The availability of coronary angiography and the balloon and stent procedure has saved many thousands of lives. In fact, a type of heart attack known as an STEMI is best treated in this way. It is less clear whether you should have angiography if you have angina or a less severe type of heart called NSTEMI.
The purpose of angiography is to discover localized blockages within coronary arteries. Treatment aimed at such blockages with either the balloon (angioplasty) and stent procedure or bypass surgery can then be performed. The three categories of patients who commonly receive treatment of blockages are: 1) Those with a severe type of heart attack, or STEMI, caused by a complete occlusion of a coronary artery. 2) Patients with unstable angina or heart attacks (non-STEMI) associated with a partial occlusion. 3) Patients with chronic, stable angina, who have symptoms despite taking appropriate medications.
While opening the completely occluded artery if you are having an STEMI is clearly beneficial, it is less clear whether angioplasty/stenting and bypass surgery are good for the other two indications.
In the early days of angiography only the balloon technique existed (angioplasty). Although beneficial in some patients, arteries in which the balloon alone was used tended to close soon after the procedure, often requiring emergency bypass surgery. Angioplasty were reserved for only the most severe types of heart attacks where nothing else could be done. Stents greatly improved the outcomes of angioplasty. Stents are little coils that are inserted into a coronary artery once a balloon opens the blockage. It became possible to treat people with angina or a heart attack in a minimally invasive way with the combined balloon and stent procedure. Unfortunately, the long-term outcomes were often not as good as bypass surgery. For example, those with diabetes, certain types of blockages, or blockages in several different coronary arteries tended to live longer with less angina if treated with bypass surgery.
The next development in cardiology was the drug coated or drug eluting stent. By covering stents with a chemical to prevent coronary arteries from closing the outcomes of the balloon and stent procedure further improved. The balloon and coated stent approach became the preferred treatment to bypass surgery for many patients. Most patients with heart attacks or angina are currently referred for this procedure.
The piece of information that's missing above is the role of medication. Just as balloon and stent technology improved so has medication. By lowering cholesterol with statins, preventing blood clots with aspirin, lowering blood pressure, and treating diabetes many heart attacks and episodes of angina could be prevented. These medications stabilize all plaques. Invasive procedures, on the other hand, treat large isolated plaques, while smaller plaques are usually not treated. Unfortunately, plaques tend to develop in multiple sites in varying sizes. If you have a large plaque in one area, smaller plaques are likely to exist elsewhere. A plaque that appears “non-significant” during angiography may be the one to cause your heart attack. Fortunately, medications will treat this plaque as well as the larger ones. Medication is thus not in competition with invasive procedures. Everyone with CAD should receive medical therapy to prevent heart attacks and angina. The balloon and stent procedure is used as additional treatment in the certain patients.
It is now unclear whether proceeding with angiography and the balloon and stent procedure is any better than medical management alone in those with angina. Noninvasive imaging, such as with a nuclear stress test, may be able to predict which patients benefit most from angioplasty and stenting after a heart attack. In the future a "scan" of your heart will determine whether angiography is appropriate.
The "competition" between bypass surgery, balloon and stenting, and medication pushes the doctors, researchers, and industry in each discipline to improve over the others. The leader of today may not be in that position tomorrow.
The aggressive approach of emergent angiography with possible balloon and stent procedure is clearly indicated for patients with certain types of heart attacks. A conservative approach, avoiding angiography while controlling risk factors and close follow-up with a cardiologist, is an acceptable option in some cases. As always, get as much information as you can prior to going to the doctor, write down your questions, and make sure your doctor discusses the risks, benefits, and alternatives of each approach.