Published in Blood 2015 Jan 8; 125:229
Authors: Cannegieter SC et al.
Risks were higher for subsequent deep venous thrombosis, pulmonary embolism, acute myocardial infarction, ischemic stroke, and death.
A recent study showed that 9.4% of patients with superficial venous thrombosis (SVT) had extension of the thrombus to the deep veins (NEJM JW Oncol Hematol Sep 11 2013), suggesting that patients with SVT might be at risk for future thrombotic problems.
To arrive at a robust estimate of the risk for venous and arterial thrombosis occurring following a SVT, investigators studied data on 10,973 patients with SVT in the Danish National Registry and 515,067 age- and gender-matched controls from the Danish population. At a median of 7 years, results were as follows:
· The incidence of deep venous thrombosis (DVT) was higher in patients than in controls (12.8 vs. 1.2 per 1000 patient-years; adjusted hazard ratio, 11.28).
· The incidence of pulmonary embolism (PE) was also higher in patients than in controls (4.5 vs. 0.9 per 1000 patient-years; adjusted HR, 4.53).
· The association of SVT with subsequent DVT and PE was stronger in men than women.
· Arterial events were more common in patients than controls: acute myocardial infarction (5.8 vs. 4.8 per 1000 patient-years; adjusted HR, 1.17) and ischemic stroke (7.2 vs. 5.5 per 1000 patient-years; adjusted HR, 1.28); the mortality rate was higher as well (45.1 vs. 33.4 per 1000 patient- years; adjusted HR 1.27).
· The rates for venous and arterial events, as well as death, were highest in the first 3 months after the SVT and gradually declined thereafter.
This analysis convincingly shows that patients with SVT are at risk for subsequent DVT, PE, acute myocardial infarction, and ischemic stroke. Whereas extension of the SVT to the deep veins might account for the heightened risk for venous thromboembolism, the increased incidence of arterial events is unexplained but consistent with the concept that arterial and venous thrombosis are different manifestations of an underlying thrombotic propensity.