Post-procedural Diffusion-weighted Magnetic Resonance Imaging Research Articles

Incidence and predictors of asymptomatic cerebral infarction following radiofrequency catheter ablation for atrial fibrillation

Abstract Backgrounds Left atrial catheter ablation has been established as an important treatment option for atrial fibrillation (AF), but it carries the risk of periprocedural thromboembolism. Periprocedural major stroke is rare, but silent stroke does not appear to be rare. Accurate risk stratification for stroke and appropriate anticoagulation management are essential. Purpose We aimed to investigate the incidence and predictors of silent cerebral infarction (CI) associated with AF catheter ablation, detected by diffusion-weighted magnetic resonance imaging (DW-MRI). Methods and Results We performed a retrospective analysis of 618 consecutive patients (age 72±10 years, persistent atrial fibrillation (PEF) 45%, CHA2DS2-VASc score 2.6±1.4) with persistent or paroxysmal AF that underwent pulmonary vein (PV) or additional ablation and post-procedural cerebral MRI 1 day after ablation. During the ablation procedure, activated clotting time (ACT) was checked every 20 minutes, and additional heparin boluses were administered as needed to maintain ACT >320 seconds. Patients were analyzed for possible demographical, medical, echocardiographic, and procedural predictors of infarction events. Post-procedure DW-MRI detected new infarction lesions in 83 patients (13.4%:CI-group). There were no differences between the CI and non-CI groups with respect to age, type of anticoagulant and complex fractionated atrial electrogram ablation. Body weight, brain natriuretic peptide and left atrial diameter were significantly higher in the CI group. Left ventricular ejection fraction (LVEF) was significantly lower in the CI than non-CI group (58.6±12.6 vs. 64.2±11.8, P<0.001). PEF was more frequent in patients with CI than non-CI group (63.9 vs. 42.1%, P<0.001). In a multivariate regression model revealed only EF was a significant predictor for the occurrence of new asymptomatic lesions on post-procedural DW-MRI (OR 0.949, 95% CI 0.92-0.98, P=0.001). Conclusions This study shows a high incidence of silent micro-embolic events after AF ablation. Lower LVEF were potential predictors of this complication.

Carotid artery stenting using a 7 French Optimo balloon guide catheter combined with a distal filter.

Carotid artery stenting (CAS) by proximal occlusion of the common carotid artery (CCA) using a balloon guide catheter (BGC) is a simple proximal protection method to prevent distal embolism, however, it requires at least an 8 French (F) system. A 7 F Optimo BGC is the smallest BGC with an inner lumen diameter of 0.071 inches, and which permits the passage of a 5 F carotid stent. We retrospectively investigated the clinical results and the safety of CAS by using a 7 F Optimo BGC combined with a distal filter. One-hundred carotid arterial stenosis patients were treated with CAS using combined protection of a 7 F Optimo BGC and a distal filter. The BGC was navigated from the femoral and radial arteries in 85 and 15 patients, respectively. The 7 F Optimo BGC was successfully navigated into the CCA in all patients, and the technical success rate of CAS was 100%. Major adverse events of any death, stroke, or myocardial infarction within 30-day after the procedure were observed in one (1%). Post-procedural diffusion-weighted magnetic resonance imaging revealed high signals in 21% of the patients, all of whom were asymptomatic. The 7 F Optimo is the smallest BGC to achieve CAS using a proximal protection system. The combined use of a 7 F Optimo BGC and a distal filter is effective for navigating the BGC and distal embolic protection.

Silent brain infarcts and early cognitive outcomes after transcatheter aortic valve implantation: a systematic review and meta-analysis.

Silent brain infarcts (SBIs) are frequently identified after transcatheter aortic valve implantation (TAVI), when patients are screened with diffusion-weighted magnetic resonance imaging (DW-MRI). Outside the cardiac literature, SBIs have been correlated with progressive cognitive dysfunction; however, their prognostic utility after TAVI remains uncertain. This study's main goals were to explore (i) the incidence of and potential risk factors for SBI after TAVI; and (ii) the effect of SBI on early post-procedural cognitive dysfunction (PCD). A systematic literature review was performed to identify all publications reporting SBI incidence, as detected by DW-MRI after TAVI. Silent brain infarct incidence, baseline characteristics, and the incidence of early PCD were evaluated via meta-analysis and meta-regression models. We identified 39 relevant studies encapsulating 2408 patients. Out of 2171 patients who underwent post-procedural DW-MRI, 1601 were found to have at least one new SBI (pooled effect size 0.76, 95% CI: 0.72-0.81). The incidence of reported stroke with focal neurological deficits was 3%. Meta-regression noted that diabetes, chronic renal disease, 3-Tesla MRI, and pre-dilation were associated with increased SBI risk. The prevalence of early PCD increased during follow-up, from 16% at 10.0 ± 6.3 days to 26% at 6.1 ± 1.7 months and meta-regression suggested an association between the mean number of new SBI and incidence of PCD. The use of cerebral embolic protection devices (CEPDs) appeared to decrease the volume of SBI, but not their overall incidence. Silent brain infarcts are common after TAVI; and diabetes, kidney disease, and pre-dilation increase overall SBI risk. While higher numbers of new SBIs appear to adversely affect early neurocognitive outcomes, long-term follow-up studies remain necessary as TAVI expands to low-risk patient populations. The use of CEPD did not result in a significant decrease in the occurrence of SBI.

