Assay Identifies Tendency for Blood Clots

A new assay detects multifactorial thrombophilia (increased tendency for blood clots) and will help determine the overall risk of recurrent venous thromboembolism (VTE). The assay can be used to monitor hemophiliacs during inhibitor bypass therapy, anticoagulation therapy, and thrombophilia, and to analyze and monitor the hemostatic system.

Technothrombin TGA, which was developed by Technoclone (Vienna, Austria), measures the generation of an enzyme called thrombin that is involved in blood clotting. A study published in the July 26, 2006, issue of the Journal of the American Medical Association (JAMA) demonstrated that Technothrombin TGA determines whether patients who have experienced a venous blood clot are at risk of developing another blood clot.

The prospective cohort study of 914 patients with first spontaneous VTE were followed up for an average of 47 months after discontinuation of vitamin K antagonist therapy. The study was conducted at the department of internal medicine I, Medical University of Vienna (Austria), between July 1992 and July 2005.

"We found that patients with a first spontaneous VTE and peak thrombin generation of less than 400 nM after discontinuation of vitamin K antagonists have a low risk of recurrence. According to Kaplan-Meier analysis, the likelihood of recurrent VTE in these patients was as low as 7% after four years. Compared with patients who had higher levels, those with peak thrombin generation of less than 400 nM had an almost 60% lower risk of recurrence. Most importantly, the group of patients with low peak thrombin generation represented two-thirds of the total patient population,” the authors wrote.

According to the article, anticoagulant treatment for patients with venous thromboembolism, often involving the deep veins of the legs or the lung, currently consists of heparin followed by vitamin K antagonists for at least three to six months. After discontinuation of anticoagulant treatment, a third of the patients experience recurrence of VTE within the next five to eight years. The case-fatality rate of recurrence is around 5%.

The authors concluded that measurement of thrombin generation identifies patients at low risk for recurrent VTE.



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Technoclone
Medical University of Vienna