My dad has "40% stenosis at it's origin" in lad & 40% plaque in the om1 of lcx. he takes aspirin, beta blocker & chol. drugs. his heart attack risk?

At risk: You father has non-obstructive coronary disease. Plaques can rupture and result in heart attack unpredictably. You cannot make this risk go away but you can reduce it by using a high potency statin drug, regardless of his cholesterol level, daily low dose aspirin, not smoking, and doing daily moderate exercise. Stents or Bypass surgery will not reduce his risk for non-obstructive disease.

Manageable: If he has no symptoms, the recommended medical regimen includes the medications he is taking. The only addition, based on his risk factors, would be an ACE inhibitor (highly recommended for diabetes, but may also be helpful otherwise). He should not smoke and all around him should not smoke. If he can be active in moderation, that's good! He should be aware of symptoms and notify his doc ASAP!

Risk assessment: This is a difficult question since most estimates are in patients without known CAD. As a starting point assume 20% 10 year risk of an event that can be modified by not smoking, taking statins, controlling blood pressure and weight and exercise 30 mins at least 3x per week. He sounds like the meds are appropriate. The % above and location is not as important as the fact that he has CAD.