By AMERICAN HEART ASSOCIATION NEWS
As the popularity of a new generation of blood thinners surges, people taking them should be aware of bleeding risks, according to a recent statement from the American Heart Association.
There are occasions when the four newer anticoagulant drugs need attention, said Amish N. Raval, M.D. the statement’s lead author and associate professor of cardiovascular medicine at the University of Wisconsin School of Medicine and Public Health in Madison. These are when patients are bleeding or are at risk for bleeding.
The drugs, known as non-vitamin K oral anticoagulants – NOACs —were approved less than a decade ago to reduce the risk of potentially deadly clots that could cause a stroke or block blood flow in the lungs or legs. The drugs are: dabigatran etexilate, sold as Pradaxa; rivaroxaban, Xarelto; apixaban, Eliquis; and edoxaban, Savaysa.
Because the drugs limit the blood’s natural clotting ability, doctors and hospitals need a plan for preventing excessive bleeding after traumatic injuries or during surgery, according to the statement.
From the 1950s until NOACs were approved, most people with the abnormal heart rhythm atrial fibrillation or who suffered from blood clots in the lower legs or lungs, called venous thromboembolism, took warfarin, sold as Coumadin. Untreated AFib is associated with a fivefold increased risk for stroke.
However, warfarin is difficult for both doctors and patients, because the drugs interact with other drugs and foods, requiring frequent office visits for blood tests and constant adjustments.
The most exciting thing about the newer anticoagulants is that they make life so much easier for patients, said Geoffrey Barnes, M.D., a cardiologist and vascular medicine specialist at the University of Michigan Health System, who was not a statement author. “It’s just so much more convenient to take a pill on a regular basis … without having to worry about getting their blood drawn all the time and getting their doses changed.”
The new drugs “have allowed doctors to get more patients on blood thinners than we used to,” Barnes said.
Although there’s no national record of how many people take NOAC drugs, an estimated one-third to half of all patients on blood thinners take them, Barnes said.
The number of people taking anticoagulant drugs is expected to rise, as the U.S. population ages and more are diagnosed with AFib and venous thromboembolism, according to the statement.
About 2.7 million to 6.1 million people in the U.S. have AFib, which is expected to rise to 12.1 million by 2030. There are about 300,000 to 600,000 reported cases of venous thromboembolism.
The lack of an antidote, which can quickly reverse the effect of anticoagulants to prevent excessive bleeding has prevented broader adoption of NOACs, according to the statement.
Warfarin can typically be reversed with vitamin K. But only one of the newer blood thinners, dabigatran, has a specific antidote: a drug called idarucizumab, said Raval.
Antidotes speed the time it takes to stop bleeding, which is critical after traumatic injuries like those suffered in car accidents, according to the statement.
Drug manufacturers are close to getting a new antidote approved, Barnes said.
“The thing I always tell patients is that number one, even when we didn’t have a reversal agent, these drugs were all studied compared to warfarin and shown to be on average just as safe, and most importantly, they significantly reduced the risk of bleeding in the brain, the most feared complication,” he said.
NOACs are more than 50 percent less likely to cause brain bleeds in people taking them to prevent strokes caused by a blocked brain artery, according to the statement.
Antidote or not, the statement recommends hospitals continue traditional resuscitation methods and use compression and tourniquets to stop bleeding. They should give intravenous fluids, red blood cells and plasma infusions.
Another limitation to emergency departments are the lack of blood tests that can quickly measure how much of the new anticoagulant is in someone’s system. Unless a patient or caretaker can tell doctors which anticoagulant the person takes and when they last took it, hospitals can’t be sure how well the body could stop bleeding.
This makes it crucial for patients taking a NOAC to keep a list of medications with them all the time.
“I usually recommend to my patients that they have a medical alert bracelet or necklace that indicate that they are on one of these drugs,” Raval said.
Most of the time, the medical team has more time to plan how they’ll manage bleeding, because medical procedures are planned, Raval said.
Before an operation to remove a gall bladder, or a colonoscopy, for example, patients simply stop taking NOACs for a day or two to clear it from the body, Barnes said.
This is a distinct advantage over warfarin, which takes approximately five days to clear, according to the statement. Warfarin patients may also require injections of heparin, a fast-acting anticoagulant only available via injection or IV, to reduce the risk of clots while waiting for their procedure.
After patients are stabilized, doctors have to consider each patient’s risk of clotting and bleeding before putting them back on their NOAC, Raval said.
The fast ramp-up of the drugs provides an advantage over warfarin, which can take up to 10 days to become fully effective.
According to experts, patient fears about the bleeding risks of the new drugs may be overblown.
“In broad strokes, I think the press on NOACs has been a bit unfair,” Raval said. “Patients who take these drugs should take some comfort in knowing that these drugs are safe.”
“I often have patients come into my office and say, ‘I don’t want to take that drug because I hear all the bad things about it on the lawyer commercials, but I never hear bad things about warfarin so it must be safer,’” Barnes said. “And I’m often telling patients, ‘Just because you don’t hear about a drug on TV doesn’t mean that it’s safer or less safe than what’s out there right now.’”
“All of these drugs have been tested in tens of thousands of people,” he said. “The bleeding we can usually manage. A stroke or blood clot often can be deadly,” Barnes said.