What Does Superficial Femoral Artery Thrombus Causing Stenosis Mean?

hi this is sagar ,my dad gets pain in his les when he walks for a distance ,the doc told to do doppler test the results came as left limb superficial femoral artey thrombus causing 80-90 stenosis..wen showed to doctor he has given cilostazol tablets..is the medication correct..wat is the actual problem