My father, 87, has been diagnosed with a 90% blockage of the right carotid artery. His doctor will not do surgery, even though Dad experiences dizzy spells. The left artery seems to be OK. He has been placed on medication to reduce cholesterol, stopped smoking in the late 40s, is very definitely not overweight. The previous cholesterol medication made him very weak. Should we investigate a stent for this problem? Or is surgery not indicated at all?