RAPID software analysis and mechanical thrombectomy for periprocedural ischemic stroke after transcatheter aortic valve implantation

Excerpt

An 88-year-old woman with severe aortic stenosis was scheduled for transcatheter aortic valve implantation (TAVI). Embolic protection devices were not available in Japan. After implantation of SAPIEN 3 Ultra RESILIA 23 mm (Edwards Lifesciences) under conscious sedation with local anesthesia (Fig. 1A–C), she remained unconscious despite the administration of anesthetic antagonists. Her neurological examination revealed aphasia, and right-sided hemiplegia, despite bispectral index (Aspect Medical Systems Inc.) values of 90. An electrocardiogram confirmed sinus rhythm. Considering that contrast-enhanced CT was more useful than magnetic resonance imaging (MRI) for the diagnosis of hyperacute periprocedural cerebral infarction within 1 h after the onset, an immediate CT scan was performed, and revealed occlusion of the left middle cerebral artery (MCA) (Fig. 1D, yellow arrow) and the distal right MCA (Fig. 1D, blue arrow). RAPID (iSchemaView) analysis showed a region of severely reduced cerebral blood flow (< 30% of that in normal tissue), representing the early infarct, of 33 ml (Fig. 1E, purple), and a region of perfusion delay of more than 6 s, representing hypoperfused tissue, of 128 ml (Fig. 1E, green), yielding mismatch ratio of 3.9 and mismatch volume of 95 ml (the target mismatch criteria of RAPID are core volume of < 70 ml, mismatch ratio of ≥ 1.8, and mismatch volume of ≥ 15 ml) [1]. Emergent recanalization of the left MCA (M2) was achieved with a Solitaire X 3.0 mm (Medtronic) after retrieval of white emboli, although the amount of white emboli retrieved was insufficient for pathologic analysis (Fig. 1F [arrow], G). She regained speech and resolution of hemiplegia immediately after recanalization. The onset (time of prosthetic valve implantation) to reperfusion time was 120 min. Thrombectomy of the distal right MCA was not attempted because of the high risk of vascular injury. A brain MRI performed the day after TAVI showed residual cerebral infarction in the right insula and postcentral gyrus, but no infarction in the left MCA territory (Fig. 1H, I). She was discharged ambulatory with mild hemispatial neglect. The addition of CT perfusion imaging to conventional CT angiography for procedural cerebral infarction during TAVI may be useful not only to identify the ischemic core and clinically significant salvageable ischemic brain but also to reduce post-reperfusion hemorrhage or malignant edema.

…