Comparison of platinum and first-generation Matrix coils in under-packed canine side-wall aneurysms: Evaluation of progressive thrombosis

University of Wisconsin–Madison, Madison, Wisconsin, United States
Neuroradiology (Impact Factor: 2.49). 12/2007; 49(11):939-45. DOI: 10.1007/s00234-007-0280-7
Source: PubMed


There is much speculation in reference to the occurrence and mechanisms of progressive aneurysm occlusion after treatment with bioactive coils. However, to our knowledge, there are no studies documenting the impact on progressive occlusion in aneurysms that are intentionally under-packed.
A total of 24 experimental side-wall aneurysms were created in canine common carotid arteries. Of these 24, 9 were treated with Guglielmi detachable coils (GDC) and 15 with first-generation Matrix (Matrix1) coils to packing densities of 22% or less. Angiograms were obtained immediately after treatment and again at the time of explant at 2 weeks, 8 weeks, or 12 weeks, and were graded utilizing the Raymond scale. At the time of the final angiography and explant all aneurysms were histologically processed and evaluated.
At the conclusion of initial coiling, near or complete occlusion was achieved in 7 of the 15 aneurysms (47%) treated with Matrix1 coils and in 2 of the 9 (22%) treated with GDC. Of the aneurysms that were incompletely occluded, six of eight (75%) treated with Matrix1 coils and two of seven (29%) treated with GDC showed progressive thrombosis at explant. Histopathological analysis demonstrated that the aneurysms treated with Matrix1 coils had increased fibrocellular tissue and inflammation, with less histological recanalization or vascular spaces, relative to those treated with GDC.
Experimental wide-necked side-wall canine aneurysms suboptimally treated with first-generation Matrix1 coils had a higher incidence of progressive occlusion and on histological analysis showed evidence of more advanced thrombus organization than did those treated with GDC.

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    ABSTRACT: Introduction: To explore the patency and growth of surgical sidewall aneurysms in rabbits. Materials and methods: Forty sidewall aneurysms were created in the right common carotid artery (RCCA). Intravenous digital subtraction angiography (DSA) through the ear vein was performed immediately after creation. Three weeks later, intra-arterial DSA through the femoral artery was performed. Aneurysm sizes (neck, width, height and volume) were measured and calculated immediately after creation and 3 weeks later. Aneurysm patency after creation was evaluated. Differences in aneurysm sizes immediately after creation and 3 weeks later were compared using the Student's t test. Results: Aneurysms and the parent artery remained patent in 38 (95%) of the 40 rabbits 3 weeks after creation. Two other rabbits (5%) showed aneurysm occlusion. There was a significant difference in aneurysm neck size 3 weeks after creation (3.6±0.9 mm vs 2.4±0.4 mm, p<0.0001). The aneurysm became wider 3 weeks later (5.8±1.5 mm vs 4.3±1.2 mm, p<0.0001). Aneurysm length was also larger than immediately after creation (6.1±1.3 mm vs 4.3±1.4 mm, p<0.0001). The aneurysm volume was larger than that created immediately (127.5±89.4 mm(3) vs 51.0±34.9 mm(3), p<0.0001). Conclusions: The patency rate of sidewall aneurysms in rabbits is high. The aneurysm keeps growing for at least 3 weeks after creation.
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