First-in-Man Study Evaluating the Emblok Embolic Protection System During Transcatheter Aortic Valve Replacement

ObjectivesThis study sought to evaluate the feasibility of complete cerebral protection during transcatheter aortic valve replacement (TAVR) with a novel embolic protection device. BackgroundEvidences and data about new cerebral embolic protection devices are lacking and scarce. MethodsA prospective, nonrandomized, multicenter, first-in-man pilot study designed to evaluate the efficacy and safety of cerebral embolic protection utilizing the Emblok embolic protection system (Innovative Cardiovascular Solutions, Grand Rapids, Michigan) during TAVR. The Emblok is a transfemoral aortic filter that provide full coverage of the epiaortic vessels. Brain diffusion-weighted magnetic resonance imaging (DW-MRI) was performed at baseline and 2 to 5 days after TAVR. Primary endpoints were technical success and immediate cerebral embolic burden after TAVR, defined as number and volume of new brain lesions detected with DW-MRI at days 2 to 5 post-TAVR compared with baseline. ResultsA total of 20 subjects were enrolled. The Emblok system was successfully positioned in all the cases. At 30-day follow-up, no major adverse cardiovascular and cerebrovascular events occurred. Nineteen (95%) patients had new ischemic defects at post-procedural DW-MRI. The median number of new lesions per patient was 10.00 (interquartile range [IQR]: 4.75 to 15.25). The total new lesion volume was 199.9 mm3 (IQR: 83.9 to 447.5 mm3) and the mean lesion volume per lesion was 42.5 mm3 (IQR: 21.5 to 75.6 mm3). Histopathologic analysis showed evidence of significant debris in 18 (90%) filters. ConclusionsThe Emblok embolic protection system appears to be feasible and safe during TAVR. The device was successfully placed and retrieved in all cases and no neurological events were observed. Cerebral total new lesion volume was similar to other trials on cerebral protection during TAVR, thus warranting a larger study. (European Study Evaluating the Emblok Embolic Protection System During TAVR; NCT03130491)

P3693Self-expandable transcatheter aortic valve implantation is associated with frequent periprocedural stroke detected by diffusion-weighted magnetic resonance imaging -Insight from propensity score match

Abstract Background Little evidence is available regarding the risk of peri-procedural stroke detected by diffusion-weighted magnetic resonance imaging (DW-MRI) after transcatheter aortic valve implantation (TAVI). Our purpose was to evaluate stroke risk after TAVI using DW-MRI by enrolling consecutive patients who underwent transfemoral TAVI and post-procedural DW-MRI. Methods We prospectively enrolled 113 consecutive patients who underwent transfemoral TAVI and post-procedural DW-MRI. We used balloon-expandable valves as first-line therapy and selected self-expandable valves only for patients with narrow sinotubular junctions or annuli. We set the primary endpoint as the number of high intensity areas (HIA) detected by DW-MRI regardless of the size of the area. To evaluate the risks of the primary endpoint, we employed a multivariable linear regression model, setting the primary endpoint as an objective variable and patient and clinical backgrounds as explanatory variables. In addition, the relationship between valve type and the number of HIAs on DW-MRI was also confirmed by the propensity score matching analysis to evaluate the robustness of the result, using a multivariable linear regression model with the protocol described in the previous manuscript. Shortly, the propensity score was calculated with a logistic regression model by setting the treatment as the response variable and baseline characteristics and procedural information that were significantly different between 2 groups (balloon expandable and self-expandable) as explanatory variables, which included age, estimated glomerular filtration rate, oversizing rate, and BAV before THV deployment. Results Median patient age was 84 years, and 36.3% were men. Ninety-three patients underwent balloon-expandable TAVI and 20 underwent self-expandable TAVI. Symptomatic stroke occurred in 6 (5.3%) whereas asymptomatic stroke occurred in 59 (52.2%) patients. The incidence of symptomatic and total stroke was higher in patients who underwent self-expandable TAVI than those who underwent balloon-expandable TAVI (30.0% vs 0.0%, p<0.001 and 90.0% vs 50.5%, p=0.001, respectively). A multivariable linear regression model demonstrated an increased primary endpoint when self-expandable TAVI was performed (p<0.001). The other covariates had no significant relationship to the primary endpoint. Akaike information criterion-based stepwise statistical model selection revealed that valve type was the only explanatory variable for the best predictive model. This result was also confirmed with the propensity score matching analysis (estimate, 2.359; 95% CI, 0.426–4.292; p=0.019) after adjustments of propensity score, in which 28 patients were matched (n=14 in each group). Conclusions Self-expandable valves were associated with increased numbers of HIA on DW-MRI after TAVI in patients with severe aortic stenosis.

