CARDIOVASCULAR JOURNAL OF AFRICA • Vol 21, No 2, March/April 2010
AFRICA
123
Advertorial
The use of anticoagulants for venous thrombo-embolism
Pulmonary embolism is a life-threaten-
ing condition with mortality as high as
17.5% within three months of onset.
1
Pulmonary embolism is also the most
common preventable cause of hospital
death. Despite these unacceptably high
risks, the effective use of anticoagulants
to prevent venous thrombo-embolisms
(VTEs) remains inconsistent.
Communication and education around
the risk of VTE as a result of major ortho-
paedic surgery, particularly hip- and knee-
replacement surgery, remains a concern.
Talib Abdool-Carrim, professor of vascu-
lar surgery at Milpark Hospital, says to
date this communication has been inad-
equate. ‘I believe medical professionals
need to be constantly reminded, as only
about 50% of hospital doctors are giving
out guidelines for prophylactics, and we
need to practice in line with the ACCP
and South African guidelines. However,
the use of anticoagulants for these patients
has increased from a specialist perspec-
tive’, Prof Abdool-Carrim says.
Orthopaedic surgeon Dick van der Jagt
believes medical professionals in South
Africa are constantly being informed about
prophylaxis for these patients, but that this
communication needs to be repeated on
an ongoing basis to prevent complacency
setting in. ‘Every patient needs to be
assessed to determine their individual risk
profile, and given appropriate prophylaxis
against VTEs’, he says.
Prof Mervyn Mer, critical care special-
ist and one of the authors of the South
African Guidelines for Prophylactic
Anticoagulation agrees that communica-
tion around this issue needs to be opti-
mised. ‘There’s no doubt that extended
prophylaxis should be given to high-risk
hip- and knee-replacement patients, and
that it should be used in conjunction with
mechanical devices such as pneumatic
compressive devices which are applied to
the lower limbs. These are a useful addi-
tion to prophylaxis agents as they assist in
moving blood around and prevent stasis.
These devices are not ideally optimal
when used alone but do further decrease
the chance of VTEs’, Prof Mer says.
According to Prof Abdool-Carrim,
anticoagulants reduce the risk of VTEs
by up to 80%. ‘There is enormous data to
support the efficacy of anticoagulants in
reducing the risk of VTE’, Prof Mer says.
‘It is not 100% guaranteed, but the risk is
reduced so substantively that the omis-
sion of anticoagulants would compromise
the medical practitioner and be difficult
to defend. The use of anticoagulants to
reduce the risk of VTE has become the
number 1 focal point in US hospitals,
with specialists being called upon to
justify their actions should these agents
be omitted.’
The newACCP guidelines recommend
the use of anticoagulants for a minimum
of 10 days for knee-replacement surgery
and up to 35 days for hip-replacement
surgery. The new South African guide-
lines are fully aligned with the ACCP
recommendations and have even extend-
ed the time period for knee-replacement
surgery to two weeks. ‘In general, proph-
ylaxis should be used whenever a patient
is immobile, and should be continued
until the patient is mobile again’, Prof
Mer says.
According to Prof Abdool-Carrim,
adequate prophylaxis is not always
prescribed for hip and knee replacements
or other major surgeries. Dr van der
Jagt concurs, saying many patients only
receive anticoagulants while in hospital.
‘However, this is often because medical
aids will not cover the treatment outside
of hospital care, and a high percent-
age of patients cannot afford to fund it
themselves. The guidelines are clear, but
unfortunately medical aids are more inter-
ested in their bottom lines’, he says.
The South African Guidelines for
Prophylactic Anticoagulation allude to
only currently registered agents, but are
updated as the industry evolves. These
guidelines have been endorsed by a
number of societies including those of
orthopaedic surgeons, vascular surgeons,
anaesthesiologists, critical care special-
ists and pulmonary specialists. For the
first time in South Africa, the guidelines
include the input of two highly regarded
international specialists in the field who
have contributed independently to the
guidelines to avoid any local bias.
Without anticoagulation treatment,
patients undergoing major orthopaedic
surgery have up to a 60% chance of devel-
oping a VTE.
1
Recent advances in the
field, however, indicate a brighter future
as treatment has evolved from warfarin to
intravenous heparin to the new oral anti-
coagulants which are due to be released
onto the market soon.
According to Dr van der Jagt, the new
oral anticoagulants offer a number of
benefits over existing treatments: they are
simple to administer, easy to manage and
don’t need to be constantly monitored. In
line with the trend to safely administer
effective prophylaxis against VTEs, the
oral agents also eliminate the need for
injections and cut down on hospital costs
as well as hospital-acquired infections
by enabling patients to continue with the
drugs at home.
Commenting on the future direction of
these treatments, Prof Mer says the next
step lies in the development of particu-
lar antidotes and the ability to measure
the effects of these agents. ‘We need
the ability to measure and monitor each
patient’s requirements rather than using
a fixed dose for most people’, he says.
‘The future for the prevention of VTEs is
definitely looking positive’, Prof Abdool-
Carrim added.
A further benefit of the new oral anti-
coagulant agents is that they offer minimal
drug–drug and drug–food interactions,
making the use of extended anticoagula-
tion therapy more practical. ‘Some of the
existing treatments do present a problem
with drug–drug and drug–food interac-
tions’, Dr van der Jagt says. ‘Choose a
preferred oral anticoagulant which will
effectively reduce the risk of clotting
without severely increasing the risk of
bleeding.’
MIMS Desk Reference
1.
. Avusa Media Ltd,
2008;
43
: 196.
