Now a large clinical trial suggests that drug-coated stents, springy lattice tubes used to prop open clogged arteries, may also work well in patients with multiple blockages. And in some patients, the stents produce equally good results with faster recovery times.
The caveats, experts say, are that people with daily or weekly chest pain from advanced coronary artery disease will probably experience slightly better relief from bypass surgery compared to stenting; but they can also count on waiting to get the full benefit of that procedure weeks to months longer than people who get stents.
Experts say the study, which is published in The New England Journal of Medicine, brings to light important trade-offs that people with complex coronary artery disease need to weigh before making a decision between the two procedures.
“I think the message here, therefore, is not a simple one -- that there’s a clear winner -- but that patients will need to choose based on their own priorities and values,” says study researcher David J. Cohen, MD, a cardiologist at St. Luke’s Mid America Heart Institute in Kansas City, Mo.
Independent experts agree.
“If you take the 50,000-mile view, it looks like these procedures got about the same results,” says A. Marc Gillinov, MD, cardiac surgeon at the Sydell and Arnold Miller Family Heart & Vascular Institute at Cleveland Clinic, in Ohio. “But if you really dig down and look at the clinical circumstances going in, you’ll see there are important differences. So the real value in this study is that it can help patients and doctors make informed decisions on an individual basis.”
Comparing the Effectiveness of Stents vs. Bypass
For the study, researchers at 85 medical centers around the world randomly assigned 1,800 patients with at least three clogged arteries around their hearts, or alternatively, a clogged left main coronary artery -- the vessel that carries the lion’s share of blood to the heart’s primary pumping chamber -- to one of two treatments: coronary artery bypass graft (CABG) surgery or percutaneous coronary intervention (PCI).
In CABG, surgeons typically saw through the breast bone and open the rib cage, a procedure that, in and of itself, requires significant downtime for recovery. Doctors usually also need to make incisions in other parts of the body, often the legs, to harvest healthy vessels that can be used to bypass blockages.
In PCI, a catheter is threaded through an artery in the groin up to the heart, where a doctor uses a video monitor and radioactive dye to locate the blockages within arteries. The doctor then inflates a balloon to compress the buildup against the artery walls and places a stent to hold the spot open.
The stents in this trial were coated with the drug paclitaxel, which is thought to help prevent the formation of scar tissue around the site of stent implantation, a problem called restenosis.
Before any procedure was performed, an interventional cardiologist and a cardiac surgeon consulted together on each case. If there was mutual agreement that the blocked vessels might be effectively opened using either procedure, the patient was cleared to enter the study.
Before patients were assigned to one procedure or the other, doctors asked patients questions about how often and how strongly they’d been feeling angina, or chest pain, their physical limitations and general quality of life. Based upon the answers, patients were scored on a scale of 1 to 100, with higher scores indicating fewer symptoms and better health status.
Those questions were asked again one month, six months, and 12 months after their procedures.
A disease severity score was also determined at study entry for each patient. This score is dependent upon the degree and extent of blockages as demonstrated on the initial angiogram, with higher scores indicating more complex disease. For subsequent analysis purposes, the patients in the study were divided into three subgroups depending upon their disease severity scores (0 to 22, 23 to 32, and 33 to 83).
In all, 903 patients received stents, while 897 had bypass surgery. In both cases, doctors tried to open all the arteries that were at least 50% blocked.
In the first phase of the study, which was published in 2009, researchers looked primarily at the risk of having a major event, like a heart attack, stroke, or having to reopen an artery that had clogged a second time. After one year, there were about 5% fewer total events in the bypass group compared to the stent group, 12.4% compared to 17.8% respectively.
More patients needed to have clogged arteries reopened in the PCI group than in the CABG group, 13.9% vs. 5.9%, respectively.
Looking at Quality of Life
When researchers looked at angina and quality of life in study participants, overall, both groups fared well. In fact, slightly more than half of people in both groups reported substantial improvement in angina as early as one month after their procedures.
But when investigators looked at those measures across various time points, and in people with more and less severe disease, differences emerged.
As was expected, people who got stents generally felt better faster, compared to the group that had bypass surgery, probably because there was less healing time required after the less invasive procedure.
But by six and 12 months after their procedures, both groups reported nearly equal improvements in physical functioning, pain, vitality, and social and mental health.
And after six months, researchers say people that went into the study with daily or weekly chest pain experienced greater relief after CABG than did those who got PCI.
“Angina relief at six months and a year was better with bypass surgery, though the difference was small,” says Cohen. “But there were clear differences in the early quality of life on a wide range of dimensions that clearly favored PCI, but those benefits were transient,” he says.
The study was sponsored by Boston Scientific, which produces paclitaxel-coated stents.