If you are dying to Alysrazor it is highly unlikely to be a gear thing. Much more likely is timing of abilities and reacting to two key abilities:
http://www.wowhead.com/spell=99308 - when this is applied, your health will be pushed down to 50%. Ideally your healers will want to let that happen then *quickly* pick you back up above 50%. If they don't do that, it's quite likely that you'll still have gushing wound on you when the other ability happens...
http://www.wowhead.com/spell=99308 - I'm sure you are already aware of tantrum, and this is the real killer, but maybe you aren't reacting to it well? The temptation is to use shield block as a dps cooldown, but in fact you are much better off saving it for when the tantrum comes. What really helped me was to configure a PowerAura that popped up (with a sound) when 'target gains tantrum') and quick reactions to tantrum is what really keeps you alive.
It's not essential to clear gushing wound before tantrum but it certainly makes it easier. What is essential is that you (and your healers) understand that tantrum means spike damage and the you are reacting to it appropriately. Shield block is an awesome cooldown to counter it, but even if you save your first shield block for the first tantrum, it is possible that the 2nd will come up. If you are doing enough DPS, you can eat worms a little earlier to avoid tantrum altogether, or you can use other cooldowns to help mitigate it. Heroic leaping to a worm can be a neat way to counter tantrum. And though you are working to push as much damage as possible, do not ever let thunderclap and demo shout (or equivalents) drop off.