Inflamed artery. Light micrograph of a section through an inflamed artery. The inner lining of the artery, the endarterium or arterial tunica intima, is thickened and inflamed. This is called endarteritis. The thickening is occluding the lumen (central space) of the artery, which reduces blood flow, compromising the delivery of oxygen to the tissues supplied by the artery. This can lead to various problems including gangrene.