Haemodynamic changes in the Moncada model of atherosclerosis.

1. The application of a non-constricting silastic cuff to the rabbit common carotid artery (CCA; n = 5) results in intimal thickening within 7 days. 2. Ultrasonography showed kinking of the CCA at the cuff edges, as well as a 13% arterial narrowing (P less than 0.02) within the cuffed segment, both at days 1 and 7. Correspondingly, the time averaged diastolic Doppler velocity (TAV) was 68.8 +/- 12.8% higher (P less than 0.025) in the cuffed region in comparison with that 1 cm proximal (P 1 cm) on day 1, and 54.2 +/- 11.5% higher at day 7 (P less than 0.05). TAV values along control silastic strips were not significantly changed. 3. There was a significant increase (P less than 0.025) in intimal area within the cuffed region (0.098 +/- 0.024 mm3) compared with both the proximal control (0.014 +/- 0.001 mm3) and with that over control silastic strips (0.021 +/- 0.004 mm3, P less than 0.01). 4. Medial area within the cuff (0.433 +/- 0.017 mm3) was decreased (P less than 0.005) compared with P 1 cm control (0.602 +/- 0.069 mm3). 5. There was gross peri-arteritic thickening involving the adventitia along the non-constricted cuffed segment. Importantly, it was also noted alongside the control silastic strip. 6. Kinking of the CCA and associated vasoconstriction cause changes in blood flow velocity along even a non-constricting cuff, and this may explain the intimal thickening previously noted in this experimental model. The peri-arteritic changes, on the other hand, appear to be a reaction to the silastic itself.