Thirteen RCTs (20 articles, 3,723 participants who underwent carotid artery stenting and 3,754 who underwent carotid endarterectomy) were included in the review. Follow-up ranged from 30 days to 5.5 years. Six trials were stopped early, three due to inferiority of carotid artery stenting.
Short-term outcomes: Carotid artery stenting significantly increased the risk of stroke (OR 1.53, 95% CI 1.23 to 1.91; 11 RCTs, I2=24.1%) and death or stroke (OR 1.54, 95% CI 1.25 to 1.89; 12 RCTs, I2=33.5%). By contrast, carotid endarterectomy was associated with significantly increased risk of myocardial infarction (OR 0.48, 95% CI 0.30 to 0.78; nine RCTs, I2=0%) and cranial nerve injury (OR 0.09, 95% CI 0.05 to 0.16; 11 RCTs, I2=0%). No other findings were statistically significant.
Long-term outcomes: Patients who underwent carotid artery stenting remained at significantly greater risk of stroke (OR 1.37, 95% CI 1.13 to 1.65; nine RCTs, I2=0%) and death or stroke (OR 1.25, 95% CI 1.06 to 1.48; 10 RCTs, I2=0%) and these findings were confirmed using pooled hazard ratios. There were no statistically significant differences in risk of death and death or disabling stroke.
Meta-regression did not identify any significant moderator variables. Subgroup analysis showed that risk of long-term stroke in patients aged over 68 was statistically significantly greater in patients who underwent carotid artery stenting; there was no difference in patients aged under 68 years. Sensitivity analysis resulted in a non-significant risk difference for the long-term outcome of death or stroke.
There was evidence of publication bias for short-term risk of death on visual inspection of a funnel plot.