Carotid stenosis, which produces symptoms, is usually significant, and though you have not mentioned the degree of stenosis, it is likely that it is more than 70%. In this situation, it is better to get the stenosis removed by either carotid endarterectomy or carotid stenting. Medications to prevent progression in any case have to be taken and would include drugs to control blood pressure and anti cholesterol medication to aggressively reach ideal levels. Lifestyle modification at this age should include careful attention to diet especially in limiting fatty foods.