There are no modern studies that compare surgical treatment or angioplasty with medical treatment of the Nineties. Indeed, quite a number of recent studies have showed just the opposite. Not only is aggressive medical treatment with surgery or angioplasty no better than modern medical treatment, but patients undergoing such treatment had much higher mortality rates. There are many reasons. The kindest view is that the training your cardiologist had was so narrow and focused that surgery or angioplasty are the only ways he knows how to treat coronary artery disease.
Cardiologists also have quotas.
They must perform at least 75 angiograms and angioplasties a year to maintain their hospital privileges. If the cardiologist is employed by a hospital, the hospital must perform several hundred heart procedures a year to maintain their accreditation. Thus, his job may depend upon keeping the operating room full. Still another reason is that doing high tech procedures is very profitable. Many hospitals would go out of business if it were not for the surgeries that they do.