Elective treatment of intracranial stenosis with the balloon-expandable Pharos Vitesse stent: 30-day stroke rate and complications.

BACKGROUND AND PURPOSE: Analysis of procedural results and 30-day outcome after intracranial angioplasty and stenting (ICAS) with the balloon-expandable Pharos Vitesse stent system in carefully selected high-risk patients in two high-volume neurovascular centers. MATERIALS AND METHODS: 92 patients scheduled for elective ICAS using Pharos Vitesse between August, 2008 and August, 2011 were included. All patients showed high-grade intracranial stenosis and recurrent ischemic events despite best medical treatment at that time. The stroke rates and complications were divided into procedural and 30-day short-term events. RESULTS: Successful stent placement was achieved in all but one patient. Ischemic procedural complications occurred in three subjects. 30-Day complications and strokes were seen in four patients: two minor ischemic strokes, one fatal hemorrhage and one non-stroke-related death. Overall, strokes occurred in 6 out of 92 patients (6.5%, 95% CI 3.0% to 13.5%). The total stroke and death rate was 7.6% (95% CI 3.7% to 14.9%). No significant correlation with previously reported risk factors could be found, although a higher rate of ischemic strokes (four out of five) in the posterior circulation was recorded. CONCLUSIONS: In patients with intracranial stenosis who experience recurrent ischemic events despite best medical treatment, ICAS, using the balloon-expandable Pharos Vitesse stent, may still be considered as an individual treatment option in high-volume neurovascular centers.

The extent of perfusion deficit does not relate to the visibility of acute ischemic lesions on fluid-attenuated inversion recovery imaging.

OBJECTIVES: Fluid-attenuated inversion recovery imaging (FLAIR) has been suggested as a surrogate marker of lesion age in acute ischemic stroke. In a subgroup analysis, we evaluated whether the extent of perfusion deficit influences FLAIR lesion visibility and thus plays a role as a confounding variable in the interpretation of FLAIR images. METHODS: A subgroup of patients from a previous study evaluating the use of FLAIR imaging as a surrogate marker of lesion age within the first 6 hours of ischemic stroke were examined to determine the influence of the amount of perfusion deficit on FLAIR lesion visibility. RESULTS: N = 48 patients were included into the analysis. In positive and negative FLAIR lesion cases the extent of perfusion deficits did not differ significantly (150 mL vs. 197 mL, P = .730) nor influenced FLAIR visibility independently. In contrast, diffusion weighted imaging (DWI) lesion volumes were larger (34 mL vs. 14 mL, P = .008) and time from symptom onset longer (180 vs. 120 minute, P = .071) in FLAIR-positive cases. CONCLUSION: Visibility of FLAIR lesions in acute stroke imaging is influenced by lesion size and time from symptom onset to MRI, but not by the amount of perfusion deficit calculated by time-to-peak (TTP) measurements.

Outcome of MRI-based intravenous thrombolysis in carotid-T occlusion.

Low recanalization rates and poor clinical outcome have been reported after intravenous thrombolysis (IV-tPA) in carotid-T occlusion (CTO). We studied clinical outcome and imaging findings of MRI-based intravenous thrombolysis in CTO. Data of patients with acute ischemic stroke and CTO treated with IV-tPA within 6 h of symptom onset based on MRI criteria were retrospectively analyzed. Vessel occlusion was defined based on MR angiography. Acute diffusion and perfusion lesion volumes and final infarct volumes after 3-7 days were delineated. The National Institutes of Health Stroke Scale (NIHSS) was used to assess the neurological deficit on admission. Recanalization was evaluated after 24 h. Clinical outcome was assessed using the modified Rankin Scale (mRS) after 90 days. Clinical and imaging data were compared to patients with middle cerebral artery main stem occlusion (MCAO). A total of 20 patients with CTO and 51 patients with MCAO were studied. Onset to treatment time, NIHSS on admission, initial diffusion and perfusion lesion volumes, and recanalization rates after 24 h were similar between groups. Final infarct volume was larger for CTO (82 vs. 30 ml, p = 0.006). Although overall outcome was not significantly different between groups (p = 0.251), independent outcome (mRS 0-2) tended to be less frequent in CTO (17 vs. 39 %), while poor outcome (mRS 4-6) appeared more common (72 vs. 43 %). The proportion of patients with good clinical outcome after intravenous thrombolysis in CTO is small. Moreover, final infarct volume is larger and clinical outcome appears to be worse compared to MCAO.

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.

Prediction of malignant middle cerebral artery infarction by magnetic resonance imaging within 6 hours of symptom onset: A prospective multicenter observational study.

OBJECTIVE: Early identification of patients at risk of space-occupying "malignant" middle cerebral artery (MCA) infarction (MMI) is needed to enable timely decision for potentially life-saving treatment such as decompressive hemicraniectomy. We tested the hypothesis that acute stroke magnetic resonance imaging (MRI) predicts MMI within 6 hours of stroke onset. METHODS: In a prospective, multicenter, observational cohort study patients with acute ischemic stroke and MCA main stem occlusion were studied by MRI including diffusion-weighted imaging (DWI), perfusion imaging (PI), and MR-angiography within 6 hours of symptom onset. Multivariate regression analysis was used to identify clinical and imaging predictors of MMI. RESULTS: Of 140 patients included, 27 (19.3%) developed MMI. The following parameters were identified as independent predictors of MMI: larger acute DWI lesion volume (per 1 ml odds ratio [OR] 1.04, 95% confidence interval [CI] 1.02-1.06; p < 0.001), combined MCA + internal carotid artery occlusion (5.38, 1.55-18.68; p = 0.008), and severity of neurological deficit on admission assessed by the National Institutes of Health Stroke Scale score (per 1 point 1.16, 1.00-1.35; p = 0.053). The prespecified threshold of a DWI lesion volume >82 ml predicted MMI with high specificity (0.98, 95% CI 0.94-1.00), negative predictive value (0.90, 0.83-0.94), and positive predictive value (0.88, 0.62-0.98), but sensitivity was low (0.52, 0.32-0.71). INTERPRETATION: Stroke MRI on admission predicts malignant course in severe MCA stroke with high positive and negative predictive value and may help in guiding treatment decisions, such as decompressive surgery. In a subset of patients with small initial DWI lesion volumes, repeated diagnostic tests are required.

Negative fluid-attenuated inversion recovery imaging identifies acute ischemic stroke at 3 hours or less.

OBJECTIVE: To evaluate the use of fluid-attenuated inversion recovery (FLAIR) imaging as surrogate marker of lesion age within the first 6 hours of ischemic stroke. METHODS: e analyzed FLAIR and diffusion-weighted imaging (DWI) sequences performed within 6 hours of symptom onset in 120 consecutive patients with ischemic stroke with known symptom onset. The visibility of acute ischemic lesions on FLAIR images was judged in two steps (on FLAIR alone and with knowledge of DWI) and compared with DWI. RESULTS: egative FLAIR in the case of positive DWI allocated ischemic lesions to a time window 3 hours or less with a high specificity (0.93) and a high positive predictive value (0.94), whereas sensitivity (0.48) and negative predictive value (0.43) were low. Lesion visibility on FLAIR images alone (35.6%) and with knowledge of DWI (62.5%) was lower than on DWI (97.1%). The sensitivity of FLAIR increased with increasing time from symptom onset from 27.0/50.0%

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.