Early follow-up and treatment recommendations for isolated calf deep venous thrombosis.

BACKGROUND

The clinical significance of isolated calf vein thrombosis (ICVT) remains controversial. Several studies have shown that the majority of ICVT do not propagate above the knee while other studies have suggested ICVT propagation and recommend full anticoagulation. The purpose of this study was to determine the progression of ICVT, identify risk factors for clot propagation, and to evaluate further thrombotic events associated with it.

METHODS

This study consisted of 156 patients and a total of 180 limbs. All patients included had ICVT involving either the tibial, peroneal, gastrocnemius, or the soleal vein. After initial diagnosis, all patients were started on prophylactic dose of low molecular weight heparin (LMWH) or unfractionated heparin, unless already anticoagulated. All limbs were monitored using duplex ultrasonography scans at intervals of 2 to 3 days, 1 to 3 months, and 6 to 8 months from the initial time of diagnosis. Outcomes examined included lysis of clot, propagation to a proximal vein, and pulmonary emboli.

RESULTS

ICVT was detected in 180 limbs of 156 patients. No significant difference was noted in the gender of the patients or limb preference. Twenty-four patents had both limbs involved. The mean age was 77 years old and the mean follow-up was 5.1 months. The soleal vein was most commonly involved. The second most common vein involved was peroneal, followed by posterior tibial and then gastrocnemius. The least commonly involved vein was the anterior tibial with only one positive result on each side. Fifteen of 180 limbs (9%) had complete resolution of the thrombus within 72 hours. Of these, six were anticoagulated to a therapeutic level. All patients had a follow-up duplex scan within 1 to 3 months' time, and none had recurrence. At the 1 to 3-month follow-up, 11 of 180 patients (7%) had propagation to a proximal vein; all of whom were in a high-risk group to develop a deep vein thrombosis (DVT), either after an orthopedic procedure, stroke, or malignancy. Nine of 156 patients developed a pulmonary emboli also diagnosed within the 1 to 3-months' time period. At the 6 to 8-month follow-up, there was no further propagation of any additional limbs and no further incidences of pulmonary emboli.

CONCLUSION

ICVT can be safely observed in asymptomatic patients without therapeutic anticoagulation. In our study, patients who have had orthopedic procedures, those with malignancy, and those that were immobile seemed to have a higher incidence of clot propagation. In this group, we recommend full anticoagulation until the patient is ambulatory or the follow-up duplex scan is negative. Our data also suggest that a follow-up duplex scan is not beneficial when performed within 72 hours or after 3 months.