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

Antioxidant capacity of orange juice is multiplied tenfold

Orange juice has greater antioxidant activity than was previously thought. Credit: SINC

The antioxidant activity of citrus juices and other foods is undervalued. A new technique developed by researchers from the University of Granada for measuring this property generates values that are ten times higher than those indicated by current analysis methods. The results suggest that tables on the antioxidant capacities of food products that dieticians and health authorities use must be revised.

Orange juice and juices from other citrus fruits are considered healthy due to their high content of antioxidants, which help to reduce harmful free radicals in our body, but a new investigation shows that their benefits are greater than previously thought.

In order to study these compounds in the laboratory, techniques that simulate the digestion of food in the digestive tract are used, which analyse only the antioxidant capacities of those substances that can potentially be absorbed in the small intestine: the liquid fraction of what we eat.

"The problem is that the antioxidant activity of the solid fraction (the fibre) isn't measured, as it's assumed that it isn't beneficial. However, this insoluble fraction arrives at the large intestine and the intestinal microbiota can also ferment it and extract even more antioxidant substances, which we can assess with our new methodology," José Ángel Rufián Henares, professor at the University of Granada, explains.

His team has developed a technique called 'global antioxidant response' (GAR), which includes an in vitro simulation of the gastrointestinal digestion that occurs in our body, whilst taking into account the 'forgotten' antioxidant capacity of the solid fraction.

The method, the details of which are published in the journal 'Food Chemistry', includes assessments of various physical and chemical parameters, such as colour, fluorescence and the relationship between the concentrations analysed and compounds indicators such as furfural.

Upon applying the technique to commercial and natural orange, mandarin, lemon and grapefruit juices, it has been proved that their values greatly increase. For example, in the case of orange juice, the value ranges from 2.3 mmol Trolox/L (units for the antioxidant capacity) registered with a traditional technique to 23 mmol Trolox/L with the new GAR method.

"The antioxidant activity is, on average, ten times higher than that which everyone thought up until now, and not just in juices, but also in any other kind of food analysed with this methodology," highlights Rufián Henares, who notes its possible application: "This technique and the results derived from it could allow dieticians and health authorities to better establish the values of the antioxidant capacity of foods."

With the help of this method, scientists have also created a mathematical model in order to classify juices according to their natural and storage conditions, which ensures that the correct raw materials and sterilisation and pasteurisation processes are used.

Source: Plataforma SINC