Pipeline, aneurysms and the FDA

Joshua A. Hirsch, Director,
January 19, 2012

Pipeline, aneurysms and the FDA

Response to "Estimating the proportion of intracranial aneurysms likely to be amenable to treatment with the pipeline embolization device." J Neurointerv Surg. 2011 Dec 2. [Epub ahead of print]

Ronil V. Chandra MBBS FRANZCR, Thabele M Leslie-Mazwi M.D and Joshua A Hirsch M.D

Department of Interventional Neuroradiology/ Endovascular Neurosurgery Massachusetts General Hospital Harvard Medical School

Corresponding Author: Joshua A Hirsch, M.D Department of Interventional Neuroradiology/ Endovascular Neurosurgery Massachusetts General Hospital 55 Fruit Street Gray 241 Boston MA 02114 E-mail: jahirsch@partners.org

We commend Brinjikji et al on their recent article estimating the proportion of intracranial aneurysms likely to be amenable to treatment with the pipeline embolization device (PED) 1. Based on aneurysm and parent artery morphology, 47% of their consecutive sample of 200 aneurysms could theoretically be treated by the PED.

We believe the paper might have been enhanced by consideration of the current FDA approved indications for use of the PED. The approved indications are for treatment of adults (22 years or greater) with large or giant (10 mm or greater) wide-necked (4mm or greater or no discernible neck) ICA aneurysms from the petrous to the superior hypophyseal segments. At least 30% or more of the aneurysms that could be treated by the PED in this theoretical analysis would have therefore been treated in an "off- label" fashion. Put differently, in the cohort examined, ICA aneurysms accounted for only 37% of the total sample. ICA aneurysms above the superior hypophyseal segment were also included, as noted in Figure 1C. Furthermore, ruptured aneurysms, which pose a relative contraindication for use of the PED, were also included. The latter was clearly acknowledged by the authors as a limitation and was required to increase overall sample size.

Many unanswered questions regarding the PED remain, particularly relating to rupture after treatment and long-term patency rates. Rather than concluding that anatomically almost half of aneurysms presenting to a tertiary neurovascular center could be treated with the PED, it might have been prudent to highlight the FDA approved indications, and useful to estimate the proportion of aneurysms that could be treated for these approved indications.

References:

1. Brinjikji W, Cloft HJ, Fiorella D, et al. Estimating the proportion of intracranial aneurysms likely to be amenable to treatment with the pipeline embolization device. J Neurointerv Surg. 2011

Conflict of Interest:

None declared

Conflict of Interest

None declared