Patient's question triggers important study about blood thinners

Physicians around the world now have guidance that can help them determine the best oral blood thinners to use for their patients suffering from blood clots in their veins, thanks to a patient of The Ottawa Hospital who asked his physician a question he couldn't answer. This new guidance is found in a study published today by JAMA, the Journal of the American Medical Association.

"Right there in the clinic, he identified an important knowledge gap for clinicians. We decided to act on it and find the answer," says hematologist Dr. Marc Carrier, who also a scientist at The Ottawa Hospital and associate professor at the University of Ottawa.

Dr. Carrier was treating Jamie Dossett-Mercer for major blood clotting in his leg veins, called deep vein thrombosis, that reached from his ankle to his groin. If one of these clots were to break off, it could travel to the lung and cause a pulmonary embolism, which is often fatal. These two common medical conditions are known together as venous thromboembolism and form the third leading cause of cardiovascular death.

In recent years, a number of new oral anticoagulants have been approved for use. Faced with eight possible therapies, Dossett-Mercer asked, "How do all these different blood thinners compare head to head?"

Dr. Carrier went looking for the answer. Although he found dozens of trials that studied the effect of different agents separately, none had analyzed all the results together.

His team reviewed 45 randomized trials (involving nearly 45,000 patients) using a process called network meta-analysis, which allows them to set a baseline treatment and compare all the other treatments to that. All the clinical trials they found compared the newer treatments to the standard of care, which is low-molecular-weight heparin (LMWH) with vitamin K antagonists.

Using the LMWH-vitamin K antagonist combination as the central node of the network, they compared safety and effectiveness with seven other anticoagulant therapies for venous thromboembolism: unfractionated heparin (UFH) with vitamin K antagonists; fondaparinux with vitamin K antagonists; LMWH with dabigatran; LMWH with edoxaban; rivaroxaban; apixaban; and LMWH alone.

While they found no major differences in effectiveness and safety, there were some notable variations.

• Patients taking the UFH-vitamin K antagonist combination had a higher percentage who experienced a recurrent blood clot within three months.
• Patients taking rivaroxaban and apixaban had a lower percentage who experienced a major bleeding event within three month.

"This will help physicians tailor their care according to patient characteristics," says Dr. Carrier. "For example, if I am worried about recurrent clotting, but I'm not too worried about the risk of bleeding, then I can select the drug with the best safety profile."

"I was already impressed with Dr. Carrier's exceptional care," says Dossett-Mercer. "But that he would do this research based on a patient question is just astounding."

Source: Ottawa Hospital Research Institute

Technique for cardiovascular diagnostics shows promise

Researcher Elira Maksuti is involved in developing and testing a promising method for diagnosing atherosclerosis, or hardening of the arteries. Credit: Staffan Larsson

A new technique developed at Sweden's KTH Royal Institute of Technology shows promise for early diagnosis and treatment of cardiovascular disease.

Hardening of the arteries, or atherosclerosis, is a common disorder that occurs when fat, cholesterol, and other substances build up in the walls of arteries and form hard structures called plaques. The condition can lead to heart attacks and strokes.

To diagnose atherosclerosis, doctors today rely on ultrasonic grayscale images to visually assess vascular function and how very large arteries move. The less mobility, the more developed the case of atherosclerosis.

But it is an indirect measurement. Better diagnoses can be made when the stiffness of the blood vessels can be analysed, explains Elira Maksuti, a researcher at the Department of Medical Imaging Technology at KTH.

"You need a doctor who is an expert and has extensive experience in order to get a good diagnosis," she says.

But by combining the technologies of shear wave elastography and ultrasound, Maksuti and researcher Erik Widmanh, have developed an inexpensive and non-invasive method not only for checking the stiffness of blood vessels, but for analysing the type of plaque present in the artery.

Maksuit says their method not only offers a potentially more effective way to diagnose atherosclerosis, but the ultrasound technology that it relies on is less expensive -- and safer -- than other imaging alternatives, such as magnetic resonance imaging (MRI) or computed tomography (CT).

