Cleaning Cat Urine from Polyester?

Forgive me if I am posting this in the wrong forum, I was just wondering if anyone has any experience with getting cat urine out of 100% polyester?
Earlier today I caught one of the kittens peeing on my favorite polyester blanket. I managed to grab the little guy and move him to the litter box before he made too big of a mess and soaked up what little pee there was with some paper towel then put the blanket it in the wash as quickly as I could. I figured that since it was such a small area that a quick cycle in the wash and it would be fine and It came out smelling clean so I dried it but now I am noticing a small patch of cat urine smell in the bottom corner.

I have had luck in the past soaking extremely saturated, dried on, garments in a white vinegar and warm water solutions for a few hours before washing and they came out like new. Is that safe for this blanket? It says it should be machine washed cold on a gentle cycle. I;d really hate to do anything that is going to damage the blanket or make it loose softness if I don't have to.

I'm also worried that now that I have washed and dried it that the smell is set and that nothing is going to get it out Any tips?

That happens fairly regularly at the shelter, and most of the blankets are polyester fleece. We just pour some enzymatic cleaner on the spot, let it sit till the next day, then machine wash as usual.

Thank you for your reply. I didn't have any enzymatic cleaner on hand. Will it still be effective in getting rid of the smell if I already washed it and am waiting to buy some? 

As far as I know, only an enzymatic cleaner can clean cat urine properly. You need the enzymes to break down the molecules that cause the odor. Here's a couple of articles on the topic - 

How To Remove Cat Urine

Combat Cat Urine

Good luck!