Further thoughts on artificial hearts

A number of people emailed me or blogged (eg. here and here) on my post, Artificial heart won't save lives. The number of transplants is constrained by the number of donated organs thus the main effect of the artificial heart, which is just a temporary stop-gap, is to redistribute organs. The artificial heart makes some people better off at the expense of other people who are made worse off. No one challenged this conclusion but it seemed to make some people uncomfortable. Two arguments were raised in opposition, both of which are weak.

First, the heart does allow some people to live a little bit longer - this is a benefit, but a few weeks of life while chained to a big machine doesn't seem like a big breakthrough to me. Second, the artificial heart could allow for better matching. Theoretically true, but there are already many more patients on the waiting list than there are hearts available so the opportunity for better matching is negligible. Consider, that for a given heart there are now 3500 people on the waiting list to choose from - how much better is the match going to be if we add a few more people to this list?

I am not against artificial hearts (some people say I have one!) perhaps one day the technology will improve enough so that someone on an artificial heart can be taken off the list, but the issue is comparative. Suppose that we put the funds gong into artificial hearts into programs to increase organ donation. One donated organ is say good for 10 years of extra life. Average time on the artificial heat is 77 days and it is not clear how many of these days represent extra days of live. Let's say very charitably that 50 days are extra then this means that one real heart is worth 73 times as much as an artificial heart (10*365/50) and that is before adjusting for quality of life.