Assessment of flow changes in the circle of Willis after stenting for severe internal carotid artery stenosis
Anna Kablak-Ziembicka1, Tadeusz Przewlocki, Piotr Pieniazek
1Department of Cardiac and Vascular Diseases, Institute of Cardiology, Jagiellonian University School of Medicine, Krakow, Poland. kablakziembicka@op.pl
Insights
Carotid artery stenting (CAS) increases middle cerebral artery (MCA) flow velocity by over 25% compared to controls. Significantly elevated MCA velocities indicate hyperperfusion syndrome after CAS.
Area of Science:
- Neurology
- Vascular Surgery
- Medical Imaging
Background:
- Carotid artery stenting (CAS) is a procedure to treat internal carotid artery (ICA) stenosis.
- Assessing cerebral blood flow post-CAS is crucial for understanding hemodynamic changes.
Purpose of the Study:
- To evaluate cerebral artery flow velocities after CAS in patients with unilateral versus bilateral ICA lesions.
- To analyze flow velocities in patients experiencing neurological complications post-CAS.
Main Methods:
- Transcranial color-coded Doppler ultrasound was used to measure systolic velocities in the middle cerebral artery (MCA) and anterior cerebral artery (ACA).
- Ninety-two patients with ICA stenosis were grouped into unilateral (n=72) or bilateral (n=20) disease, compared to 50 controls.
- Velocities were assessed ipsilateral and contralateral to the CAS site before and within 24 hours after the procedure.
Main Results:
- Uncomplicated CAS led to a >25% increase in ipsilateral MCA (iMCA) velocity compared to controls.
- In bilateral disease, iMCA flow increased by 30%, with collateral flow via the anterior communicating artery (ACoA) also increasing, normalizing contralateral MCA velocities.
- Hyperperfusion syndrome occurred in 2.2% of patients (both bilateral), showing 2.7- to 7.4-fold higher MCA velocities post-CAS compared to pre-CAS levels.
Conclusions:
- Uncomplicated CAS causes a significant increase in ipsilateral MCA velocity.
- Severely elevated MCA velocities post-CAS are indicative of hyperperfusion syndrome, particularly in patients with bilateral disease.
Purpose:
To assess flow velocities in the cerebral arteries after carotid artery stenting (CAS) in patients with unilateral versus bilateral lesions and analyze velocities in patients with neurological complications after CAS.
Methods:
Ninety-two patients (68 men; mean age 63.2 +/- 8.4 years, range 44-82) with internal carotid artery (ICA) stenoses were divided according to unilateral (group I, n = 72) or bilateral (group II, n = 20) disease. Fifty age- and gender-matched patients without lesions in the extra- or intracranial arteries served as a control group. Transcranial color-coded Doppler ultrasound was performed prior to and within 24 hours after CAS in the test groups; systolic velocities were assessed ipsilateral (i) and contralateral (c) to the CAS site in the middle cerebral artery (MCA) and anterior cerebral artery (ACA).
Results:
Collateral flow via the anterior communicating artery (ACoA) was found in all group-II patients and 90% of group-I patients. After CAS, collateral flow through the ACoA ceased, and the velocity increased by 26% in the iMCA in group I compared to controls (p < 0.001). In group II, iMCA flow increased by 30% (p < 0.001) and flow via the ACoA (p < 0.001) increased, resulting in normalization of cMCA velocities (p = 0.928). In 89 (96.7%) subjects, CAS was uncomplicated. Hyperperfusion syndrome occurred in 2 (2.2%) patients, both with bilateral ICA stenoses; 1 (1.1%) transient ischemic attack was seen in a patient with unilateral disease. In the patients with hyperperfusion syndrome, the MCA velocities were 2.7- and 7.4-fold higher, respectively, versus before CAS and 2-fold higher than in controls.
Conclusion:
Uncomplicated CAS results in an iMCA velocity increase >25% compared to controls. MCA velocities in hyperperfusion syndrome were greatly increased versus before CAS and in controls.
