Prognostic value of CT before thrombolytic therapy in iliofemoral deep venous thrombosis

PURPOSE: To prospectively assess the computed tomographic (CT) findings of iliofemoral deep venous thrombosis (DVT) and evaluate their relevance to the treatment of DVT with catheter-directed thrombolysis. MATERIALS AND METHODS: Twenty-four consecutive patients with symptomatic iliofemoral DVT were studied with both nonenhanced and contrast-enhanced CT before thrombolytic therapy. Mean duration of clinical symptom was 15.8 days +/- 20.8 (range, 1-90 d). Selected CT findings were prospectively evaluated and correlated with duration of symptoms and outcome of thrombolytic therapy, including attenuation number of the thrombus on nonenhanced CT (in HU), presence of venous distention (distention ratio: vein diameter divided by the diameter of corresponding normal contralateral vein), and poor venous wall demarcation. The following threshold variables were also evaluated: attenuation greater than or equal to60 HU and distention ratio greater than or equal to1.5. RESULTS: CT was suggestive of DVT in all patients, although different patterns were present. Higher attenuation on noncontrast CT was seen in patients who had favorable outcome of thrombolytic therapy compared to poor responders (66.1 +/- 8.7 vs 45.9 +/- 9.6; P < .0001). Distention ratio was also significantly higher in the good response group (2.6 +/- 1.4 vs 1.4 +/- 0.7; P < .05). Recent onset of clinical symptoms was associated with better outcome (9.4 d +/- 8.9 vs 28.6 d +/- 31.2; P < .03). Multiple-stepwise regression analysis of these variable produce the results of "attenuation >60" as the most predictive variable of favorable outcome of thrombolysis, followed by "distention ratio >1.5" and poor demarcation. CONCLUSION: Selected CT findings are better predictors of a favorable outcome of thrombolytic therapy than duration of clinical symptoms alone.