Introduction: Reports vary in incidence of silent brain infarcts after cardiovascular and cerebrovascular procedures. In a systematic review we compared rates of radiographic brain infarcts (RBI) and clinical strokes among different carotid artery procedures: carotid endarterectomy (CEA), and carotid stenting (CAS) with or without protection devices.
Methods: We searched MEDLINE and 4 other databases for subject headings and text related to brain infarcts in carotid artery interventions from inception through February 2015. We included articles with carotid interventions if brain MRI was performed systematically, RBI and stroke incidence were reported, and compared infarct rates between different devices in CAS.
Results: Of 6332 articles retrieved, 65 studies (5982 patients) met the inclusion criteria. There were 26 cohorts in CEA, 39 in CAS with distal protection, 8 in CAS with proximal protection with or without flow reversal, 10 in CAS with unspecified devices and 10 in CAS without protection. MRI diffusion-weighted imaging scan was performed pre-procedure in 64 studies and post-procedure in all 65 studies. Overall, 1761 subjects (29.4%) had infarcts on MRI, whereas only 191 (3.2%) manifested as clinical strokes. Only 11% of subjects with infarcts were found to have clinical strokes and the rate did not differ between 36 studies that determined strokes systematically and the remainder without systematic examination. CEA had lower incidence of RBI compared to CAS (15.9% (239/1524) vs 34.0% (1522/4482), p<0.001) but not of strokes (2.5% (37/1500) vs 3.4% (154/4482), p=0.07). RBI incidences differed among embolism protection methods in CAS: 24.3% (70/288) in proximal protection, 35.7% (740/2075) in distal protection, 32.6% (489/1502) in unspecified devices, and 36.1% (223/617) without protection; incidence of stroke were not significantly different among the procedures with 2.4% (7/288), 3.3% (69/2075), 3.1% (46/1502), and 5.2% (32/617), respectively.
Conclusion: Only 1 of 9 periprocedural radiographic infarcts during carotid endarterectomy or stent result in clinical strokes. CEA has a lower incidence of RBI compared to CAS.