Transcranial Doppler microembolic signals and serum marker evidence of brain injury during transcatheter aortic valve implantation

Abstract

Recent studies have shown that transcatheter aortic valve implantation (TAVI) is associated with new foci of restricted diffusion on cerebral magnetic resonance imaging suggestive of cerebral microembolism. The aim of the present investigation was to quantify the cerebral embolic load and to evaluate during which phase of the TAVI procedure microembolism occurs. We also evaluated the association between the cerebral embolic load and post-procedural release of S100B, a serological marker of cerebral injury. In 21 patients, we described the extent and intra-procedural distribution of microemboli during the TAVI procedure using the transcranial Doppler technique. S100B, a marker of astroglial injury, was measured for 24 h after the procedure, and the area under the curve (AUC(24h) ) relating S100B to time was calculated. During the TAVI procedure, a mean of 282 ± 169 emboli was detected, 37% occurred during manipulation of the aortic arch/root/valve by guide wires and catheters, 22% occurred immediately after balloon dilatation of the native valve and 41% occurred during frame expansion of the valve prosthesis. S100B increased in all patients with a peak at 1 h after the procedure and returned to baseline after 4 h. There was a positive correlation between the total amount of cerebral microemboli and the AUC(24h) for S100B (r = 0.68, P < 0.001). None of the patients developed neurological impairment. TAVI is associated with a substantial amount of cerebral microemboli. The microembolic load correlates to the degree of post-procedural release of a marker of cerebral injury.