yeah it works.
you shoudl focus on bringing down armor with the buff.
that way you won't lifesteal back to full on first turn.

on the last turn before it runs out you can use vampiric hunger and hit enemy vitals to easily heal back to full.

though death wish alone won't even bring you near close to low life.
the best way I developed was to actually let one of my toons go berserk and die.
then I painshackle + living on the edge and use last rites.

I have high crit so when it crits it does 7k+ damage to whoever is shackled. and you resurrectet a mate back to full, while also being at a descent level of health to benefit from death wish.