Impaired clearance of microemboli and cerebrovascular symptoms during carotid stenting procedures
Giovanni Orlandi1, Simona Fanucchi, Simone Gallerini
1Department of Neuroscience, University of Pisa, Pisa, Italy. g.orlandi@neuro.med.unipi.it
Insights
Low middle cerebral artery flow velocity, not microemboli, may precede cerebrovascular symptoms (CVSs) during carotid artery stenting (CAS). This finding suggests flow velocity is a key indicator for preventing procedural complications.
Area of Science:
- Neurology
- Interventional Cardiology
- Medical Imaging
Background:
- Transcranial Doppler (TCD) monitoring reveals frequent microemboli during carotid artery stenting (CAS).
- Cerebrovascular symptoms (CVSs) occurrence is not clearly linked to microembolic load during CAS.
Purpose of the Study:
- To investigate the relationship between TCD-derived embolic signals, hemodynamic parameters, and procedural CVSs.
- To assess the predictive value of microembolic signals and middle cerebral artery (MCA) flow velocity for CVSs during CAS.
Main Methods:
- Fifty-four patients with >70% carotid stenosis underwent 57 CAS procedures under TCD monitoring.
- MCA mean blood flow velocity and microembolic signals (isolated and showers) were recorded.
- CVSs, including transient ischemic attack, transient monocular blindness, and stroke, were documented.
Main Results:
- Nine patients (15.8%) experienced CVSs during CAS.
- Significantly lower MCA mean blood flow velocity was observed in patients with CVSs (36 cm/s) compared to those without (48 cm/s).
- The number of isolated microembolic signals and microembolic signal showers did not significantly differ between groups with and without CVSs.
Conclusions:
- Low MCA flow velocity may hinder microembolic load clearance, potentially preceding CVSs during CAS.
- MCA flow velocity, rather than microembolic load, appears to be a critical factor for predicting CVSs during CAS.
Background:
Transcranial Doppler monitoring shows a high prevalence of microemboli during carotid artery stenting (CAS); however, the occurrence of cerebrovascular symptoms (CVSs) does not seem to be related to the microembolic load.
Objective:
To evaluate embolic and hemodynamic transcranial Doppler monitoring findings and their relationships with the occurrence of procedural CVSs. Patients Fifty-four patients who had carotid stenosis of more than 70% underwent a total of 57 CAS procedures during transcranial Doppler monitoring of mean blood flow velocity and microembolic signals in the middle cerebral artery. The occurrence of transient ischemic attack, transient monocular blindness, and stroke during the CAS procedure was considered CVSs.
Results:
Nine (15.8%) of the 57 patients had CVSs during the procedure (ie, 6 patients with transient ischemic attack, 1 with transient monocular blindness, 1 with a minor stroke, and 1 with a major stroke). The mean blood flow velocity median values were statistically significantly lower (P < .001) in the group of 9 patients with CVSs (36 cm/s; interquartile range, 32.3-38.5) compared with the 48 without CVSs (48 cm/s; interquartile range, 41.5-52). The median number of isolated microembolic signals was similar in the 2 groups (72; interquartile range, 66-81 vs 75; interquartile range, 67-83.5). The median number of microembolic signal showers (clusters of too many signals to be counted separately in one cardiac cycle) presented a nonsignificant prevalence in the patients with CVSs (9; interquartile range, 7.5-11.2) compared with the ones without CVSs (8.2; interquartile range, 7-9).
Conclusion:
The low flow velocity in the middle cerebral artery may impair the clearance of the microembolic load and should be considered a precursor of CVSs during the CAS procedure.
Related Concept Videos
01:15Ischemic Stroke l: Introduction
01:26Transient Ischemic Attack l: Introduction