I think this underscores why it is important to find the best possible surgeon, who can perform the procedure efficiently and without delay (because he has done so many of them successfully) -- and therefore you are on the heart-lung machine for a shorter time than might otherwise be the case. And therefore the chances of pump head being an after-effect are lessened. My surgeon did my complex surgery in 5 hours, and my cardio told me some surgeons take twice that long.