Broadening the factor V Leiden paradox: pulmonary embolism and deep-vein thrombosis as 2 sides of the spectrum

Abstract

<jats:title>Abstract</jats:title><jats:p>Risk factors for deep-vein thrombosis have been shown not to be always the same as for pulmonary embolism. A well-known example is the factor V Leiden (FVL) paradox: the FVL mutation poses a clearly higher risk for deep-vein thrombosis (DVT) than for pulmonary embolism. We aimed to expand this paradox and therefore present risk estimates for several established risk factors for DVT and pulmonary embolism separately. When such separate risk estimates could not be retrieved from the literature, we calculated these risks in our own data, a large population-based case-control study on venous thrombosis (the MEGA study). Our results showed that the FVL paradox can be broadened (ie, the risk factors oral contraceptive use, pregnancy, puerperium, minor leg injuries, and obesity have an effect comparable with FVL). Furthermore, we found that pulmonary conditions, such as chronic obstructive pulmonary disease, pneumonia, and sickle cell disease, were risk factors with an opposite effect: a higher risk of pulmonary embolism, but little or no effect on DVT. These findings suggest that pulmonary embolism and DVT may not always have the same etiology, and encourage unraveling this phenomenon in further studies.</jats:p>

The risk of venous thrombosis in individuals with a history of superficial vein thrombosis and acquired venous thrombotic risk factors

“…These findings are in line with the results of previous research showing some risk factors for venous thrombosis to have a differential effect on deep vein thrombosis and pulmonary embolism, suggesting that the etiology of these 2 diseases is not always the same. 9 However, CIs were wide and overlapped for the different subtypes of venous thrombosis. Therefore, this finding should be interpreted with caution.…”

“…2,3 However, in up to 10% of individuals with previous SVT who develop deep vein thrombosis, this occurs in the contralateral leg, 10 indicating that systemic hypercoagulability also plays a role in the development of venous thrombosis after SVT. 9 Despite an increasing amount of research, many physicians still view SVT as a benign, self-limiting disorder. 2,3 Our findings provide evidence to the contrary.…”

Association Between Anemia and Cerebral Venous Thrombosis

“…20 Another contributing factor could be that men with CVT more often have an infection or a recent operation as a risk factor, and these conditions are also associated with anemia. 4 Finally, a lower risk of CVT among women with anemia might be related to the high prevalence of female patients who used oral contraceptives.…”

Deep Vein Thrombosis: Review and Update

“…Antithrombin deficiency, (12) protein-C deficiency, (12) protein-S deficiency (type I), (13) dysfibrinogaemia (14) are some of the inherited factor that may contribute to development of DVT and PE. Factor V Leiden increases the risk of DVT more than it does for PE, a phenomenon referred to as the Factor V Leiden paradox.…”