Angel Heart is a spin off (sort of) of City Hunter, which happens after Kaori gets killed in a car accident. She had volunteered for organ donation in that case, but then as her heart was going to be transplanted it gets stolen by the Mafia, who wants to use it on their best killer. A young and very pretty girl called "Glass Heart" because she's so cold and emotionless. Anyway, the girl stays in a coma for one year, until they were going to unplug her, then she wakes up and escapes because in fact she was getting sick of her job... and eventually meets up with Ryo.
It's pretty good, in fact, almost as good as my favourite manga by this author (which is Family Compo)