This article references:
Gallas S, Januel AC, Pasco A, et al. Long-Temr Follow-Up of 1036 Cerebral Aneurysms Treated by Bare Colis: A Multicentric Cohort Treated between 1998 and 2003. AJNR Am J Neuroradiol first published on August 13, 2009 as doi: 10.3174/ajnr.A1744.
The authors analyzed the long-term stability of treatment of cerebral aneurysms treated exclusively with GDC, focusing in re-treatments and re-bleeding rates during follow up.
The authors have been meticulous in data recollection, once, these patients have been followed since 1998. Additionally, the fact to be a multicentric trial, demands a greater author commitment for the patients follow up, according to strict designed protocol.
The experience presented here, is the continuum of the data reported by the authors previously in 2005 and 2008 in this journal. Now, nevertheless, the totality of the series including unruptured and ruptured intracranial aneurysms. The authors describe the radiological findings in a considerable sample of 1036 aneurysms treated in 929 patients, with a mean of follow up of 66 months and, a very significant number over than 400 aneurysms followed more than five years.
The results of this multicentric trial must be analyzed cautiously, before to be extrapolated as part of the standard treatment of “aneurysms”. In this experience near 90% of lesions were smaller of 10 mm, and, only 2% of the lesions were giant and therefore, similar to reports of ISAT, these results could be validated just for a sub-type of patients with small aneurysms of the anterior circulation, in a good clinical status, that after a multidisciplinary evaluation were defined as good candidates to endovascular treatment , thus, there was an important selection bias and, unfortunately, exclude those lesions that have an elevated risk of treatment failure.
In this report, as well as previous publications, the authors unfortunately did not describe the characteristics of the parent vessel and his relation with the neck of the aneurysm; the dome: neck ratio was not considered and presumably, due to high rate of effectiveness reported, one would suppose that the majority of lesions had small neck or at least a favorable dome: neck ratio; although 10% required balloon remodeling assisted technique.
Regarding re-treatment group, there is lack of morphological data (i.e. size, neck diameter, Location) to analyze if, with the current endovascular technology available, these numbers could dramatically be reduced. Hence, special consideration is necessary to evaluate the 731 aneurysms that initially showed a complete occlusion, given that, it is in this group of lesions in where, really it is reflected the treatment stability over-time. Once removed the patients who died and those that were lost during the follow up, a total of 611 aneurysms was finally followed and of these, 109 (17,8%) showed a negative variation during follow up (Subtotal or incomplete) according to illustrated in table 4. Although, this result it’s in agreement with published data regarding recanalization/regrowth rates, it’s remarkably that the majority of aneurysms were small lesions , with apparent favorable dome: neck ratio and, would be expected a better result. However, these results refer to think that a greater volumetric filling and/or, the use of biological materials that promotes a more stable intra-aneurysmal thrombosis may perhaps reduce these numbers even more.
The re-bleeding rate did not surpass 1% , this demonstrates once again that the endovascular treatment of cerebral aneurysms with GDC is effective and clinically protective. But, at the same time it generates the question about the necessity of re-treatment and what are the criteria for the decision making. Currently, there is not an objective, validate and, reproducible methodology to evaluate the immediate initial occlusion and, comparatively help us to interpret the morphologic changes over the time. The work of the authors with this cohort of patients will continue generating valuable information to the world of Neurointerventionism and bring answers to this nascent specialty.
Pedro Lylyk MD.