The technique was tested on artificial blood vessels, or "phantom" vessels, which allowed the researchers to experiment with not only vascular stiffness, but also pressure and flow.

Maksuti says that with the success of tests on these phantoms, the next step is testing the technique with blood vessels from pigs. "These tests also look very promising," she says.

"We see two major future applications before us," she says. "The first is to determine when a patient's blood vessels are becoming rigid, that is, when the atherosclerosis process begins.

"The second application is to be able to diagnose the type of calcification -- or plaque -- present in the blood vessel." Not all plaque is the same: it ranges from hard to soft. If the plaque is soft and has a thin, hard shell, it is more likely to come loose inside the blood vessel.

It's a difficult distinction to determine. But the information is critical in deciding whether to open the artery surgically. "Today it is rather a matter of guessing. A doctor cannot know," she says. And to complicate matters, such operations can also generate strokes.

Source: KTH The Royal Institute of Technology

Wearable tech for battlefield, people at risk for heart attacks

The wearable system, under development by Sentient Science and the University at Buffalo, includes electrodes that relay data to a sensor, which connects with a remote computer network.
Credit: University at Buffalo

Wearable devices can count the steps you take and the calories you burn. But can they help soldiers in the field? Or prevent someone from having a heart attack?

Researchers at Sentient Science and the University at Buffalo say yes.

The sensor and software development company is working with UB engineering professor Albert H. Titus to create wearable technology that fuses real-time medical and physiological data with computer models. The system would then send personalized alerts indicating when the individual's level of stress, fatigue and resilience may put them in danger.

The work is funded by a $150,000 grant from the Office of Naval Research's Small Business Technology Transfer program, which enlists small businesses and research institutions to develop technology with military and commercial applications.

"Whether carrying 100 pounds of gear up a mountain or avoiding makeshift bombs, today's soldiers face incredible physical and mental stress," said Titus, PhD, professor and chair of UB's Department of Biomedical Engineering. "Our wearable system aims to measure how the body reacts to those challenges and combine that information with algorithms designed to help keep soldiers as safe as possible."

The wireless system, which is under development, will feature a series of electrodes that measure heart rate, brain activity and other vital signs. The electrodes may be attached to the skin like a Band-Aid or sewn into clothing that hugs the skin -- researchers are still deciding the best method.

The electrodes will relay information to a sensor (slightly smaller than a dime, attached to the skin like a patch), which will deliver that information to a remote computer network.

"It's like the hospital when you have a bunch of wires and equipment monitoring a patient. We're taking that technology and compressing it into a lightweight, wireless system," said the project's principal investigator Jennifer Haggerty, a research scientist and implementations manager at Sentient. Haggerty is an alumnus of UB.

As the information enters the computer network, it will fuse with Sentient's DigitalClone Live software, which has been validated by NASA and used to test the materials and components in the Hubble telescope, the F-35 fighter jet, wind turbines and other products.

The software includes complex algorithms that consider things like the terrain, weather and other environmental information, as well as the soldier's activity level. It will analyze the data and send personalized health alerts to soldiers and, if necessary, emergency medical facilities in the field. The idea is to improve soldiers' cognitive and physical abilities, making them more resilient and less prone to physical and psychological injuries.

In addition to serving the armed forces, the technology has commercial applications as a health-monitoring device. Sentient is exploring how the sensor can be applied to everyday items such as baseball caps. The individual wearing the cap would receive personalized health alerts regarding their risk of suffering a heart attack and other potential danger.

Source: University at Buffalo

The bloody truth: How blood donations can save animals' lives

Donated blood can be quickly regenerated by the animal’s organism. Credit: Felizitas Steindl / Vetmeduni Vienna

Blood transfusions are of importance not only in human medicine. Also animals do need blood donations. The University of Veterinary Medicine, Vienna operates a blood bank for dogs for more than a decade. But also cats can donate blood for acute emergencies. Horses need blood donations especially during operations that involve high blood loss. Sheep, goats and other ruminants require transfusions when plagued by serious infestations of parasites. Three vets from different areas of expertise explain how blood transfusions work with different animal species and how they can save lives.

