What are the chances of coming out of a coma after a brain aneurysm?

Depends: The lenghth of coma depends on a number of things including how much brain damage can be seen on the MRI scan, the age of the patient, and how long the patient has already been in coma. If the patient is young thn there is always some hope.

Varies: I'd say if one goes into a "coma" after aneurysm rupture, all depends on what level of neurologic impairment is associated with it. What i mean to say is that a coma patient's examination tells one a lot about the level and site of injury. Generally, younger and otherwise healthy patients recover with higher likelihood. Recovery can be protracted...

It varies: There are many factors that need to be considered such as the age of the patient, the amount of blood from the aneurysm, the location of the aneurysm, how quick and aggressive was the up front treatment. Other factors that may contribute to the coma-like state need to be treated such as seizures or hydrocephalus.