Self-expandable transcatheter aortic valve replacement is associated with frequent periprocedural stroke detected by diffusion-weighted magnetic resonance imaging

BackgroundLittle evidence is available regarding the risk of peri-procedural stroke detected by diffusion-weighted magnetic resonance imaging (DW-MRI) after transcatheter aortic valve replacement (TAVR). Our purpose was to evaluate stroke risk after TAVR using DW-MRI by enrolling consecutive patients who underwent transfemoral TAVR and post-procedural DW-MRI. MethodsWe prospectively enrolled 113 consecutive patients who underwent transfemoral TAVR and post-procedural DW-MRI. We used balloon-expandable valves as first-line therapy and selected self-expandable valves only for patients with narrow sinotubular junctions or annuli. We set the primary endpoint as the number of high intensity areas (HIA) detected by DW-MRI regardless of the size of the area. To evaluate the risks of the primary endpoint, we employed a multivariable linear regression model, setting the primary endpoint as an objective variable and patient and clinical backgrounds as explanatory variables. ResultsMedian patient age was 84 years, and 36.3% were men. Ninety-three patients underwent balloon-expandable TAVR and 20 underwent self-expandable TAVR. Symptomatic stroke occurred in 6 (5.3%) whereas asymptomatic stroke occurred in 59 (52.2%) patients. The incidence of symptomatic and total stroke was higher in patients who underwent self-expandable TAVR than those who underwent balloon-expandable TAVR (30.0% vs. 0.0%, p<0.001 and 90.0% vs. 50.5%, p=0.001, respectively). A multivariable linear regression model demonstrated an increased primary endpoint when self-expandable TAVR was performed (p<0.001). The other covariates had no significant relationship to the primary endpoint. Akaike information criterion-based stepwise statistical model selection revealed that valve type was the only explanatory variable for the best predictive model. ConclusionsSelf-expandable valves were associated with increased numbers of HIA on DW-MRI after TAVR in patients with severe aortic stenosis.

Double Filtration During Carotid Artery Stenting Using a Novel Post-Dilation Balloon With Integrated Embolic Protection

ObjectivesThis study evaluated the safety and performance of the Paladin System, a novel angioplasty balloon with an integrated embolic protection filter designed to increase embolic protection during post-dilation. BackgroundThe risk of major adverse events during carotid artery stenting (CAS) is equivalent to carotid endarterectomy. However, the risk of minor stroke remains higher with CAS. Much of this risk occurs during post-stent dilation. MethodsA total of 106 patients were enrolled in 5 centers in Germany. The study’s primary endpoint was all-cause death, myocardial infarction, and stroke at 30 days post-procedure. Pre- and post-procedural diffusion-weighted magnetic resonance imaging evaluated new ischemic lesions in 30 subjects. Filter histomorphometric analysis was performed in 23 patients. Retrospective analyses compared outcome rates to historical controls. ResultsDevice and procedural success rates were 100%. The combined major adverse event rate (death, myocardial infarction, and stroke) at discharge and at 30 days was 0% and 1.0%, respectively. The single adverse event was a stroke, which occurred at day 12 and was believed unrelated to the device or procedure. New ischemic lesions were found in 11 (36.7%) patients in the diffusion-weighted magnetic resonance imaging subset. New ipsilateral lesions were seen in 9 (30.0%) patients. Mean lesion volume per patient was 0.010 cm3. Debris was present in all filters, and approximately 90% of captured particles were <100 μm. ConclusionsUse of the Paladin System for post–stent dilation during CAS appears safe, and it may effectively decrease the number of embolic particles reaching the brain, which may help reduce the risk of procedure-related stroke. (A Multi-Center Study to Evaluate Acute Safety and Clinical Performance of Paladin® Carotid Post-Dilation Balloon System With Integrated Embolic Protection; NCT02501148)

Effect of a Cerebral Protection Device on Brain Lesions Following Transcatheter Aortic Valve Implantation in Patients With Severe Aortic Stenosis: The CLEAN-TAVI Randomized Clinical Trial.

Stroke remains a major predictor of mortality after transcatheter aortic valve implantation (TAVI). Cerebral protection devices might reduce brain injury as determined by diffusion-weighted magnetic resonance imaging (DWMRI). To determine the effect of a cerebral protection device on the number and volume of cerebral lesions in patients undergoing TAVI. Investigator-initiated, single center, blinded, randomized clinical trial in higher-risk patients with severe aortic stenosis undergoing TAVI at the University of Leipzig Heart Center. Brain MRI was performed at baseline, 2 days, and 7 days after TAVI. Between April 2013 and June 2014, patients were randomly assigned to undergo TAVI with a cerebral protection device (filter group) or without a cerebral protection device (control group). The last 1-month follow-up occurred in July 2014. TAVI with or without a cerebral protection device (filter system). The primary end point was the numerical difference in new positive postprocedure DWMRI brain lesions at 2 days after TAVI in potentially protected territories. The first hierarchical secondary outcome was the difference in volume of new lesions after TAVI in potentially protected territories. Among the 100 enrolled patients, mean (SD) age was 80.0 (5.1) years in the filter group (n = 50) and 79.1 (4.1) years in the control group (n = 50), and the mean (SD) procedural risk scores (logistic EuroScores) were 16.4% (10.0%) in the filter group and 14.5% (8.7%) in the control group. For the primary end point, the number of new lesions was lower in the filter group, 4.00 (interquartile range [IQR], 3.00-7.25) vs 10.00 (IQR, 6.75-17.00) in the control group (difference, 5.00 [IQR, 2.00-8.00]; P < .001). For the first hierarchical secondary end point, new lesion volume after TAVI was lower in the filter group (242 mm3 [95% CI, 159-353]) vs in the control group (527 mm3 [95% CI, 364-830]) (difference, 234 mm3 [95% CI, 91-406]; P = .001). Considering adverse events, 1 patient in the control group died prior to the 30-day visit. Life-threatening hemorrhages occurred in 1 patient in the filter group and 1 in the control group. Major vascular complications occurred in 5 patients in the filter group and 6 patients in the control group. One patient in the filter group and 5 in the control group had acute kidney injury, and 3 patients in the filter group had a thoracotomy. Among patients with severe aortic stenosis undergoing TAVI, the use of a cerebral protection device reduced the frequency of ischemic cerebral lesions in potentially protected regions. Larger studies are needed to assess the effect of cerebral protection device use on neurological and cognitive function after TAVI and to devise methods that will provide more complete coverage of the brain to prevent new lesions. clinicaltrials.gov Identifier: NCT01833052.

