If its corkscrew shaped, then you can use it also to open bottels of wine...

Going back to the TOPIC, initially the focus was on using baboons or chimps because they are closer to humans on the evolutionary ladder. However, many complained on ethical grounds.

For some reason, Pig livers are very similar to human livers and they would be simple to raise. Also, as pointed out, pig heart valves have been successfully used in humans for many years.