Postprocedural Diffusion-weighted Imaging Research Articles

Findings of Angiography and Carotid Vessel Wall Imaging Associated with Post-Procedural Clinical Events after Carotid Artery Stenting.

Vessel wall imaging (VWI) for carotid plaque is better for detecting unstable carotid plaque such as intraplaque hemorrhage (IPH), lipid-rich necrotic core (LRNC), and thin/ruptured fibrous cap. However, the role of VWI before carotid artery stenting (CAS) is unclear. Thus, this study aimed to determine the findings of symptomatic carotid stenosis before CAS on angiography and carotid VWI and to evaluate the imaging findings associated with post-procedural clinical events after CAS. This retrospective study included 173 consecutive patients who underwent carotid VWI, CAS, and post-procedural diffusion-weighted imaging (DWI) after CAS. Findings of unstable plaque on carotid VWI and unstable findings on angiography were analyzed. We also analyzed the incidence of post-procedural clinical events, any stroke, myocardial infarction (MI), and death within 30 days of CAS. Of 173 patients, 101 (58.4%) had initial ischemic symptoms and positive findings on DWI. Symptomatic patients were significantly higher in patients with IPH than in patients without IPH (62.4% vs. 45.8%, P=0.031). Degree of stenosis, thrombus of the stenotic lesion, flow delay of internal carotid artery, and flow arrest by filter thrombus had significantly higher prevalence in the symptomatic group. Twenty patients (11.6%) had post-procedural clinical events such as any stroke, clinical symptoms, and/or MI. Hyperlipidemia and intraluminal thrombus on angiography were identified as significant factors influencing post-procedural events after CAS. An intraluminal thrombus on angiography was identified as a significant factor influencing post-procedural clinical events after CAS.

Impact of Time Interval between Index Event and Stenting on Periprocedural Risk in Patients with Symptomatic Carotid Stenosis.

ObjectiveThe purpose of this study was to evaluate the impact of time interval between index event and stenting on the periprocedural risk of stenting for symptomatic carotid stenosis and to determine the optimal timing of stenting. MethodsThis retrospective study included 491 (322 symptomatic [65.6%] and 169 asymptomatic [34.4%]) patients undergoing carotid stenting. The symptomatic patients were categorized into Day 0–3, 4–7, 8–10, 11–14, 15–21, and >21 groups according to the time interval between index event and stenting. Periprocedural (≤30 days) risk for clinical (any neurological deterioration) and radiological (new infarction on postprocedural diffusion-weighted imaging) events of stenting in each time interval versus asymptomatic stenosis was calculated with logistic regression analysis adjusted for confounders, and provided as odds ratio (OR) and 95% confidence interval (CI). ResultsOverall clinical event rate (4.3%) of stenting for symptomatic carotid stenosis was higher than that for asymptomatic stenosis (1.2%; OR, 3.979 [95% CI, 1.093–14.489]; p=0.036). Stenting in Day 0–3 (13.2%; OR, 10.997 [95% CI, 2.333–51.826]; p=0.002) and Day 4–7 (8.3%; OR, 6.775 [95% CI, 1.382–33.227]; p=0.018) was associated with high risk for clinical events. However, the clinical event rates in stenting after 7 days from index event (Day 8–10, 1.8%; Day 11–14, 2.5%; Day 15–21, 0%; Day >21, 2.9%) were not different from that in stenting for asymptomatic stenosis. Overall radiological event rate (55.6%) in symptomatic stenosis was also higher than that in asymptomatic stenosis (35.5%; OR, 2.274 [95% CI, 1.553–3.352]; p<0.001). The high risk for radiological events was maintained in all time intervals (Day 0–3 : 55.3%; OR, 2.224 [95% CI, 1.103–4.627]; p=0.026; Day 4–7 : 58.3%; OR, 2.543 [95% CI, 1.329–4.949]; p=0.005; Day 8–10 : 53.6%; OR, 2.096 [95% CI, 1.138–3.889]; p=0.018; Day 11–14 : 57.5%; OR, 2.458 [95% CI, 1.225–5.021]; p=0.012; Day 15–21 : 55.6%; OR, 2.271 [95% CI, 1.099–4.764]; p=0.028; Day >21 : 54.8%; OR, 2.203 [95% CI, 1.342–3.641]; p=0.002). ConclusionThis study showed that as stenting was delayed, the periprocedural risk for clinical events decreased. The clinical event risk was high only in stenting within 7 days and comparable with that for asymptomatic stenosis in stenting after 7 days from index event, although the radiological event risk was not affected by stenting timing. Therefore, our results suggest that delayed stenting after 7 days from symptom onset is a safe strategy for symptomatic stenosis.

