It depends upon a lot of factors. First, if it's an emergency situation, your odds drop markedly. Think of it this way: If you knew you were going to blow out a tire on the freeway, you'd pull over, get the spare ready, call for help, and pull far off the road. But, if you were going along at 75 MPH and the front driver's side tire suddenly blew, in a tunnel in the middle of nowhere, you might not have the same result.

Survival depends upon immediate diagnosis with a cross-sectional CT scan or bedside ultrasound. If you're across the street from the Mayo Clinic, that helps. If you're up North in the woods by yourself, well, you're probably not going to survive a dissection. The survival rate drops by 1% an hour if its untreated, although once it fully dissects you can bleed out very quickly.

The takeaway is that if your surgeon recommends surgery, get a second opinion to confirm it, and then do it. Waiting until it happens is too late. It's the most complex surgery there is and you want to make sure your surgeon is fully prepped, well in advance, with all the blood/plasma/staff/resources necessary for a great outcome.