Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the symptoms of Atherosclerosis ?
    ### Response:
    Atherosclerosis usually doesn't cause signs and symptoms until it severely narrows or totally blocks an artery. Many people don't know they have the disease until they have a medical emergency, such as a heart attack or stroke.
                
Some people may have signs and symptoms of the disease.
    