Risk factors: There are two main types of risk factors for postoperati
ve thromboembolism. Patient-related factors include a history of throm
boembolism neoplasia, resistance to activated protein C and other coag
ulation disorders. Factors related to the operative period comprise an
other type of risk The high morbidity and mortality of this ''bipolar'
' disease involving both deep vein thrombosis and pulmonary emboli inc
ites renewed efforts to reduce its incidence. Prophylaxis: The level o
f risk Varies with each surgical procedure requiring case by case adap
tation of the prophylaxis protocol. Low-molecular weight heparin has b
een widely used. Diagnostic strategy: Since clinical expression is ins
ufficiently sensitive and the risk persists despite adequate prophylax
is, the question is raised as to the most appropriate means of diagnos
is. Ongoing progress in technical tools including duplex Doppler of th
e lower limbs and spiral scan have greatly changed diagnostic strategi
es. Noninvasive explorations have become the gold standard compared wi
th invasive phlebography and pulmonary angiography. Therapeutic strate
gy: Curative treatment, itself carrying a high risk of severe morbidit
y, has also undergone significant changes. Oral anticoagulants remain
the mainstay of long-term treatment but, on the basis of recent report
s, low-molecular weight heparin has tended to replace standard heparin
.