Purpose of Technology: Flow diverters are stents tunneled through blood vessels to the site of an intracranial aneurysm to block the blood vessel opening to the aneurysm. The stent diverts blood flow past the aneurysm opening, prohibiting inflow to the aneurysm, with the intent of causing hemostasis within the aneurysm, endothelial growth at the opening to the aneurysm, and, eventually, occlusion of the aneurysm.

Rationale: Flow diverter devices (FDDs) are intended to incur less short-term, treatment-associated morbidity than open surgery and provide an endovascular treatment option when stent-assisted coiling is difficult or unfeasible, such as for giant, wide-necked aneurysms.

Controversy: Concerns about the safety and efficacy of FDDs compared with other options exist due to limited comparative data and the requirement of FDDs to take several months for occlusion to occur, during which time patients are given antiplatelet therapy that can inhibit coagulation if rupture does occur. There may be a greater risk of unintentionally occluding non-target blood vessels than for other treatments.

Relevant Questions:

  • What proportion of patients have aneurysm occlusion when an FDD is used? How do occlusion outcomes compare with other interventions?
  • What complications are associated with FDDs? How do complications compare with other interventions?
  • Have definitive patient selection criteria been established?

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