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The ABCs of Antiphospholipid Syndrome (APS)

Blood Clot

What is Antiphospholipid Syndrome?

Antiphospholipid syndrome (APS) is a rare condition that mainly increases the risk of blood clots and pregnancy-related complications. It occurs in less than one percent of the general population, and is more common in people with certain autoimmune disorders such as systemic lupus erythematosus (SLE).  About half of people with APS have what is known as primary APS. They are less likely to develop another autoimmune disease. When APS occurs in people with other systemic autoimmune diseases, such as lupus, the disease affects more women than men.

APS is marked by the presence of proteins called antiphospholipid antibodies (aPL) in the blood. These signal the immune system to try to attack healthy cells. As a result, patients with APS can experience blood clots throughout the body including heart attacks and strokes. A deep vein thrombosis (DVT) is the most common type of clot that forms in blood vessels. It usually appears in the legs or other extremities. Symptoms of a DVT include swelling, pain, and/or redness in the affected area. People are more likely to develop this type of clot if they are inactive or immobilized for prolonged periods of time, such as during bed rest or on a long airplane trip. A potential complication of a DVT is a pulmonary embolism. This occurs when a clot from a DVT in the leg breaks off and travels to the lung.

Blood clots can also form in another part of the body and then travel to an area of the brain, where they can get lodged and starve brain cells of blood, causing a stroke. A small percentage of people with APS experience widespread, catastrophic clotting with a high risk for fatality. Women with APS also face associated risks during pregnancy, including premature delivery and miscarriages.

Diagnosis and Treatment of APS

APS is diagnosed using blood tests that measure the presence of three antibodies: anticardiolipin antibodies, anti-beta-2 glycoprotein I (a?2GPI) antibodies and lupus anticoagulant. Because many people without APS may have evidence of these antibodies on a single blood test (often a result of an infection), a doctor will order multiple tests to confirm the diagnosis.

People with aPL but no history of blood clots or other symptoms of APS usually do not require medication, or perhaps may be given low-dose aspirin if they have additional cardiovascular disease risk factors. For those who do experience clots, treatment can involve the use of blood-thinning drug warfarin.

When APS is managed properly, the majority of people with the illness can live normal, full lives.

Different aspects of APS are discussed in my “Top 10 Questions and Answers” patient article series available within the publications section of my physician page, including:

  1. APS, aPL, ab: All the abbreviations can get confusing quickly, and keeping track of the APS terminology is a challenge. Learn more terms you need to know when you speak with your doctor about APS.
  2. Smoking increases the risk of blood clots in people with APS. Avoid smoking and participate in counseling programs to help you quit if you currently smoke. Learn more about blood clot prevention assessment to reduce your risk.
  3. The current management approach allows the majority of women with APS to have normal pregnancies and deliver healthy babies. Learn more about APS and pregnancy.
  4. Researchers are looking at promising new approaches involving the use of immunotherapy drugs to treat APS at its source. Learn more about potential new treatments.
  5. APS ACTION (Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking) is an international research network focused on conducting clinical research studies with a commitment to preventing, treating and curing aPL-associated symptoms. Learn more about the registry and how you can participate.

Dr. Doruk Erkan is a rheumatologist at the Barbara Volcker Center for Women and Rheumatic Diseases at HSS, and Associate Professor of Medicine at Weill Cornell Medicine, with a long-standing interest in Antiphospholipid Syndrome (APS). In addition to his clinical practice, his research interests include identification of factors that increase the risk of blood clots, potential prevention strategies, and new APS treatments. He has been the principal investigator in multiple clinical trials ranging from mechanistic studies to drug trials for difficult-to-treat APS patients. Dr. Erkan has been a member of multiple APS-related national/international committees as well as an invited speaker at numerous conferences. He is the Executive Committee C-chair of the international APS research network, APS ACTION (Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking); and was the organization committee chair of the chaired 15th International Congress on Antiphospholipid Antibodies, which took place in September 2016.

For more information about the HSS Lupus & APS Center of Excellence, visit https://www.hss.edu/lupus-aps-center-of-excellence.asp.



The information provided in this blog by HSS and our affiliated physicians is for general informational and educational purposes, and should not be considered medical advice for any individual problem you may have. This information is not a substitute for the professional judgment of a qualified health care provider who is familiar with the unique facts about your condition and medical history. You should always consult your health care provider prior to starting any new treatment, or terminating or changing any ongoing treatment. Every post on this blog is the opinion of the author and may not reflect the official position of HSS. Please contact us if we can be helpful in answering any questions or to arrange for a visit or consult.