Feasibility and Safety of Paclitaxel-Coated Balloon Angioplasty for the Treatment of Intracranial Symptomatic In-Stent Restenosis.

Objective: Symptomatic in-stent restenosis (sISR) is the major cause of medium- or long-term cerebral infarctions in patients who underwent percutaneous transluminal angioplasty and stenting for severe intracranial atherosclerotic stenosis. This study aims to evaluate the feasibility and safety of paclitaxel-coated balloon (PCB) angioplasty for the treatment of intracranial sISR.Methods: We report 11 cases of PCB angioplasty for intracranial sISR. Lesion locations and number were as follows: intracranial internal carotid artery (n = 4), M1 segment of middle cerebral artery (MCA) (n = 1), V4 segment of vertebral artery (n = 6). The technical success rate, periprocedural complications, and short-term outcome were retrospectively analyzed.Results: All procedures were successfully performed without periprocedural complication. Asymptomatic vessel dissection after PCB inflation occurred in one case. Postprocedural diffusion-weighted imaging (DWI) showed new asymptomatic ipsilateral infarction in one case. All 11 cases did not experience ipsilateral stroke or death within 30 days or ischemic stroke in the territory of the target artery between 31 and 90 days after procedure.Conclusion: This preliminary study indicates that PCB angioplasty is feasible and safe for the treatment of intracranial sISR. Further studies are needed to clarify its efficiency and long-term outcome.

Predictors of New Ischaemic Brain Lesions on Diffusion Weighted Imaging After Carotid Stenting and Endarterectomy: A Systematic Review

Objectives Peri-procedural ischaemic brain lesions on diffusion weighted imaging (DWI) after carotid endarterectomy (CEA) and carotid artery stenting (CAS) have been related to a higher chance of recurrent cerebrovascular events. This systematic review provides an overview of patient characteristics associated with increased risk of new DWI lesions. Methods MEDLINE, EMBASE, and Cochrane library databases were systematically searched (update November 2018) for studies reporting post-procedural DWI lesions after CEA or CAS. Data derived from both procedures were analysed separately. Studies reporting predictive features that were present prior to intervention were assigned to 10 categories: age, gender, cardiovascular risk factors, symptomatology, plaque vulnerability, atherosclerotic burden, cerebrovascular haemodynamics, carotid/arch anatomy, inflammatory markers, and markers of coagulation. A semi-quantitative analysis was performed by plotting studies that found an association between the investigated features and DWI lesions against those that did not find an association. Results Forty-six studies (5018 patients) were included: 10 reported only CEA, 33 CAS, and three both interventions. 68.0% of 1873 CEA patients and 55.9% of 3145 CAS patients were symptomatic. The weighted prevalence of DWI lesions was 18.1% (95% CI 14.0–22.7%) in CEA patients compared with 40.5% (95% CI 35.4–45.7%) in CAS patients. Studies reporting on CEA patients predominantly found an increased risk in symptomatic patients (two of seven studies, including 848/1661 patients), those with impaired haemodynamics (five of five studies), and increased inflammatory markers (two of three studies). Studies reporting on CAS patients often found a positive association with age (10/26 studies), high plaque vulnerability (25/34 studies), or complex carotid/arch anatomy (three out of five studies). Conclusions For patients undergoing CEA, symptomatic status, impeded cerebral haemodynamics, and increased inflammatory markers are associated with increased susceptibility to peri-operative DWI lesions. In CAS patients, higher age, plaque vulnerability and complex carotid/aortic arch anatomy were identified as risk factors. These clinical predictors may assist with decision making on patient selection for medical treatment, CEA or CAS.

