New test to identify patients at low blood clot risk
determine which patients with venous thromboembolism (VTE) are at
low risk for recurrence and can therefore avoid unnecessary and
potentially dangerous long-term anticoagulant treatment.
The test, called TechnothrombinTGA, is manufactured by Technoclone and is currently used to measure the generation of an enzyme called thrombin, which is involved in blood clotting.
Researchers at the Medical University of Vienna in Austria have discovered that patients without recurrent VTE have lower thrombin generation than patients with recurrence.
Therefore they concluded that the TechnothrombinTGA test could indirectly detect thrombophilia - an increased tendency for blood clots - and therefore could help establish the overall risk of recurrent VTE in a patient, and determine if an indefinite anticoagulant therapy is appropriate or not.
"Over the years, extensive routine thrombophilia screening has become common practice but it is expensive and may be inconclusive," said the researchers.
"Using this inexpensive and simple commercially available laboratory method developed to measure thrombin generation, we are now able to identify patients in whom the long-term risk of recurrent VTE is almost negligible."
Anticoagulant treatments for patients with VTE currently involve heparin, followed by vitamin K antagonists for at least three to six months. Indefinite treatment may be indicated in patients who have a second-episode of VTE.
However, because prolonged anticoagulant drugs affect the blood's ability to clot, anticoagulant therapy can potentially be fatal as it can increase the risk of severe bleeding. Therefore the treatment challenge is to balance the recurrent thromboembolism risk with the risk of fatal haemorrhage related to anticoagulant therapy.
"Considering the incidence rates of severe or fatal haemorrhage related to anticoagulant therapy and the case-fatality rate of recurrent VTE, patients with low peak thrombin generation would almost certainly not benefit from indefinite anticoagulant therapy," said the researchers.
"The identification of patients who might benefit from indefinite anticoagulant treatment is now one of the main goals in thrombosis research."
The research was published on 26 July in the Journal of the American Medical Association (JAMA).
