Cardiologists were once quick to perform surgical procedures on people with blocked arteries and chest pain, but a new study of more than 5,000 patients has shown that medications are often just as effective as stents and bypass surgery in preventing heart attack and death.
UNC cardiologist Christopher Kelly, MD, answered questions about what the study means for people with heart disease.
Why are stents and bypass surgeries used?
The coronary arteries supply the heart muscle with blood. When plaque develops on the walls of the arteries and narrows them, blood isn’t able to flow through as easily. If the artery closes down altogether, you have a heart attack. If the artery closes only partially, you get chest pain when you exert yourself, since the heart is working harder and needs more blood than the diseased artery can provide. Narrowing of the arteries is the problem that stents and bypass surgeries are supposed to fix. A stent is a metal tube the cardiologist inserts into the artery to prop it back open. Bypass surgery is when a surgeon takes an artery or a vein from elsewhere in the body and creates a pathway around the blockage.
What did this study find that will affect people with heart disease?
This study looked at the specific situation where an artery is partially blocked, causing chest pain with physical exertion that gets better with rest. You would think intuitively that opening the artery with a stent or bypass would be a good thing, and it might prevent somebody from having a heart attack later. But this trial showed that when people have stable chest pain, stents do not prevent heart attacks or death more than medications.
What do you mean by “stable chest pain”?
Stable angina is chest pain that’s in a stable pattern. You exert yourself, and a predictable amount of exertion causes chest pain that gets better with rest. Unstable angina is new onset chest pain, or pain that is happening at rest, or pain that is becoming more severe or frequent than it was before. An unstable pattern of chest pain may be a sign of a heart attack. In that case, stents—or bypass, if there are extensive blockages in the arteries—are clearly beneficial and better than medication.
Do we know why stents and bypass aren’t as effective for people with stable angina?
Heart attacks often don’t originate from severe blockages. Instead, it’s usually a small plaque that breaks down and causes blood to clot in the coronary artery, so that in a matter of seconds a mild plaque becomes a complete blockage. That’s why stents can relieve chest pain but don’t prevent a heart attack. The strategy for preventing heart attacks has a lot to do with using platelet-blocking medications, so that if a plaque does rupture, a clot doesn’t form to block the entire artery. We also use a medication called a statin, which blocks cholesterol synthesis, because cholesterol contributes to the instability of plaque. These strategies prevent heart attacks more effectively than putting in stents.
What medications are prescribed for chest pain?
If you have any amount of plaque in your arteries, you should consider taking an aspirin and a statin to lower your cholesterol. Those medications don’t address pain but do help prevent heart attacks. The main medications used to treat pain fall into three groups: beta blockers, nitrates (such as Imdur, or isosorbide mononitrate) and ranolazine (Ranexa). Typically, a patient can be controlled with one or more of those medications. If the medicines aren’t adequate or the side effects are unbearable, that’s when we would go to a stent.
What about people who already had a stent or bypass surgery?
A stent can’t be removed, and a bypass surgery can’t be undone. But before you get another stent, you should definitely try medications.
Are there any exceptions to these findings?
Yes, there are several caveats. This study didn’t include people who have disease in the left main artery, which supplies 70 percent of the heart muscle with blood. Disease there poses a significant threat to life, and those patients were not included in this trial. People who have heart failure from a weakened heart muscle also were not included in this study. The decision to do stenting or surgery for these groups will depend on a lot of other factors.
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