Angina, the medical term for chest pain or discomfort caused when the heart muscle doesn’t get enough oxygen-rich blood, is not in itself a disease. The American Heart Association says that angina, which may feel like pressure or squeezing in your chest and can also cause discomfort in your shoulders, arms, neck, jaw or back, is a symptom of a more significant, underlying heart problem.
A primary cause of insufficient blood flow to the heart is a blocked blood vessel. An artery clogged with plaque or due to vascular disease, known as ischemia, is often corrected when an interventional cardiologist inserts a stent into the constricted artery. The stent is a device that expands against the walls of the artery to open more space for blood to flow properly. Coronary artery stents are lifesaving for patients who are having a heart attackand for those with moderate to severe arterial blockages.
But new research suggests that stenting may be no better than a placebo in reducing chest painwhen angina is caused by milder, so-called “stable” angina, in which just one blood vessel is constricted and there are no other signs of heart disease. This finding may have a significant effect on how cardiologists treat chest pain in these patients going forward.
[See: The Facts on Heart Disease.]
The study, called the ORBITA trial, was a blinded, randomized, placebo-controlled study of 200 patients with stable angina, in which researchers compared stenting with a simulated procedure in which a stent was not implanted. The results, published in November in the journal The Lancet, showed that stenting had no significant additional benefit over the placebo treatment on patient symptoms or quality of life.
“The most important reason we give patients a stent is to unblock an artery when they are having a heart attack. However, we also place stents into patients who are getting pain only on exertion caused by narrowed, but not blocked arteries. It’s this second group that we studied,” Dr. Rasha Al-Lamee, lead author of the study from the National Heart & Lung Institute at Imperial College London, said in a release. “Surprisingly, even though the stents improved blood supply, they didn’t provide more relief of symptoms compared to drug treatments, at least in this patient group.”
Stents Still Important for More Serious Disease
While the study was praised by other cardiologists, many fear that people may misunderstand it. “The results and message are not consistent in my opinion,” said Dr. David Zhao, chief of cardiology and director of the Heart and Vascular Center of Excellence at Wake Forest Baptist Medical Center. His main concern is that these patients are not necessarily ones who would receive a stent in the first place because they don’t show enough signs that a heart attack may be coming. “We generally don’t send these patients to the cath lab, period. If they are not that sick, a stent is not going to make them better,” he says. However, sicker patients do require stenting. “So it is probably not wise to apply these patients to generalize to others. That can do damage to those who truly need it,” he says.
Those with stable angina also comprise a relatively small subset of patients with heart disease. “It is important to recognize that one vessel narrowing probably affects about 10 percent of people getting the procedure, so [the study] speaks to some patients we care for but not as many as [the study] estimated,” says Dr. Manesh Patel, chief of the division of cardiology and the division of clinical pharmacology at Duke University School of Medicine.
Nevertheless, Patel says that “To some extent, this [study] changes the conversation a little.” That conversation is focused on how to treat angina pain and discomfort if stenting is not really helpful. Fortunately, there are several other options. The first step, Patel says, is to find out exactly what is causing the pain. “Is it really the blockage, or is it something in the heart muscle itself,” he says. Cardiologists can measure the pressure on an artery, and “many of us direct who we stent based on pressure across the blockage.” In other words, if the pressure is low, the pain may not be from the blockage but due to some other cause, such as a blood clot, a vascular spasm or coronary microvascular disease in the heart’s smallest arteries.
Other Options for Pain Relief
If a blocked artery is confirmed, several medication options are available, including nitroglycerin, beta blockers and calcium channel blockers, which lower blood pressure and, in turn, lower the stress put on the heart. Patients typically require a regimen of more than one medicine, Zhao says, which is very successful if the patient complies with treatment. He thinks this study will encourage patients and doctors to try medication first, before stenting.
“We have known for a long time that, in stable coronary artery disease, a stent does not alter mortality, so this study is reassuring for those who don’t want a stent,” Zhao says. “That won’t cause the patient serious damage or death. To relieve pain in these patients, I would treat aggressively with medications, with the understanding that I am not doing any harm from a mortality standpoint. I can reassure patients – let’s try medications and see if they help or not, and it is not going to cause you to die suddenly or have a massive heart attack.”
Patients with coincidental issues like high blood pressure or high cholesterol need to control those problems as well, says Dr. Nauman Mushtaq, medical director of cardiology at Northwestern Medicine Central DuPage Hospital, with their own medications like antihypertensive drugs, low-dose aspirin or statins and, especially, with lifestyle changes. “We don’t stress that enough,” he says. Medical advances are important, he stresses, but, “The next thing to address in our society are the primordial risk factors, things like how we live our life:Do we walk or take the stairs, do we eat the right foods, is there access to a grocery store in the neighborhood, is there pavement to walk on and ride bikes on? All this good old stuff does make a difference.”