Flow Diverting Stent Helps Contain Cerebrovascular Defects

An innovative flow diverter embolization device protects susceptible patients from large and giant brain unruptured aneurysms.

The Stryker (Kalamazoo, MI, USA) Surpass Streamline Flow Diverter is a cobalt chromium braided stent that directs blood flow within an intracranial artery away from a weakened blood vessel sac or aneurysm. The high-mesh density of the braid is achieved by increasing the number of braid wires in concert with device diameter; while the 2 mm device has 48 braided wires, the 3 and 4 mm devices have 72 braided wires, and the 5 mm device has 96 wires, providing a more uniform pore density over different sizes.

Filament sizes change from 25 to 36 mm, depending on the device diameter. The increase in wires maintains consistent density across a range of vessel sizes, thereby facilitating reliable and consistent occlusion of the aneurysm over time, and helping to reduce the risk of a future rupture. In addition, the braid angle is designed to prevent unwanted changes in mesh density around curves and to minimize foreshortening. The Surpass Streamline Flow Diverter is loaded within a 3.7-Fr distal catheter with a pusher catheter and accepts a 0.014-inch micro-guidewire.

Surpass Streamline can be positioned using the Surpass delivery system, designed for consistent deployment; the Halo delivery system, which provides atraumatic access to distal vasculature using an intermediate catheter, improving stent fit and climbing performance; or the Streamline delivery system, which allows it to be repositioned distally or proximally, and to be redeployed until precise placement and enhanced vessel apposition are achieved.

“Surpass Streamline is the first flow diverter indicated for large and giant posterior communicating artery aneurysms; these unruptured aneurysms are more challenging, due to their location and surrounding anatomy,” said professor of radiology and neurological surgery Philip Meyers, MD, of New York Presbyterian/Columbia University Medical Center (NY, USA). “The stent is designed to reliably open and provide consistent mesh density across the neck of the aneurysm to aid in aneurysm occlusion while maintaining perforator artery patency.”

While originally indicated for wide-necked or fusiform aneurysms from the petrous segment to the clinoid segment of the internal carotid artery (ICA), flow diversion today is being more broadly applied to small aneurysms, anterior cerebral artery aneurysms, recurrent aneurysms, and other endoluminal and intra-saccular defects.