Dunn and Turpie1 provide a comprehensive review of studies that have evaluated various approaches to perioperative anticoagulation when warfarin sodium therapy needs to be interrupted to perform surgery. In their review, they consider the risks and benefits of using perioperative intravenous heparin or subcutaneous therapeutic-dose low-molecular-weight heparin (LMWH) as "bridging therapy," while patients are not orally anticoagulated. They conclude by recommending such bridging therapy for patients with mechanical mitral valves and for those with atrial fibrillation with a history of thromboembolic stroke. This recommendation assumes that, similar to warfarin therapy, intravenous heparin and therapeutic-dose LMWH reduce the risk of cardioembolism by about 75%. We made the same assumptions in a previous risk-benefit analysis of bridging therapy using intravenous heparin2; however, randomized trials have since disproved this assumption in patients with atrial fibrillation.3 Most notably, within 2 weeks of acute stroke, therapeutic-dose LMWH has been shown to be no more effective than aspirin at preventing recurrent ischemic stroke (odds ratio of 1.1 in favor of aspirin [95% confidence interval, 0.6-2.2]). The efficacy of unfractionated heparin and LMWH therapy is also uncertain in patients with mechanical heart valves; in pregnant patients, indirect comparisons suggest that both are less effective than warfarin therapy.4 Therefore, it should not be assumed that heparin or LMWH is as effective as warfarin therapy for preventing systemic embolism in patients with atrial fibrillation or a prosthetic heart valve.
Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more
Subscribe for full-text access to content from 1998 forward and a host of useful features
Activate your current subscription (AMA members and current subscribers)
Purchase Online Access to this article for 24 hours
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and
Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early
dhildhood mortality and growth failure data and their association with maternal
Thank you for submitting a comment on this article. It will be reviewed by JAMA Internal Medicine editors. You will be notified when your comment has been published. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest*
Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 3
Customize your page view by dragging & repositioning the boxes below.
More Listings atJAMACareerCenter.com >
and access these and other features:
Enter your username and email address. We'll send you a link to reset your password.
Enter your username and email address. We'll send instructions on how to reset your password to the email address we have on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.