8 Potential Health Benefits of Aloe Vera
Taking Blood Thinners After A Stroke Does Not Improve Outcomes, Study Says
Researchers report that about 15 million people around the world have a stroke in the course of a year. About 62% of those people will have an ischemic stroke where blood flow to the brain is stopped due to arterial blockages.
A stroke is an emergency — if you or someone is experiencing stroke symptoms, call 911.
The main treatment for an ischemic stroke is a clot-busting medication that breaks up the arterial clots to allow regular blood flow to the brain. This medication must be delivered within 3 hours of the stroke occurring.
After a stroke, a doctor may prescribe blood-thinning medications to help prevent clots from forming again.
Now, scientists from the Washington University School of Medicine in St. Louis, MO, reported on new research at the American Stroke Association's International Stroke Conference 2024.
Their findings indicate that giving blood thinners in addition to clot-busting medications when a person has an ischemic stroke did not improve the person's 90-day outcome.
Researchers also found that the combination of blood thinners and clot-busting medication did not increase a person's risk of bleeding in the brain.
During either a stroke or a heart attack — when an arterial blockage stops blood from flowing to the heart — doctors may administer clot-busting medications called thrombolytics.
People who have either a stroke or heart attack may also be prescribed a blood thinner to help keep clots from forming and lower their risk of having another one.
According to Dr. Opeolu M. Adeoye, BJC HealthCare Distinguished Professor of Emergency Medicine and chair of the Department of Emergency Medicine at the Washington University School of Medicine in St. Louis, MO, and lead author of the current study, the research team decided to assess what type of effect adding blood thinners to clot-busting medications would have on people with ischemic stroke.
That was because, while treatment with clot-busting medications works for ischemic stroke, about half of treated patients experience disability 3 months after stroke even with this treatment.
"In the setting of heart attacks, adding these blood thinners to clot-busting medications improved rates of opening blood vessels and improved outcomes," Dr. Adeoye explained to Medical News Today. "We wanted to see if using this approach would also improve outcomes in stroke."
For this study, Dr. Adeoye and his team analyzed results from the Multi-Arm Optimization of Stroke Thrombolysis (MOST) trial, encompassing study participants from 57 medical centers in the United States.
Study participants in the MOST trial had ischemic stroke severe enough that rehabilitation would likely be necessary.
All participants received a standard clot-busting medication within three hours of the stroke beginning. Participants then received either one of two blood thinners — argatroban or eptifibatide — within 75 minutes of administration of the clot-busting medication plus a 2-hour infusion of the blood thinner, or a placebo.
Upon analysis, researchers found the addition of blood thinners to the clot-busting medication did not improve a participant's level of physical function at 90 days after an ischemic stroke.
For this reason, the MOST trial was stopped in July 2023 after the results of the first 500 study participants out of a planned 1,200 participants and determined it highly unlikely that a benefit would be found if the research was completed.
Dr. Adeoye said they were surprised by the negative results.
"Reopening clotted blood vessels is the goal with stroke treatment," he explained. "We had shown in earlier studies that the medications may improve outcomes, so we were surprised when we found no benefit from the treatments."
"We believe the key difference between MOST and our prior studies is that the prior studies were done in an era before thrombectomy (physically removing clots through a procedure). As such, any potential benefits of the medications were somewhat blunted by the fact that 44% of MOST patients underwent thrombectomy," he added.
Despite the negative outcome, Dr. Adeoye said there are positive takeaways for scientists when it comes to future research in ischemic stroke treatment.
The study also showed that the two blood thinners used did not significantly increase the risk of bleeding into the brain.
"We have definitely shown that these two medications do not work for improving outcomes and that adding blood thinners to clot-busting medication [does] not increase rates of bleeding into the brain. As we go forward, these findings will inform future research in the area."
– Dr. Opeolu M. Adeoye
"Bleeding into the brain is the most important safety concern in treating stroke patients with clot-busting medication and/or blood thinners," Dr. Adeoye added. "We found that adding additional blood thinners did not improve rates of bleeding into the brain. This means that this approach is safe and worthy of further investigation."
