Procedure-Related Complications and Early Neurological Adverse Events of Unprotected and Protected Carotid Stenting:Temporal Trends in a Consecutive Patient Series

Protected versus Unprotected Carotid Artery Stenting : Meta-Analysis of the Current Literature

Objective

To compare peri-operative any symptomatic stroke after carotid angioplasty and stenting (CAS), based on the application or absence of a cerebral protection device.

Methods

A systematic literature review using PubMed, Embase, and the Cochrane Central was done across an online data base from January 1995 to October 2016. Procedures which were performed due to carotid dissection or aneurysm, procedures using covered stents or conducted in an emergency, were excluded. The primary endpoint was perioperative any symptomatic stroke within 30 days after the procedure. A fixed effect model was used in cases of heterogeneity less than 50%.

Results

In the 25 articles included in this study, the number of stroke events was 326 (2.0%) in protected CAS and 142 (3.4%) in unprotected CAS. The use of cerebral protection device significantly decreased stroke after CAS (odds ratio [OR] 0.633, 95% confidence interval [CI] 0.479–0.837, p=0.001). In the publication bias analysis, Egger’s regression test disclosed that the intercept was -0.317 (95% CI -1.015–0.382, p=0.358). Regarding symptomatic patients (four studies, 539 CAS procedures), the number of stroke was six (1.7%) in protected CAS and 11 (5.7%) in unprotected CAS. The protective effect against stroke events by cerebral protection device did not have a statistical significance (OR 0.455, 95% CI 0.151–1.366, p=0.160).

Conclusion

The use of protection device significantly decreased stroke after CAS. However, its efficacy was not demonstrated in symptomatic patients. Routine use of protection device during CAS should be critically assessed before mandatory use.

Meta-analysis of the Effect of Stent Design on 30-Day Outcome After Carotid Artery Stenting

Purpose: To review the contemporary literature and analyze whether stent cell design plays a role in 30-day outcomes after carotid artery stenting (CAS). Methods: A systematic review of the literature was undertaken that identified 9 studies comparing the effect of different cell design on 30-day outcome in patients undergoing CAS. Random-effects models were applied to calculate pooled outcome data for mortality and cerebrovascular morbidity. Results are reported as the odds ratio (OR) and 95% confidence interval (CI). Results: The 9 studies included 8018 patients who underwent 8028 CAS procedures (4018 open-cell stents, 4010 closed-cell stents). Six studies were retrospective in design, one was a registry, and only two studies prospectively compared the effect of different cell designs. Nearly half of the patients (3452, 43.1%) were symptomatic, with no significant difference between the closed- and open-cell stent groups (p=0.93). During the first month after the procedure, there were no significant differences in mortality (OR 0.69, 95% CI 0.39 to 1.24, p=0.21), transient ischemic attacks (OR 0.95, 95% CI 0.69 to 1.30, p=0.74), or strokes (OR 1.17, 95% CI 0.83 to 1.66, p=0.37). Conclusion: This meta-analysis showed that 30-day cerebrovascular complications after CAS were not significantly different for the open-cell group in comparison to the closed-cell group. Future prospective clinical trials comparing different free cell areas and other stent design properties are still needed to further investigate whether stent design plays a significant role in the results of carotid stenting.

Insights into temporal patterns of hospital patient safety from routinely collected electronic data

BACKGROUND

The last two decades have seen an unprecedented growth in initiatives aimed to improve patient safety. For the most part, however, evidence of their impact remains controversial. At the same time, the healthcare industry has experienced an also unprecedented growth in the amount and variety of available electronic data.

METHODS

In this paper, we provide a review of the use of routinely collected electronic data in the identification, analysis and surveillance of temporal patterns of patient safety.

RESULTS

Two important temporal patterns of the safety of hospitalised patients were identified and discussed: long-term trends related to changes in clinical practice and healthcare policy; and shorter term patterns related to variations in workforce and resources. We found that consistency in reporting is intrinsically related to availability of large-scale, fit-for-purpose data. Consistent reported trends of patient harms included an increase in the incidence of post-operative sepsis and a decrease in central-line associated bloodstream infections. Improvement in the treatment of specific diseases, such as cardiac conditions, has also been demonstrated. Linkage of hospital data with other datasets provides essential temporal information about errors, as well as information about unsuspected system deficiencies. It has played an important role in the measurement and analysis of the effects of off-hours hospital operation.

CONCLUSIONS

Measuring temporal patterns of patient safety is still inadequate with electronic health records not yet playing an important role. Patient safety interventions should not be implemented without a strategy for continuous monitoring of their effect.

Design and development of mechanical embolic protection devices

Carotid angioplasty and stenting (CAS) is rapidly becoming an acceptable alternative to carotid endarterectomy in many patients. Much of the success of CAS is credited to advances in equipment dedicated to this minimally invasive approach. Lower profile delivery systems, tapered stent designs and most importantly, development of mechanical cerebral embolic protection devices (EPDs) have contributed to a reduction in periprocedural neurological complications that now rival results of carotid endarterectomy. Despite a lack of level one evidence in support of EPDs, a meta-analysis as well as two recent institutional reports of CAS with and without EPDs suggest a reduced stroke risk when a mechanical protection device is incorporated as part of the procedure. Since the original description by Theron and colleagues, embolic protection systems are markedly improved in ease of use and effectiveness. The three primary groups of EPDs are distal balloon occlusion, distal filtration and proximal occlusion. Although the ideal EPD has yet to materialize, this review provides insight into current design systems and the accompanying strengths and weaknesses of each.

The role of embolic protection devices during carotid stenting prior to cardiac surgery in asymptomatic patients: empty filters?

OBJECTIVES

The purpose of this study was to analyze the debris captured in the distal protection filters used during carotid artery stenting (CAS).

