Endarteria

Endarteriums are arteries whose supply area cannot be supplied by an anatomically preformed collateral, i.e. an anastomosis with another artery. And this means that in the case of vascular blockage, for example in arteriosclerosis, there are no bypasses like in arteries with collaterals. Any prolonged interruption of a cardiac endarteria thus results in a infarct, i.e. a final tissue destruction in the area of the muscle tissue supplied, the so-called heart attack.

https://de.wikipedia.org/wiki/Kollaterale _{(Wikipedia CC-by-sa-3.0)}