High posterior cerebral artery flow predicts ischemia recurrence in patients with internal carotid artery occlusion

Area of Science:

• Neurology
• Vascular Medicine
• Medical Imaging

Background:

• Symptomatic internal carotid artery occlusion (ICAO) poses a significant risk for recurrent stroke.
• Leptomeningeal collaterals are crucial for brain perfusion but their recruitment indicates hemodynamic compromise.
• Posterior cerebral artery (PCA) P2 segment flow velocity is a potential marker for collateral recruitment.

Purpose of the Study:

• To evaluate the utility of transcranial duplex (TCD) derived PCA-P2 flow velocity in predicting recurrent ipsilateral ischemia in patients with ICAO.
• To assess the accuracy of PCA-P2 flow velocity, in conjunction with clinical factors, for risk stratification.

Main Methods:

• Retrospective analysis of clinical and ultrasound data from 111 patients with symptomatic ICAO.
• Logistic regression models were used to test systolic PCA-P2 flow velocity and clinical variables (TIA, NIHSS) as predictors of recurrent ischemic events.
• Comparison of PCA-P2 flow velocities between patients with and without recurrent ischemia.

Main Results:

• Recurrent ischemic events occurred in 13 out of 111 patients.
• Significantly increased ipsilateral PCA-P2 systolic flow velocity was observed in patients with recurrent ischemia (median 86 cm/s vs. 60 cm/s, p<0.001).
• Previous transient ischemic attack (TIA) and lower NIH Stroke Scale (NIHSS) scores were also associated with recurrence. A combined model achieved 89.2% accuracy.

Conclusions:

• Elevated PCA-P2 flow velocity on TCD ultrasound reflects intensified leptomeningeal collateral recruitment in ICAO patients.
• This non-invasive parameter, combined with clinical data, effectively identifies patients at high risk for recurrent stroke.
• PCA-P2 flow velocity offers a valuable tool for risk stratification in symptomatic ICAO.