Cerebral protection with a reverse flow system appears more effective at preventing brain injury than using filters or unprotected carotid artery stenting. The reverse flow system may offer a method of decreasing the frequency of minor strokes occurring during carotid artery stenting, research presented at the British Society of Interventional Radiology meeting found.
Stephen Goode, Sheffield Vascular Institute, Northern General Hospital, Sheffield, UK told delegates at the annual meeting of the British Society of Interventional Radiology in 2011 that following the recent publication of two large randomised clinical trials (ICSS and CREST), there is evidence to suggest that there is a higher risk of minor stroke following carotid artery stenting than endarterectomy, when predominantly filter protection is used.
“This increased risk may be due to increased embolization during the procedure. The aim of our pilot study was to assess the effectiveness of flow reversal as a means of cerebral protection in carotid artery stenting by looking at surrogate markers of brain injury.
Materials and methods:
The reverse flow system was used in 15 patients. MRI scans were performed pre- and three hours, 24 hours and 30 days post-intervention to assess for the presence and number of new ischameic lesions using diffusion weighted imaging. Transcranial Doppler recordings were made from the ipsilateral middler cerebral artery during the procedure to assess for microembolic signals. The data was analysed against a historical cohort of 15 unprotected and 15 filter protected patients, performed by the same operators.
There were less diffusion weighted imaging positive scans in patients undergoing reverse flow cerebral protection and a fewer diffusion weighted imaging lesions when compared to the filter protected and unprotected historical cohorts.
“We found fewer microembolic signals in patients undergoing reverse flow protected carotid artery stenting , and this was particularly noticeable during the stages of the procedure known to be prone to embolic events. There were 45 microembolic events with patients who had reverse flow protection, 80 microembolic events in the unprotected cohort and 138 events in the filter-protected group.
“The findings from this pilot study suggest that cerebral protection with a reverse flow system appears more effective than protection with a filter, or no protection at all, and we are planning a large, randomised trial comparing distal vs. proximal protection devices,” said Goode.