Factors Associated with Postprocedural Diffusion-Weighted Imaging–Positive Lesions in Endovascular Treatment for Unruptured Cerebral Aneurysms

In endovascular treatment for cerebral aneurysms, the appearance of asymptomatic thromboembolic lesions detected by postprocedural diffusion-weighted imaging (DWI) can be a surrogate marker for estimating the potential risk of symptomatic thromboembolism. The aim of this study was to clarify factors associated with postprocedural DWI-positive lesions in endovascular treatment for unruptured cerebral aneurysms. Patients with untreated unruptured cerebral aneurysms undergoing endovascular treatment were consecutively enrolled. Treatment techniques were classified into simple coiling, balloon-assisted coiling, stent-assisted coiling, and flow-diverter placement. Head magnetic resonance imaging was performed within 3 months before and 24 hours after the procedure to assess the appearance of DWI-positive lesions. Among 376 aneurysms in 355 patients that were analyzed, 232 (61.7%) had postprocedural DWI-positive lesions. In univariate analyses, age (P= 0.001), dome size (P < 0.001), neck size (P < 0.001), treatment technique (P= 0.029), and total procedural time (P < 0.001) were significantly associated with postprocedural DWI-positive lesions. In the multiple logistic regression model, older age (odds ratio, 1.33; 95% confidence interval, 1.10-1.60; P= 0.003; per decade), flow-diverter placement (odds ratio, 4.93; 95% confidence interval, 1.33-20.92; P=0.016; compared with simple coiling), and longer procedural time (odds ratio, 1.66; 95% confidence interval, 1.26-2.21; P < 0.001; per hour) were associated with postprocedural DWI-positive lesions. Older age, flow-diverter placement, and longer procedural time were associated with postprocedural DWI-positive lesions in endovascular treatment for unruptured cerebral aneurysms.

Cholesterol Crystals in Embolic Debris are Associated with Postoperative Cerebral Embolism after Carotid Artery Stenting

Object: We investigated possible associations among the presence of cholesterol crystals in embolic debris, the proportions of debris components, and postoperative cerebral embolism in patients undergoing carotid artery stenting (CAS). Methods: Sixty-seven consecutive procedures were performed for internal carotid artery stenosis with CAS at our hospital between November 2015 and February 2018. Procedures for emergency CAS for stroke in evolution or crescendo transient ischemic attack were excluded (n = 12). The embolic debris from remaining procedures (n = 55) was stained with hematoxylin-eosin and the red blood cells, white blood cells, and fibrin were quantified by color-based segmentation. Cholesterol crystals and calcification were examined histopathologically. Diffusion-weighted imaging (DWI) was performed 1–3 days after CAS, and the images were used to classify procedures according to the presence of new lesions. Results: Of the 55 CAS procedures, new DWI lesions were identified after 32. One patient had symptomatic cerebral embolism. Higher proportions of patients with cholesterol crystals in embolic debris (17 vs. 78%, p < 0.001) and higher proportion of white blood cells (mean 2.3 [0–9.9] vs. 4.2% [0–29.9%], p < 0.01) were observed in the embolic debris of procedures with and without new DWI lesions. Conclusions: Cholesterol crystals were common in the embolic debris from patients with postoperative ischemic lesions after CAS. These results suggest that inflammatory destabilization of the intraplaque lipid component is related to postprocedural DWI lesions.

