked up and having to be replaced but not leaking, so not sure if it is the same thing. If he had a plastic stent put in, it is more likely to get blocked sooner, but usually in a couple months or so. They replaced my boyfriends original plastic stent with a metal mesh one that wasn't as likely to get blocked so quickly. When they did the Whipple the stent was taken out with all the other stuff they remove, so its no longer an issue.