in order to protect the heart, we need to do cardio plea just -- cardiopliga.takes about five minutes to do this to protect the heart and get it nice and cold so we can open the heart with impunity. brian lamb: a lot of things, why would that have to be open heart surgery instead of using the catheter? dr. patrick o'gara: this may have been done a few years ago prior to the routine use of the transcatheter valves we currently have. it could have also been that this person, although he had critical aortic stenosis, was resilient enough enough withstand this surgery. what we saw here is the test was -- chest was open, that large yellow thing was the beating heart at the onset of the video. the surgeon was preparing the field prior to making an incision to expose the valve and then take it out and replace it with another valve called a prosthesis. this is the type of cardiac surgery that has been with us for decades, which is highly successful and sets a high bar for our ability to prove that these transcatheter techniques will be equally effective in lower risk p