Impact of varying levels of hyperglycemia on clinicoradiographic outcomes after endovascular reperfusion treatment

We evaluated the effects of admission hyperglycemia with different cut-off levels on 3-month outcomes, infarct growth, and hemorrhagic transformation in acute stroke patients with large artery occlusion of anterior circulation who received endovascular treatment (EVT). Between January 2011 and May 2016, patients that underwent EVT with pre-procedural and post-procedural diffusion-weighted imaging were identified from a multicenter registry. Normoglycemia was defined as a glucose level ≤ 110 mg/dL, moderate hyperglycemia as >110 and ≤170 mg/dL, and overt hyperglycemia as >170 mg/dL. Its effects on poor outcomes (3-month modified Rankin Scale score 3–6), infarct growth, and parenchymal hematoma type 2 were analyzed. Of 720 patients encountered, 341 patients were eligible. There was a statistically significant difference in glycated hemoglobin levels between the normoglycemia/moderate hyperglycemia and overt hyperglycemia groups (p < 0.001). Moderate hyperglycemia (odds ratio 2.37 [95% confidence interval 1.26–4.45], p = 0.007) and overt hyperglycemia (2.84 [1.19–6.81], p = 0.019) were associated with poor outcomes. Post-procedural infarct volumes were significantly greater in hyperglycemic patients (padjusted = 0.003). Only overt hyperglycemia (9.28 [1.66–51.88], p = 0.011) was associated with parenchymal hematoma type 2. Overall hyperglycemia was associated with poor outcomes and infarct growth, whereas overt hyperglycemia was associated with parenchymal hematoma type 2.

Risk Factors of Contralateral Microembolic Infarctions Related to Carotid Artery Stenting.

This study sought to analyze the incidence of contralateral microembolic infarctions (MIs) on diffusion-weighted imaging (DWI) following protected carotid artery stenting (CAS) and compared the difference of risk factors between ipsilateral and contralateral lesions. From April 2010 to March 2017, 147 CASs in 140 patients were performed. All the patients underwent DWI within 1 week before and 24 hrs after the procedures. CAS was successfully completed in 145 (98.6%) of the 147 procedures. Forty-nine (33.8%) patients with new MIs revealed on postprocedural DWI were enrolled. They were divided into ipsilateral and contralateral groups based on the side of the CAS and MIs. The ipsilateral group indicates patients with MIs exclusively on the side of CAS. The contralateral group includes patients with MIs on the opposite side of the CAS or both sides. Patients with MIs at vertebrobasilar territory were excluded. Patient characteristics, morphology of the carotid artery and aortic arch, and procedural data were retrospectively assessed and compared between the two groups. Twenty-two (15.2%) and 14 (9.7%) patients were assigned to the ipsilateral and contralateral groups, respectively. Advanced age, left-sided stenosis, severe aortic arch calcification (AAC) on chest X-ray and contralateral carotid occlusion significantly increased the occurrence of contralateral MIs. On multivariable logistic regression analysis, severe AAC was statistically more frequent in the contralateral group. In the present study, the incidences of contralateral MIs after CAS is relatively not low. Advanced aortic atherosclerosis is statistically predictive for contralateral MIs. AAC on chest X-ray is a useful finding for estimating aortic atherosclerosis in candidates for CAS.

Role of terminal and anastomotic circulation in the patency of arteries jailed by flow-diverting stents: from hemodynamic changes to ostia surface modifications.

