PREVALENCE AND DISTRIBUTION OF CALF VEIN-THROMBOSIS IN PATIENTS WITH SYMPTOMATIC DEEP VENOUS THROMBOSIS - A COLOR-FLOW DUPLEX STUDY

Purpose: This retrospective study was performed to identify the patter ns of calf vein thrombosis in patients in whom deep vein thrombosis (D VT) was suspected and to better define the role of color-flow duplex s canning (CDS) in the evaluation of this patient population. Methods: O ver a recent 9-month period, we reviewed the vascular laboratory chart s of 540 symptomatic patients (696 Limbs) who underwent CDS for clinic ally suspected acute DVT. Patients who had a previous episode of DVT w ere excluded. Results: CDS satisfactorily visualized all three paired calf veins in 655 of the limbs (94%). Inadequate scans (n = 41) were a ttributed to edema in 29, excessive calf size in eight, and anatomic i naccessibility in four. Peroneal veins were the most difficult to visu alize (n = 29), followed by posterior tibial (n = 10) and anterior tib ial (n = 9) veins. CDS identified acute DVT in 159 of 655 Limbs (24%) that had adequate scans. Calf vein thrombi were detected in 110 of the 655 limbs (17%) and in 69% of the 159 Limbs with DVT. Clots were conf ined to the calf veins in 53 limbs with DVT (33%). Isolated calf vein thrombi were found in 45% of outpatient limbs and in 27% of inpatient limbs with DVT. The peroneal (81%) and posterior tibial veins (69%) we re more frequently involved (p < 0.001) than the anterior tibial veins (21%). In Limbs with calf DVT, the prevalence of thrombosis isolated to the peroneal and posterior tibial veins was similar (37% and 25%, r espectively); no limb had an isolated anterior tibial DVT (p = 0.02). Conclusion: CDS is a reliable method for evaluating calf veins for DVT . Calf vein thrombosis is common in patients who have acute DVT and of ten occurs as an isolated finding. The peroneal and posterior tibial v eins are involved in the majority of cases; thrombi occur much less fr equently in the anterior tibial veins. We conclude that CDS should be the noninvasive method of choice for the initial evaluation of patient s in whom DVT is suspected, and we recommend that calf veins should al ways be studied but that routine scanning of the anterior tibial veins may not be necessary.