TREATMENT OF EXPERIMENTAL ANEURYSMS USING COLLAGEN-COATED MICROCOILS

ENDOVASCULAR TREATMENT OF certain surgically difficult aneurysms is cu rrently performed using fibered microcoils or electrolytically detacha ble microcoils to obliterate these lesions by forming an intra-aneurys mal thrombus. Unfortunately, this treatment options results in a signi ficant incidence of incomplete obliteration of treated aneurysms. A th rombus can recanalize, resulting in further aneurysm growth and subseq uent rupture. Nineteen aneurysms were surgically created in 10 pigs us ing jugular venous pouches. The aneurysms were allowed to mature for p eriods of 7 days as long as 11 weeks prior to embolization. Fourteen r emained patent for embolization. The aneurysms were then embolized (9 with collagen-coated microcoils, 5 with dacron-fibered platinum microc oils). Follow-up angiograms were obtained prior to sacrifice at 1, 3, 6, 9, and 12 weeks postembolization, and the embolized aneurysms and p arent vessels were harvested for histopathological studies. The curren t study was designed to evaluate the potential efficacy of collagen-co ated microcoils in providing an enduring therapy for aneurysms by comp aring this new embolic device with the standard dacron-fibered platinu m microcoils in a swine common carotid artery side wall aneurysm model . The aneurysms treated with collagen microcoils were completely oblit erated with a collagen-rich fibrous scar with no histological evidence of residual thrombus or recanalization. Additionally, after treatment of experimental aneurysms with collagen microcoils, re-endothelializa tion across the former aneurysm neck was seen. In contrast, aneurysms embolized with dacron-fibered microcoils contained persistent thrombus surrounded by a relatively immature scar with residual aneurysmal lum en and lack of endothelium. This preliminary study suggests that colla gen-coated microcoils can produce a mature endovascular scar and endot helial barrier that is superior to a thrombus. This treatment may hold promise form permanent treatment of surgically difficult aneurysms.