OBJECTIVE The outcome for jailing arterial branches that emerge near intracranial aneurysms during flow-diverting stent (FDS) deployment remains controversial. In this animal study, the authors aimed to elucidate the role of collateral supply with regard to the hemodynamic changes and neointimal modifications that occur from jailing arteries with FDSs. To serve this purpose, the authors sought to quantify 1) the hemodynamic changes that occur at the jailed arterial branches immediately after stent placement and 2) the ostia surface values at 3 months after stenting; both parameters were investigated in the presence or absence of collateral arterial flow. METHODS After an a priori power analysis, 2 groups (Group A and Group B) were created according to an animal flow model for terminal and anastomotic arterial circulation; each group contained 7 Large White swine. Group A animals possessed an anastomotic-type arterial configuration to supply the territory of the right ascending pharyngeal artery (APhA), while Group B animals possessed a terminal-type arterial configuration to supply the right APhA territory. Subsequently, all animals underwent FDS placement, thereby jailing the right APhAs. Mean flow rates and velocities inside the jailed branches were quantified using time-resolved 3D phase-contrast MR angiography before and after stenting. Three months after stent placement, the jailed ostia surface values were quantified on scanning electron micrographs. The data were analyzed using descriptive statistics and group comparisons with parametric and nonparametric tests. RESULTS The endovascular procedures were feasible, and there were no findings of in situ thrombus formation on postprocedural optical coherence tomography or ischemia on postprocedural diffusion-weighted imaging. In Group A, the mean flow rate values at the jailed right APhAs were reduced immediately following stent placement as compared with values obtained before stent placement (p = 0.02, power: 0.8). In contrast, the mean poststenting flow rates for Group B remained similar to those obtained before stent placement. Three months after stent placement, the mean ostia surface values were significantly higher for Group B (527,911 ± 306,229 μm2) than for Group A (89,329 ± 59,762 μm2; p < 0.01, power: 1.00), even though the initial dimensions of the jailed ostia were similar between groups. A statistically significant correlation was found between groups (A or B), mean flow rates after stent placement, and ostia surface values at 3 months. CONCLUSIONS When an important collateral supply was present, the jailing of side arteries with flow diverters resulted in an immediate and significant reduction in the flow rate inside these arteries as compared with the prestenting values. In contrast, when competitive flow was absent, jailing did not result in significant flow rate reductions inside the jailed arteries. Ostium surface values at 3 months after stent placement were significantly higher in the terminal group of jailed arteries (Group B) than in the anastomotic group (Group A) and strongly correlated with poststenting reductions in the velocity value.

Flow Diverter Therapy With the Pipeline Embolization Device Is Associated With an Elevated Rate of Delayed Fluid-Attenuated Inversion Recovery Lesions.

Flow diversion using the Pipeline Embolization Device is reported as a safe treatment of aneurysms. Complete aneurysm occlusion, however, occurs in a delayed fashion with initial persistent filling of the aneurysm dome. We hypothesized that this transflow across metallic struts may be associated with thromboembolic events. Forty-one consecutive patients undergoing aneurysm treatment with the Pipeline Embolization Device and a comparison group of 78 Neuroform stent-mediated embolizations were studied. Patients' charts, procedure notes, platelet function, and anticoagulation state were analyzed. Serial magnetic resonance images were assessed for the presence of newly occurring diffusion-weighted imaging and fluid-attenuated inversion recovery (FLAIR) lesions at multiple postprocedure time ranges (average days post procedure [Pipeline Embolization Device/Neuroform]: T1=1, T2=73/107, T3=174, T4=277/335, and T5=409). In addition, diffusion-weighted imaging or FLAIR burden was estimated by lesional diameter summation. Pipeline patients were more likely to have new ipsilateral FLAIR lesions at all time points studied (30.6% versus 7.2% of patients at T=2 and 34.5% versus 6.2% at T=4). The mean FLAIR burden was significantly increased for Pipeline patients (10.1 versus 0.7 mm at T=2 and 8.8 versus 1.9 mm at T=4). Overall 34% (14/41) of Pipeline patients experienced a new FLAIR lesion at anytime when compared with 10% (8/78) of Neuroform stent-coil patients. Postprocedural diffusion-weighted imaging did not predict future FLAIR lesions suggesting a nonprocedural cause. The Pipeline Embolization Device is associated with increased rate of de novo FLAIR lesions occurring in a delayed fashion and distinct from perioperative diffusion-weighted imaging lesions. The cause and clinical effect of these lesions are unknown and suggest the need for prudent follow-up and evaluation.

Silent ischemic events after Pipeline embolization device: a prospective evaluation with MR diffusion-weighted imaging

BackgroundThe development of ischemic events is relatively common after endovascular interventions, and flow diverters may pose a particular threat owing to their increased technical complexity and high metal content.ObjectiveTo investigate...

New cerebral lesions at magnetic resonance imaging after carotid artery stenting versus endarterectomy: an updated meta-analysis.

