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Harvard Heart Letter | May 2008
Heart Beat
Heparin: a risky bridge over troubled waters?
Warfarin
keeps blood from clotting where it shouldn’t, such as in a chamber of
the heart, on a heart valve, or inside unbroken blood vessels. Millions
of people take warfarin (Coumadin, generic) to prevent a clot-caused
stroke, pulmonary embolism, or deep-vein thrombosis.
It
isn’t yet clear how best to handle warfarin when a colonoscopy, oral
surgery, cataract removal, or other minor surgery is needed. There are
three options — stay on warfarin (which increases the chances of
bleeding during the procedure and for awhile afterward); stop taking
warfarin for a few days before and after the procedure (which increases
the chances of having a stroke or pulmonary embolism); or temporarily
replace warfarin with heparin or another short-acting anticoagulant
“bridge” (which increases the chances of bleeding).
Researchers
with the Anticoagulation Consortium to Improve Outcomes Nationally
(ACTION) study looked at how more than 1,000 people fared after
temporarily stopping warfarin for outpatient surgery. The majority
stopped all anticoagulation. In this group, just seven people (0.6%)
developed a stroke, deep-vein thrombosis, or other clot-caused problem,
and nine (0.8%) had a bleeding problem. In the small group of people
who used a heparin bridge, none developed a clot but 13% had a bleeding
problem.
This study, which was published in Archives of Internal Medicine,
suggests that most people can safely halt warfarin for up to a week or
so to have minor surgery. For people at high risk for a blood clot —
those who have had a pulmonary embolism, deep-vein thrombosis, or a
prior stroke, or who have cancer or a clotting disorder — replacing
warfarin with a bridge of heparin or other short-acting anticoagulant
may be needed.
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