Risk Factors for Cerebral Embolization After Carotid Artery Stenting With Embolic Protection

Meta-analyses of randomized trials have shown an increased risk of periprocedural stroke after carotid artery stenting (CAS) compared with carotid endarterectomy, which may differ in specific patient subgroups. Knowledge of risk factors for cerebral embolic lesions during CAS may impact treatment decisions for the individual patient, but these factors have not been extensively studied. We aimed to identify factors predictive for cerebral ischemic lesions during embolic protected CAS. Preprocedural and postprocedural diffusion-weighted magnetic resonance imaging was performed for evaluation of new cerebral ischemic lesions in 728 (86.9%) of 837 consecutive patients undergoing CAS with cerebral embolic protection. Multivariable logistic regression analyses were performed to identify factors predictive for embolic lesions. New ischemic lesions were found in 32.8% of patients. Age, hypertension, lesion length, lesion eccentricity, and aortic arch type III were significantly associated with new ischemic lesions; calcified lesions were negatively associated. In 25% of these patients embolic lesions were also found in the contralateral hemisphere. Predictive factors for contralateral lesions were age, >50% stenosis of the contralateral internal carotid artery, and an aortic arch type II, with a trend for aortic arch type III. Age, hypertension, lesion morphology, and aortic arch type were predictive for procedural-related cerebral embolic lesions during embolic protected CAS. Age, significant contralateral carotid stenosis, and complex aortic arch type were predictive for bilateral ischemic lesions. The clinical implications of ischemic lesions are not yet fully understood.

Impact of Asymptomatic Cerebral Lesions in Diffusion-Weighted Magnetic Resonance Imaging After Carotid Artery Stenting

This study sought to analyze the impact of new asymptomatic cerebral ischemic lesions, found in diffusion-weighted magnetic resonance imaging (DW-MRI) after carotid artery stenting (CAS) in relation to other risk factors for major adverse cerebral and cardiovascular events (MACCE) defined as death, stroke, and myocardial infarction. After CAS, new cerebral lesions have been reported in up to 70% of patients. The impact of asymptomatic lesions on prognosis after CAS has not been studied. Eight hundred thirty-seven consecutive patients underwent CAS with cerebral embolic protection. In 728 patients (86.9%), a pre- and post-procedural DW-MRI was available; these patients were included in the analyses. Multivariate Cox regression analysis and Kaplan-Meier estimates were performed to identify independent risk factors for MACCE at follow-up. Clinical, procedural, and lesion characteristics and DW-MRI findings were included in the analyses. Post-procedure new cerebral ischemic lesions were detected in 32.8% (n = 241) of patients. Fifteen patients (1.79%) had a periprocedural MACCE and were therefore excluded from the analysis. At a mean follow-up of 766.8 ± 513.4 days (range 30 to 2,577 days), MACCE occurred in 45 patients (6.2%). Cox regression analysis and Kaplan-Meier estimates both identified diabetes as the only significant independent risk factor of MACCE. Asymptomatic cerebral lesions after CAS were not associated with MACCE. Beyond 30 days, diabetes is the only risk factor of MACCE at follow-up. Asymptomatic cerebral embolic events after CAS had no prognostic impact.

Cerebral embolization in asymptomatic versus symptomatic patients after carotid stenting

