, Volume 60, Issue 10, pp 1075–1084 | Cite as

New generation Hydrogel Endovascular Aneurysm Treatment Trial (HEAT): a study protocol for a multicenter randomized controlled trial

  • Karl R. Abi-Aad
  • Rami James N. Aoun
  • Rudy J. Rahme
  • Jennifer D. Ward
  • Jason Kniss
  • Mary Jeanne Kwasny
  • Mithun G. Sattur
  • Matthew E. Welz
  • Bernard R. BendokEmail author
Interventional Neuroradiology



Aneurysm recanalization constitutes a limitation in the endovascular treatment of intracranial aneurysms using conventional bare platinum coils. The development of platinum coils coupled with hydrogel polymers aimed at decreasing the rates of recurrence by way of enhanced coil packing density and biological healing within the aneurysm. While enhanced occlusion and durability has been shown for the first generation hydrogel coils, their use was limited by technical challenges. Less data is available regarding the second-generation hydrogel coils which have been designed to perform like bare platinum coils.


The new generation Hydrogel Endovascular Aneurysm Treatment Trial (HEAT) is a multicenter, randomized controlled trial that compares the health outcomes of the second-generation HydroCoil Embolic System with bare platinum coils in the endovascular intracranial aneurysms. The primary endpoint is aneurysm recurrence, defined as any progression on the Raymond aneurysm scale, over a 24-month follow-up period. Secondary endpoints include packing density, functional independence, procedural adverse events, mortality rate, initial complete occlusion, aneurysm retreatment, hemorrhage from treated aneurysm, and any aneurysm recurrence.


Patient recruitment initiated in June 2011 and ended in January 2016 in 46 centers. Six hundred eligible patients diagnosed with an intracranial aneurysm, ruptured or unruptured were randomly assigned to one of the two treatment arms.


The HEAT trial compares the durability, imaging, and clinical outcomes of the second-generation hydrogel versus bare platinum coils in the endovascular treatment of ruptured or unruptured intracranial aneurysms. The results of this trial may further inform current endovascular treatment guidelines based on observed long-term outcomes.


Intracranial aneurysms Endovascular coils Hydrogel coil Bare platinum coil Subarachnoid hemorrhage 



New generation Hydrogel Endovascular Aneurysm Treatment Trial


Bare platinum coil


First-generation HydroCoil


Institutional review board


Electronic data capture


Procedure electronic case report form


Data and Safety Monitoring Board


Informed consent form


Compliance with ethical standards


The HEAT study was funded by MicroVention, Inc.

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All procedures performed in the studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Karl R. Abi-Aad
    • 1
  • Rami James N. Aoun
    • 2
  • Rudy J. Rahme
    • 3
  • Jennifer D. Ward
    • 3
  • Jason Kniss
    • 3
  • Mary Jeanne Kwasny
    • 4
  • Mithun G. Sattur
    • 1
  • Matthew E. Welz
    • 1
  • Bernard R. Bendok
    • 1
    Email author
  1. 1.Department of Neurological SurgeryMayo ClinicPhoenixUSA
  2. 2.Department of General SurgeryCleveland ClinicClevelandUSA
  3. 3.Department of Neurological SurgeryNorthwestern UniversityChicagoUSA
  4. 4.Department of Preventive MedicineFeinberg School of Medicine, Northwestern UniversityChicagoUSA

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