Venous Haemodynamics and Morphology in Relation to Recanalisation and Thrombus Resolution in Patients with Proximal Deep Venous Thrombosis

Abstract

Objective:

Follow-up studies of deep venous thrombosis (DVT) are needed to gain increased knowledge of the process of recanalisation over time. In this study modern diagnostic techniques were used to analyse changes in venous circulation during the process of recanalisation and thrombus resolution.

Design and setting:

Prospective follow-up study of patients with symptomatic DVT referred to a vascular diagnostic laboratory. The patients were evaluated by repeated examinations with colour duplex ultrasound and computerised strain-gauge plethysmography.

Patients:

Eighteen consecutive patients with acute DVT occluding the calf veins and femoropopliteal vein segments.

Main outcome measures:

Ultrasonographic assessment of thrombus resolution and flow patterns in deep and superficial veins. Plethysmographic determination of venous volume and venous outflow capacity.

Results:

At 3 months' and 6 months' follow-up, 33% and 56%, respectively, were recanalised but almost all limbs still had some degree of functional outflow obstruction. Duplex evaluation further demonstrated a complex pattern of recanalisation with thrombus resolution from above, from below or both. Computerised strain-gauge plethysmography showed a progressive time-related increase in venous outflow capacity and venous volume over 6 months, but volumetric variables could not be used to distinguish between limbs with patent veins and those with still-occluded veins. None of the limbs had completely compressible femoropopliteal venous segments at the end of the follow-up.

Conclusion:

The combination of these two modern diagnostic techniques, suitable for repeated studies, can provide detailed information on morphological and haemodynamic changes occurring during the process of recanalisation and thrombus resolution.