Minor Events and the Risk of Deep Venous Thrombosis

Abstract

Backgtound Deep venous thrombosis is a common disease, with genetic and acquired nsk factors Many patients have a history of minor events (short penods of iramobihsaüon such äs prolonged travel, short illness. ramor surgery or injunes) before onset of venous thrombosis However. the role of these mmor events has received httle formal study Also, we do not know how mmor events might mteract with the presence of genetic prothrombotic defects (factor V Leiden mutation factor II mutation, protein C S and antithrombin deficiency) Patients and Methods On the basis of case-control data from a thrombosis Service m the Netherlands we added a follow-up penod for a casecross-over analysis of minor events äs nsk factors, and a case only analysis toi the mteraction with factor V Leiden A total of 187 patients with first. objectively diagnosed venous thrombosis of the legs, aged 15-70, without underlymg malignanues and without major acquired nsk factors entered the study Tor the analy sis of minor events in the case-cross-over analysis we used a matched odds ratio, m the case only analysis we used the multiphcative s\nergy mdex Results In 32 6% ot the 187 patients with deep venous thrombosis who did not have major acquired nsk tactors, mmor events were the only external nsk factors Minor events mcreased the nsk of thrombosis about 3-fold äs estimated m the case-cross-over analysis (odds ratio 2 9, 95% confidence interval l 5-5 4) The synergy mdex between minor events and factor V Leiden mutation m the case-only analysis was 0 7 (95% confidence interval 03-15) Therefore, persons with factor V Leiden mutation who expenence a minor event will have an estimated nsk mcrease of about 17-fold. which exceeds the sum of the mdividual nsk factors Condusions Mmor events are hkelv to play an important role m the development of deep venous thrombosis, especially m the presence of genetic prothrombotic conditions

Deep vein thrombosis and air travel: record linkage study

“…A 30 day period of increased risk has been assumed previously, and a recent study reported a median interval of two days (range 1-14) between a trigger event and subsequent thrombosis 16. We examined the risk over intervals up to 30 days, using a model that allowed different incident rate ratios in three successive periods after travel, and we concluded that most of the excess risk was captured in the two weeks after a flight.…”

Epidemiology and Risk Factors for Venous Thrombosis

“…Research-based definitions of immobility due to bedrest differ, but a duration of 4 days seems reasonable. Minor forms of immobility, such as after minor surgery or injury, have also been linked to thrombosis risk (33).…”

Minor Injuries as a Risk Factor for Venous Thrombosis

“…In studies [7][8][9]14 that focused on major injuries, an asymptomatic venous thrombosis was detected in 0.4% to 12% of the trauma patients, despite prescribed prophylaxis. One study 15 found a 3-fold increased risk of venous thrombosis after minor events. However, minor events included, among others, travel, minor surgery, and minor trauma, and no information regarding minor trauma alone was available.…”