In a new study, researchers found that invasive procedures such as bypass surgery and stenting—commonly used to treat blocked arteries—are no better at reducing the risk for heart attack and death in patients with heart disease than drugs and lifestyle changes alone.
However, such procedures offer better symptom relief and quality of life for some patients with chest pain.
The research was conducted by a team at NIH/National Heart, Lung and Blood Institute and elsewhere.
Coronary artery disease, which is caused by narrowed arteries that reduce blood to the heart, is the most common type of heart disease.
It affects about 18 million Americans and is the leading cause of death in the United States.
Symptoms can vary, but some people do not have them at all and may not know they have heart disease until they experience chest pain, a heart attack, or sudden cardiac arrest.
To find out whether an invasive or conservative strategy would be more effective in reducing these kinds of events, researchers studied the impact of both on heart attack, hospitalization for unstable angina, heart failure, resuscitated cardiac arrest, and cardiovascular death.
An additional key outcome of the study was quality of life.
The study followed more than 5,000 patients with stable heart disease and moderate to severe heart disease for a median of 3.2 years.
It compared an initial conservative treatment strategy to an invasive treatment strategy.
The conservative treatment strategy involved medications to control blood pressure, cholesterol, and angina (chest discomfort caused by inadequate blood to the heart), along with counseling about diet and exercise.
The invasive treatment strategy involved medications and counseling, as well as coronary procedures performed soon after patients recorded an abnormal stress test.
The study allowed tests that assess coronary blood flow restriction, called ischemia, to determine who could participate in the study.
Over the years of the trial, 21% of patients in the conservative treatment group ended up having a stent implant or bypass surgery; the rest continued medication alone.
Of those in the intervention group, revascularization was performed in 79%, three-quarters of them receiving stents and the others, bypass surgery.
By the end of the trial, the death rate between the two groups proved to be essentially the same: among the participants who had invasive procedures, 145 died, compared to 144 who received medication alone.
The overall rate of disease-related events was similar among those who took medication alone: 352 experienced an event such as heart attack, compared to 318 who had invasive procedures.
The team says the heart damage related to a procedure was not as serious in terms of the risk of subsequent death compared to heart attacks that occurred spontaneously, unrelated to any procedure.
There is an impressive, sustainable improvement in patients’ symptoms, function and quality of life with an invasive strategy for up to four years of follow-up.
However, this benefit was only observed in roughly two-thirds of those who had angina at baseline and no benefit was seen in those who had no symptoms.
For patients with angina, or chest pain, the comparative benefits of an invasive procedure over medical therapy alone were more consistent throughout the trial.
Two other companion studies did not show a reduced risk for death and heart attack for participants who had advanced chronic kidney disease, stable coronary disease, as well as moderate or severe ischemia with the invasive treatment compared to the conservative treatment.
There were no benefits in quality of life, even if participants had angina symptoms.
The lead author of the study is David Maron, M.D., director of the Stanford Prevention Research Center at Stanford University.
The study is published in the New England Journal of Medicine.
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