I don't want to develop blocked arteries. What steps can I take?

Several. Don't smoke, watch you cholesterol, blood pressure and blood sugar and maintain an active lifestyle. Use medicines when needed. But also know that there is no guarantee that nothing will happen and you can't avoid getting older or change genetics, but you will be able to shift the odds in your favor.
Life style. As close to vegan diet as you can get with variety of fruit and veg, avoid concentrated sweets, exercise regularly, no smoking, yearly physical to make sure your blood pressure and cholesterol are excellent and that you don't have diabetes. Time management and stress management skills help.