After reviewing this study, Dr. José Morales, vascular neurologist and neurointerventional surgeon at Pacific Neuroscience Institute in Santa Monica, CA, told MNT he found the findings very interesting.
"We typically do not give any sort of blood thinners for the first 24 hours after receiving a thrombolytic agent because of the presumed risk of intracranial hemorrhage [bleeding in the brain]," Dr. Morales explained. "But it's been an open question that hadn't been tested in randomized clinical controlled trials whether or not there was some safety there."
"I think [the findings] put it all in perspective for us that although the thrombolytic medications have a short half-life, trying to enhance antiplatelet regimens against the potential risk of residual thrombosis or atherothrombosis is not particularly effective," he added. "Things to look for in the future will be to look to see if other agents might be used adjunctively and safely."
MNT also spoke with Dr. Cheng-Han Chen, a board-certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, about this study.
Dr. Chen said the parallels between stroke — also called "brain attack" — and heart attack are driving research to see if treatments typically used for heart attacks would also be beneficial treatment for stroke.
"They didn't find a benefit to these medications, which was unfortunate, but at least they didn't find any evidence of harm, either," he continued. "So it remains to be seen whether there are also very specific types of stroke treatments that would involve these medications. I think it would be helpful to study other avenues of drug delivery [… ] [and] it would be great to see other research with other types of blood thinners."
New Model Identifies Drugs That Shouldn't Be Taken Together
Any drug that is taken orally must pass through the lining of the digestive tract. Transporter proteins found on cells that line the GI tract help with this process, but for many drugs, it's unknown which of those transporters they use to exit the digestive tract.
Identifying the transporters used by specific drugs could help to improve patient treatment because if two drugs rely on the same transporter, they can interfere with each other and should not be prescribed together.
Researchers at MIT, Brigham and Women's Hospital, and Duke University have now developed a multipronged strategy to identify the transporters used by different drugs. Their approach, which makes use of both tissue models and machine-learning algorithms, has already revealed that a commonly prescribed antibiotic and a blood thinner can interfere with each other.
"One of the challenges in modeling absorption is that drugs are subject to different transporters. This study is all about how we can model those interactions, which could help us make drugs safer and more efficacious, and predict potential toxicities that may have been difficult to predict until now," says Giovanni Traverso, an associate professor of mechanical engineering at MIT, a gastroenterologist at Brigham and Women's Hospital, and the senior author of the study.
Learning more about which transporters help drugs pass through the digestive tract could also help drug developers improve the absorbability of new drugs by adding excipients that enhance their interactions with transporters.
Former MIT postdocs Yunhua Shi and Daniel Reker are the lead authors of the study, which appears today in Nature Biomedical Engineering.
Drug transport
Previous studies have identified several transporters in the GI tract that help drugs pass through the intestinal lining. Three of the most commonly used, which were the focus of the new study, are BCRP, MRP2, and PgP.
For this study, Traverso and his colleagues adapted a tissue model they had developed in 2020 to measure a given drug's absorbability. This experimental setup, based on pig intestinal tissue grown in the laboratory, can be used to systematically expose tissue to different drug formulations and measure how well they are absorbed.
To study the role of individual transporters within the tissue, the researchers used short strands of RNA called siRNA to knock down the expression of each transporter. In each section of tissue, they knocked down different combinations of transporters, which enabled them to study how each transporter interacts with many different drugs.
"There are a few roads that drugs can take through tissue, but you don't know which road. We can close the roads separately to figure out, if we close this road, does the drug still go through? If the answer is yes, then it's not using that road," Traverso says.
The researchers tested 23 commonly used drugs using this system, allowing them to identify transporters used by each of those drugs. Then, they trained a machine-learning model on that data, as well as data from several drug databases. The model learned to make predictions of which drugs would interact with which transporters, based on similarities between the chemical structures of the drugs.
Using this model, the researchers analyzed a new set of 28 currently used drugs, as well as 1,595 experimental drugs. This screen yielded nearly 2 million predictions of potential drug interactions. Among them was the prediction that doxycycline, an antibiotic, could interact with warfarin, a commonly prescribed blood-thinner. Doxycycline was also predicted to interact with digoxin, which is used to treat heart failure, levetiracetam, an antiseizure medication, and tacrolimus, an immunosuppressant.
