This week, researchers presented the results of a study that compared the effectiveness of stents and angioplasty in treating patients with stable angina and significant heart-artery blockages. Given the type of patients analyzed under this study, the results were not terribly surprising, though they could have a short-term impact on the sale of stents.
The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation study, also known as COURAGE, was an important clinical trial designed to see whether treating patients with these conditions reduced their risks of heart attack or death. The COURAGE results, presented at an American College of Cardiology meeting, were also published online at the New England Journal of Medicine and have been widely discussed in the media.
Profile in COURAGE
To better understand the COURAGE trial itself, imagine two 60-year old men. Let's call them Smith and Jones. Each man predictably develops chest tightness when climbing stairs or mowing the lawn. Evaluation shows that their stress-test results are similar: Each man's heart receives less blood flow with exercise than expected. Both men are then scheduled for coronary angiography. The amount of blockage in their heart arteries is similar, revealing at least one artery with a 70% or greater blockage.
In most U.S. hospitals, both Smith and Jones would first undergo angioplasty, a procedure in which a tiny balloon is inserted to open the blockage. Afterwards, they would both receive a stent, a wire-mesh tube inserted into the artery to keep it open after the angioplasty. More than 1 million stent procedures are performed annually in the United States, with Johnson & Johnson (NYSE:JNJ) and Boston Scientific (NYSE:BSX) being the largest manufacturers of stents.
Both men would also be placed on medications, probably including a statin -- such as Pfizer's (NYSE:PFE) Lipitor, Merck (NYSE:MRK) and Schering-Plough's (NYSE:SGP) Vytorin, or AstraZeneca's (NYSE:AZN) Crestor -- to lower their cholesterol levels.
The COURAGE study was designed to give medical therapy for angina and coronary artery disease to "Jones" type patients, while "Smith" patients received similar medical therapy and a stent to open their tight blockages. Each type made up half of the study. All of the patients were then monitored for an average of more than four years.
So how did Smith and Jones do?
One might think that heart attacks occur as arteries get progressively narrowed over the years, and that the most narrowed arteries are the ones causing heart attacks and deaths. Yet research published in the late 1980s showed that heart attacks frequently result from mild blockages, not the more severe ones, because the milder blockages have more fat and inflammatory cells. These less tight blockages, which we would call "vulnerable plaques," are more likely to cause a heart attack or sudden cardiac death. In comparison, tighter blockages have more fibrous tissue with less fat and inflammatory cells. These tighter blockages restrict the blood flow and cause predictable chest pain, but they are actually less likely to cause heart attacks.
Prior studies comparing angioplasty to medical therapy in patients with stable angina have not shown that patients treated with angioplasty had fewer heart attacks or deaths. Those studies demonstrated that patients undergoing stenting had improved symptoms with less chest discomfort. Other studies demonstrated the value of angioplasty in patients with heart attacks or threatened heart attacks -- but that is not the kind of patient that the COURAGE study evaluated.
So even though Smith should have a reduced risk for subsequently suffering a heart attack or dying after getting his stent, the COURAGE results showed that Smith and Jones did about the same in terms of their recovery. The group that was initially treated with medications had a higher risk of requiring an angioplasty procedure or bypass surgery over the next four-plus years than did the group that received the stent -- 32.6% versus 21.1%. And patients who were stented also had less chest discomfort.
Yet both groups had statistically similar rates of death, heart attack, stroke, or risk of being hospitalized for acute coronary syndrome. The presence of a stent apparently had no effect on these factors.
The stakes for stents
Will the COURAGE trial substantially change how often doctors recommend stents, or how often patients decline them? How will the study affect the sales of stents or medications? The potential for a decline in stent sales is indeed substantial; statistics show that 85% of stents are placed in patients with stable coronary artery disease.
There will be much debate about the COURAGE studies. For example, stent proponents have called this just-completed trial a "historical" trial, since the stents used in the COURAGE trial were the older, bare metal stents, not the drug-eluting stents currently being used. Other cardiologists, however, point out that no data exists to indicate that using drug-eluting stents reduces heart attacks or death more than using bare metal stents.
In the short run, there may be a decline in the number of patients who undergo stenting, but long-term stent sales will be strong. Ultimately, some patients might decline a stent, if they realize that the stent would not prevent a heart attack or death. But many more patients will opt for relief from the chest discomfort that stents provide. And since the COURAGE trial used existing medications, there is no reason to expect increased drug sales, either.
The more things change, the more they stay the same.
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Fool contributor Dr. Michael Cecil is a cardiologist and the author of Drugs for Less: The Complete Guide to Free and Discounted Prescription Drugs. If you would like to discuss the article, email him at [email protected]. Dr. Cecil does not own any of the stocks mentioned in the article. The Fool has a disclosure policy
