CABG Guidelines Get New Update
Hormone replacement out, aspirin in, as cardiology
experts change the rules for coronary artery bypass graft surgery
(Bethesda, MD) The American College of Cardiology (ACC)
and the American Heart Association (AHA) have issued a revised set of guidelines
for the management of patients undergoing coronary artery bypass grafting. In
contrast to the previous guidelines published in 1999, the new update says no to
hormone replacement therapy and yes to aspirin for patients undergoing this common
surgical procedure.
The new guidelines also stress the importance of statin
and beta blocker therapy in all post-CABG patients, as well as anticoagulation
with warfarin in patients who develop sustained abnormal heart rhythms after bypass. The document
is published on the Web sites of the American College of Cardiology at http://www.acc.org/clinical/guidelines/cabg/index.pdf
and the American Heart Association www.americanheart.org and will appear in the
September 1 issue of the Journal of the American College of Cardiology and the August 31 issue of the Circulation: Journal of the American Heart Association.
We've significantly updated a number of sections of the 1999 guidelines to
incorporate the most recent evidence from randomized trials. One important
example is in the area of hormone replacement. Until the randomized trials were
published, we were generally recommending the initiation of hormone therapy in
women after their bypass, but in this document, it is not recommended at all,
said Dr. Kim Eagle, co-chair of the guidelines writing committee.
The updated guidelines continue to emphasize quality of life as well as
quantity. The guidelines now recognize that CABG is very effective for the
relief of symptoms, even when it may not prolong life, said Dr. Robert A.
Guyton, co-chair of the writing committee. This is an important evolution for
us. In the 1990s, when guidelines for CABG were first issued, we focused more on
quantity, but now we are interested in the quality of life, as well as length of
life, he said.
An important aim of the revised guidelines is to optimize the medical
management of bypass surgery patients, Dr. Eagle said. They really focus on
treating atherosclerosis after CABG. For example, in the past, many patients
were told to discontinue aspirin for some time prior to their surgery to reduce
bleeding risk, but now we know that staying on aspirin is good for patients
because it reduces the likelihood that their grafts will clot, he said.
Another area that has been significantly updated is the
section comparing multivessel angioplasty and stenting with bypass surgery. Recent evidence from
randomized trials now suggests that either option is reasonable, with five-year
outcomes of both techniques showing similar results.
It's fair to say that the era of coronary stenting has
improved, or reduced the need for repeat vascularization in patients who need
stents. At the same time, the broader use of the left internal mammary artery
has improved the benefit of coronary bypass surgery. So, on the one hand, angioplasty has a lower
upfront risk, but on the other hand, there is a larger likelihood that patients
who get angioplasty will require subsequent interventions. So, for patients who
are eligible for both therapies, a lot of the final decision comes down to their
own personal preference, he said.
However, the jury is still out as to the relative benefit of off-pump CABG. Although the results
of several small studies appear to show fewer neurologic complications with
off-pump bypass, the guidelines committee did not feel that
their evidence was compelling enough to make a specific recommendation in favor
of the newer technique.
One of the big questions many patients have had is
whether the risk of stroke or other neurologic complications is lower with
off-pump bypass surgery. But so far, the answer to that question is not
absolutely clear. If you actually look at randomized clinical trials that have taken eligible patients for either
methodology, the amount of difference in length of stay or neurologic
complications has not been dramatic and we still have yet to prove to ourselves
that off-pump bypass is dramatically better than on-pump bypass. We're certainly
in no position right now to say that every patient who has bypass surgery should
have it off-pump, Dr. Eagle said.
Source: The American College of Cardiology, press release, August 5, 2004
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Last Editorial Review: 9/3/2004
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