Microemboli Detection in Acute Ischemic Stroke Could Be an Early Marker of Poor Cognitive Outcome.

Background: We investigated the burden of microembolic signals (MESs) in patients with acute ischemic stroke and their impact on long-term cognitive function.

Methods: This prospective study included consecutive patients with ischemic stroke without prior dementia or severe neurological deficits, recruited from the stroke unit (Centro Hospitalar Universitário de São João, Porto, Portugal), between December 2020 and May 2022. Transcranial Doppler monitoring was performed within 72 hours of symptom onset for 60 minutes of monitoring, with 30 minutes dedicated to each cerebral circulation: bilateral M1 segments of the middle cerebral artery and bilateral segments P2 of the posterior cerebral artery. Recordings were analyzed for MES by a blinded expert. The primary aim was to determine the association of MES with cognitive status at 12 months, evaluated using a 7-point cognitive scale.

Results: Between November 2020 and May 2022, we included 316 patients, with a median age of 67 (interquartile range, 59-76) years with 68% males. Thirty-nine patients had MES (12.3%), with a median (interquartile range) of 3 (1-7) counts among those who were positive. The occurrence of MES was higher in patients who underwent thrombolysis and thrombectomy, those who were not previously on statins, and those with a higher National Institutes of Health Stroke Scale score (P<0.05). The worst cognitive outcome occurred in patients with MES with an adjusted odds ratio of 2.04 (95% CI, 1.27-3.28; P<0.01).

Conclusions: Patients who are MES-positive in the acute phase have twice the likelihood of experiencing worse cognitive outcomes 12 months after stroke. The detection of MES using transcranial Doppler could be considered in future studies as an early marker of poor cognitive performance, helping to stratify high-risk patients. Future trials should investigate whether early antithrombotic treatment could improve long-term cognitive function in stroke survivors (Clinicaltrials.gov ID: 06735274).