• Posted November 23, 2021

Years of Blood Thinners After Stenting Might Not Be Necessary

Folks who've had a clogged artery reopened probably can stop taking blood thinners sooner than previously thought, a new study argues.

Patients are regularly prescribed blood thinners for a year or more after angioplasty. This is to make sure that blood doesn't clot inside the metal stent that now holds their artery open. That could cause a heart attack or stroke.

But heart doctors are prescribing these blood thinners longer than necessary because guidelines are based on clinical trial data that's become outdated, according to new findings.

"Our current guidelines may not apply to the average person, in practice," said lead researcher Dr. Neel Butala, a cardiology fellow at Massachusetts General Hospital in Boston. "The average person today getting a stent may be better off with shorter dual antiplatelet therapy" (which is aspirin plus a blood thinner).

Guidelines now call for most patients to take aspirin and blood thinner for more than a year and as long as 30 months to prevent blood clots from forming in their stent, Butala said.

But that guidance is based on a single clinical trial that took place about a decade ago. Butala and his fellow researchers suspected that improvements in stent technology likely had changed the equation, making long-term blood thinners unnecessary for many.

Patients today are "more likely to receive a second-generation drug-eluting stent," Butala said. The newer stents have a thinner structure and are coated with improved time-release drugs, both of which reduce clotting risk and therefore the need for blood thinners.

To test their theory, the researchers gathered data from more than 8,800 patients who participated in the original clinical trial. They compared them to more than 568,000 present-day patients with similar heart problems.

The researchers found that modern patients indeed were more likely to receive a second-generation stent, and also were more likely to be getting treatment for a heart attack versus chest pain.

Those differences mean that patients are more likely to be harmed by long-term blood thinners than helped, the new study concluded.

Patients on long-term blood thinners are more than twice as likely to suffer dangerous bleeding, but they no longer get any significant benefit for reducing clotting within the stent or avoiding a heart attack or stroke, researchers said.

"In a contemporary population, we actually found that the benefit disappears," Butala said.

These results should lead heart doctors to reconsider the length of time stent patients take blood thinners, said Dr. Roxana Mehran, director of interventional cardiovascular research and clinical trials with the Icahn School of Medicine at Mount Sinai in New York City. She was not involved with the new study.

"They're showing that the treatment effects of prolonged blood thinners have limited applicability with the current practice of [angioplasty] and the kinds of devices that we have available to us," Mehran said.

"We really need to be cognizant of these blood thinners. You can't just apply them like, 'OK, you've got to take this for the rest of your life,'" Mehran continued. "I think we need to individualize and talk to our patients, bring our patients into the equation, and make really shared decisions about the risk/benefit ratio for them."

That's not to say people shouldn't take blood thinners at all; rather, they might only take them for three to six months following their stenting procedure, Butala said.

"A lot of the newer trials for newer stents suggest that shorter-duration dual antiplatelet therapy -- even less than 12 months, like six months or one month -- is actually not inferior to longer duration," Butala said. "All of the trials have been moving towards shorter and shorter and shorter [dual antiplatelet therapy]."

And some patients might still need to take long-term blood thinners, Butala added. Folks likely should take the drugs longer if they've received a smaller stent, are smokers, or have health problems like diabetes, prior heart attack, high blood pressure, congestive heart failure or kidney disease.

Patients should talk with their doctor before making any change to their prescription regimen, Butala and Mehran said.

"It's not like everyone should stop taking all their meds, because that's dangerous," Butala said. "They should rely on their doctor to make sure their treatment is individualized and reflects the patient in front of them."

The findings were published Nov. 16 in the journal Circulation.

More information

The Mayo Clinic has more about angioplasty.

SOURCES: Neel Butala, MD, cardiology fellow, Massachusetts General Hospital, Boston; Roxana Mehran, MD, director, interventional cardiovascular research and clinical trials, Icahn School of Medicine at Mount Sinai, New York City; Circulation, Nov. 16, 2021