Clarification of embolic source in ischaemic stroke by non-obstructive general angioscopy.

Background: Aortogenic stroke is an important subtype of embolic strokes, yet lacks a diagnostic method for proactive identification. Non-obstructive general angioscopy (NOGA) is a catheter-based technique to observe spontaneously ruptured aortic plaques (SRAPs), a potential embolic source of ischaemic stroke.

Objectives: This study aimed to identify the embolic source of ischaemic stroke using NOGA.

Methods: From June 2022 to January 2024, 321 consecutive patients with acute ischaemic stroke were hospitalised. 25 underwent emergent mechanical thrombectomy and NOGA. The aortic arch was screened using NOGA, and atherosclerotic materials from the SRAPs were sampled and pathologically analysed. Transoesophageal echocardiography (TEE) was performed the day after catheterisation to investigate intracardiac thrombus, patent foramen ovale and aortic plaques. The primary outcome was the diagnosis of aortogenic stroke.

Results: NOGA identified seven SRAPs in the aortic arch as potential embolic sources. Of those, one patient with atrial fibrillation and cardiac chamber thrombus was diagnosed as having a cardiogenic stroke. The findings of the six remaining cases included aortic arch plaque (also observed via TEE) (n=2), thrombus in an artificial aortic graft wall (n=1), and cholesterol crystals in sampled materials indicating plaque rupture (n=3). The Brain-Heart team finally diagnosed these 6 cases (24%) as aortogenic stroke. 16 patients were diagnosed with cardiogenic stroke. One was diagnosed with paradoxical embolism. The remaining two cases (8%) with unidentified embolic sources were diagnosed with cryptogenic stroke.

Conclusions: Using a systematic diagnostic protocol for embolic source detection, the Brain-Heart team could proactively diagnose aortogenic stroke and clarify embolic source.