In our study, CAS 30-day periprocedural complication rate was 3.3% (9 of 276), which is consistent with previous studies in asymptomatic carotid artery stenosis.(4, 12) The overall periprocedural complications were not different between the three groups according to the pretreatment statin dose, and showed no linear trend of association to the statin dose. In addition, when the analysis was conducted comparing use to no-use of statin before CAS, there was no difference in the results.
Statin is considered an option to prevent periprocedural complications. Pretreatment statin use has been shown by previous studies to significantly decrease the frequency of cardiovascular, cerebrovascular, and secondary stroke events after vascular procedures or endarterectomy.(9, 16–22) This effect might be due to multiple effects of statin, such as plaque stabilization and reduction of intravascular thrombosis. Preventive effects of statins are supported by findings of statin use being associated with reduced plaque volume and atheroma regression in the carotid circulation,(23) in addition to less embolic debris during CAS.(24) However, all of these studies included both symptomatic and asymptomatic patients.(25) There is no study about the pretreatment statin effects on periprocedural complications of CAS limited to asymptomatic patients. In contrast to studies with symptomatic carotid artery stenosis, our study demonstrated no significant dose-dependent or absolute statin effects in preventing periprocedural complications in asymptomatic patients with carotid artery stenosis. There is a possible explanation for this finding. A previous study suggests that infiltration of the fibrous cap with foam cells, fibrous cap thinning, and plaque rupture are more commonly presented in patients with symptomatic carotid artery stenosis than in asymptomatic patients.(26) Similar to acute coronary syndromes, plaque ruptures are an important pathoetiological factor of neurological deterioration as a result of carotid artery stenosis. During stent deployment, embolism from the carotid artery plaque is generally responsible for the majority of new ischemic lesions. Based on this study, the multiple pleiotropic effects of statins did not alter the risk of periprocedural complications in asymptomatic patients with carotid artery stenosis because the plaques are generally more stable. Nonetheless, caution is advised in the interpretation of our results, which showed that there is no protective effect of statin, limited to the periprocedural period. Statins are known to have protective effects on long-term outcome.(6, 27)
Here, we found LDL lowering effects of statin. However, statins have multiple pleiotropic effects, such as promoting endothelial function, reducing inflammation, affecting arterial myocyte proliferation, migration and apoptosis, as well as regulating platelet activity, plaque stability, and the coagulation process. Therefore, LDL is not the only concern when contemplating successful risk reduction.(28, 29) As previous studies suggest, statin treatment should be given in accordance to the global vascular risk factor and not chiefly according to base LDL level(30, 31). Consistently, our results indicated that LDL levels alone did not correlate with the risk of periprocedural complications.
Our study has several limitations. First, it includes a relatively small sample, and it is a retrospective study. Second, there was a lack of data for pretreatment duration. Thus, it was not possible to evaluate where this parameter was associated with periprocedural complications. Third, we lacked information on the type of stents used. Previous studies have shown a higher risk of periprocedural stroke in patients treated with open-cell stent devices compared to those given closed-cell devices.(32, 33) Fourth, we cannot be certain that there were no differences in the original plaque morphology or vascular anatomy of the groups considered, which might have differentially influenced the risk of periprocedural complications. Therefore, our results should be verified in randomized trials or prospective trials with larger datasets.
In conclusion, this study shows that statin pretreatment did not have dose-dependent or absolute effects on periprocedural complications risk in patients undergoing CAS for the treatment of asymptomatic carotid artery stenosis.