Blood can hardly be created through artificial means, but it can be transferred within a species. Reasons for a blood transfusion among dogs and cats are usually serious accidents, large operations, certain types of cancer, cases of intoxication with rat poison, serious infectious diseases such as the tick-borne babesiosis, and blood illnesses including haemolytic or inherited bleeding disorders such as haemophilia.

At the University of Veterinary Medicine, Vienna dog owners can bring their animals to donate blood regularly or as needed. Blood donations two to four times a year per dog is the maximum. About 15 minutes are required for a donation. Dogs must have a minimum weight of 25 kilograms and usually donate about 450 millilitres of blood. For cats, depending on their size, the amount taken is about 50 millilitres. Cats are typically sedated for the procedure. For most dogs, on the other hand, donating blood does not involve any serious stress. Should a donation cause too much anxiety or stress, the animal will be excluded as a donor.

Not all blood is alike

As with people, animals also have different blood types. Animal blood, as well as human blood, is divided into various groups based on different surface proteins found on the red blood cells. More than twelve different blood type systems have been described for dogs, although in practice dogs are only tested for DEA 1.1 positive or DEA 1.1 negative. Cats exhibit three different types of blood, horses eight and bovines eleven. The transfusion of an unsuitable blood type can have fatal consequences for animals, especially when a cat with blood type B receives type A blood. For horses and ruminants, the first time transfusion of 'wrong' donor blood is generally safe. With each additional transfusion, however, blood types become crucial, as the animals have produced antibodies against the foreign blood that can cause serious immune reactions.

Blood donations come with a health check

Dogs and cats can be registered as blood donors at the Clinical Unit of Internal Medicine Small Animals of the Vetmeduni Vienna. The animals receive a donor card and undergo a thorough examination before each donation. This mandatory health check includes a complete blood count, a test for blood parasites, and a check-up for viral infections.

"Donating blood does not harm the animals. The donated amount can be quickly regenerated by the animal's organism," says specialist for small animal internal medicine and blood bank coordinator Nicole Luckschander-Zeller. "We pay special attention to making sure that donor animals feel good during donation. That's why, after every donation, we give the animals a little snack."

Dog and cat blood is not only used as a whole. Individual blood components, such as plasma or erythrocyte concentrates, are stored and used when needed.

Horses as blood donors and recipients

There are various reasons for blood donations in equine medicine. These include clotting disorders of the blood, anaemia, poisonings or serious infectious diseases as well as perioperative blood loss. For the latter, blood is stored and kept ready for use during surgery in areas with strong blood supply, such as the nose and jaw. A blood transfusion helps to sustain adequate circulation of the animal during the operation and speeds recovery.

"The owners of diseased horses occasionally bring the suitable donor animal with them," says René van den Hoven, director of the Clinical Unit for Equine Internal Medicine at the Vetmeduni Vienna. The hospital also maintains a number of its own donor horses. The number of donations and the volume of the blood collected are registered in the horse's file, making it possible to plan future dates for donations without compromising the animal's health.

A maximum of five to seven litres of blood can be collected from a horse per donation. The blood must then be transfused into a patient within just a few hours. Storing whole equine blood is not a suitable option. As only plasma is desired for some treatments, the plasma is separated from the whole blood. Plasma is used for specific applications, for example to improve the healing of complicated wounds or during eye operations. Patients with massive protein loss can also be successfully treated with plasma. Protein loss may occur as a consequence of serious burn trauma, severe diarrhoea, tumours or chronic inflammatory intestinal disease, pleurisy or peritonitis.

Ruminants with anaemia need donated blood

Sheep, goats, lamas and alpacas are especially at risk of being infested by blood-sucking parasites out on the pasture. Ingested through the mouth, the worms come to inhabit the intestinal tract. A high level of parasitic infestation leads to serious cases of anaemia that may be fatal for the animals. "These acute patients require a rapid blood transfusion. Ruminants also receive blood for wounds with heavy blood loss, though this luckily is not often the case," explains the specialist for ruminant medicine, Lorenz Khol

Source:University of Veterinary Medicine -- Vienna