Complex sentence: Infarction is tissue death (necrosis) caused by a reduction/stoppage in blood flow due to artery blockages, mechanical compression, rupture, or vasoconstriction.
Split into simpler sentences: Infarction is tissue death (necrosis) due to ischemia, which is inadequate blood supply to the affected area. It may be caused artery blockages, rupture, mechanical compression or vasoconstriction.