BackgroundCarotid endarterectomy (CEA) or stenting (CAS) are associated with a relatively low rate of clinical events, but diffusion-weighted imaging (DWI) is increasingly being used to compare the incidence of new ischemic lesions. Therefore, we conducted an updated meta-analysis on the occurrence of post-procedural new DWI lesions after CAS versus CEA.Methods and ResultsMEDLINE, Cochrane, ISI Web of Science and SCOPUS databases were searched and 20 studies (2 randomized and 18 non-randomized) with a total of 2104 procedures (CAS = 989; CEA = 1115) were included. The incidence of new DWI cerebral lesions was significantly greater after CAS than CEA (40.3% vs 12.2%; 20 studies; 2104 patients; odds ratio [OR] 5.17; 95% confidence interval [CI], 3.31-8.06; p<0.00001). Also peri-procedural stroke (17 studies; 1833 patients; OR 2.01; 95% CI, 1.14-3.55; p=0.02) and stroke or TIA (17 studies; 1833 patients; OR 2.40; 95% CI, 1.42-4.08; p=0.001) were significantly increased after CAS. This latter clinical advantage in the CEA group over CAS was tempered when CEA procedures were performed with shunting in all instead of selective shunting or when CAS was performed with only closed cell stents instead of both closed and open cell stents, however, no significant differences between subgroups emerged.ConclusionsCAS is associated with an increased incidence of post-procedural brain DWI lesions. This greater amount of ischemic burden may also reflect a higher rate of cerebral events after CAS. However, whether recent technical advances mainly for CAS could potentially reduce these ischemic events still remains to be evaluated.

Stroke : Highlights of Selected Articles

<i>Stroke</i> : Highlights of Selected Articles

Anatomical risk factors for ischemic lesions associated with carotid artery stenting.

The purpose of this study was to investigate the anatomical risk factors for ischemic lesions detected by diffusion-weighted imaging (DWI) associated with carotid artery stenting (CAS). DWI was performed within four days after CAS in 50 stenotic lesions between January 2008 and September 2013. We retrospectively analyzed the correlation between the anatomical factors and ischemic lesions associated with CAS. Post-procedural DWI revealed new ischemic lesions after 24 (48%) of the 50 CAS procedures. All three patients with common carotid artery tortuosity, defined as the presence of severe angulation (less than 90 degrees) in the common carotid artery, developed new ischemic lesions. However, there were no significant differences between the patients with and without tortuosity, likely due to the small number of cases. Meanwhile, seven of eight patients with internal carotid artery tortuosity, defined as the presence of severe angulation (less than 90 degrees) in the cervical segment of the internal carotid artery, developed new ischemic lesions. A multivariate analysis showed internal carotid artery tortuosity (odds ratio: 11.84, 95% confidence interval: 1.193-117.4, P= 0.035) to be an independent risk factor for the development of ischemic lesions associated with CAS. Anatomical factors, particularly severe angulation of the internal carotid artery, have an impact on the risk of CAS. The indications for CAS should be carefully evaluated in patients with these factors.

Reperfusion Injury on Magnetic Resonance Imaging After Carotid Revascularization

Reperfusion injury can be revealed as delayed gadolinium enhancement in the subarachnoid space on a fluid-attenuated inversion recovery image, which is designated as a hyperintense acute reperfusion marker (HARM). We sought to investigate the occurrence and predictors of HARM and its association with new ischemic infarcts after carotid revascularization. Forty-five patients who underwent carotid endarterectomy or stenting were prospectively enrolled. Diffusion-weighted imaging and fluid-attenuated inversion recovery were performed before and 24 hours after the procedures. Postprocedural fluid-attenuated inversion recovery was done after intravenous gadolinium injection. HARM was observed in 8 (17.8%) patients. Of these, 4 patients showed neurological deterioration associated with HARM. These symptomatic HARMs disappeared on follow-up magnetic resonance imaging. Patients with symptomatic HARM were older (P=0.010) and had more frequent leukoaraiosis (P=0.012) and higher postprocedural systolic blood pressure (P=0.025) than those without. New brain infarcts on postprocedural diffusion-weighted imaging were identified in 13 (28.9%) patients. HARM was not associated with new infarcts. HARM after carotid revascularization is not uncommon. Symptomatic HARM was associated with old age, underlying leukoaraiosis, and postprocedural high blood pressure.

