Compliance matching stent placement in the carotid artery of the swine promotes optimal blood flow and attenuates restenosis.

ABSTRACT

OBJECTIVES: We assessed the value of a gradient-compliant stent in an animal model. METHODS: Bilateral carotid arteries were stented with nitinol stents having variable-oversizing, variable-stiffness, and with (CMS, 10 animals) and without (SMART, four animals) compliance-matching endings. Angiography, hemodynamic, scanning-electron-microscopic and histological analyses were performed at 3-month. The protocol was completed in 14 among 19 swines. RESULTS: Transient (1-month) exaggerated recoil, attributable to stress-induced phasic inhibition of vasorelaxation, developed at CMS endings. At mid-term, all stents were endothelialized; CMS-stents, but not SMART-stents, were incorporated into walls (one-strut-thickness). Restenosis developed outside SMART-stents (cell migration+wall-compensatory enlargement) whereas CMS-stents elicited no or focalized cell-accumulations at endings that bulged vascular walls radially outward. SMART-stents were blood-flow neutral, whereas CMS-stents favored (higher-stiffness, higher-oversizing) or opposed (lower-stiffness, less-oversizing) carotid blood flow. CONCLUSIONS: Direct carotid stenting with stents having compliance-matched endings and specific requirements of stiffness and oversizing can optimize blood flow to the brain and restrict local restenosis.