Nutritional support to prevent carotid artery dissection

Background:  I am a 44-year-old male (I am thin, exercise regularly, and eat a primarily vegetarian diet plus fish).  Six months ago, I had a severe stroke caused by a spontaneous arterial dissection of my right carotid artery.  The CT angiogram further identified evidence of a previous (already healed) dissection on my left carotid artery (the evidence being a skin flap on the arterial wall).

Q:   Is there anything that can be done to prevent recurrence of a carotid artery dissection?  My trusted neurologist has already indicated that I should take an aspirin a day, but was unaware of any literature suggesting any management measures (such as nutritional support, etc.) to prevent another dissection.