March 30, 2020
Do stents and surgery lead to better outcomes for patients with stable heart disease? Or do medication and lifestyle changes offer a more promising path forward?
This decades-old debate finally has been answered in a set of National Institutes of Health-funded studies published Monday in the New England Journal of Medicine.
It turns out that bypass surgery and stenting – a procedure to treat blocked arteries – are no better at reducing the risk of heart attack and death than the more conservative strategy of medication and lifestyle changes. There's one notable exception: some patients with chest pain experience better symptom relief and higher quality of life after the invasive procedures.
These findings are based on the final outcomes of the International Study of Comparative Health Effectiveness with Medical and Invasive Approaches.
"Previous studies have reached similar conclusions as ISCHEMIA, but they were criticized for not including patients who had severe enough disease to benefit from the procedures," said Dr. Yves Rosenberg, study co-author and chief of the National Heart, Lung and Blood Institute. "ISCHEMIA studied only patients with the most abnormal stress tests.
"These findings should be applied in the context of careful attention to lifestyle behaviors and guideline-based adherence to medical therapy, and will likely change clinical guidelines and influence clinical practice."
In the meantime, patients should discuss with their doctors the best strategy for them.
Ischemic heart disease, also referred to as coronary artery disease, occurs when the blood supply to the heart is slowed due to narrowed or constricted arteries. While a blood clot could be the cause, the most common culprit is the buildup of plaque, known as atherosclerosis.
Almost 18 million Americans have coronary artery disease and it is a leading cause of death. Many people don't know they have it until they experience chest pain, a heart attack or sudden cardiac arrest.
The ISCHEMIA trial followed more than 5,000 patients with stable heart disease and moderate to severe heart disease for about 5 years. Most of the participants had a history of chest pain, with 21% of them experiencing it daily or weekly. Another 35% reported they didn't have any chest pain for at least a month before enrolling in the trial.
Some patients were randomly assigned a conservative treatment strategy featuring medications to control blood pressure, cholesterol and chest pain, as well as counseling about diet and exercise. The others also received more invasive procedures, including bypass surgery and stenting.
By the end of the five-year span, 21% of patients in the conservative treatment group needed a stent implant or bypass surgery. In the more invasive treatment group, 79% needed revascularization, three-fourth of which were stenting and the rest bypass surgery.
Overall, 145 people in the invasive procedure group died compared with 144 in the conservative treatment group. The rate of disease-related events like heart attacks also was similar between the two groups.
The researchers found one significant difference between the two groups: while patients in the conservative treatment group had fewer cardiovascular events during the first two years of the trial, patients in the other group has fewer such events in the last two years because of an increase in heart attacks in that group during the first six months.
"We have known and confirmed in this study that stent and surgical procedures have a risk of some heart damage," said Dr. Judith Hochman, study chair and senior associate dean for Clinical Sciences at New York University's Grossman School of Medicine. "However, we saw that 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."
The researchers noted that patients with chest pain experienced the most benefits from bypass surgery or stenting.
"ISCHEMIA showed an impressive, sustainable improvement in patients' symptoms, function and quality of life with an invasive strategy for up to four years of follow-up," said Dr. John Spertus, director of health outcomes research at Saint Luke's MidAmerica Heart Institute in Kansas City, Missouri. "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."
Dr. David Maron, director of the Stanford Prevention Research Center at Stanford University, added, "Taken together, the quality of life and clinical results suggest that there is no need for invasive procedures in patients without symptoms. For those with angina, our results show it is just as safe to begin treating with medication and lifestyle change, and then if symptoms persist, discuss invasive treatment option."
The two studies, "Initial Invasive or Conservative Strategy for Stable Coronary Disease," and "Health-Status Outcomes with Invasive or Conservative Care in Coronary Disease," can both be found in The New England Journal of Medicine.