Stent retrievers have revolutionized endovascular treatment of acute ischemic stroke (AIS). Animal studies showed that mechanical thrombectomy (MT) may cause endothelial injury and intimal layer edema. Using transcranial color-coded duplex-sonography (TCCS) we observed postprocedural hemodynamic changes in the treated vessel.
We studied AIS patients with large intracranial artery occlusion in whom MT with stent retrievers was performed. Only those with complete recanalization (modified TICI-2b or 3) as assessed by postprocedural digital subtraction angiography (DSA) and in whom early control TCCS was performed were retained. Patients treated with intra-arterial thrombolysis or stenting were excluded.
In 31 patients treated within a time period of 4 years (29 with middle cerebral artery [MCA] and 2 with basilar artery [BA] occlusion), postacute stroke brain-DSA confirmed complete recanalization without residual stenosis or vasospasm. However, in 27 (17 men, mean age 66.3 years) of them TCCS (mean 3.4 days after MT) showed very segmental acceleration of blood flow velocities in the affected arteries (MCA maximum peak systolic velocity [PSVmax] at least >35% as compared to the contralateral side at the same depth; BA PSVmax >40% as compared to velocities at different depths of the same vessel). None showed clinical deterioration. TCCS follow-up (mean 20 days) showed normalization in 14 of 16 cases.
Our TCCS study provides preliminary evidence of focal acceleration of blood flow velocities after MT. Without residual stenosis or vasospasm, this may be a sign of endothelial layer disruption/intimal injury. Further studies are needed to confirm our results.