Traditional open heart surgery was the gold standard up until the last eight to 10 years. During this type of surgery, a cardiothoracic surgeon split the sternum — the breastbone – and exposed the aortic valve. Next, the aortic valve leaflets were removed and then hand-sewn into a new aortic valve. Treating aortic stenosis with an open heart procedure took approximately three to four hours in the operating room. Then, patients would need critical care afterward, spending a night or two in the ICU, and about five days in the hospital, in total.