CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 10, November 2012
574
AFRICA
Simplifying venous thromboembolism management:
a new and safer era
During the course of October, Bayer
hosted a lecture tour in major centres
throughout South Africa on venous
thromboembolism (VTE) management.
Spanning the interests of a healthcare
team approach to the management of
VTE, lectures were presented by the
eminent vascular physician Dr Cohen
and our South African counterparts;
haematologist Prof Peter Jacobs and
specialist vascular surgeon Dr James
Tunnicliffe.
VTE is a ubiquitous condition seen
across all specialities. It is the third most
common cause of mortality, with 10%
of all deaths associated with or caused
by VTE. VTE is also the third most
common cardiovascular disease, with
more than one-third of cases representing
recurrent VTE. Deep-vein thrombosis
(
DVT) and pulmonary embolism (PE)
commonly occur in the community, as
well as pre- and post-hospitalisation for
acute medical illness or surgery. Patients
undergoing major orthopaedic surgery
are particularly at risk. In the absence of
thromboprophylaxis, DVT develops in 40
to 60% of patients undergoing total knee
or total hip replacement; and in 10 to 40%
of medical and general surgery patients.
In an interview with Dr Cohen, the
context of VTE management in resource-
limited settings such as sub-Saharan
Africa was discussed. ‘The chronic nature
of VTE and its complications, such as
post-thrombotic syndrome and pulmonary
hypertension, place an enormous burden
on the healthcare system’, he said.
Data presented in his lecture indicated
that post-thrombotic syndrome occurs in
20
to 50% of patients after symptomatic
deep-vein thrombosis (DVT). Of
pulmonary embolism (PE) patients, 4%
will develop pulmonary hypertension,
which is difficult to manage. Morbidity
at eight years post-VTE is 45% for DVT
and 55% for PE.
‘
Diagnosis can be difficult and VTE is
oftenmissed as a cause of death’, Dr Cohen
stated, placing a further morbidity burden
on the healthcare system. ‘Diagnosis of
DVT requires a comprehensive history
and clinical examination.’
Half of DVT cases are asymptomatic,
and for diagnosis, Dr Tunnicliffe and
Dr Cohen were in agreement that
compression ultrasound at two sites is not
sufficient. Imaging is also difficult in the
obese patient. It is therefore essential to
perform a good evaluation.
Dr Cohen advised that the primary-
care physician request the radiologist
to view intervening segments from the
traditional two-point compression. ‘In the
UK, it is standard to look from groin into
calf and also to look up into the abdomen
if nothing presents in the lower limb’, he
said.
Furthermore, limitations of current
therapies, which are inconvenient and
cumbersome,maycontributetosuboptimal
treatment of VTE and subsequent
complications including recurrences.
Currently recommended treatments for
VTE include unfractionated heparin
(
UFH), low-molecular weight heparin
(
LMWH), fondaparinux and vitamin K
antagonists (VKAs), usually warfarin.
UFH, LMWH and fondaparinux require
parenteral administration, while the oral
VKAs have a slow onset of action, require
regular coagulation monitoring and have
numerous drug and food interactions.
‘
These limitations make the
management of patients with VTE
difficult and they negatively affect quality
of life’, stated Dr Cohen in introducing
the new anticoagulant agents that could
overcome these considerations. ‘In many
countries rivaroxaban is now used for
VTE management. The use of one drug to
manage blood clots without the need for
therapeutic dose monitoring is ideal.’This
furnishes the advantages of improving
adherence and reducing overall treatment
costs by negating the need for dose
Dr Cohen is a vascular physician and
epidemiologist involved in clinical work,
designing, managing and analysing
clinical trials from phase I to IV. He
is the chairman and member of many
international steering committees for
multicentre trials, and epidemiological
and pharmaco-economic studies.
He has participated in cardiovascular
clinical trials on anticoagulants,
thrombolytic agents, and antiplatelet,
antihypertensive and lipid-lowering
drugs. He has undertaken numerous
meta-analyses, economic analyses and
large epidemiological studies.
Dr Cohen has written or co-authored
numerous articles and abstracts since
1990;
many in the
Lancet
,
New England
Journal of Medicine, Annals of Internal
Medicine
,
Archives of Internal Medicine
and
British Medical Journal
.
He is also
a member of a number of international
special-interest societies and serves as
an educational supervisor at the Royal
College of Physicians.
Dr Cohen is an advisor on the
prevention of venous thromboembolism
(
VTE) to the UK Government Health
select committee, the all-party working
group on thrombosis, the Department of
Health and the National Health Services.
He is also an advisor to Lifeblood:
the thrombosis charity and is the
founder of the European educational
charity, the Coalition to Prevent Venous
Thromboembolism.
His main interests continue to be
in the screening and prevention of
vascular disease. He specialises in the
primary and secondary prevention of
cardiovascular disease, prevention of
stroke and coronary artery disease, and
prophylaxis and treatment of venous
thromboembolism.
Alexander (Ander) T Cohen, MB BS,
MSc, MD, FRACP
Honorary consultant vascular physician,
Department of Vascular Surgery, King’s
College Hospital, London
