Venous thromboembolism: duration, IVC filters, and hypercoagulable workup.

Venous thromboembolism (VTE), which includes deep venous thrombosis (DVT) and pulmonary thromboembolism (PE), is the third most common cause of cardiovascular mortality in the U.S., after coronary heart disease and stroke. VTE is a systemic disease which may develop spontaneously (idiopathic, unprovoked) or secondary to some identifiable provocative or environmental risk factor. Classifications into unprovoked, surgical, and provoked are useful, since such a classification correlates with the cumulative risk of recurrence and, therefore, influences the duration of therapy and the appropriateness of laboratory investigation. VTE most commonly affects the deep venous system of the pelvis or lower extremity, but can also occur in less common sites such as the upper extremity, mesenteric veins, ovarian veins, cerebral veins and retinal veins. The anatomic site(s) is of importance as it may also influence diagnostic testing and duration of therapy. The management of VTE (symptomatic or asymptomatic) can be divided into immediate (up to the first 10 days), early long-term (up to three months), and late long-term (beyond three months) therapy. The objective of immediate management is to shut down thrombin generation and to prevent thrombus extension and embolisation. The objective of early long-term therapy is to prevent thrombus recurrence, embolisation and the post thrombotic syndrome (PTS) and to promote the lysis of the thrombus; recurrence in this phase is particularly problematic since there is a higher case fatality rate. The objective of late long-term management is to prevent thrombus recurrence and embolisation and to prevent or reduce PTS since ipsilateral recurrence is a particular risk factor for PTS. Unprovoked VTE may be a manifestation of an inherited or acquired thrombophilic state and, hence, esoteric laboratory testing may be indicated in some cases. This article will address only three of these considerations—the role of late long-term anticoagulation, utilization of an IVC device to interdict embolisation and the judicious use of esoteric laboratory testing.