ASSESSMENT OF REGIONAL VASCULAR DISTENSIBILITY IN DISEASED ILIOFEMORAL ARTERIES BY INTRAVASCULAR ULTRASOUND

The influence of atherosclerosis on distensibility of iliac and superf icial femoral arteries was assessed retrospectively in 28 patients usi ng intravascular ultrasound. Distensibility was related to lesion morp hology, lesion geometry, percentage area stenosis, effect of balloon a ngioplasty, hypertension and patient's age. In 10 patients, free lumen area remained unchanged during the cardiac cycle. From the remaining 18 patients, a total of 135 cross-sections underwent qualitative and q uantitative analysis. Cross-sections without a lesion were compared wi th those showing soft/hard and eccentric/concentric lesions. At normal sites, iliac arteries showed greater distensibility than femoral arte ries (6.5 +/- 2.4% vs. 3.5 +/- 0.9%; p less than or equal to 0.05). Ha rd lesions in iliac arteries were less distensible than soft lesions; in femoral arteries this difference was less pronounced. Lesion geomet ry did not influence arterial distensibility. Intravascular ultrasound revealed no difference in distensibility when normal cross-sections w ere compared with those having a <50% or a 50% to 90% area stenosis. I n contrast, a significant decrease in femoral artery distensibility wa s found in the presence of > 90% stenosis (0.4%). Comparison of cross- sections before and after balloon angioplasty revealed a marked increa se in distensibility of iliac arteries following intervention; in the femoral artery, there was practically no change in distensibility. Hyp ertension and increasing age proved to have no significant influence o n arterial distensibility. This study demonstrates that intravascular ultrasound is potentially a powerful tool to assess arterial distensib ility and the influence of atherosclerosis on vascular dynamics.