Identifying interactions
To test those predictions, the researchers looked at data from about 50 patients who had been taking one of those three drugs when they were prescribed doxycycline. This data, which came from a patient database at Massachusetts General Hospital and Brigham and Women's Hospital, showed that when doxycycline was given to patients already taking warfarin, the level of warfarin in the patients' bloodstream went up, then went back down again after they stopped taking doxycycline.
That data also confirmed the model's predictions that the absorption of doxycycline is affected by digoxin, levetiracetam, and tacrolimus. Only one of those drugs, tacrolimus, had been previously suspected to interact with doxycycline.
"These are drugs that are commonly used, and we are the first to predict this interaction using this accelerated in silico and in vitro model," Traverso says. "This kind of approach gives you the ability to understand the potential safety implications of giving these drugs together."
In addition to identifying potential interactions between drugs that are already in use, this approach could also be applied to drugs now in development. Using this technology, drug developers could tune the formulation of new drug molecules to prevent interactions with other drugs or improve their absorbability. Vivtex, a biotech company co-founded in 2018 by former MIT postdoc Thomas von Erlach, MIT Institute Professor Robert Langer, and Traverso to develop new oral drug delivery systems, is now pursuing that kind of drug-tuning.
The research was funded in part by the National Institutes of Health, the Department of Mechanical Engineering at MIT, and the Division of Gastroenterology at Brigham and Women's Hospital.
Can You Eat Kale If You Take Blood Thinners Or Aspirin? Here's What Health Experts Say
The key is consistency.
Reviewed by Dietitian Maria Laura Haddad-Garcia
Packed with nutrition and versatility, kale, a non-starchy cruciferous vegetable, is often referred to as a superfood. That said, superfood is a marketing term (not scientific), and not one food provides all the nutrients we need. Key nutrients found in this veggie include vitamin C, plant-based calcium, glucosinolates and antioxidants like beta-carotene, lutein and zeaxanthin.
Kale also contains ample amounts of vitamin K, a fat-soluble vitamin that assists in blood clotting and bone health. Because of its vitamin K content, people who take certain blood-thinning medications may wonder if they should avoid eating kale and other foods high in vitamin K due to drug-nutrient interactions.
Read on to learn more about the connection between kale and blood thinners, plus ways to safely eat kale if you're on these medications.
Related: 4 Supplements You Shouldn't Be Taking If You Have High Blood Pressure, According to a Dietitian
What Are Blood Thinners?The technical terminology for blood thinners is anticoagulants. Anticoagulants are often prescribed to people who have heart or blood vessel diseases, atrial fibrillation, are at risk of clots after surgery, have had a heart valve replacement, heart attack or congenital heart defects. The American Heart Association lists common brands as:
Apixaban (Eliquis)
Dabigatran (Pradaxa)
Edoxaban (Savaysa)
Heparin (various)
Rivaroxaban (Xarelto)
Warfarin (Coumadin)
Marlyene Perez, M.S., RDN, a registered dietitian nutritionist from Top Nutrition Coaching, says, "Blood thinners, also known as anticoagulants, are medications that prevent the formation of blood clots. They do not "thin" the blood; instead, they interfere with the blood clotting process to reduce the risk of clot formation." They increase the amount of time it takes for your blood to clot.
But "Not all blood thinners interact with vitamin K. If you are prescribed a blood thinner, you should contact your physician about the effects of your specific medications," notes Maria Fraga, RD, CDCES, CDN, a registered dietitian and director of the Diabetes Alliance at the Mount Sinai Health System.
For example, Peggy Kraus, M.A., RCEP, CDCES, a registered clinical exercise physiologist and certified diabetes care and education specialist with Peggy Kraus Coaching, says, "There are no food-drug interactions with the newer antiplatelet medications such as Rivaroxaban (Xarelto), Dabigatran (Pradaxa) and Apixaban (Eliquis)."