Previous studies have investigated the development of new ischemic brain lesions on diffusion-weighted magnetic resonance imaging (DW-MRI) after carotid artery stenting (CAS). The rate of ischemic brain injury after CAS for asymptomatic stenosis has not been extensively studied but is presumed to be less likely than in symptomatic patients. This study assessed the occurrence of cerebral embolization after CAS for asymptomatic vs symptomatic carotid stenosis. During an 18-month period, 40 patients undergoing CAS under filter embolic protection were prospectively evaluated. Transcranial Doppler (TCD) during CAS and preprocedural and 24-hour postprocedural DW-MRI were used to assess cerebral embolization. Univariate and nonparametric analyses were used to compare differences in cerebral embolization after CAS in asymptomatic and symptomatic patients. CAS was performed for 23 asymptomatic (58%) and 17 symptomatic (42%) carotid stenoses. The median microembolic counts detected by TCD were 285 (interquartile range [IQR], 182-376) for asymptomatic and 313 (IQR, 170-426) for symptomatic carotid stenosis (P=.6). DW-MRI was available for assessment in 20 asymptomatic and 14 symptomatic patients. New acute cerebral emboli detected with DW-MRI occurred in 10 asymptomatic (50%) and 7 symptomatic patients (50%) undergoing CAS (P=.9). The ipsilateral and total median number of DW-MRI lesions between groups were not statistically significantly different at, respectively, 1 (IQR, 0-2.5) and 1.5 (IQR, 0-3) for asymptomatic vs 0.5 (IQR, 0-2) and 0.5 (IQR, 0-3) for symptomatic carotid stenosis (P>.5). One asymptomatic patient sustained a minor stroke after CAS. No new neurologic events occurred in symptomatic patients. The 30-day stroke-death rate was 2.5% in this series. Cerebral embolization, as detected by TCD and DW-MRI, occurs with a similar frequency after CAS for asymptomatic and symptomatic carotid stenosis. Because postprocedural ischemic brain injury occurs in approximately half of asymptomatic patients, the safety of CAS under filter embolic protection for asymptomatic carotid stenosis is uncertain and warrants further study.

A diffusion-weighted magnetic resonance imaging-based study of transcervical carotid stenting with flow reversal versus transfemoral filter protection

Transfemoral carotid artery stenting (CAS) has been associated with a high incidence of embolic phenomena and silent brain infarction. The goal of this study was to compare the incidence of new ischemic cerebral lesions on diffusion-perfusion magnetic resonance imaging (MRI) sequences after transcervical CAS performed with carotid flow reversal vs stenting via transfemoral approach with distal filter protection. During a 26-month period, 64 consecutive patients diagnosed with significant carotid stenosis by ultrasound imaging were assigned to transcervical CAS with carotid flow reversal or a transfemoral approach with a distal filter. The Rankin stroke scale was administered by an independent neurologist, and diffusion-weighted MRI (DW-MRI) studies were performed ≤24 hours before and ≤24 to 48 hours after the procedure. DW-MRI studies were compared by two neuroradiologists not involved in the study and blinded for time, clinical status, and treatment option. Hyperintense DW-MRI signals found after the procedure were interpreted as postoperative ischemic infarcts. All patients were assessed at 1, 6, and 12 months after the intervention. The distribution of demographic and pathologic variables was similar in both groups. All procedures were technically successful, with a mean carotid flow reversal time of 22 minutes. Twenty-one (70%) and 23 patients (69.69%) were symptomatic in the transcervical and transfemoral groups, respectively (P=.869). After intervention, new postprocedural DW-MRI ischemic infarcts were found in four transcervical (12.9%) and in 11 transfemoral (33.3%) patients (P=.03), without new neurologic symptoms. No major adverse events occurred at 30 days after the intervention. All patients remained neurologically intact, without an increase in stroke scale scoring. All stents remained patent, and all patients remained stroke-free during follow-up. In multivariate analysis, age (relative risk [RR], 1.022; P<.001), symptomatic status (RR, 4.109; P<.001), and open-cell vs closed-cell stent design (RR, 2.01; P<.001) were associated with a higher risk of embolization in the transfemoral group but not in the transcervical group. These data suggest that transcervical carotid stenting with carotid flow reversal carries a significantly lower incidence of new ischemic brain infarcts than that resulting from transfemoral CAS with a distal filter. The transcervical approach with carotid flow reversal may improve the safety of CAS and has the potential to improve results in especially vulnerable patients such as the elderly and symptomatic.

Efficacy and Safety of Single versus Dual Antiplatelet Therapy for Coiling of Unruptured Aneurysms

Although the efficacy of antiplatelet therapy for coiling of unruptured cerebral aneurysms has been reported, regimens for this therapy are not yet well established. The aim of this retrospective study was to analyze correlations among the modes of antiplatelet use, aneurysmal configuration, coiling methods, and complications to elucidate the optimal antiplatelet therapy for coiling. The study population comprised 154 patients with unruptured aneurysms who underwent coiling with antiplatelet therapy at our institution between 2001 and 2009. The patients were categorized by mode of antiplatelet therapy (single [n = 64] or dual [n = 90]), neck size (wide [n = 80] or narrow [n = 74]), and technique used (simple [n = 42] or adjunctive [n = 112]). The incidences of hemorrhagic/ischemic complications and abnormalities on postprocedural diffusion-weighted magnetic resonance imaging (DWI) in each group were statistically assessed. Hemorrhagic complications occurred in 1 case (1.5%) with single antiplatelet therapy and in 2 cases (2.2%) with dual antiplatelet therapy. Symptomatic ischemic complications occurred in 5 cases (7.8%) with single therapy and in 4 cases (4.4%) with dual therapy. Abnormalities were detected by DWI in 27 cases (42%) with single therapy and in 31 cases (34%) with dual therapy. No significant difference was found between modes of antiplatelet therapy even when the technique used was taken into account. In cases of wide neck, however, there were significant differences in the rate of symptomatic ischemic complications (single, 21.7%; dual, 3.5%; P = .014) and DWI abnormalities (single, 37.8%; dual, 20.9%; P = .048). Our data suggest that dual antiplatelet therapy may better prevent ischemic complications from coiling for wide-necked aneurysms compared with single antiplatelet therapy.

