For the past 60 years, those suffering from atrial fibrillation had only one choice of blood thinner -- one that was far from perfect -- to address a life-threatening situation. But now there are new products on the market. "They're enormous breakthroughs," says Hugh Calkins, a professor of Medicine at Johns Hopkins. Roughly 2.7 million Americans suffer from atrial fibrillation, a condition in which the heart beats irregularly. Untreated atrial fibrillation doubles the risk of heart-related deaths and increases the risk for stroke by fivefold, according to the American Heart Association. That's because with atrial fibrillation, the heart isn't pumping in a regular rhythm, so there's a higher risk of clots developing that could go from the heart to the brain, causing a stroke. To prevent this, the majority of atrial fibrillation patients are put on blood thinners to prevent the formation of life-threatening clots.
Blood Thinners Past: Process and Health Maintenance
Until recently, the only blood thinner on the market was warfarin, also known as Coumadin. But it's complex to administer and monitor, requiring regular blood tests to ensure that the blood is neither too thick nor too thin, at a level that protects you from having a stroke but also from the risk of bleeding. Initially, such tests are required every two to three days, then every week, then once a month. Also, the way Coumadin works is by blocking vitamin K. Eating large amounts of foods that contain vitamin K, like green, leafy vegetables, prevents Coumadin from working, so patients need to limit their intake of these foods or at least eat a similar amount on an almost daily basis. It also interacts adversely with antiobiotics, says Vincent Bufalino, senior vice president of Cardiovascular Services for Advocate Health Care in Chicago, Illinois. Bufalino says that the new products do not require regular blood tests and don't interact negatively with antibiotics or food, so they have become popular quickly.
How the New Blood Thinners Work
There are various clotting factors that interact in a series of steps, called a clotting cascade, to form a blood clot. Warfarin works by interfering with the liver's production of several of these clotting factors, explains Christian Ruff, a cardiologist at Boston's Brigham and Women's Hospital and an assistant professor of medicine at Harvard Medical School. He says that means it takes several days for warfarin to work; one has to wait for the factors already produced to be used up. The new blood thinners are active immediately, as they target and inhibit a single factor.
Blood Thinner Side Effects: Not a One-Size-Fits-All
The biggest danger of being on blood thinners is that since clotting doesn't happen, it's difficult to stop bleeding once it occurs. Ruff said these new drugs cut serious bleeding rates in half compared to Coumadin. He has prescribed the new medications widely and considers them "a very good alternative." Both the American College of Chest Physicians and the European Society of Cardiology state that the new products are preferable to Coumadin.
New Generation of Blood Thinners
The three drugs are more alike than different. Pradaxa has been on the market the longest, for three years, so physicians have the most clinical experience with it. But Calkins says this drug can cause some gastrointestinal symptoms, so those prone to nausea should stay away from it. Xarelto is the only one of the three that you can take once a day; the other two need to be taken twice a day, Calkins says, adding that he recommends these new drugs to almost every patient diagnosed with atrial fibrillation. He says that while blood can take two to three weeks to be thinned out with Coumadin, it only takes two hours with the new drugs.
However, the new drugs aren't perfect. There isn't yet a way to instantly reverse bleeding, should it occur. Those on Coumadin can be given fresh or frozen plasma or vitamin K to stop the bleeding if, for example, a patient cuts himself while shaving. No such remedy exists for the new drugs, however, though there are currently options under development. "The ability to reverse life-threatening bleeding has not been identified," says Bill Matthai, a clinical associate professor of medicine at the Perelman School of Medicine at the University of Pennsylvania. But Calkins says since the rate of bleeding is lower with the new drugs, large clinical trials showed there wasn't excess mortality. "It's almost never an issue," he says.
Cost currently is the major barrier. While Coumadin cost about $4 a month, in addition to the costs of blood tests, the newer medications cost between $200 and $300, says Elizabeth Renner, a clinical pharmacist specialist in the Frankel Cardiovascular Center at the University of Michigan Health System. Though prescription drug insurance plans often cover the medications, the patient's co-pay may still be high.
