Bleeding and clotting disorders affect a large number of patients annually. Because these disorders have the potential to quickly become life-threatening, accurate diagnosis followed by timely and effective treatment is key.. Research examining novel treatment techniques for bleeding and clotting disorders will be presented today at the 53rd Annual Meeting of the American Society of Hematology held in San Diego, CA, December 10 – 13, 2011.
Bleeding disorders, such as hemophilia B, are a group of conditions that result when the blood cannot clot properly. In normal clotting, platelets, the cells that cause the blood to clot, stick together and form a plug at the site of an injured blood vessel, allowing the injured site to heal. Although the body naturally dissolves blood clots after an injury has completely healed, sometimes clots form on the inside of vessels without an obvious injury or do not dissolve naturally, leading to clotting disorders such asvenous thromboembolism (VTE).
New ways to diagnose and treat
?In the United States alone, over half a million people a year develop inappropriate blood clots called thrombosis, and at least 100,000 people die each year from a pulmonary embolism. Because these clots can be so deadly, and can occur unbeknownst to the patient, it is important that we find new ways to diagnose and treat them,? noted Charles Abrams MD, 2011 ASH Secretary, and Professor of Medicine at the University of Pennsylvania School of Medicine in Philadelphia. ?While bleeding disorders, such as hemophilia, are less common than clotting disorders, they can still be extremely dangerous. Results of ongoing clinical studies provide hope for potential new treatments and demonstrate the next generation of gene therapy to correct defective genes.?
Aspirin and VTE
One of these studies shows that administering aspirin after standard therapy for venous thromboembolism (VTE) may prevent the recurrence of potentially deadly blood clots.
Venous thromboembolism or VTE is a clotting disorder that includes both deep-vein thrombosis and pulmonary embolism, which can lead to chest pain, rapid pulse, shortness of breath, and, in extreme cases, sudden death. Patients who suffer from VTE are given oral anticoagulants, such as warfarin, to help prevent clot growth and dissolve existing clots or emboli (detached clots) in the veins. Other anti-thrombotic treatments include anti-platelet agents, such as aspirin, which block the formation of blood clots in the arteries by preventing platelets from clumping together and obstructing the blood flow to the heart or brain, which can cause a heart attack or stroke.
Effectively preventing recurrence
Recurrence of these deadly clots develops in 15 to 20% of patients who suffer from VTE two years after they finish conventional warfarin treatment. Although extending anticoagulant treatment has been found to be effective in preventing recurrence, it is also associated with an increased bleeding risk. The use of aspirin as an alternative therapy to oral anticoagulants has been controversial because the drug is used to stop blood clots in the arteries and not veins. In addition, results of previous studies that have assessed its ability to reduce recurrence rates for VTE have been contradictory.
Unprovoked VTE
To assess the efficacy and safety of aspirin for the prevention of VTE recurrence after a conventional course of oral anti-coagulation therapy, researchers from several Italian institutions embarked on the randomized, double-blind, placebo-controlled WARFASA study. The team sought to determine whether low-dose aspirin prevented recurrent symptomatic VTE when given for two years following an initial six to 12 months of warfarin therapy. Patients enrolled in the study with a first unprovoked VTE (clot that occurs in the absence of known risk factors, such as prolonged immobilization, surgery, or trauma), who had completed six to 12 months of oral anticoagulant treatment were randomized to receive a daily dose of aspirin (205 patients) or placebo (197 patients) for at least two years, with follow-up for up to 36 months. The primary efficacy outcome was objectively confirmed recurrent symptomatic VTE and VTE-related death. Clinically relevant (major and non-major) bleeding were the main safety outcomes.
Clinical relevance
VTE recurrence was observed in 28 of the 205 patients who received aspirin and 43 of the 197 patients who received placebo (6.6% vs. 11.2% per patient-year, respectively). While on study treatment, 23 patients who received aspirin and 39 patients who received placebo experienced VTE recurrence (5.9% vs. 11.0 % per patient-year, respectively). Major bleeding occurred in one patient in each treatment group, with a similar incidence of clinically relevant non-major bleeding.
Is aspirin beneficial in VTE?
?There has been significant debate on whether giving aspirin to a patient who suffers from VTE is beneficial,? said lead study author Cecilia Becattini, MD, Assistant Professor of Internal Medicine in the Internal and Cardiovascular Medicine and Stroke Unit at the University of Perugia in Italy. ?Our study shows that aspirin, a common and low-cost drug found in most medicine cabinets, can be a valid alternative to oral anticoagulants for the extended treatment of VTE.?
Dr. Becattini will present this study in an oral presentation on Monday, December 12, at 3:15 p.m. PST
Aspirin After Oral Anticoagulants for Prevention of Recurrence in Patients with Unprovoked Venous Thromboembolism. The WARFASA Study
Abstract: 543
Program: Oral and Poster Abstracts
Type: Oral
Session: 332. Antithrombotic Therapy: Venous Thromboembolism
When: Monday, December 12, 2011: 2:45 PM
Where: Marriott Hall 4 (San Diego Marriott Marquis & Marina)
