The 8th edition of guidelines on
antithrombotic and thrombolytic therapy from the American
College of Chest Physicians (ACCP) is out. The 900-page
document boasts more than 700 recommendations for the
prophylaxis, treatment and followup of blood clot disorders.
The full guidelines, along with a 40-page executive
summary, were published as a supplement to the June
issue of Chest.
Highlights include new advice on
anticoagulation during pregnancy and a full chapter
on how to manage patients on longterm antithrombotic
therapy undergoing surgery.
The old guidelines recommended that thrombosis-prone
patients who become pregnant should be taken off vitamin
K antagonists (VKAs) such as warfarin as soon as possible
because the drugs increase the risk of birth defects
and miscarriage. This advice remains, but the new version
makes allowances for women at high risk for blood clots,
such as those with certain types of mechanical heart
valves, recommending that they continue on VKAs and
switch to low-molecular weight heparin (LWMH) or unfractionated
heparin (UFH) closer to the birth. This brings the guidelines
in line with what's currently being done in Europe,
explains guideline author Dr Shannon Bates, a thromboembolism
specialist at McMaster University.
If a woman is a candidate for discontinuation
of VKAs, it's recommended to put her on LWMH or UFH.
You can either follow your patient closely with frequent
pregnancy tests and initiate the new drug once conception
is confirmed, or you can start her on LMWH or UFH before
she tries to get pregnant, advise the guidelines.
The chapter on following patients on longterm antithrombotic
therapy is good news for physicians. These individuals
need special attention when they go under the knife,
as the anticoagulants they're on boost the risk of bleeding.
Until now, the recommendations on how to bridge these
patients were based on a very thin evidence base, but
the section on perioperative management addresses many
of the pressing issues.
For people taking warfarin, there
are a number of options. If they're undergoing a small
procedure such as cataract surgery, it may be possible
to simply lower the dose. You can also stop warfarin
five days before the operation and substitute with LMWH.
In special cases, you may even choose to continue warfarin
therapy until 48 hours before the procedure and then
give a low dose of vitamin K.
Traditionally, the guidelines issued by the ACCP had
a tendency to be "very North American-based," Dr Bates
told NRM. It's a concern the new edition has
tried to address by increasing the number of international
experts on the panels a change Dr Bates welcomes.
"It makes more sense to have guidelines that are applicable
to everyone," she says.
To make the heavy document more
user-friendly, the authors have also altered the set-up
of the chapters. They now begin with the recommendations,
followed by tables outlining the evidence from clinical
trials. To further help physicians find the information
that applies to their practice, the chapters are organized
according to specific patient populations and their
concerns, rather than divvying them up by treatment