Another significant issue with the new products is that since regular blood tests aren't required, there's no way to ensure that the patients are, indeed, taking the blood thinners as they should to keep themselves safe. There is no routine blood test required to monitor the new agents, Ruff says. But compliance is important, he adds. So "extra emphasis must be placed on physicians, nurses, and pharmacists to remind patients of the importance of taking their blood thinners as prescribed, without missing doses." He says that even though these new agents do not require routine blood monitoring, it's important to contine to routinely monitor patients.
When Blood Thinners Aren't For You: 2 Helpful Devices
For people who can't tolerate blood thinners, like those who have recurrent gastrointestinal bleeding or are prone to falls, two new devices could offer an alternative. One, called the Lariat, closes off the pouch where clots tend to form, in the left atrial appendage, thus minimizing stroke risk. A catheter carrying the Lariat device is inserted under the patient's rib cage, while another catheter guides it into place. Henry Ford Hospital in Michigan was the first in that state approved for the procedure, and cardiologists there have been performing it for the past two years. Though the device has been approved for tissue closure, it hasn't specifically been authorized for closing off the left atrial appendage. The potential risk is bleeding that can be caused from sticking a needle in the area around the heart. Still, William O'Neill, medical director of the Center for Structural Heart Disease at Henry Ford, says it's worked well in the 40 procedures he has performed. "It's been very effective and very safe," he says, offering potential for the 10 to 15 percent of patients who are candidates for blood thinners but cannot take them. But Bill Matthai, clinical associate professor of Medicine at the Perelman School of Medicine at the University of Pennsylvania, says the jury is still out on whether those who have had the Lariat procedure can avoid taking blood thinners. That's the hope, but it hasn't yet been firmly established, he says.
Another device, the Watchman, is also a left atrial appendage closure system. Though not yet approved for use in the U.S., it's expected to gain Food and Drug Administration approval sometime within the next year. Brigham and Women's Hospital's Christian Ruff cautions that any surgical procedure comes with risks, and that "high-volume centers will be the best alternative" if patients decide to proceed with one of these surgeries.
Which Blood Thinner Is Right for You?
So who are the best candidates for these new drugs? The American Heart Association recommends that patients speak with their doctors about the appropriate choice and dose of a blood thinner, since there is no "one-size-fits-all" approach, said the Association's president, Elliott Antman.
Renner says that the new drugs haven't been tested in every type of patient, so many who have been using Coumadin choose to continue doing so, comforted that health care providers have a great deal of experience with it. Lynne Braun, a professor of Nursing at Rush University and board member of the Preventive Cardiovascular Nurses Association, says a 2012 survey she coauthored to determine whether patients would switch to a new product indicated that 42 percent of patients wanted to stay on Coumadin, and one of the reasons was that they appreciated having their blood regularly monitored. Patients who would be paying a large amount out of pocket for the new products also may decide to stick with this drug. And those with an artificial valve need to stay on Coumadin, since the new drugs haven't been tested in that setting. Calkins says that it could depend on "how much they like the Coumadin nurse." Some patients don't mind the companionship that routine blood tests entail, but if they don't relish regular contact with a nurse and they have first-rate prescription drug coverage, they might want to switch to one of the new drugs, he says. He adds that though Coumadin costs less, patients need to evaluate how much their time is worth with regular blood tests, weighing such factors as transportation time and parking.
Advice for Caregivers of Those on Blood Thinners
Braun says those caring for patients on any kind of blood thinner should try to prevent bleeding by safeguarding the household so the patient avoids falls. They should also observe their loved ones to catch any indications of bleeding. Don't forget to look in less obvious places, such as in the mouth; also look for blood in the stool, which could be a sign of gastrointestinal bleeding.