AT EUROPCR 2016
PARIS (FRONTLINE MEDICAL NEWS) – The TriGuard neuroprotection device for use during transcatheter aortic valve replacement effectively prevented strokes while raising no safety concerns in a pooled analysis of three controlled trials, according to Dr. Alexandra J. Lansky.
The TriGuard, which is investigational in the United States but approved in Europe, also significantly reduced the risk of central nervous system infarction, as assessed by diffusion-weighted MRI. Moreover, when imaging did show CNS infarcts in patients with the TriGuard in place during their TAVR (transcatheter aortic valve replacement), the total brain lesion volume was about 40% less than in controls without the neuroprotection device, according to Dr. Lansky , professor of medicine and director of the cardiovascular clinical research program at Yale University in New Haven, Conn.
“Essentially what’s happening is that we’re reducing with this device the frequency of CNS infarctions, and also reducing the size of the lesions when they are present,” she said at the annual congress of the European Association of Percutaneous Cardiovascular Interventions.
The TriGuard is designed to fill an unmet need for stroke protection in TAVR patients. The incidence of clinical stroke within 30 days after TAVR in recent randomized controlled trials is 1.5%-6%. But there is clear evidence of underreporting of stroke in these trials. When neurologists examine TAVR patients or the patients are evaluated by serial testing using the NIH Stroke Scale plus brain imaging, the 30-day stroke rates are 15%-28%, according to the cardiologist.
“We know that about 50% of these strokes happen in the periprocedural period, and stroke is one of the strongest predictors of mortality, conferring a three- to ninefold increased risk,” Dr. Lansky emphasized.
She presented a pooled analysis including 59 TriGuard recipients and 83 controls who underwent TAVR in the DEFLECT I and III trials and the NeuroTAVR registry. They were evaluated using the NIH Stroke Scale before TAVR and again at 4 and 30 days post procedure. In addition, they underwent brain imaging via diffusion-weighted MRI 4 days post TAVR.
Stroke as defined by the Valve Academic Research Consortium–2 (VARC2) criteria occurred in none of the TriGuard group but in 6% of controls. And stroke as defined by the American Stroke Association, which requires a worsening score on the serial NIH Stroke Scale measurements plus imaging evidence of CNS infarction, occurred in 0 TriGuard-protected patients and in 19% of controls.
The incidence of CNS infarction on MRI was 92% in controls and 72% in the TriGuard group. Thus, 28% of patients with the TriGuard in place developed no brain infarct lesions at all; that’s a first for any TAVR neuroprotection device, according to Dr. Lansky.
In patients with CNS lesions, the total lesion volume was 101 mm3 in the TriGuard group, compared with 174 mm3 in the controls. The average lesion volume was 25 mm3 in the TriGuard group versus 43 mm3 in the controls.
TriGuard is a relatively simple device consisting of a single-wire nitinol frame and mesh filter with a pore size of 130 mcm. It’s designed to deflect emboli during TAVR while allowing maximal cerebral blood flow. After being delivered by a 9 French sheath from the contralateral femoral artery, the device sits at the roof of the aortic arch. Importantly, it covers all three cerebral arteries, Dr. Lansky said. The device is held in position by a stabilizer in the innominate artery.
Although introducing an additional element into TAVR raises the theoretic possibility of safety concerns, no safety signal was seen in the pooled analysis. In-hospital major adverse event rates were similar in the two groups.
Asked why 72% of patients with the TriGuard in place nonetheless developed CNS infarcts, Dr. Lansky said she believes the device has gaps on the sides that allow smaller emboli to pass through. Future iterations of the TriGuard will address this.
The clinical significance of the CNS infarcts seen on MRI in TAVR patients is a controversial issue among interventional cardiologists. Some cardiologists consider these to be silent lesions of dubious clinical relevance. That’s not Dr. Lansky’s view.
“When you track these MRI lesions out to 30 days, many times they disappear. They don’t disappear because there’s no damage; they disappear because the cells die. When you talk to neurologists about the MRI lesions, they will tell you that they actually represent cell death and correlate with brain infarction,” she said.
Dr. Nicolo Piazza commented that he considered the pooled analysis findings hypothesis generating but not definitive because of baseline imbalances between the two study arms. The control group had numerically higher – albeit not statistically significantly so – rates of atrial fibrillation at hospital admission as well as higher Society of Thoracic Surgeons risk scores, both of which increase stroke risk, noted Dr. Piazza of McGill University in Montreal.
Dr. Lansky replied that the much larger ongoing pivotal randomized, phase III REFLECT trial should provide definitive answers.
She reported receiving institutional research grant support from Keystone Heart, which produces the TriGuard device.