Predictors of periprocedural brain lesions associated with carotid stenting.

BACKGROUND: Carotid stenting carries a risk of periprocedural stroke. We aimed at determining predictors of cerebral ischemic events associated with stenting for symptomatic carotid stenosis. METHODS: 127 patients who had been studied by diffusion-weighted MR imaging (DWI) before and on the day after carotid stenting were included. Six clinical variables and 5 variables characterizing the target carotid artery and aortic atherosclerosis were analyzed as potential risk factors for new ipsilateral DWI lesions after stenting. RESULTS: Among all variables assessed, only age, length of stenosis and carotid intima-media thickness (IMT) significantly modified the risk of new lesions after stenting. Age ≥68 years, stenosis ≥15 mm and IMT ≥1.3 mm were identified as the best thresholds to predict new lesions. In the subgroup of patients ≥68 years with carotid stenosis ≥15 mm in length and IMT ≥1.3 mm, the risk of new lesions was markedly higher than in patients to whom no more than two of these factors applied (odds ratio 7.250, 95% CI 1.612-34.513, p = 0.005). The use of this simple predictive model correctly identified patients who had new lesions after stenting with high specificity (0.96) and a negative predictive value (0.83), while the positive predictive value was moderate (0.60) and sensitivity was low (0.23). CONCLUSIONS: The risk of stenting for symptomatic carotid stenosis may vary with clinical and morphological patient characteristics. Further research is needed to validate these results and to evaluate the safety of stenting versus endarterectomy in specific patient subgroups.

Carotid plaque surface irregularity predicts cerebral embolism during carotid artery stenting.

BACKGROUND AND PURPOSE: Carotid artery stenting (CAS) is associated with the risk of periprocedural embolic events. The procedural risk may vary with plaque characteristics. We aimed at determining the impact of carotid plaque surface irregularity on the risk of cerebral embolism during CAS. METHODS: Solid microembolic signals (MES) during CAS for symptomatic carotid stenosis were assessed by means of dual-frequency transcranial Doppler ultrasound. Study endpoint was the number of solid MES during CAS in 12 patients with irregular carotid stenosis compared to 12 matched patients with smooth carotid stenosis. RESULTS: A total of 438 solid MES were detected. The cumulative number of solid MES was 329 in patients with irregular plaques and 109 in those with smooth plaques. The proportion of subjects in whom solid MES were detected was higher in the irregular plaque group (11/12) than in the smooth plaque group (5/12) (p = 0.030). The numbers of solid MES per CAS procedure and per hour of CAS procedure were both higher in patients with irregular plaques than in those with smooth plaques (p = 0.008 and 0.015, respectively). CONCLUSIONS: Carotid plaque surface irregularity predicts solid cerebral embolism during stenting of symptomatic carotid artery stenosis.

Older age and greater carotid intima-media thickness predict ischemic events associated with carotid-artery stenting.

BACKGROUND: Carotid-artery stenting (CAS) may be complicated by stroke. We aimed to determine predictors of procedure-related ischemic events. METHODS: We analyzed new ischemic lesions in diffusion-weighted MRI (DWI) after CAS in 147 patients with symptomatic high-grade carotid stenosis. Nine covariates were assessed as potential risk factors for new lesions in DWI: age, gender, hypertension, diabetes, dyslipidemia, smoking status, severity of stenosis, side of intervention and carotid intima-media thickness (IMT). RESULTS: From the nine covariates assessed, only age and IMT were independently associated with new DWI lesions. An age of 68 years and an IMT of 1.5 mm gave the best separation between high- and low-risk populations. The subgroup of patients <68 years who had an IMT ≤1.5 mm had the lowest rate of new DWI lesions (11.3%). This rate was greater in patients ≥68 years (30.0%; odds ratio, OR, 3.4; 95% confidence interval, CI, 1.1-10.8) and in patients with an IMT >1.5 mm (36.4%; OR 4.5; 95% CI 1.2-17.0) and was particularly high in patients aged ≥68 years with IMT >1.5 mm (69.6%; OR 18.0; 95% CI 4.8-71.9). CONCLUSIONS: Older age and greater IMT are independently associated with the risk of CAS-related ischemic events. This risk is particularly high in those patients in whom older age and greater IMT coincide.

Cerebral embolism during carotid artery stenting: role of carotid plaque echolucency.

BACKGROUND: Carotid artery stenting (CAS) is associated with the risk of intraprocedural stroke. A better understanding of specific risk factors could help to improve the procedure and to reduce the overall risk of CAS. We addressed the role of carotid plaque echolucency as potential risk factor for cerebral embolism during CAS. METHODS: We prospectively evaluated carotid plaque echolucency by use of a computer-assisted measure of echogenicity, the gray scale median (GSM), in 31 consecutive patients with symptomatic high-grade carotid stenosis that were scheduled to undergo CAS. Dual-frequency transcranial Doppler ultrasound was used to detect solid cerebral microemboli during CAS. RESULTS: 27 of the 31 patients met all inclusion/exclusion criteria.Solid cerebral microemboli were detected during 17 of 27 CAS procedures. The GSM of the target plaques was lower in subjects with intraprocedural embolism (37.9 +/- 20.8) than in those without (58.2 +/- 25.7) (p = 0.040). A receiver-operating characteristic analysis showed that the GSM that gave the greatest separation between plaques with a higher and a lower probability of intraprocedural embolism was 50: the proportion of subjects with intraprocedural embolism was 85% in CAS of echolucent plaques (GSM <50) and 42% in CAS of echogenic plaques (GSM > or =50) (p = 0.031). CONCLUSIONS: CAS of both echolucent and echogenic carotid plaques may be associated with cerebral embolism, particularly CAS of echolucent plaques. Plaque echolucency alone does not reliably identify patients at particularly high risk of intraprocedural embolism, but should be considered as one of a broad panel of risk factors of CAS.