Featured Research

from universities, journals, and other organizations

Low-dose anticoagulation therapy can be used safely with new design mechanical heart valve

Date:
May 15, 2014
Source:
American Association for Thoracic Surgery (AATS)
Summary:
Less aggressive anticoagulation therapy, combined with low-dose aspirin, can be used safely in conjunction with a newer generation mechanical heart valve, a study shows. Patients under 65 years of age requiring heart valve replacement have had to choose between a mechanical valve that may last a lifetime but requires aggressive anti-clotting treatment with warfarin, and a biological (cow or pig) valve that does not require warfarin treatment but will need replacement in 10-20 years.

Less aggressive anticoagulation therapy, combined with low-dose aspirin, can be used safely in conjunction with a newer generation mechanical heart valve. These findings from the first phase of a randomized clinical trial are published in The Journal of Thoracic and Cardiovascular Surgery, an official publication of the American Association for Thoracic Surgery.

Patients under 65 years of age requiring heart valve replacement have had to choose between a mechanical valve that may last a lifetime but requires aggressive anti-clotting treatment with warfarin, and a biological (cow or pig) valve that does not require warfarin treatment but will need replacement in 10-20 years. Aggressive anti-clotting treatment is accompanied by significant risk of bleeding, while inadequate treatment can result in an increased incidence of stroke.

Therefore, the choice between valve types for physicians and patients narrows to one of avoidance of the risk, pain, and costs of reoperation for valve obsolescence versus avoidance of the lifetime composite risk of bleeding and thromboembolism and the nuisance of ongoing anticoagulation management. Both valve types can develop complications which, although rare, can result in reoperation, stroke, or death.

The US Food and Drug Administration (FDA) approved a randomized trial to test the safety of less aggressive anti-clotting treatment than the American Heart Association/American College of Cardiology guidelines currently recommend, in patients implanted with a newer generation On-X heart valve. "This is a bileaflet mechanical valve approved by the FDA, which is designed to function with less anticoagulation, or in some cases, antiplatelet therapy only," explains John D. Puskas, MD, Professor of Cardiothoracic Surgery at the Icahn School of Medicine at Mount Sinai, and Chairman of the Department of Cardiothoracic Surgery, Mount Sinai Beth Israel, New York, NY.

In this first phase of the three-phase Prospective Randomized On-X Anticoagulation Clinical Trial (PROACT), conducted under an FDA investigational device exemption, 375 aortic valve replacement patients with elevated risk factors for clotting were randomized into control (190) and test (185) groups from September 2006 to December 2009 at 33 US centers. Patients in the control group received standard treatment of warfarin to maintain a target range of the International Normalized Ratio (INR) of 2.0-3.0. Patients in the treatment group received low-dose warfarin, targeting an INR of 1.5-2.0, after an initial 90 postoperative days of standard therapy. All patients received 81 mg aspirin daily.

The patients were followed up by in-person visits at three months, six months, and one year after surgery and then annually for between five and eight postoperative years to accrue the necessary 800 patient-years of follow-up mandated by the FDA. During these visits, electrocardiography or echocardiography was performed as required by the protocol and as clinically indicated. All patients maintained with warfarin therapy were followed up using weekly home INR testing through a central telephone or online database.

"The results show that anticoagulation may be safely reduced in patients following aortic valve replacement with this approved bileaflet mechanical prosthesis," says Dr. Puskas. "INR can be safely maintained between 1.5 and 2.0. With low-dose aspirin, this resulted in a significantly lower risk of bleeding, without a significant increase in thromboembolism. In high-risk recipients of On-X valves, the INR should be assiduously kept above 1.5 to maximize the safety and effectiveness of this therapeutic change," he concludes.

The investigators caution that results from the present trial should not be extrapolated to other prostheses, mechanical mitral valve replacements, or patients undergoing double aortic valve/mitral valve replacement. The present standard of care for all mechanical AVR patients outside the PROACT study remains conventional anticoagulation, as indicated by the American Heart Association/American College of Cardiology guidelines.

Two further phases of PROACT are planned. The second will be used to compare current anticoagulant therapy versus aspirin and/or clopidogrel only in selected lower risk patients requiring atrial valve replacement. The third will compare standard anticoagulation therapy versus INR goal of 2 to 2.5 in patients requiring mitral valve replacement.


Story Source:

The above story is based on materials provided by American Association for Thoracic Surgery (AATS). Note: Materials may be edited for content and length.


Journal Reference:

  1. John Puskas, Marc Gerdisch, Dennis Nichols, Reed Quinn, Charles Anderson, Birger Rhenman, Lilibeth Fermin, Michael McGrath, Bobby Kong, Chad Hughes, Gulshan Sethi, Michael Wait, Tomas Martin, Allen Graeve. Reduced anticoagulation after mechanical aortic valve replacement: Interim results from the Prospective Randomized On-X Valve Anticoagulation Clinical Trial randomized Food and Drug Administration investigational device exemption trial. The Journal of Thoracic and Cardiovascular Surgery, 2014; 147 (4): 1202 DOI: 10.1016/j.jtcvs.2014.01.004

Cite This Page:

American Association for Thoracic Surgery (AATS). "Low-dose anticoagulation therapy can be used safely with new design mechanical heart valve." ScienceDaily. ScienceDaily, 15 May 2014. <www.sciencedaily.com/releases/2014/05/140515113231.htm>.
American Association for Thoracic Surgery (AATS). (2014, May 15). Low-dose anticoagulation therapy can be used safely with new design mechanical heart valve. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2014/05/140515113231.htm
American Association for Thoracic Surgery (AATS). "Low-dose anticoagulation therapy can be used safely with new design mechanical heart valve." ScienceDaily. www.sciencedaily.com/releases/2014/05/140515113231.htm (accessed September 23, 2014).

Share This



More Health & Medicine News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Liberia Pleads for Help to Fight Ebola

Liberia Pleads for Help to Fight Ebola

AP (Sep. 22, 2014) Liberia's finance minister is urging the international community to quickly follow through on pledges of cash to battle Ebola. Bodies are piling up in the capital Monrovia as the nation awaits more help. (Sept. 22) Video provided by AP
Powered by NewsLook.com
Ebola Doctor Says Border Controls Critical

Ebola Doctor Says Border Controls Critical

AP (Sep. 22, 2014) A Florida doctor who helped fight the expanding Ebola outbreak in West Africa says the disease can be stopped, but only if nations quickly step up their response and make border control a priority. (Sept. 22) Video provided by AP
Powered by NewsLook.com
Global Ebola Aid Increasing But Critics Say It's Late

Global Ebola Aid Increasing But Critics Say It's Late

Newsy (Sep. 21, 2014) More than 100 tons of medical supplies were sent to West Africa on Saturday, but aid workers say the global response is still sluggish. Video provided by Newsy
Powered by NewsLook.com
Sierra Leone in Lockdown to Control Ebola

Sierra Leone in Lockdown to Control Ebola

AP (Sep. 21, 2014) Sierra Leone residents remained in lockdown on Saturday as part of a massive effort to confine millions of people to their homes in a bid to stem the biggest Ebola outbreak in history. (Sept. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins