Sep 2, 2015
Deep venous thrombosis of the calf causes an undue amount of consternation. What's the best way to manage these?Anticoagulate, serial ultrasound, do nothing? We break down the evidence to help you decide.
Propagation to proximal veins
Compression stockings and post thrombotic syndrome
Post thrombotic syndrome (PTS) is a horrible consequence of DVT. Reflux from valve injury and venous hypertension lead to chronic edema, pain, and leg ulcerations. If there’s something that can mitigate that in our patients, we’d want them to have it. The incidence of PTS in proximal DVTs is around 50%, depending on the source you read. In calf DVTs, it’s lower: somewhere around 10 to 24%.
There is good evidence that compression stockings can decrease the incidence of PTS.
A 2014 Lancet study, suggested that there was no benefit to compression stockings. The above two trials used stockings or no stockings, this one used the 30-40 mm Hg graduated compression stockings or placebo, which was a 5 mmHg stocking. Results: no benefit of compression stockings over placebo socks. Does this study show that stockings don't make a difference? Or was the placebo not actually a placebo since there was still some degree of compression, albeit light. I think you could interpret all of this data in several ways.
ACCP recommends compression stockings for proximal DVTs (ankle pressure of 30-40 mm Hg). Start as soon as possible and continue for 2 years. That is a grade 1A recommendation. How this will change based on more recent evidence remains to be seen. Distal DVTs, even more unclear.
Duration of treatment
Type of treatment:
No superior agent. Unfractionated heparin, LMWH, vitamin K antagonists-nothing superior. Many providers are using oral Xa inhibitors, but these are unstudied (yet still heavily used). You can extrapolate that LMWH is aba inhibitor, albeit by a different mechanism, so an oral Xa inhibitor should be effective too, but we don’t have direct evidence to answer that question.
Different treatment recommendations and guidelines
2012 ACCP: serial ultrasound for low risk clots and treat high risk clots (cancer, close to the popliteal vein, history of prior DVT)
National Clinical Guideline Centre: did not mention the treatment of isolated distal DVT because the guideline “... focused on proximal DVT rather than isolated calf vein DVT as the latter is less likely to cause post thrombotic syndrome than proximal DVT and also less likely to embolize to the lungs."
International Consensus Statement on Prevention and Treatment of Venous Thromboembolism: 3 months of oral anticoagulants for all calf clots
Up to date: Treat for 3 months (based on poor evidence) versus 2 weeks of serial US
Hematologist Tom Deloughery
Jeff Kline 3 weeks of rivaroxaban. Permanent anticoagulation for active cancer, unprovoked clot
Rob O: 6 weeks anticoagulant and 2 years compression stockings