Is this really a question of “fault”?
Seems to me it’s more the fact that some circumstances, by their very nature, make some medical procedures either prone to failure or prone to the development of secondary problems.
Treatment is being denied based on a patient's behavior in causing his/her problems, so fairness dictates that all voluntary behavior should be treated the same. Take intravenous drugs or engage in unsafe sex practices and get AIDS, ride a motorcycle and get your bones broken, climb a mountain and snap your spine, any unnecessary risk should lead to denial of government-provided treatment if that's the standard.