Aspirin, a pretty common medication, is an antiplatelet, which prevents platelets from clumping together to form a clot and is often prescribed to people who have had a heart attack or stroke.
How Vitamin K Helps with Blood ClottingVitamin K is one of the four fat-soluble vitamins and plays a role in blood clotting and bone health. Perez says, "Vitamin K helps synthesize various proteins, 'clotting factors,' such as prothrombin. Without sufficient vitamin K, these factors are not activated, and the clotting process is impaired." For example, when you get a cut, vitamin K synthesizes the proteins that help the blood to clot so you stop bleeding.
Does Kale Interact with Blood Thinners?As mentioned above, kale contains ample amounts of vitamin K. One cup of raw kale contains 80 micrograms (mcg) of vitamin K, or about 66 to 89% of the recommended daily intake. And research shows that cooking kale can increase the vitamin K content because heat causes vitamin K to be released. Because of this, people on these medications may think they should avoid kale and other foods high in vitamin K. However, the issue is when they eat them inconsistently or in large quantities.
A sudden change in the amount of vitamin K you consume can cause dangerous bleeding (if you consume less) or blood clots (if you consume more). "It's not about avoiding vitamin K, rather the importance of keeping vitamin K intake consistent on a daily basis," notes Fraga.
Perez says that if kale is eaten in inconsistent amounts, "The vitamin K can interfere with the balance of clotting factors and influence the effectiveness of the warfarin." It counteracts the effects of the blood thinner.
Tips for Consuming Kale SafelyThe best way to make sure your medications are working as they should is to consume consistent amounts of foods, kale and other green leafy vegetables which are rich in vitamin K. "Maintain consistent, portion-controlled vitamin K intake to avoid instability of the anticoagulant effects of the medications and regularly monitor blood clotting parameters like the International Normalized Ratio (INR) to assess your diet and medications effectiveness," says Perez.
If you need more clarification about portion sizes and blood clotting monitoring, contact your health care team for guidance. The key is to be consistent. For example, "If you have a serving of kale or broccoli one day, you should plan to have a serving the next day. The idea is to keep your vitamin K intake consistent," Fraga recommends.
Related: Healthy Kale Recipes
Other Foods to ConsiderWhile you don't have to avoid foods that contain vitamin K altogether, eating a variety of nutrient-dense vegetables is important for overall health.
"If you are concerned about the vitamin K content of kale or other cruciferous veggies, consider alternative veggies that have lower vitamin K content like cucumbers, tomatoes and bell peppers," says Perez. Kraus adds, "Sweet potatoes, winter and summer squash, eggplant, corn, mushrooms and turnips are also low in vitamin K."
Other foods and beverages that might impact the effectiveness of your blood thinners or aspirin include alcohol, herbs and other green leafy vegetables. For people who take warfarin, occasional drinking can lead to internal bleeding, and heavier drinking may cause bleeding of the opposite, resulting in possible blood clots, strokes and heart attacks.
Frequently Asked Questions What foods cannot be eaten with blood thinners?If you're on blood thinners, you don't need to avoid specific foods but moderate those high in vitamin K to prevent drug-nutrient interactions. Caution is warranted if you consume alcohol, as alcohol can increase the effects of blood thinners.
Do green vegetables thicken or thin the blood?Green vegetables contain vitamin K, an essential nutrient involved in blood clotting.
Can you eat peanut butter on blood thinners?Peanut butter does not contain large amounts of vitamin K, but it contains vitamin E. Taking vitamin E (as in supplements) with a blood-thinning medication can increase anti-clotting activity and increase your risk of bleeding. But eating peanut butter should not yield the same results. A two-tablespoon serving of peanut butter provides about 20% of the daily value of vitamin E.
The Bottom LineBefore modifying your dietary intake of kale, ask your health care provider if it interferes with your blood-thinning medication. Most likely, you don't have to avoid it or other green vegetables (spinach, cabbage, Brussels sprouts, collard greens), but aim for a consistent daily intake instead. Working with a registered dietitian or another health care professional is best for individualized recommendations.
Read the original article on Eating Well.
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