Dissection of aorta is rare but a k own side effect of dvr, and yes it's a life threatening condition, however if the surgeon have adequate exposure of operative field it may be managed. A pre procedure 2 d echo even if normal, it doesn't rule out the possibility of dissection as it's a procedure related complication. However if m very sure the doctor's must have tried to salvage your father after dissection was noted, as no surgeon would like to lose his patient. Hoping this would help bring some closure.
Regards Dr Priyank Mody