American Society of Hematology

ASH Observes Deep-Vein Thrombosis Awareness Month

Published on: March 21, 2014

(WASHINGTON)–The American Society of Hematology (ASH), the world’s largest professional society concerned with the causes and treatment of blood disorders, aims to raise awareness of potentially deadly blood clots during March – Deep-Vein Thrombosis (DVT) Awareness Month. ASH’s mission is to further the understanding, diagnosis, treatment, and prevention of blood disorders, and this includes ongoing efforts to support research, clinical, and policy programs that seek to improve quality of life for patients suffering from blood clots.

Often called a “silent killer,” DVT is a type of blood clot that forms in a major vein of the leg or, less commonly, in the arms, pelvis, or other large veins in the body. Between 300,000 and 600,000 Americans are affected by these clots annually, which can quickly turn deadly when they detach and travel to the lungs, blocking blood flow in what is called a pulmonary embolism (PE). According to the Centers for Disease Control and Prevention, PE and other DVT-related complications take the lives of approximately 60,000–100,000 Americans each year, and approximately 5 to 8 percent of the U.S. population has one of several genetic risk factors for developing these inappropriate blood clots. ¹

“DVT is ‘silent’ in two ways. First, the public is largely unaware of this condition, despite the fact that it is the third most commonly diagnosed vascular condition following only heart attack and stroke. Second, a clot may have no obvious symptoms, even if it breaks off and travels to the lungs,” said ASH Vice President and blood clot expert Charles Abrams, MD, of the University of Pennsylvania.

While DVT is common, it may be prevented by knowing about and managing the following risk factors:

• Age (risk rises as age increases)
• Obesity
• A family history of DVT or PE or an inherited (family) condition that increases the risk of blood clotting
• Surgery, especially for joint replacement or cancer
• Cancer and some of its treatments (chemotherapy)
• Hospitalization for certain medical conditions
• Slowed blood flow in a deep vein, due to injury, surgery, or immobilization
• Taking birth control pills or hormone therapy, including for postmenopausal symptoms
• Pregnancy as well as during several weeks after delivery
• Placement of a central venous catheter or pacemaker

Individuals who experience any one of the following symptoms of DVT or PE should notify a doctor immediately or go to the emergency room:

• Unexplained swelling of the leg or arm
• Pain, tenderness, or “heaviness” in the leg that may only be present when standing or walking
• Feeling of increased warmth in the area of the leg or arm that is swollen or that hurts
• Redness or discoloration of the skin
• Sudden shortness of breath
• Pain in the chest (especially when taking a deep breath)
• Unexplained cough

“Because of the potential for DVT to turn into a life-threatening event, it is critical for Americans to know if they are at risk of a blood clot and how to recognize the symptoms,” said ASH blood clot expert spokesperson Mary Cushman, MD, of the University of Vermont.

Visit the patient resources section of the ASH website to access general information about blood clots and blood clot risk factors, more information about preventive measures and treatments, and a list of organizations that support patients with clotting disorders.

¹ Deep Vein Thrombosis: Data and Statistics Accessed March 6, 2014

For more information please contact Kaitlin Bressler at or 202-552-4925.

The American Society of Hematology ( is the world’s largest professional society concerned with the causes and treatment of blood disorders. For more than 50 years, the Society has led the development of hematology as a discipline by promoting research, patient care, education, training, and advocacy in hematology. The official journal of ASH is Blood (, the most cited peer-reviewed publication in the field, which is available weekly in print and online.

back to top