There have been a number of men that have died, but to my recollection it is usually when experimenting on their own, as another poster has pointed out.
I am what some might call "kink positive", although on the milder side than most, but there should NEVER be ANY excuse for this. It disgusts me when this "sex game gone wrong" line gets thrown out as a way to get men off a murder charge.
Noone can consent to being killed (notwithstanding euthanasia laws in some countries but that's clearly a different scenario) and I cannot believe that can even be considered as a line of defence, that someone consented to an act so extreme it could result in death.
Even if a woman (or man) consents to an extreme practice, even if the perpetrator has that consent signed in triplicate, if anyone wants to practice extreme things such as this you have a responsibility to do it safely and your partner's safety is paramount. If you cannot do that then you should face the full weight of the law, not be given a get out of gaol free card.
If I signed up to go bungee jumping, for example, and the operator was negligent and I died you can be damn sure someone would be in gaol.
To be honest I doubt the man in question is even into BDSM, it's just a convenient excuse that gets trotted out in situations like this.