I spent several hundred dollars trying various Nature’s Miracle formulations for when my cats played litter box wars while we were on vacation to no avail. I am glad it worked for you.
The guy at the upholstery cleaning place I took my sofa cushions when I gave up said that they use hydrogen peroxide in a concentration just high enough not to bleach that particular fabric. IIRC, he said it usually worked out to about 8%. Not an easy thing to find. They also seal the odiferous object in a plastic bag, if it’s small enough. After treatment they check with a uV light and repeat if necessary.
The Anti Icky Poo got rid of a lot of it, but the odor would still come back to haunt me, most notably on hot and/or humid days.
The stuff that doesn’t work on cat pee is pretty excellent for washing horse standing wraps. I just add it to the bleach dispenser.
Yeah both the pretreater and treater of Anti Icky Poo failed on my carpet.
‘My Pet Peed’ blows Nature’s Miracle out of the water. I swear it’s liquid lye. This stuff dissolves anything protein based, and I mean anything. You have to wear gloves while using it (ask me how I know). But it will remove anything protein based–just spray to saturate and walk away. No retreating needed. It evaporates to plain water within an hour. However, if you walk around barefoot within that hour after applying, you will give yourself a Russian pedicure (also ask me how I know).
The stuff is like 60 bucks a gallon but it’s the best 60 bucks I ever spent. It will completely remove–permanently–all stains and oders from pee or poop or vomit or blood. Yup, even blood. I even used it on 12 year old “mystery stain” on a bedroom carpet that came with my house. Stain was so bad (dark brown, splatter, about 12" wide by 30" long) it was disclosed at closing. Now THAT is one hell of a product.
Anti-Icky Poo. Stupid name, excellent urine neutralizer.
Chicamuxen
I make my own with a combination of hydrogen peroxide, vinegar, baking soda, dish soap and lemon extract. Worked with the high-anxiety cat who peed everywhere except the box! It saved my couch, mattress, bedding, carpet, etc. Cat has since been rehomed.
Bumping for update from the OP. 
I did try the product Laurierace recommended-- on a spot I thought was dog urine, not cat. There wasn’t a smell to begin with (that a human could smell, anyway-- it was an old spot) so I can’t comment on taking OUT the urine smell… but the product has its own STRONG scent that I associate with kennels (probably for good reason) so be forewarned that there’s a strong scent. Not unpleasant exactly but I wasn’t expecting a lingering smell because the product I usually use (Outright/Simple Solution) doesn’t leave a strong smell.
