In my case, the aneurysm started dissecting a couple of centimeters above the valve. The saw "Fluid" around my heart and decided to do a pericardial window. That's when they discovered that the pericardium was full of blood and blood clots, but get this, they still hadn't found the dissecting aneurysm. By the time the helicopter was landing at Cleveland, I coded. Once I got to see Doc McCarthy (He actually came to see me on another floor because he didn't think I'd ever make it) he told me that just about the time the helicopter set down, the aorta actually ripped to shreds just above the valve. Why am I here? Only God knows. Doctor McCarthy couldn't even believe it.
Once the aorta comes apart, your pretty much done. This is why I wonder what symptoms John had before hand. I know he had some and must have just dismissed them as something else. I'm afraid that's one we'll never know.