To Treat or Not to Treat: Below the Knee DVT

Case

A 42 year old male with a past medical history of paroxysmal atrial fibrillation and L4 radiculopathy due to a remote back injury presents to the ED with chief complaint of right foot and calf pain. The pain is described as cramping and burning that gradually worsened over the 3 days prior to presentation. He is not on anticoagulation. He denies shortness of breath, hemoptysis, history of deep vein thrombosis (DVT) or pulmonary embolism, hormone use, or active cancer. He smokes 2 packs of cigarettes daily. Vital signs are within normal limits. Exam is remarkable for diffuse tenderness to palpation of the R foot and calf with no swelling, erythema, or palpable cords. Sensation and dorsalis pedis (DP) and posterior tibial (PT) pulses are intact. 

A right lower extremity ultrasound was performed which revealed a near occlusive thrombus in one of the paired gastrocnemius veins. The common femoral and popliteal veins demonstrated normal duplex waveforms and compressibility, and the remaining visualized upper calf veins were otherwise patent by color flow Doppler. 

Diagnosis

The patient was diagnosed with a below the knee DVT (BKDVT).  

Discussion 

A Discussion on the ED Management of BKDVT 

The diagnosis and management of proximal DVTs is usually fairly straightforward (anticoagulation vs IVC filter), but what therapy should be recommended when the DVT occurs below the knee? 

Below the knee deep vein thrombosis (BKDVT) is defined as thrombosis of the deep venous system of the leg distal to the popliteal vein, involving the tibial, peroneal, soleus, and gastrocnemius veins. The management of BKDVTs is based on the likelihood of proximal propagation of the DVT and potential development of pulmonary embolism. 

The American College of Chest Physicians (ACCP) describes the only consensus guidelines for isolated BKDVT management, but these guidelines are considered “grade 2C”. [1] This means these are weak recommendations based on low-quality evidence. The ACCP recommends anticoagulation only for severely symptomatic or high risk patients with BKDVT. [1] High risk factors include pregnancy, malignancy, immobilization, multiple trauma, hormone use, and smoking. In patients without high risk features, a surveillance ultrasound of the extremity is recommended in 2 weeks to monitor for clot propagation. [1] If there is any evidence of proximal extension of the clot on the surveillance ultrasound, anticoagulation is recommended (Figure 1). [1]  

Figure 1. Algorithm for the management of DVT based on the 2012 CHEST guidelines. [1] 

Most BKDVTs will resolve spontaneously without anticoagulation. However, the possibility of propagation and embolization represent serious risks. Rates of BKDVT propagation to the proximal veins ranged from 3% to 32% in a systematic review. [2] In a case-control study, propagation to the proximal veins was seen in 5% of cases compared to 1.4% of patients on anticoagulation, with pulmonary embolization reported in 4.3% of patients compared to 1.6% of patients on anticoagulation. [3] The recent blind, prospective CALTHRO study similarly described a significantly higher rate of complications at 3 months in patients with BKDVT compared to patients without BKDVT. [4] Despite this finding, the majority of untreated BKDVTs had uncomplicated clinical courses. [4] 

Given the mixed evidence for anticoagulation versus imaging surveillance, the optimal management of BKDVT remains unclear. Practitioners should carefully weigh the options for anticoagulation versus imaging surveillance, since each option presents unique risks of bleeding and clot propagation/embolization, respectively. Patients at high risk for bleeding may benefit from follow-up ultrasound imaging, while patients who cannot easily access follow-up care or have a low risk for bleeding complications may be managed with anticoagulation. It is possible that patients presenting to the ED may disproportionately preselect for anticoagulation management as patients with severe symptoms will often seek emergency care. Shared decision making is critical in the management of BKDVT, since there are no clear best practices. 

Case Resolution 

The patient received a dose of apixaban (Eliquis) in the ED and was discharged home with a prescription for Eliquis and a vascular follow-up appointment in 1 week. 

Take-Away Points

• If patients are symptomatic or have high risk factors, treatment for BKDVT consists of anticoagulation and follow-up surveillance ultrasound in 1-2 weeks. 

• Asymptomatic patients can be discharged with a follow-up surveillance ultrasound in 1-2 weeks. Anticoagulation does not need to be initiated unless there is clot propagation on ultrasound. 

• Shared decision making is essential, with careful consideration of high risk patients, bleeding risk, and ability to access follow-up care. 

Keywords 

• Below the knee DVT 

• Deep vein thrombosis 

• Anticoagulation 

• Ultrasound 

AUTHOR: Nichole Michaeli, MD, MPH is a third year resident at Brown University/Rhode Island Hospital. 

FACULTY REVIEWER: Victoria Leytin, MD

References

1.     Kearon, C., Akl, E. A., Comerota, A. J., Prandoni, P., Bounameaux, H., Goldhaber, S. Z., ... & Kahn, S. R. (2012). Antithrombotic therapy for VTE disease: antithrombotic therapy and prevention of thrombosis: American College of Chest Physicians evidence-based clinical practice guidelines. Chest, 141(2), e419S-e496S.

2.     Masuda, E. M., & Kistner, R. L. (2010). The case for managing calf vein thrombi with duplex surveillance and selective anticoagulation. Disease-a-month, 10(56), 601-613.

3.     Utter, G. H., Dhillon, T. S., Salcedo, E. S., Shouldice, D. J., Reynolds, C. L., Humphries, M. D., & White, R. H. (2016). Therapeutic anticoagulation for isolated calf deep vein thrombosis. JAMA surgery, 151(9), e161770-e161770.

4.     Palareti, G., Cosmi, B., Lessiani, G., Rodorigo, G., Guazzaloca, G., Brusi, C., ... & Legnani, C. (2010). Evolution of untreated calf deep-vein thrombosis in high risk symptomatic outpatients: the blind, prospective CALTHRO study. Thrombosis & Haemostasis, 104(5), 1063.