When plaque builds in the carotid arteries, surgeons step in to perform an endarterectomy, angioplasty or stenting to prevent patients from having a stroke. But the procedure itself is tricky and sometimes a piece of the plaque can break away and reach the brain, causing a stroke.
W. L. Gore & Associates (Flagstaff, Arizona) has just received FDA approval for a device that reverses the flow of blood during stenting procedures, offering a level of protection unavailable before.
"The Gore Flow Reversal System is really a game-changer in terms of neuroprotection," Stuart Broyles, PhD, Stroke Interventions Business Unit leader at Gore, told Medical Device Daily.
The Gore Flow Reversal System is neuroprotection technology that literally reverses the flow of blood at the treatment site prior to crossing the lesion so there's almost no chance that particles could escape to the brain.
"The current standard relies on continuous normal blood flow where debris that's released from the lesion is captured upstream or closer to the brain in a mechanical filter," Broyles said.
"In our case, we're flushing blood in the opposite direction of normal flow passed the lesion to flow down the balloon sheath to be filtered outside the body."
Flow reversal is achieved by selectively blocking the common carotid and external carotid artery blood flow.
After establishing an arteriovenous shunt, blood from collateral vessels via the Circle of Willis is redirected to the lower pressure venous return. Emboli — plaque debris — are then continously directed away from the brain during flow reversal.
"The hypothesis, which our clinical data support, is that the reversal of flow mitigates risk of particles making it passed the distally placed filter and reaching the brain," Broyles said. "It also means that we can establish flow reversal before you have to interact with the lesion your dealing with. You don't have to worry about knocking off some of the plaque before the patient is protected."
Embolic filters commonly used as the primary neuroprotection device must go across the lesion, leaving the patient unprotected and vulnerable during the procedure.
Broyles said there is currently no other product on the market that uses continuous flow reversal.
Daniel Clair, MD, of the Cleveland Clinic Foundation (Cleveland) and national co-principal investigator for the Gore EMPiRE clinical study, said that the Gore Flow Reversal System may help to establish carotid stenting as the therapy of choice for a greater number of patients.
In the EMPiRE study, the safety and efficacy of the Gore Flow Reversal System during carotid artery stenting was assessed in patients at high risk for carotid endarterectomy. The study met the primary endpoint of major adverse events of death, stroke, transient ischemic attack and myocardial infarction. The 30-day stroke death, and MI rate was 3.7% and the death / any stroke rate was 2.9%.
The study also showed positive results for some of the most challenging patient populations with a low death, stroke and MI rate of 2.6% for octogenarians and 3.8% for symptomatic patients.
Gore is manufacturing the Reversal System internally, with plans to roll out the device in a controlled manner, first identifying and training doctors.
"A big part of what we do is to focus on developing the knowledge base in the clinical population to understand the mechanisms so that this is a good part of their armamentarium," Broyles said. "There is some training required, but not that much more than seen for other stents and stent delivery systems."
Gore also reported FDA approval of a modified version of the Gore TAG Thoracic Endoprosthesis for the treatment of thoracic aortic aneurysms (TAAs).
The original Gore TAG was approved in 2005 (MDD, March 25, 2005) as the first endovascular grafting system approved in the U.S. to treat TAA.
A new delivery catheter includes a soft flexible tip to the leading end of the delivery system, improving flexibility at the wire/catheter interface to facilitate tracking through the challenging aortic anatomy. A hub component has also been modified to improve ease of use and durability.
The Gore TAG was approved in Europe, Japan and South Korea several years ago. Gore has already begun distribution of the upgraded delivery system, and plans to roll out across the U.S. within the next few months.