A prospective study of the natural history of femoropopliteal artery stenosis using duplex ultrasound.

A foreknowledge of impending femoral artery occlusion might allow prevention of a deterioration in ischaemia by percutaneous transluminal angioplasty (PTA) in the preocclusive stage. A window of opportunity exists before a femoral stenosis progresses to occlusion and its treatment by PTA becomes more difficult, riskier and associated with lower patency. The size of this window is unknown. This is the first report of a study of the natural history of femoral stenoses using Duplex ultrasound. The aims of the study were to determine in patients with symptomatic peripheral arterial disease: (1) the incidence of progression from stenosis to occlusion; (2) the change in severity of stenosis over time; and (3) the relationship between severity of stenosis and progression to occlusion. The velocity ratio (VR) of 43 femoral artery stenoses in 38 patients was measured by Duplex ultrasound. The examination was repeated after a median of 28 (range 5-76) weeks. Nine/43 (21%) stenoses progressed to occlusion within a median of 13 weeks. Little overall change in VR was demonstrable if occlusion did not occur. Only stenoses with a VR > 3 progressed to occlusion in the study period. The data suggest that severe stenoses progress more rapidly than moderate, with a relatively brief window of opportunity. If PTA is to be undertaken, stenoses with a VR greater than 3 should be treated with minimum delay.