Endarterectomy versus angioplasty in patients with symptomatic severe carotid stenosis (EVA-3S) trial raised an alert as it recommended that CAS procedure should be done only with the use of distal cerebral protection devices with filter to protect against cerebral embolization . The importance of this recommendation was arguable because the patients without cerebral protection was an average of 8 years older and most of the strokes does not occur during the stenting procedure but later in the clinical course, so the non-usage of CPD was not the only cause of embolic complications and hard to blame. Also, the small number of patients in the non CPD group made the difference of a little significance.
In a recent publication by Cho YD and colleagues , they analyzed a total of 539 symptomatic CAS procedures from four studies; of these, 345 were done with CPD and 194 were done without protection device. The number of stroke was six (1.7%) in protected CAS and 11 (5.7%) in unprotected CAS which was statistically non-significant (p = 0.160) and so the use of CPD did not significantly decrease the events of stroke after CAS.
The pros of using CPDs with filter are the ability to keep the flow during CAS procedure and to protect the brain from embolization. The cons of those devices are the dislodgement of materials during its deployment which is attributed to its large crossing profile, low flexibility and torquability, and also the danger of cerebral micro embolization after its deployment because of flow around and through the filter, pore size, bad apposition in tortuous vessels, and during its retrieval .
Although the usage of CPDs may seem important in brain protection, it remains a debatable topic as the risk of cerebral embolization is present in all stages of CAS: passing the lesion with a wire, pre-dilatation, placement of the protection device, stent deployment, and post dilatation [13, 14].
The lesion load in our study was low, as new cerebral ischemic lesions were noted only in one case (1/91). This result was in keeping with previous studies [15, 16]. The explanations for this could be: first, the use of better materials nowadays concerning the exchange system and the use of flexible guiding catheters instead of the long sheath; second, diminishing the number of device manipulations across the lesion before stent placement by non-use of filter and limited use of pre-stenting balloon dilatation which was selectively done in forty-one cases with tight stenotic lesions to permit passage of the stent across the lesion; third, the use of stent with closed cell design and its placement before angioplasty balloon dilatation in most of our cases. Closed cell designed stents can provide better scaffolding to the carotid lesion and hence decrease the danger of plaque extrusion via the interstices of the stent during its deployment, post dilatation, and after finishing the procedure . Two previous studies showed a trend of better outcome with closed cell stents [18, 19]; fourth, our study focus was on clinical periprocedural complications which is related to the use or non-use of CPD in contrast to most of other studies which did not evaluate the efficacy of the CPD according to the symptomaticity and also there were great differences in the primary endpoints (stroke versus stroke or death versus stroke and death) and the duration of follow-up and its impact on the study conclusion .
The only case in our study which experienced a clinical deterioration was a left carotid artery stenting. This finding was similar to what was reported by Naggara and his colleagues. They found that CAS performed for left carotid stenosis was associated with higher ipsilateral strokes than with right-sided stenting . This higher rate of periprocedural complications may be explained by difficulty in access to the left common carotid artery which takes more time to reach stenotic segment and hence more complications are likely to occur. Also, during stenting of the right side, the occurrence of strokes in the non-eloquent right hemisphere may pass asymptomatic.