Does Guardian Angel prevent loss of stacks on Bloodthirster?
The tooltip for Guardian Angel (GA) says
Passive Unique: Revives your champion upon death, restoring 750 health and 375 mana. 5 minute cooldown.
But as far as I neither Kill or Death counter are increased for the involved champions nor any gold is given to the "killer" when the passive of GA triggers.
Since stacks on Stack-Items (e.g. Bloothirster) are lost upon death, I wonder if being revived from GA's effect counts as a death or not.
The lol.wikia.com article on Death states it as Ways to prevent death when reaching zero health which confuses me even more.
Solution 1:
The League Wikia has a page explaining "Removal of stacks, buffs or effects".
Upon death, if the champion killed...had built up stacks on one of a handful of items, those effects are lost
Stacks lost upon death (one third rounded up, unless otherwise noted)
Mejai's Soulstealer
Leviathan
Sword of the Occult
The Bloodthirster (half)
Cho'Gath's Feast (half)
In the "Ways to prevent death when reaching zero health" section,
Effects that prevent you from dying always occur in a set order:
Zilean's Chrono Shift
Guardian Angel
Anivia's Rebirth
"Prevent death" should be interpreted literally. At 0 HP or less, Guardian Angel triggers and automatically brings your champion to 750 HP. Even though there is a delay for the stasis animation where the champion is untargetable and invulnerable, the champion did not die.
But I encourage somebody to record a video because that's the most convincing evidence.
Solution 2:
When Guardian Angel's passive triggers, you don't count as having died. You will keep stacks on Bloodthirster and other items that lose stacks on death, you will keep your blue/red buff, etc. And, like you noted, no kills or deaths or assists are awarded.
You don't die unless you are killed while the Guardian Angel passive is on cooldown.
Source: V1.0.0.79 Patch Notes
Positive buffs are no longer lost on pseudo-death (Chrono Shift, Guardian Angel.)
Solution 3:
When the guardian's angel passive is activated, it doesn't count as a death. After your hp reaches 0, you are motionless for a short period of time and afterwards you restore 750 health and 375 mana. Bloodthirster would not lose any stacks until you die with the GA in cooldown.