Abstract Body: Introduction:
Previous evidence indicated that transcranial doppler (TCD) parameters were associated with functional outcome in large vessel occlusion stroke (LVOS) patients who undergo mechanical thrombectomy (MT). We aim to 1) evaluate if TCD-derived pulsatility index (PI) and mean flow velocity (MFV) may predict clinical outcomes in LVOS after successful MT reperfusion, and to 2) assess if the PI is different in patients that received intravenous thrombolysis (IVT), indicating potential beneficial impact on microvascular reperfusion.

Methods:
This is a retrospective analysis of consecutive patients treated with MT for AIS secondary to a middle cerebral artery (MCA) M1 segment or intracranial internal carotid artery terminus (ICA) LVO. The study period spanned from January 1, 2018, to June 12, 2024; we only included patients with excellent reperfusion, defined as thrombolysis in cerebral infarction [TICI] grade 2c-3, who had TCD studies within 24 hours of their procedure. Patients without TCD studies, or with a poor temporal window were excluded. Ipsilateral and contralateral MFV and PI were collected for both the MCA and anterior cerebral artery (ACA). The primary outcome was the correlation between 3-month functional outcomes, assessed using the modified Rankin Scale (mRS), and the collected TCD parameters. Statistical correlations were performed using Pearson correlation.

Results:
Out of 1962 patients treated within the study period, 703 had MCA-M1 or i-ICA occlusions and TICI 2c-3, and only 229 had TCD within 24h and a good temporal window. Median age was 64.5 (IQR 56-75.5) years and 126 patients (55%) were males, 187 (81.7%) had an MCA-M1 and 42 (18.3%) an ICA-T occlusion. The median ASPECTS score was 8 (IQR 7-9) and the rate of IVT was 29.3%. Functional independence and mortality at 90 days were 49.3% and 14.4%, respectively. There was no association between MCA MFV (linear correlation coefficient -0.016;p=0.88) or PI (-0.08;p=0.47) and mRS at 90 days. The mean PI in patients that received IVT and did not receive IVT was comparable (mean 1.24 [SD0.06] vs 1.73 [SD0.54];p<0.001; adjusted for hypertension and occlusion location).

Conclusion:
In a homogeneous population of i-ICA/MCA-M1 occlusion with full reperfusion, TCD-derived parameters were not found to be associated with clinical outcomes. The PI was comparable between patients with and without IVT, and the finding substantiates the suggestion of IVT-related microvascular clearance.