In the News
September 7, 2008
The results of the COURAGE trial
Is stenting a better treatment for patients with stable angina then medical therapy alone?
Coronary artery disease (blockages or narrowings in the arteries of the heart) is still the number one cause of death in this country. It is common for individuals who previously were entirely well to suddenly succumb to an unexpected heart attack or end up in our intensive care units quite ill. But many individuals have gradual narrowings of the arteries of the heart which do not produce a heart attack (or “myocardial infarction”) but result in oppressive chest discomfort with exertion, commonly called "angina". Sometimes this only occurs with unusual exertion such as changing a tire in a snowstorm, but often it results in angina with more common activities such as walking up the hill or carrying packages. Often such patients are taken to the cardiac catheterization laboratory where an angiogram reveals severe narrowings in one or more arteries which are then treated with bypass surgery or, more commonly these days, with dilatation of the narrow part of the artery and placement of one or more stents, small coiled mesh-like devices which prop the artery open and keep it from narrowing again. But as the technology of stents has improved, so has medical therapy and until recently it was not clear which was preferable. The COURAGE trial (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) was designed to answer this question. In this controlled clinical trial, patients with stable angina were randomized to receive either the best possible medical therapy in combination with stent placement (technically known as percutaneous coronary intervention (PCI)) or optimal medical therapy alone. To be eligible for the study each patient had to have undergone cardiac catheterization and to have been shown to have at least one coronary artery with a 70% or greater narrowing, and also to have had a positive stress test. The trial involved 2287 patients and the patients were followed for an average of 4.6 years.
What was optimal medical therapy? All patients were treated with drugs that decrease the tendency of blood to clot - either aspirin, or if the patient was intolerant to aspirin, a drug known as clopidogrel (Plavix). They were given drugs that diminish the likelihood of developing angina: metoprolol (a beta blocker), amlodipine (a calcium channel blocker) and isosorbide mononitrate (a long-acting form of nitroglycerin) in addition, all patients received aggressive therapy to reduce their cholesterol levels using statins and other drugs. Many patients also received additional medication to lower blood pressure and to reduce the work of the heart.
What did the study show? The primary endpoint of the study was death or heart attack. There was no difference between the two forms of therapy. Nineteen percent of people in the PCI group and 18.5% in the medical therapy group suffered either death or heart attack during the time of follow-up. There was also no difference between the two groups in strokes or hospitalizations for cardiac disease. These results did not change when patients who had had a previous heart attack, were diabetic, or had multivessel coronary disease were looked at separately. Both groups showed substantial improvement in their symptoms, but initially some what more patients in the PCI group were entirely free of angina. In a recent publication in August of this year a further follow-up of these groups showed that by the end of three years there was no longer any meaningful difference in symptoms between the two groups.
What have we learned from this study?
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Copyright © 2008 Massachusetts Medical Society. All rights reserved. Weintraub et al. N Engl J Med 2008;359:677-87
For patients with stable, unchanging angina good medical therapy saves as many lives and prevents as many heart attacks as to stent procedures. Placing stents improved symptoms modestly more than did medical therapy, but this difference disappeared by three years in follow-up. So there should be no pressure felt to go through stent procedures to prevent death or heart attack if angina can be controlled medically.
It is very important to understand the difference between stable and unstable angina. Unstable angina, or angina that is new in onset or becoming worse as time passes, as well as angina that occurs at rest or with minimal exertion is much more likely to lead to a serious event in the near future, with the likelihood of a clot suddenly forming in a coronary artery being relatively high. Unstable angina demands immediate attention and carries a high risk. But stable angina which is not changing and is predictable - you know when it is likely to occur and it is clearly related to exertion - is in a very different category and can be treated with aggressive medical therapy. It is equally important to understand that the results achieved in this study were with optimal medical therapy - which means a combination of medications designed to reduce the workload of the heart and treat risk factors such as hypertension and high cholesterol, and of course it also means that these medications need to be taken exactly as prescribed, not forgotten, and not discontinued.
More information about these studies can be obtained from the original articles which are linked below:
Boden et al. Optimal medical therapy with or without PCI for stable coronary disease. N Engl J Med 2007;356:1503-16.
Weintraub et al. Effect of PCI on quality of life in patients with stable coronary disease. N Engl J Med 2008;359:677-87.