EX-VIVO HUMAN CAROTID-ARTERY BIFURCATION STENTING - CORRELATION OF LESION CHARACTERISTICS WITH EMBOLIC POTENTIAL

Purpose: To develop an ex vivo human carotid artery stenting model tha t can be used for the quantitative analysis of risk for embolization a ssociated with balloon angioplasty and stenting and to correlate this risk with lesion characteristics to define lesions suitable for balloo n angioplasty and stenting. Methods: Specimens of carotid plaque (n = 24) were obtained circumferentially intact from patients undergoing st andard carotid endarterectomy. Carotid lesions were prospectively char acterized on the basis of angiographic and duplex findings before enda rterectomy and clinical findings. Specimens were encased in a polytetr afluoroethylene wrap and mounted in a now chamber that allowed access for endovascular procedures and observations. Balloon angioplasty and stenting were performed under fluoroscopic guidance with either a Palm az stent or a Wallstent endoprosthesis. Ex vivo angiograms were obtain ed before and after intervention. Effluent from each specimen was filt ered for released embolic particles, which were microscopically examin ed, counted, and correlated with various plaque characteristics by mea ns of multivariate analysis. Results: Balloon angioplasty and stenting produced embolic particles that consisted of atherosclerotic debris, organized thrombus, and calcified material. The number of embolic part icles detected after balloon angioplasty and stenting was not related to preoperative symptoms, sex, plaque ulceration or calcification, or artery size. However, echolucent plaques generated a higher number of particles compared with echogenic plaques (p < 0.01). In addition, inc reased lesion stenosis also significantly correlated with the total nu mber of particles produced by balloon angioplasty and stenting (r = 0. 55). Multivariate analysis revealed that these two characteristics wer e independent risk factors. Conclusions: Echolucent plaques and plaque s with stenosis greater than or equal to 90% produced a higher number of embolic particles and therefore may be less suitable for balloon an gioplasty and stenting. This ex vivo model can be used to identify hig h-risk lesions for balloon angioplasty and stenting and can aid in the evaluation of new devices being considered for carotid balloon angiop lasty and stenting.