At age 2, I was a candidate for a monkey heart transplant, as I had a perforated aortic valve and surgery on tissue with the consistency of wet-toilet paper in an infant had a very high mortality rate (the girl on the table before I went in had died). My parents declined the monkey transplant. Good thing. The intended recipients of multiple attempts at the monkey hearts, died. I eventually received a primitive mechanical implant, which I quickly outgrew. By the 80s I had another surgery to replace it (https://en.wikipedia.org/wiki/Bj%C3%B6rk%E2%80%93Shiley_valv...). This had it's own dangers, as the strut would fail along 2 ends of a sizing graph (most people were at the larger size end). I sat safely on the bell curve. I kept that into my 30s which caused various problems with the aortic stem and thickening of the left ventricle.

Now I'm rocking the On-X, which is superior in innumerable ways.