ELASTIC RESPONSE OF HUMAN ILIAC ARTERIES IN-VITRO TO BALLOON ANGIOPLASTY USING HIGH-RESOLUTION CT

Previous angioplasty studies have used angiography and intravascular u ltrasound to obtain vascular dimensions. These imaging methods do not always provide reliable measurements due to limitations in image orien tation and resolution. In this study, high-resolution (0.1 x 0.1 x 0.5 mm) transverse CT slices were obtained from human common-iliac arteri es in vitro to study their elastic response pre- and post-angioplasty, Seven iliacs from five patients were imaged over the physiological pr essure range both pre- and post-angioplasty. Contrast was obtained wit h humidified air surrounding the artery. Angioplasty was done with 10 or 12 mm diameter Medi-Tech balloon catheters with a balloon pressure of 300 kPa held for 30 s. Lumen cirumference, c, measured from the ima ges, was plotted against pressure, P, and curve fitting showed c = A(1 - e(- KP)) + B where A, K, and B are fitting parameters. Six lesions appeared soft and were compressed, while one was calcified and partial ly lifted off the wall. Normalized changes in parameters B and K were much higher post-angioplasty in the calcified lesion, and were over 3 standard deviations from the means of the normalized changes in the si x compressed lesions. Balloon/stenosed lumen diameter ratios greater t han 1.2 produced a lumen area increase of 38.6 +/- 4.1%(S.D.)(n = 3); ratios less than 1.2 produced an increase of 4.4 +/- 5.1%(S.D.)(n = 4) . There was no correlation between area increase and balloon/normal lu men diameter ratio (the value used clinically). Arteries with lesions containing stiffer plaques that tear from the artery wall during angio plasty appear more distensible over the physiological pressure range p ost-angioplasty. (C) 1998 Elsevier Science Ltd. All rights reserved.