How Angioplasty Treats Blocked Arteries

Angioplasty procedure
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Angioplasty—also called "percutaneous transluminal coronary angioplasty," or PTCA—is a catheterization procedure aimed at relieving blockages within arteries, most commonly in the coronary arteries.

Angioplasty works by inflating a tiny balloon within the artery at the site of an atherosclerotic plaque, flattening the plaque and reducing the stenosis (blockage) within the artery. In almost every case angioplasty is accompanied by insertion of a stent.

How Angioplasty Is Done

To perform an angioplasty, the doctor uses a catheter (a long, thin, flexible tube) that has a deflated balloon attached to it. The catheter is passed across the plaque that is producing the blockage, and the balloon is inflated under pressure. The expansion of the balloon compresses the plaque against the wall of the artery. When the balloon is deflated and removed, the plaque remains at least partly compressed, so the blockage is reduced.

While angioplasty was originally performed as a stand-alone procedure, today a stent is also inserted whenever angioplasty is performed on a coronary artery. A stent is an expandable “scaffold” that helps support the wall of the artery at the site of angioplasty, in order to keep the plaque compressed. The collapsed stent is placed over the balloon before it is inserted. Then, when the balloon is inflated, the plaque is compressed and the stent is expanded at the same time. When the balloon is then deflated and removed, the stent is left in place, helping to keep the plaque compressed and the artery open.

When It's Helpful

Angioplasty is quite effective in reducing the symptoms of stable angina. So the main reason for doing angioplasty in a coronary artery is to treat angina that remains persistent despite attempts at medical therapy. While it may seem surprising to many, angioplasty (even when a stent is inserted) has not been shown to be more effective than medical therapy in reducing the subsequent risk of myocardial infarction (heart attack), or to improve survival. So the main reason for performing angioplasty is to relieve stable angina that has persisted despite attempts to treat it medically.

The second reason angioplasty (and stenting) is often used in treating coronary artery disease is in people who have acute coronary syndrome (ACS). In ACS, an acute blockage of a coronary artery has occurred because a plaque has ruptured and a clot has formed within the artery. When ACS is occurring, a heart attack is very likely unless the artery is opened. During ACS, the available evidence shows that angioplasty and stenting can help substantially to improve overall cardiac outcomes.

The coronary arteries are not the only arteries in which angioplasty is routinely used to treat obstructive atherosclerotic plaques. Angioplasty is also applied to the carotid arteries (which supply the brain), the renal arteries (which supply the kidneys) and the leg arteries.


The most common complication following angioplasty alone is restenosis— the formation of a new blockage at the site of the compressed plaque. Restenosis is a relatively gradual process caused by the new growth of tissue—probably in response to the trauma produced in and around the vessel wall by the angioplasty itself. The incidence of restenosis has been greatly diminished by the use of stents, especially drug-eluting stents (DES), which are coated with medication that inhibits the growth of tissue, thus reducing restenosis.

Before the era of stents, late restenosis occurred in nearly 30% of patients who had angioplasty alone. The use of bare metal stents reduced this risk to less than 15%, and drug-eluting stents reduced it further to less than 10%.

A less common problem, but a more devastating one, is thrombosis (blood clotting) at the site of angioplasty/stenting. Stent thrombosis is a sudden and often catastrophic event, which typically produces acute and complete obstruction of the affected artery. Thrombosis is most commonly seen soon after the angioplasty procedure (that is, within days to weeks). However, when a stent has been inserted during the angioplasty (which is almost always the case today), a low risk of thrombosis persists for several months to several years after the procedure. The risk of thrombosis is significantly reduced by the use of anti-platelet drugs—which, however, also carry some risk.

Other complications that can occur during angioplasty include damage to the organ being supplied by the blood vessel being treated (including heart attack, kidney damage or stroke), cardiac arrhythmias, or bleeding.

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Article Sources
  • Authors/Task Force members, Windecker S, Kolh P, et al. 2014 ESC/EACTS Guidelines on Myocardial Revascularization: The Task Force on Myocardial Revascularization of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS)Developed with the special contribution of the European Association of Percutaneous Cardiovascular Interventions (EAPCI). Eur Heart J 2014; 35:2541.
  • Fihn SD, Blankenship JC, Alexander KP, et al. 2014 ACC/AHA/AATS/PCNA/SCAI/STS Focused Update of the Guideline for the Diagnosis and Management of Patients with Stable Ischemic Heart Disease: a Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines, and the American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol 2014; 64:1929.