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Patients, not pictures: why complete occlusion may be a complete disaster
  1. David F Kallmes1,
  2. David Fiorella2,
  3. Waleed Brinjikji1,
  4. Colin P Derdeyn3
  1. 1 Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
  2. 2 Cerebrovascular Center, Stony Brook University Medical Center, Stony Brook, New York, USA
  3. 3 Department of Radiology, University of Iowa, Iowa City, Iowa, USA
  1. Correspondence to Dr David F Kallmes, Department of Radiology, Mayo Clinic, 200 First Street SW, Minnesota 55905, Rochester, USA; kallmes.david{at}

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The Pipeline for Uncoilable or Failed Aneurysms (PUFS) trial is a landmark trial in neurointervention, with reverberations that continue to echo years after completion.1 First, it was the initial Premarket Approval (PMA) trial for an endovascular aneurysm device. PMA trials are now the norm. Second, this device led to a paradigm shift in the treatment of aneurysms, with a focus on endoluminal rather than endosaccular aneurysm treatment. Indeed, a large fraction of patients are now treated with flow diversion rather than coils.2 Last, and perhaps inappropriately, PUFS used ‘complete aneurysm occlusion’ as its primary efficacy outcome. This last feature has set a standard that is now being applied by the FDA across the board to subsequent PMA trials of new endovascular aneurysm treatment devices, including both endoluminal and endosaccular devices (WEB-IT, NCT02191618; LVIS Pivotal Trial, NCT01793792). This ‘complete occlusion’ policy shift has been adopted even though there are no compelling data to suggest that complete aneurysm occlusion results in different clinical outcomes compared with near complete aneurysm occlusion. Indeed, available evidence suggests that rates of recurrence, retreatment, and hemorrhage are relatively similar between these two angiographic outcomes.3 4

This mandate for complete occlusion is a particular problem for traditional and well-established endosaccular devices such as detachable coils: subtotal occlusion with endosaccular coils is clearly protective from recurrent hemorrhage. In the pivotal International Subarachnoid Aneurysm Trial (ISAT) that conclusively established coiling as superior to clipping for selected patients with ruptured aneurysms, only 66% of endovascularly-treated aneurysms were completely occluded at first angiographic follow-up.5 6 The remainder had subtotal occlusion or neck remnants (26%), incomplete occlusion (8%), or unknown angiographic outcomes (11%). …

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  • Contributors All authors contributed to the conception, drafting, revisions and approval of this commentary. DFK is the guarantor of this work.

  • Funding DK: Research support from Medtronic, MicroVention, NeuroSigma, Shape Memory Therapeutics, IndumedX, Sequent Medical, NeuroSave; DF: Research support from MicroVention, Penumbra, Sequent, Siemens; WB: None; CD: None.

  • Competing interests DFK: Consulting for Medtronic (all funds to the institution), ownership stake in Marblehead Medical. DF: Consulting for Medtronic, MicroVention, Codman, Penumbra, Sequent; WB: CEO of Marblehead Medical. CD: None.

  • Provenance and peer review Not commissioned; internally peer reviewed.