Researchers at the Medical University of Vienna have developed a new test that may help
predict the recurrence of blood clots in the veins, known as venous thromboembolism
VTE has two forms: deep-vein thrombosis (DVT) and pulmonary thromboembolism
(PE). DVT occurs when a clot forms deep in veins, usually in the lower extremities (legs,
thighs or hip area), and is often associated with pain and swelling. When one of these
clots partially or completely breaks free, it can travel through the bloodstream and lodge
in the lungs, causing an embolism. PE is a serious complication that can result in
permanent damage to the lungs and, in some cases, death.
Dr. Gregor Hron and his colleagues have determined that in the future by measuring the
blood protein thrombin, healthcare providers can predict the likelihood of a patient
experiencing a second VTE. Patients could then be further classified as either at high or
low risk for a recurrence. The ability to better assess the probability of future blood clots
would allow doctors to make more informed treatment decisions, especially whether or
not to prescribe anticoagulant heparin therapy.
The study, "Identification of Patients at Low Risk for Recurrent Venous
Thromboembolism by Measuring Thrombin Generation," was published in the July 26,
2006 issue of the Journal of the American Medical Association. A total of 914 patients
who had previously experienced a VTE were monitored for an average of 47 months after
completing their initial treatment. During that time, 100 patients in the study experienced
a second clot.
Investigators found that two-thirds of the patients showed lower levels of thrombin
production, corresponding with a 60% reduced risk of recurrent clots. The other one-third
produced significantly greater amounts of thrombin.
"Using a simple, commercially available laboratory method developed to measure
thrombin generation, we were able to identify patients in whom the long-term risk of
recurrent venous thromboembolism is almost negligible," reported study authors.
Anticipating recurrent VTE takes on even more significance when taking into account the
side effects of anticoagulant therapy. By helping doctors make more informed treatment
decisions, these tests could potentially spare low thrombin-producing patients from
having to endure unnecessary treatment side effects.
"Considering the incidence rates of severe or fatal hemorrhage related to anticoagulant
therapy and the case fatality rate of recurrent venous thromboembolism, patients with low
peak thrombin generation would almost certainly not benefit from indefinite
anticoagulant therapy. Consequently, extensive thrombophilia screening appears to be
unnecessary in this large, low-risk patient group," added study authors.
Source: HealthDay News, July 25, 2006