Noun and の adjective
けっかん
彼は血管が切れそうなぐらい怒っていた。
He was so angry that his veins were popping out.
The pipe that holds your blood is your blood vessels.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. The けつ goes to けっ.