Bilateral occlusion of CA are very rare case. As a rule, such situation has an acute features and causes to death. In another way,chronic bilateral stenosis of CA causes to dysfunction of hippocampus and cognitive deficits.More: http://lushchyk.org/en/prof.html and http://angio-veritas.com/en/technologies/
The CA-1 region of hippocampus is highly active and thus very vulnerable to energy deficits. You find necrosis there in patients with frequent GM seizures, too.