Incidence of embolism associated with carotid artery stenting: open-cell versus closed-cell stents

Carotid artery stenting (CAS) can be an alternative option for carotid endarterectomy in the prevention of ischemic stroke caused by carotid artery stenosis. The purpose of this study was to evaluate the influence of stent design on the incidence of procedural and postprocedural embolism associated with CAS treatment. Ninety-six symptomatic and asymptomatic patients, consisting of 79 males and 17 females, with moderate to severe carotid artery stenosis and a mean age of 69.0 years were treated with CAS. The stent type (48 closed-cell and 48 open-cell stents) was randomly allocated before the procedure. Imaging, procedural, and clinical outcomes were assessed and compared. The symptomatic subgroup (76 patients) was also analyzed to determine the influence of stent design on outcome. New lesions on postprocedural diffusion-weighted imaging (DWI) were significantly more frequent in the open-cell than in the closed-cell stent group (24 vs 12, respectively; p = 0.020). The 30-day clinical outcome was not different between the 2 stent groups. In the symptomatic patient group, stent design (p = 0.017, OR 4.173) and recent smoking history (p = 0.036, OR 4.755) were strong risk factors for new lesions on postprocedural DWI. Stent design may have an influence on the risk of new embolism, and selecting the appropriate stent may improve outcome.

Diffusion-weighted lesions after carotid artery stenting are associated with cognitive impairment

The effect of carotid artery stenting (CAS) on cognitive function is still debated. Cerebral microembolism, detectable by post-procedural diffusion-weighted imaging (DWI) lesions, has been suggested to predispose to cognitive decline. Our study aimed at evaluating the effect of CAS on cognitive profile focusing on the potential role of cerebral microembolic lesions, taking into consideration the impact of factors potentially influencing cognitive status (demographic features, vascular risk profile, neuropsychological evaluation at baseline and magnetic resonance (MR) markers of brain structural damage). Thirty-seven patients with severe carotid artery stenosis were enrolled. Neurological assessment, neuropsychological evaluation and brain MR were performed the day before CAS (E0). Brain MR with DWI was repeated the day after CAS (E1), while neuropsychological evaluation was done after a 14-month median period (E2). Volumes of both white matter hyperintensities and whole brain were estimated at E0 on axial MR FLAIR and T1w-SE sequences, respectively. Unadjusted ANOVA analysis showed a significant CAS∗DWI interaction for MMSE (F=7.154(32), p=.012). After adjusting for factors potentially influencing cognitive status CAS∗DWI interaction was confirmed for MMSE (F=7.092(13), p=.020). Patients with DWI lesions showed a mean E2–E0 MMSE reduction of −3.1, while group without DWI lesions showed a mean E2–E0 MMSE of +1.1. Our study showed that peri-procedural brain microembolic load impacts negatively on cognitive functions, independently from the influence of patients-related variables.

Abstract TP161: Evaluation Of On-treatment Platelet Reactivity During Carotid Artery Stenting Using The VerifyNow System

