I am afraid the evidence does point to the fact that there is a clear advantage both in terms of quality of life and mortality benefit (for instance in those patients who have a narrowing of more than 50% in the left main stem ie the major branch on the left side of the heart, only 50% will survive beyond three years on medical treatment alone).
Of course mild to moderate narrowing in a small noncritical vessel will neither confer a survival advantage nor cause a dramatic change in your quality of life.
This however is not always easy to predict because certain moderate sized branches can still cause significant symptoms. Decisions for treatment have to be individualized and expectations realistic to avoid later disappointment.
