Lipid-engorged macrophages are killed by

Chemical modification of the proteins or lipids in plasma low-density lipoprotein (LDL) leads to abnormal LDL that is not recognized by the liver LDL receptors, and so is not cleared by the liver. The modified LDL is taken up by macrophage scavenger receptors. Lipid-engorged macrophages infiltrate under blood vessel endothelium and are killed by the high content of unesterified cholesterol they have accumulated. This occurs in the development of atherosclerotic plaques, which, in extreme cases, can more or less completely occlude a blood vessel. Reference: Harpers illustrated biochemistry 30th edition