The results of a simplified technique for safe carotid stenting in the elderly

The purpose of this study was to report the preliminary experience of a modified transcervical carotid angioplasty and stenting (CAS) technique with filter protection and flow reversal only during filter placement in patients unsuitable for transfemoral CAS and at high risk for carotid endarterectomy (CEA). Twenty-five of 132 patients, aged 75 to 86 years old, with severe carotid stenosis had been selected. Eighteen patients had transient ischemic attacks (TIAs) in the last month and seven patients were asymptomatic. Patients with limited life expectancy were not included. The common carotid artery (CCA) was mobilized and cannulated. The flow in the internal carotid artery (ICA) was reversed by occluding the proximal CCA and connecting the introducing sheath to a blood transfusion bag positioned close to the floor, instead of returning it directly to the venous system. This produced retrograde flow in the ICA in all patients as a result of greater pressure gradient. The carotid filter was inserted to the distal ICA under retrograde flow and then antegrade flow was resumed and CAS was performed. All patients were autotransfused except for four patients who had severe renal insufficiency to avoid readministration of contrast media. All procedures were successful except in one patient converted to open endarterectomy because of CCA dissection (technical success rate 97.5%) and one patient who had a TIA involving the right hand 10 hours after CAS and recovered completely after 3 hours (event rate 2.5%). Reversed flow was visualized with intraoperative angiography in the ICA in all patients. Twenty-two patients were discharged the next morning and three (12%) on the following day because of hypotension. The duration of reversed flow was 1 to 4 minutes (mean, 1.5 minutes), the amount of blood collected was 100 to 400 mL (mean, 250 mL), and none of these patients had any hemodynamic disturbance during the procedure. Creatinine levels showed no increase postoperatively in either patient. The patients were followed-up clinically and with color Duplex scan for 3 to 24 months, so far, and they are free of symptoms or significant restenosis. The results of this preliminary study indicate that the transcervical approach with flow reversal during the insertion of the protecting filter allows CAS with minimal interruption of cerebral circulation and is simple and safe in patients unsuitable for CEA and transfemoral CAS for anatomic reasons. Further research with randomization and with pre-procedure and post-procedure diffusion-weighted magnetic resonance imaging (DW-MRI) is required in order to expand the indications of this method.

Randomized clinical trial of open-cell vs closed-cell stents for carotid stenting and effects of stent design on cerebral embolization

The effect of stent design on cerebral embolization has not been established. The purpose of this trial was to contrast the incidence of subclinical cerebral embolization in high-risk patients undergoing carotid artery stenting (CAS) with open-cell vs closed-cell stents. During an 18-month period, 40 patients were randomized (1:1) to undergo CAS with open-cell (Acculink, n = 20) or closed-cell stents (Xact, n = 20). A single filter device for embolic protection (Accunet filter) was used. Transcranial Doppler (TCD)-detected microembolic signals (MES) during CAS and preprocedural and 24-hour postprocedural diffusion-weighted magnetic resonance imaging (DW-MRI) were used to determine cerebral embolization. Univariate and nonparametric analyses were used to assess associations between stent design and cerebral embolization. CAS was performed in 17 symptomatic patients (43%) and 23 asymptomatic patients (57%) with a similar number of open-cell and closed-cell stents (9/8 and 11/12, respectively). The total and poststenting median ipsilateral MES counts detected by TCD were 264 (interquartile range [IQR], 222-343) and 48 (IQR, 41-66) for open-cell stents and 339 (IQR, 163-408) and 53 (IQR, 23-88) for closed-cell stents, respectively (P > .56). New acute cerebral emboli detected with DW-MRI occurred in 53% and 47% of patients undergoing CAS with open-cell and closed-cell stents, respectively (P = 1.0). The total and ipsilateral median numbers of DW-MRI lesions between groups were not statistically significantly different (ie, 2 [IQR, 0-4] and 1 [IQR, 0-3] for open-cell stents and 1 [IQR, 0-3] and 1 [IQR, 0-2] for closed cell-stents, respectively; P > .4). One asymptomatic patient undergoing CAS with an open-cell stent sustained a minor stroke; the 30-day stroke-death rate in this series was 2.5%. Cerebral embolization, as detected by TCD and DW-MRI, occurs with similar frequency after CAS with open-cell and closed-cell stents. This randomized trial does not support the superiority of any stent design with respect to cerebral embolization.

