Collagen microbeads: experimental evaluation of an embolic agent in the rete mirabile of the swine.

Abstract

PURPOSE: To evaluate the histologic and angiographic effects of collagen microbeads as an embolic agent in the swine rete mirabile. METHODS: Human collagen particles (380 +/- 100 microns) of spheroidal shape and smooth surface were used to embolize the rete mirabile in five swine. Control angiograms and pathologic examinations were obtained immediately and sequentially from 3 to 35 days after embolization. RESULTS: The collagen particles were easy to inject through microcatheters. Embolization was always angiographically complete and persistent for at least 5 weeks. Histologic studies showed occlusion of 25% to 50% of the rete vessels. After 3 and 5 weeks' follow-up, transmural and adventitial chronic inflammation was present. Inflammatory infiltrates included lymphohistiocytic cells and scattered eosinophils. The foreign-body giant-cell reaction was pronounced. No evidence of angionecrosis or focal hemorrhage was shown. CONCLUSIONS: Collagen microbeads are a promising experimental embolic agent, with potential future applications in humans.