Introduction and purpose The purpose of this retrospective analysis is to compare chemically inert and second generation ‘bioactive’ endovascular coils in the treatment of cerebral aneurysms. This small, non-randomized study includes long term follow-up conventional angiography (mean Cerecyte date 29 months, mean bare platinum date 38 months) not previously described in the literature. Data analysis includes initial occlusion rates, recanalization rates, outcome, packing density and follow-up assessment of coil performance and stability.

Materials and methods Cases were collected between 2002 and 2009 based on coil treatment composed of strictly bare platinum or biologically active coils. Ninety cases were assembled; 50 aneurysms were treated using Micrus bare platinum coils and 40 aneurysms were treated with Cerecyte (Micrus Endovascular) coils. Two cases were excluded from analysis in each group due to aneurysm characteristics, partial thrombosis and fusiform anatomy. Patient medical records were retrospectively reviewed for information regarding coil manufacturer, treatment details, follow-up angiographic date and outcome.

Results Persistent complete occlusion rates were similar between the bare platinum and Cerecyte populations (35.4% (17/48) and 39.5% (15/38)), respectively. Progressive occlusion was noted in 43.5% (10/23) of patients in the Cerecyte population compared with the bare platinum population which recorded a rate of 19.4% (6/31). Comparison of final follow-up between the two groups (Cerecyte versus bare platinum) was performed using Fisher's exact test; however, statistical significance was not achieved within this small assortment of patients (p=0.0542).

Short term follow-up data, at 6 and 12 months, were available for 70% (26/37) and 51% (19/37) of the Cerecyte population and 71% (32/45) and 58% (26/45) of the bare platinum group, respectively. Long term follow-up data, at 3 and 5 years, were available for 41% (15/37) and 2.7% (1/37) of the Cerecyte population and 49% (22/45) and 24% (11/45) of the bare platinum group, respectively.

Mean aneurysm volume and size delineations were conducted for both study cohorts. The bare platinum mean volume was 217.96 mm³, with 20 aneurysms smaller than 7 mm and 28 aneurysms measuring 7 mm or greater. In the Cerecyte group, the average aneurysm size was determined to be 587.70 mm³, with 18 aneurysms smaller than 7 mm and 20 aneurysms measuring 7 mm or greater.

Initial mean packing density calculated in the bare platinum group was 23.07±11.88% (n=45) and 28.68±18.38% in the Cerecyte population (n=33). Aneurysmal recanalization was demonstrated on follow-up angiography in three (17.6%) cases within the bare platinum population. In comparison, only a single case (6.6%) of recanalization was noted in the Cerecyte population.

Adverse clinical outcome and treatment related death occurred in 2% (1/48) of patients within the bare platinum group. No complications of this nature occurred in the Cerecyte population.

Conclusion The results of this single center, single physician experience suggest that Cerecyte coils have a satisfactory and superior durable treatment profile compared with bare platinum coils, demonstrating lower recanalization rates and fewer devastating outcomes in this small cohort. Higher packing attenuation was also achieved in the Cerecyte faction. However, due to the non-randomized, retrospective nature of this small dataset, no definitive clinical conclusions can be drawn.