Beth Waldron and Stephan Moll, MD write….
While much is known about blood clots and clotting disorders, there is still much being learnt. Medical information changes over time as new clinical trials, research studies and evidence-based guidelines contribute to knowledge of and treatments for blood clots and clotting disorders. Many of today’s standards of treatment are based upon what was learned from publications in the past.
Over the past year, a number of publications emerged which will influence future clinical decisions and potentially impact your care. Here is a summary of the ‘top clinically relevant publications from 2012’ and how they may affect you.
1. ACCP Guidelines 2012
Healthcare professionals use clinical guidelines developed by the American College of Chest Physicians (ACCP) to determine the most up-to-date recommendations and clinical evidence related to the prevention, diagnosis and treatment of blood clots. These guidelines, which are over 800 pages in length, address a wide variety of thrombosis-related topics, such as:
- Determining a patient’s risk for developing DVT or PE
- How to prevent DVT and PE
- How to treat DVT and PE and minimize its complications and recurrence.
The ACCP guidelines were updated in 2012 to reflect the most current scientific evidence and standard-of-care consensus available.
- The ACCP guidelines are lengthy and written for clinicians in mind. However, the ACCP has created several patient education guides which summarize key topics in the guidelines. These patient summaries are available here.
If you wish to see the ACCP guidelines:
- A ‘quick reference’ summary used by clinicians can be found here.
- The full 800 pages of recommendations can be found here.
2. Xarelto (rivaroxaban) in the treatment of pulmonary embolism
A large clinical trial comparing the blood thinner Xarelto (rivaroxaban) with warfarin in the treatment of patients with newly diagnosed pulmonary embolism (PE) was published in the New England Journal of Medicine in March, 2012. The study, called EINSTEIN-PE, showed that Xarelto was (a) as effective as warfarin in preventing new clots, (b) caused the same amount of overall clinically relevant bleeding, and (c) caused less major bleeding.
This study, in conjunction with a previous study examining DVT, led to the FDA’s approval of Xarelto on November 2, 2012 for the treatment of DVT and PE and the prevention of its recurrence.
The published study is: The Einstein Investigators. Oral rivaroxaban for the treatment of symptomatic pulmonary embolism. NEJM 2012;366:1287-97.
- A summary and links to the publication can be found on Clot Connect here.
3. Aspirin for clot prevention
A good example of how research changes clinical practice relates to whether aspirin is effective in preventing DVT and PE. There had been some evidence over the years that aspirin had a small protective effect against DVT and PE, but that protection was thought to be mild. Therefore, the conclusion has been for years that aspirin did not, in any major way, protect from DVT and PE.
Two new studies were published in the past year which investigated this issue more . One study, called WARFSA, found that aspirin reduced the risk of recurrence for DVT and PE in patients with a previous unprovoked clot, once they had finished standard length of blood thinner therapy, with no apparent increase in the risk of major bleeding.
The other study, called ASPIRE, did not find that aspirin significantly lowered the risk of recurrence for DVT and PE. This is different from the finding of the above WARFSA study. However, the ASPIRE study did determine that aspirin had significant benefit regarding the overall risk of major vascular events (heart attacks, strokes, DVT and PE) when all were grouped together. And, aspirin did not increase the risk of major bleeding.
What do the two studies mean in practice? It is still not clear whether aspirin can prevent DVT and PE in patients with a history of unprovoked clots. However, aspirin is now considered to have some benefit nonetheless (on arterial and venous clots when considered together), with no detectable increase in major bleeding risk. In persons who have been told by their physician they will be ending anticoagulant therapy for an unprovoked DVT or PE, a discussion about beginning aspirin to prevent vascular events appears to be appropriate.
The two aspirin studies are:
Aspirin for Secondary VTE Prevention – WARFASA trial
Becattini C et al. Aspirin for preventing the recurrence of venous thromboembolism. N Engl J Med. 2012 May 24;366(21):1959-67.
A summary of WARFASA can be found, here.
Aspirin for Secondary VTE Prevention – ASPIRE trial
Brighton TA et al. Low-dose aspirin for preventing recurrent venous thromboembolism. N Engl J Med. 2012 Nov 22;367(21):1979-87.
A summary of ASPIRE can be found, here.
4. Managing blood thinners when having surgery
If you are taking a blood thinner and are having surgery, your medication may need to be temporarily stopped and/or a different medication used during that time (called a bridging therapy). A practical discussion of the many issues about when to discontinue anti-platelet drugs, warfarin and the new oral anticoagulants at times of surgery, written for health care professionals, was published in:
Ortel TL. Perioperative management of patients on chronic antithrombotic therapy. Hematology Am Soc Hematol Educ Program. 2012;2012:529-35. The full article is available to read here.
A supplementation to this publication can be the practical treatment guidelines for the 3 new oral anticoagulants developed at the University of North Carolina, for
Last updated: February 7, 2013