Atherosclerotic plaque composition assessed by virtual histology intravascular ultrasound and cerebral embolization after carotid stenting

Previous studies have investigated the predictive value of clinical and morphologic parameters for distal embolization during carotid interventions. The composition of the atherosclerotic plaque, using virtual histology intravascular ultrasound (VH-IVUS) imaging obtained with an IVUS catheter that is advanced through the lesion after a filter has been placed distally, has not been evaluated as a marker for cerebral embolization. The purpose of this study was to assess the relationship between atherosclerotic plaque composition determined with VH-IVUS and the occurrence of cerebral embolization after carotid artery stenting (CAS). During a 10-month period, 24 patients undergoing CAS procedures using a filter device for embolic protection were prospectively evaluated. All patients underwent VH-IVUS exams at the time of the intervention, transcranial Doppler (TCD) monitoring during CAS, and pre- and 24-hour postprocedural diffusion-weighted magnetic resonance imaging (DW-MRI) exams. Using VH-IVUS, plaque components were characterized as fibrotic, fibrofatty, dense calcium, and necrotic core. The frequency of Doppler-detected microembolic signals (MES) during CAS and the incidence and location of acute postprocedural embolic lesions detected with DW-MRI were assessed to determine cerebral embolization. Univariate and correlation analyses were used to assess the association between plaque composition and frequency of cerebral embolization. No periprocedural transient ischemic attacks, strokes, or deaths occurred within 30 days. Seventeen patients (71%) demonstrated new acute cerebral emboli in DW-MRI. Of these, all revealed ipsilateral lesions and 12 (50%) had contralateral lesions. For the entire study group, the median number of ipsilateral DW-MRI lesions was 1 (range, 0 to 3), and TCD MES counts were 227 (interquartile range, 143-315). Volumetric VH-IVUS analysis revealed that there was a trend for larger median dense calcium volume in patients with ipsilateral subclinical cerebral embolism detected with DW-MRI (33.2±24.5 mm3 vs 11.4±6.1 mm3; P=.08). Scatter plots of plaque components revealed statistically significant correlation between fibrofatty plaque volume (Spearman r=0.49; P=.016) and number of new ipsilateral lesions in DW-MRI. Degree of cerebral embolization during CAS measured with TCD correlated with plaque burden, necrotic core, fibrofatty, and fibrous volumes. Plaque composition, as determined by VH-IVUS, only weakly correlates with the degree of cerebral embolization after carotid stenting. Specifically, there is a trend for larger dense calcium volume in patients with distal embolization. Of note, the proportion of necrotic core, which has traditionally been considered the main component of a vulnerable or unstable plaque, is not definitely associated with subclinical cerebral embolization after CAS when a filter device for embolic protection is used. The role of VH-IVUS in evaluating plaque composition during CAS remains unestablished and warrants further investigation.

A Prospective Evaluation of Cerebral Infarction following Transcervical Carotid Stenting with Carotid Flow Reversal

Objective: Cerebral embolisation constitutes the main source of complications during transfemoral carotid artery stenting (CAS) and is associated with a high incidence of silent brain infarction. The goal of this study is to evaluate the incidence of new ischaemic cerebral lesions following transcervical CAS with carotid flow reversal for neuroprotection. Materials and Methods: Thirty-one consecutive patients underwent transcervical CAS with carotid flow reversal. A stroke scale and diffusion-weighted magnetic resonance imaging (DW-MRI) were performed within 24 h before and after the procedure. DW-MRI studies were compared blindly by two independent neuroradiologists. New hyper-intense DW signals were interpreted as ischaemic infarcts. The progress of all patients was followed for at least 30 days following intervention. Results: All procedures were technically successful. Nineteen (61%) patients were symptomatic Mean carotid flow reversal time was 22 min. There were no major adverse events at 30 days. All patients remained neurologically intact without increase in the stroke scale. Thirty subjects had paired DW-MRI studies. Post-procedural DW-MRI ischaemic infarcts were found in four (12.5%) patients, all ipsilateral to the treated hemisphere and asymptomatic. During follow-up, all stents remained patent and all patients remained stroke-free. Conclusions: These data suggest that transcervical carotid stenting with carotid flow reversal carries a low incidence of new ischaemic infarcts, significantly lower than that reported with transfemoral CAS. The transcervical approach with carotid flow reversal may improve the safety of CAS and has the potential to produce results comparable to those of carotid endarterectomy.

A Prospective Evaluation of Cerebral Infarction following Transcervical Carotid Stenting with Carotid Flow Reversal

Objective Cerebral embolisation constitutes the main source of complications during transfemoral carotid artery stenting (CAS) and is associated with a high incidence of silent brain infarction. The goal of this study is to evaluate the incidence of new ischaemic cerebral lesions following transcervical CAS with carotid flow reversal for neuroprotection. Materials and Methods Thirty-one consecutive patients underwent transcervical CAS with carotid flow reversal. A stroke scale and diffusion-weighted magnetic resonance imaging (DW-MRI) were performed within 24 h before and after the procedure. DW-MRI studies were compared blindly by two independent neuroradiologists. New hyper-intense DW signals were interpreted as ischaemic infarcts. The progress of all patients was followed for at least 30 days following intervention. Results All procedures were technically successful. Nineteen (61%) patients were symptomatic Mean carotid flow reversal time was 22 min. There were no major adverse events at 30 days. All patients remained neurologically intact without increase in the stroke scale. Thirty subjects had paired DW-MRI studies. Post-procedural DW-MRI ischaemic infarcts were found in four (12.5%) patients, all ipsilateral to the treated hemisphere and asymptomatic. During follow-up, all stents remained patent and all patients remained stroke-free. Conclusions These data suggest that transcervical carotid stenting with carotid flow reversal carries a low incidence of new ischaemic infarcts, significantly lower than that reported with transfemoral CAS. The transcervical approach with carotid flow reversal may improve the safety of CAS and has the potential to produce results comparable to those of carotid endarterectomy.

