Reply:
======

* L. Pierot

We have read with great interest the letter of Pelz and Lownie, and we are grateful for their interesting comments regarding our paper on the WEBCAST-2 study.1 We wish to make the following comments in response.

1.  Because Pelz and Lownie are only challenging the “high” efficacy of WEB treatment, it probably implies that they concur with the high safety profile of the WEB device reported in WEBCAST-2. This is the primary concern when dealing with aneurysm treatment, and all published results of good clinical practice studies evaluating WEB (WEBCAST, French Observatory, and WEB-IT) have indeed confirmed similar high safety results: low morbidity (between 0.7% and 3.2%) and no mortality at 1 month.2⇓–4 For reference, the meta-analysis cited by Pelz and Lownie reports mortality of 1.7% for surgical treatment of unruptured aneurysms, with the rate of unfavorable outcome at 6.7%.5

2.  Pelz and Lownie are probably right when they write that “high” efficacy might not be the appropriate wording to qualify WEBCAST-2 anatomical results. Still, the rate of adequate occlusion at 1 year is 80.0%, consistent with observations from other WEB good clinical practice studies.2,3 Although we know that neck remnant is rarely associated with rupture or rerupture, adequate occlusion is really what matters once safety is confirmed. It is also important to point out that patients with wide-neck bifurcation aneurysms—the target population of the WEBCAST-2 study—represent a challenging and difficult-to-treat population, regardless of the treatment technique. We actually agree that long-term follow-up is needed to properly evaluate the stability of aneurysm treatment and claim “high” efficacy. Long-term follow-up has been obtained in a small, retrospective European series, but the most important data will come from the good clinical practice studies where 5 years' follow-up is foreseen.6

3.  Interestingly, Pelz and Lownie are comparing the efficacy of WEB treatment with surgical treatment. Kotowski et al5 report 2 interesting facts in their meta-analysis: aneurysm occlusion data are missing for 82.2% of all clipped aneurysms in the analyzed series, and there was no long-term follow-up available. With that in mind, can we scientifically consider surgical treatment “effective” from a long-term anatomic standpoint?

## References

1.  1. Pierot L, Gubucz I, Buhk JH, et al. Safety and efficacy of aneurysm treatment with the WEB: results of the WEBCAST-2 study. AJNR Am J Neuroradiol 2017;38:1151–55 doi:10.3174/ajnr.A5178 pmid:28450432
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo5OiIzOC82LzExNTEiO3M6NDoiYXRvbSI7czoyMToiL2FqbnIvMzgvMTIvRTExMC5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

2.  2. Pierot L, Costalat V, Moret J, et al. Safety and efficacy of aneurysm treatment with WEB: results of the WEBCAST study. J Neurosurg 2016;124:1250–56 doi:10.3171/2015.2.JNS142634 pmid:26381253
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.3171/2015.2.JNS142634&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=26381253&link_type=MED&atom=%2Fajnr%2F38%2F12%2FE110.atom) 

3.  3. Pierot L, Moret J, Turjman F, et al. WEB treatment of intracranial aneurysms: clinical and anatomical results in the French Observatory. AJNR Am J Neuroradiol 2016;37:655–59 doi:10.3174/ajnr.A4578 pmid:26514608
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiIzNy80LzY1NSI7czo0OiJhdG9tIjtzOjIxOiIvYWpuci8zOC8xMi9FMTEwLmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

4.  4. Fiorella D, Molyneux A, Coon A, et al. Demographic, procedural, and 30-day safety results from the WEB Intra-saccular Therapy Study (WEB-IT). J Neurointerv Surg 2017 Jan 17. [Epub ahead of print] doi:10.1136/neurintsurg-2016-012841 pmid:28096478
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTE6Im5ldXJpbnRzdXJnIjtzOjU6InJlc2lkIjtzOjk6IjkvMTIvMTE5MSI7czo0OiJhdG9tIjtzOjIxOiIvYWpuci8zOC8xMi9FMTEwLmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

5.  5. Kotowski M, Naggara O, Darsaut TE, et al. Safety and occlusion rates of surgical treatment of unruptured intracranial aneurysms: a systematic review and meta-analysis of the literature from 1990 to 2011. J Neurol Neurosurg Psychiatry 2013;84:42–48 doi:10.1136/jnnp-2011-302068 pmid:23012447
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiam5ucCI7czo1OiJyZXNpZCI7czo3OiI4NC8xLzQyIjtzOjQ6ImF0b20iO3M6MjE6Ii9ham5yLzM4LzEyL0UxMTAuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

6.  6. Pierot L, Klisch J, Liebig T, et al. WEB-DL endovascular treatment of wide-neck bifurcation aneurysms: long-term results in a European series. AJNR Am J Neuroradiol 2015;36:2314–19 doi:10.3174/ajnr.A4445 pmid:26228882
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czoxMDoiMzYvMTIvMjMxNCI7czo0OiJhdG9tIjtzOjIxOiIvYWpuci8zOC8xMi9FMTEwLmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

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