Av Nadia Arshad
Stipendiat ved TREC
Isolated superficial vein thrombosis (iSVT) is a blood clot in the vein that occurs 
frequently. Initially, it was thought to be a self-limiting condition. Later, researches have shown that the presence of such a clot could increase the chances of developing a clot in the deep vein (DVT) and in the lung, called a pulmonary embolism (PE). Clots in the deep veins and in the lungs are the two main complications of venous blood clots. What are the chances that a superficial blood clot reoccurs as a clot in the deep vein? This is not clear and few scientific studies have so far investigated this question. A recent study published in the Journal of Thrombosis and Hemostasis discussed the long-term chances of re-developing a blood clot in patients with a first-time superficial blood clot in the lower limbs and compared them with those having a blood clot above the knee (proximal DVT).
The study was conducted between November 2004 and January 2006 in hospitals and private clinics in France. A total of 547 patients older than 18 years with superficial vein clots (285) and a blood clot above the knee (262) participated in the study. The authors found that compared with blood clot above the knee, superficial blood clot occurred frequently as superficial clots and less often as a clot in the deep vein. Varicose veins (enlarged veins mostly present in legs) did not play any role in the recurrence of blood clots. Moreover, half of superficial venous blood clots reoccurred as deep venous blood clots.
The authors of this study suggest that superficial venous blood clots, if occurred, should not be ignored, as these clots could be the strong forecasters of deep venous blood clots in the later stage. Therefore, patients’ history of superficial clots should be given attention when deciding about the treatment for venous blood clots.
Reference: Galanaud JP, Sevestre MA, Pernod G, Kahn SR, Genty C, Terrisse H, et al. Long-term Risk of Venous Thromboembolism Recurrence after Isolated Superficial Vein Thrombosis. J Thromb Haemost (2017).