OBJECTIVE: We evaluated the correlation between point-of-care measurement of on-treatment platelet reactivity and postoperative thromboembolic events in patients undergoing carotid artery stenting (CAS) for atherosclerotic carotid artery stenosis. METHODS: Thirty patients receiving dual antiplatelet treatment, including clopidogrel, before CAS were prospectively enrolled. On-treatment platelet reactivity was measured within 24 h before CAS using both the VerifyNow P2Y12 and aspirin assays and light transmittance aggregometry (LTA) with ADP (LTA-ADP) and collagen (LTA-collagen) as the agonists. The endpoint was defined as the detection of acute ipsilateral ischemia on diffusion-weighted imaging (DWI) within 72 h after CAS. Cut-off values for high on-treatment platelet reactivity were established by receiver operating characteristic curve analysis. RESULTS: A significant correlation was observed between VerifyNow P2Y12 reaction units (PRUs) and LTA-ADP and between VerifyNow aspirin reaction units (ARUs) and LTA-collagen. Small abnormalities were observed on DWI in 9 patients (30.0%), and transient ischemic attack was found in 2 (6.67%). Patients with ischemic events had significantly higher mean pre-CAS PRU values (286.42 ± 85.95 vs. 195.28 ± 90.05; p = 0.027) and lower mean pre-CAS PRU percent inhibition (11.71 ± 12.40 vs. 41.52 ± 22.51; p = 0.0027) than those without ischemic events. In the univariate analysis of the endpoint, 4th quartile PRU values (risk ratio [RR]: 3.0; 95% confidence interval [CI]: 1.00-8.92; p = 0.0533), 1st quartile PRU percent inhibition (RR: 6.33; 95% CI: 1.57-25.42; p = 0.0021), and 4th quartile LTA-ADP (RR: 3.06; 95% CI: 1.17-8.00; p = 0.0341) were found to increase the risk of abnormality detection on postprocedural DWI. The optimal cut-offs for high on-treatment platelet reactivity were 264 for pre-CAS PRU values (area under the curve [AUC]: 0.82; 95% CI: 0.65-0.99), 29 for PRU percent inhibition (AUC: 0.89; 95% CI: 0.77-1.01), and 38 for LTA-ADP (AUC: 0.80, 95% CI: 0.67-0.98). CONCLUSION: This study indicates that the new point-of-care VerifyNow P2Y12 assay might help identify patients who are at higher risk for thromboembolic events after CAS.

Cerebral Perfusion Affects the Risk of Ischemia during Carotid Artery Stenting

Background: Patients with impaired perfusion in the hemisphere ipsilateral to a stenotic internal carotid artery may have a higher risk of cerebral ischemic complications than those with normal perfusion. We therefore studied whether the occurrence of new ischemic lesions after carotid artery stenting is related to cerebral perfusion. Methods: In 45 patients with symptomatic carotid artery stenosis, CT perfusion and magnetic resonance diffusion-weighted imaging (DWI) were performed before carotid artery stenting; DWI was repeated within 2 days thereafter. Cerebral blood volume (CBV), mean transit time (MTT), and cerebral blood flow (CBF) were measured with CT perfusion in the cortical flow territory of the middle cerebral artery. Hyperintense lesions on postprocedural DWI not visible on baseline DWI were considered new cerebral ischemic lesions. The relation between CBF, CBV, and MTT and new ipsilateral ischemic lesions was tested with logistic regression. Results: In 11 of the 45 (24%) patients, new ischemic lesions were found in the ipsilateral hemisphere. The occurrence of these lesions was related to a lower CBF [adjusted odds ratio (aOR), 0.96; 95% confidence interval (CI), 0.92–1.00] and a longer MTT (aOR, 1.65; 95% CI, 1.02–2.66) compared with ipsilateral hemispheres without new lesions. Conclusions: Patients with impaired cerebral perfusion are more prone to develop ischemic lesions during carotid artery stenting. This suggests that in ischemic stroke during or after carotid artery stenting, embolic and hemodynamic mechanisms act in concert.

Aortic calcification on plain chest radiography predicts embolic complications during carotid artery stenting

Aortic arch calcification (AC) on conventional angiograms has recently been shown to be associated with embolic complications during carotid artery stenting (CAS). Because conventional angiography is not routinely carried out in patients prior to CAS, a less invasive, commonly available diagnostic modality is warranted to identify AC. We investigated the occurrence of AC on routinely acquired chest radiographs and its influence on diffusion-weighted imaging (DWI) lesions as surrogate markers for stroke. A total of 152 patients (mean age: 67.5 +/- 8.9 years, 112 men) underwent CAS and completed pre- and post-procedural DWI. AC larger than 1 cm in length was classified as relevant and could be detected in 63 patients (41.4%) on plain chest radiographs. In patients with AC, significantly more new DWI-lesions were found than in patients without AC [median 2; interquartile range (IQR): 0-7 vs. median 1, IQR: 0-2; P < 0.05]. After multivariate regression analysis, AC was independently associated with new post-procedural DWI lesions. AC is a common finding in patients with a high-grade carotid stenosis and predicts embolic complications during CAS. Since AC can be detected on plain chest radiography, this diagnostic tool is useful to identify high-risk patients for CAS.