Atherosclerotic Plaque Composition and Cerebral Embolization after Carotid Stenting

Background: Previous studies have investigated the predictive value of clinical and morphologic parameters for distal embolization during carotid interventions. The composition of the atherosclerotic plaque using virtual histology intravascular ultrasound (VH IVUS) imaging at the intervention site has not been evaluated as a marker for cerebral embolization. The purpose of this study was to assess the relationship between atherosclerotic plaque composition determined with VH IVUS and the occurrence of cerebral embolization after carotid angioplasty and stenting (CAS). Methods: During a 10-month period, 24 patients undergoing CAS procedures using a filter device for embolic protection (Accunet Filter, Abbott Vascular, Santa Clara, Calif) were prospectively evaluated. All patients underwent VH IVUS imaging before the intervention, transcranial Doppler (TCD) monitoring during CAS, and preprocedural and 24-hour postprocedural diffusion-weighted magnetic resonance imaging (DW-MRI). VH-IVUS characterized plaque components as fibrotic, fibrofatty, dense calcium, and necrotic core. The frequency of Doppler-detected microembolic signals (MES) during CAS and the incidence and location of acute, postprocedural embolic lesions detected with DW-MRI was assessed to determine cerebral embolization. Univariate and linear regression analyses were used to assess the association between plaque composition and the frequency of cerebral embolization. Results: No periprocedural transient ischemic attacks, strokes, or deaths occurred at 30 days. DW-MRI demonstrated new acute cerebral emboli in 14 patients (58%). All revealed ipsilateral lesions, and eight (32%) had also contralateral lesions. For the entire study group, the median number of DW-MRI lesions was two (range, 0-173) and the TCD MES counts were 222 (interquartile range, 152-322) .Of the plaque components, DW-MRI determined that only dense calcium was significantly associated with cerebral embolization. The proportion of dense calcium was significantly larger in patients with cerebral embolization (5.7% ± 2.2% vs 1.2% ± 0.3%, P = .04). Findings on postprocedural DW-MRI did not correlate with the proportion of fibrotic, fibrofatty, and necrotic core. Degree of cerebral embolization during CAS measured with TCD did not correlate with plaque composition. Conclusions: Plaque composition, as determined by VH IVUS, correlates with the degree of cerebral embolization after CAS but not during the intervention. Specifically, the proportion of dense calcium is strongly associated with the occurrence of cerebral embolization after CAS. Of note, the proportion of necrotic core, which has traditionally defined the presence of a vulnerable or unstable plaque, does not correlate with the degree of distal embolization after CAS when a filter device for embolic protection is used. Optimal management and strategies to prevent distal embolization after CAS of lesions with significant dense calcium warrant further investigation.

Reduction of postprocedure microemboli following retrospective quality assessment and practice improvement measures for carotid angioplasty and stenting

We have previously demonstrated a 70% incidence of microemboli on diffusion weighted magnetic resonance imaging (DW-MRI) following carotid angioplasty and stenting (CAS). The purpose of this study is to compare the incidence of microemboli in two distinct time periods when procedural modifications were implemented into a CAS program. Following a retrospective quality review of our CAS cohort (n = 27) from November 2004 through April 2006 (period 1), we enrolled patients (n = 20) from May 2006 through February 2008 (period 2) undergoing CAS into a prospective cohort that included obtaining pre- and postprocedure DW-MRI exams. Procedural modifications during period 2 included the preferential use of closed-cell systems (60% vs 0% in period 1), early heparinization at the initiation of arterial access, and elimination of an arch angiogram. The hospital records of these 47 patients were reviewed; symptoms, comorbidities, lesion characteristics, periprocedural information, and postoperative outcomes were collected. The incidence and location of acute, postprocedural microemboli were determined using DW-MRIs. Twenty (74%) CAS patients from period 1 and seven (35%) patients from period 2 demonstrated acute microemboli on postprocedural DW-MRI (P = .02). The mean number of microemboli in period 1 was 4.1 +/- 5.3 vs 1.5 +/- 2.7 during period 2 (P = .04). Two of the 27 patients (7.4%) during period 1 experienced temporary neurologic changes that resolved within 36 hours. None of the patients during period 2 exhibited any neurologic changes. Patient demographics, comorbidities, and presenting symptoms were similar between the two groups except for smoking prevalence, female presence, and obesity (BMI > 30). Period 2 patients when compared with period 1 had more technically challenging anatomy with more calcified lesions (68% vs 27%), longer lesions (15.9 mm vs 8.2 mm), and higher incidence of ulceration (55% vs 27%) (all P < .04). Despite successful performance of 47 consecutive CAS procedures without permanent neurologic sequelae, significant reductions in periprocedural embolic events as identified via DW-MRI lesions may be achieved through implementation of quality improvement measures identified through continuous outcome analysis. The long-term neurologic benefits associated with reduced subclinical neurologic events remains to be determined.