Objective: Lower extremity deep vein thrombosis is often isolated to the sinusoidal veins draining the gastrocnemius and soleus muscles. The purpose of this study was to establish the incidence rate of propagation of isolated gastrocnemius and soleal vein thrombosis (IGSVT) into the deep veins of the calf and thigh.
Methods: All patients who were referred for color flow duplex ultrasonography (CFDU) for suspected deep vein thrombosis were prospectively evaluated for IGSVT. Patients with IGSVT received no systemic anticoagulation therapy and underwent serial CFDU at 5, 9, 14, 30, and 90 days after recruitment. The incidence and extent of IGSVT propagation were noted. Factors predictive of IGSVT extension were sought, including age, gender, side, symptoms, ambulatory status, and the presence of comorbid illness, including cardiac disease, cancer, hypercoagulable states, recent surgery or trauma, and previous venous disease.
Results: One hundred thirty-five limbs with IGSVT were studied for 3 months, and 16.3% of cases with IGSVT extended the thrombus to the level of the adjacent tibial, or peroneal, veins or higher. Only 3% of the cases with IGSVT propagated as cephalad as the popliteal vein, and 90.9% of IGSVT propagation occurred within 2 weeks of CFDU diagnosis. No IGSVT propagated to the level of the popliteal vein beyond 2 weeks from the time of CFDU diagnosis. No IGSVT extended into the deep veins of the thigh. By the end of the 3-month study period, 45.9% of thrombi had completely resolved. Only the presence of cancer was prognostic for IGSVT progression.
Conclusion: During the 3-month study period, the short-term incidence rate of untreated IGSVT propagation to the level of the popliteal vein, even in the presence of cancer, was only 3%. Follow-up imaging to detect IGSVT propagation beyond 2 weeks from the time of diagnosis may not be necessary.