I think not. Usually this task is made by using field "To deadline", for example if "To Deadline" is less than 1 hour than make BOLD style. Note that this works only if this field is present in current view.
You cannot do a simple %age calculation - you can only say a specific time interval from the deadline.
Using "To Deadline" can give performance issues - in fact in version 5 it made a view for one of our customers virtually useless. If that is the case, you can use a scheduled DB rule to set a custom code field to a value when the relevant time is reached and then use this cudtom field to highlight the rows. If you need help with such rules just ask.