Sasuke killed him, indirectly in a way. I think he knew about Itachi overusing the Sharingan and it's drawbacks on his eyes and energy (well, of course he did!) and so, he played his own best cards against him. It was only after Kirin Sasuke realized that he didn't really stand much chance, because his chakra was out. Apparently Itachi's chakra was also, but somehow he managed to summon Susanoo.
Yeah, but as the post above implies, Sasuke did do some good damage to Itachi. That Shuriken technique really gave him a crippling.