ischaemic stroke vs ischemia

ischaemic stroke and ischemia both are nouns.

Word	Noun	Adjective	Verb	Adverb
ischaemic stroke	Yes	No	No	No
ischemia	Yes	No	No	No

As nouns, ischemia is a hypernym of ischaemic stroke; that is, ischemia is a word with a broader meaning than ischaemic stroke:

ischaemic stroke: the most common kind of stroke; caused by an interruption in the flow of blood to the brain (as from a clot blocking a blood vessel)
ischemia: local anemia in a given body part sometimes resulting from vasoconstriction or thrombosis or embolism

Other hypernyms of ischaemic stroke include apoplexy, cerebrovascular accident, CVA, stroke, ischaemia.

ischaemic stroke (noun)	ischemia (noun)
the most common kind of stroke; caused by an interruption in the flow of blood to the brain (as from a clot blocking a blood vessel)	local anemia in a given body part sometimes resulting from vasoconstriction or thrombosis or embolism