The DEFLECT III (A prospective randomised evaluation of the TriGuard embolic deflection device during transcatheter aortic valve replacement) trial, which Alexandra Lansky (Yale University School of Medicine, New Haven, USA) presented at the 2015 American College of Cardiology Annual Scientific Session (14–16 March, San Diego, USA), indicates that use of the cerebral protection device TriGuard (Keystone Heart) in patients undergoing transcatheter aortic valve implantation (TAVI) is associated with an increase in the proportion of patients free from ischaemic brain lesions. This is the first study of cerebral protection to have this finding.
Lansky stated that the rate of disabling stroke after TAVI is “going down” with newer generation TAVI devices, this she said was “fantastic”. However, “neuroprotection during TAVI is essential” she added “as silent ischaemic brain emboli occur in virtually all patients” and questioned whether these lesions were truly “silent”—commenting: “As cardiologists, we are not very good at detecting new neurologic symptoms in our patients following TAVI.” Lansky explained that 58–100% of patients have evidence of a silent brain lesion (identified with diffusion weighted magnetic resonance imaging; DW-MRI) after TAVI; these lesions are associated with neurocognitive decline, a more than two-fold increased risk of dementia, and a more than three-fold risk of stroke.
Therefore, the aim of the DEFLECT III study was to compare the safety and efficacy of a cerebral protection device (TriGuard) compared with no cerebral protection in patients undergoing TAVI. As it was an exploratory study to benchmark events for the design of a pivotal randomised control trial, there was no formal hypothesis testing. Overall, 86 patients scheduled for TAVI were randomised to undergo the procedure with the device (45) or without the device (38; control group). Follow-up was performed in-hospital.
According to the safety analysis (full patient cohort), the in-hospital rate of major adverse cardiac and cerebrovascular events (MACCE) was similar between groups: 22.2% for the cerebral protection group vs. 31.6% for the control group. Therefore, Lansky reported, use of the TriGuard device was found to be safe.
In an intention-treat analysis of diffusion weighted MRI, follow-up data were available for 32 patients in the device group and for 25 patients in the control group. This analysis showed that the device was associated with a 19% reduction both in single lesion volume (median lesion volume 28mm3 vs. 34.5mm3 for the control group) and in maximum lesion volume (53.6mm3 vs. 66.2mm3, respectively). More importantly, the device was associated with a 42% increase in the percentage of patients with no ischaemic brain lesions on DW-MRI (22% vs. 12.5% for the control group).
The per-treated analysis defined by complete cerebral vessel coverage was achieved in 26 patients in the device group and for 25 patients in the control group. These data showed that the device was associated, respectively, with 41% and 45% reductions in single and maximum lesion volume and was also associated with a 55% increase in the percentage patients who were completely free from ischaemic brain lesions. Lansky commented: “That a cerebral protection device can increase the proportion of patients free from brain lesions has never been shown before. We were able to protect brains completely in an almost a third of patients [27% of device-group patients had no evidence of an ischaemic brain lesion]. That is new and should be the goal of neuroprotection.”
She also noted that patients in the device group, at discharge, had better short-term memory and better delayed memory than patients in the control group. Lansky commented: “We also looked at Montreal Cognitive Assessment (MoCA) score and found that patients who underwent TAVI with protection had better cognition on discharge compared with those who underwent TAVI without protection.” However, Lansky explained that the true magnitude of cognitive benefits will require a powered randomised trial.
The FDA has now approved an investigational device exemption trial of TriGuard (REFLECT), which is expected to start enrolment soon.