Many problems in the management of venous thromboembolism remain
unsolved because there has been a failure to undertake adequate study of
the correlation of clinical and pathological events, and to determine the
natural history and prognosis of the disease against which the results of
treatment may be measured.This thesis is based on study of a large series of cases of venous thromboembolism in which the pattern of venous involvement was determined
by venography and /or surgical exploration. From the results of this study
it is concluded that a segmental concept of venous thromboembolism is
fundamental to the understanding of the clinical manifestations and to a rational approach to the many problems that are encountered.The study demonstrates the arrangements of the collateral circulation
which determine the varying clinical picture with venous occlusion at
different levels in the deep venous system. The collateral circulation to
the femoro- popliteal segment is always adequate and venous insufficiency
does not result. In the iliofemoral segment, the collateral arrangements
are inadequate and venous insufficiency results.Contrary to popular belief thrombosis in the iliofemoral venous segment
is frequently primary not secondary to propagation from the lower leg.
Thrombosis of the upper segment is not only the most important type of
thrombosis in regard to leg morbidity but is the common source of major
pulmonary embolism. On the basis of the results of these studies a rational approach to treatment is proposed, emphasis being placed on the
importance of venography in diagnosis and management
