Cerebral embolisation during transcatheter edge-to-edge repair of the mitral valve with the MitraClip system: a prospective, observational study

Background: New ischaemic brain lesions on magnetic resonance imaging (MRI) are reported in up to 86% of patients after transcatheter edge-to-edge repair of the mitral valve (TEER-MV). Knowledge of the exact procedural step(s) that carry the highest risk for cerebral embolisation may help to further improve the procedure. Aims: The aim of this study was to identify the procedural step(s) that are associated with an increased risk of cerebral embolisation during TEER-MV with the MitraClip system. Furthermore, the risk of overt stroke and silent brain ischaemia after TEER-MV was assessed. Methods: In this prospective, pre-specified observational study, all patients underwent continuous transcranial Doppler examination during TEER-MV to detect microembolic signals (MES). MES were assigned to specific procedural steps: (1) transseptal puncture and placement of the guide, (2) advancing and adjustment of the clip in the left atrium, (3) device interaction with the MV, and (4) removal of the clip delivery system and the guide. Neurological examination using the National Institutes of Health Stroke Scale (NIHSS) and cerebral MRI were performed before and after TEER-MV. Results: Fifty-four patients were included. The number of MES differed significantly between the procedural steps with the highest numbers observed during device interaction with the MV. Mild neurological deterioration (NIHSS <= 3) occurred in 9/54 patients. New ischaemic lesions were detected in 21/24 patients who underwent MRI. Larger infarct volume was significantly associated with neurological deterioration. Conclusions: Cerebral embolisation is immanent to TEER-MV and predominantly occurs during device interaction with the MV. Improvements to the procedure may focus on this procedural step.