BACKGROUND

CAS is an option available to high-risk patients requiring revascularization. Filters are suggested for optimal stroke prevention during CAS.

METHODS

From May 2005 to June 2007, filters from 59 asymptomatic patients who underwent CAS were collected and sent to a specialized laboratory for light-microscope and histological analysis. Peri- and postprocedural outcomes were assessed during 1-year follow-up.

RESULTS

On the basis of biomedical imaging of the filter debris, the captured material could not be identified as embolized particles from the carotid plaque. On histological analysis the debris consisted mainly of red blood cell aggregates and/ or platelets, occasionally accompanied by granulocytes. We found no consistent histological evidence of embolized particles originating from atherosclerotic plaques. Post-procedure, three neurological events were reported: two (3.4%) transient ischemic attacks (TIA) and one (1.7%) ipsilateral minor stroke.

CONCLUSION

The filters used during CAS in asymptomatic patients planned for cardiac surgery often remained empty. These findings may be explained by assuming that asymptomatic patients feature a different atherosclerotic plaque composition or stabilization through antiplatelet medication. Larger, randomized trials are clearly warranted, especially in the asymptomatic population.

Carotid Artery Stenting: Relationship between Experience and Complication Rate

To investigate the evidence for the relationship between volume and outcome for carotid artery stenting. We performed a systematic review of the literature to examine the influence of experience and/or volume on outcome for carotid artery stenting. The primary search strategy was to identify studies presenting year-on-year data. The Pubmed, Embase, Medline and the Cochrane Collaboration databases were searched. Studies with over 100 interventions were included. The main outcome measure compared across studies was all stroke/death. Where possible, comparable data were pooled and analysed using meta-regression techniques. It was not possible to perform a standard systematic review and meta-analysis because of the lack of data from randomised studies. When redundant studies were excluded, four sizeable case series and one registry met the inclusion criteria. When the case series results were pooled, the χ2-test for trend demonstrated a significant reduction in the combined stroke and death rate over time. Meta-regression analysis of case series data allowed the setting of thresholds for ‘acceptable’ stroke/death rates. Where year-on-year data are available, published stroke and death rates for carotid artery stenting show improvements over time. While advances in technology and pharmacology may in part be responsible, temporal improvement in outcomes demonstrated in both early and contemporary time-frames together with the consistency of the results suggests the presence of a learning curve. In active carotid artery stenting units, it may take almost 2-years before the stroke/death rates fall below an arbitrary 5% threshold.

Classification for carotid artery stenting complications: manifestation, management, and prevention

Carotid artery stenting is a rapidly evolving method for treating carotid artery disease. Various intraprocedural and postprocedural complications have been reported in the literature. However, the absence of a unified classification scheme for these complications makes it difficult, if not impossible, to study their precise incidence, predictors, and management. The aim of this article is to propose the first joint classification of periprocedural complications, to analyze their incidence and etiology, and suggest possible ways to manage and prevent them. This classification is intended to be used as a common platform for prompt recognition, evaluation, treatment, and universal study of the complications during carotid stenting procedures. For this purpose, the opinions of the major experts on carotid interventions worldwide were merged with all the available information reported in the English-language literature to present as accurately as possible the management and prevention of carotid stenting complications according to this proposed classification.

The results of a new distal protection method in intervention for chronic total occlusion of the superficial femoral artery

Aims. To determine the efficacy of a new distal protection method in SFA CTO interventions. Methods and Results. From June 2003 to February 2009, ninety-two consecutive, chronic total occlusions of superficial femoral arteries were treated with catheter-based intervention using a bidirectional approach. Nine of these cases were managed with our original, distal protection method, based on symptoms, angiographic images, wire resistance, and intravascular ultrasound images. The average age was 73 years; eight patients were male. The mean occlusion length was 17.1 cm. A distal protection balloon was inserted from the retrograde sheath in the popliteal artery and placed distal to the occluded lesion after successful wire crossing. Lesion dilatation with a balloon was performed antegradely and debris was removed by 6Fr. guiding catheter. Debris was retrieved from all lesions, consisting mainly of thrombus. Where we decided not to use the distal protection method, there was no distal thromboembolism. Conclusion. In SFA-CTO intervention, the risk of distal embolization is 10%, which can be anticipated and eliminated by the distal protection method.

Current role of emboli protection devices in percutaneous coronary and vascular interventions

After the observation that distal embolization is a frequent complication of coronary and vascular interventions, mechanical emboli protection devices (EPD) have been developed and tested in different vascular territories. The most frequently used device type incorporates a guidewire with a filter that is placed distal to the target lesion, unfolded, and then retrieved at the end of the procedure. Alternative approaches are based on transient flow obstruction using proximal or distal balloon occlusion. The procedure is then performed under flow reversal or flow arrest and the blood column is evacuated prior to restoration of flow. The efficacy of EPD in reducing major adverse cardiac events among patients undergoing percutaneous intervention of aortocoronary bypass grafts has been demonstrated in a randomized trial. In the acute myocardial infarction setting, EPD failed to improve outcomes. Although randomized data in carotid artery stenting are lacking, a broad, but not unanimous, consensus supports the use of these devices. While a small randomized trial showed disappointing results of emboli protection in renal stenting, no data are available for lower extremity interventions.

Carotid artery stenting versus carotid endarterectomy: current status

Carotid occlusive disease remains an important cause of ischemic stroke. The results of large, randomized, clinical trials have established the benefit of surgical revascularization in patients with symptomatic or asymptomatic carotid stenosis. The introduction of balloon angioplasty and stenting of the extracranial carotid artery as a potential alternative to surgery has been received with enthusiasm by patients and physicians. Whether or not this enthusiasm is justified fully has yet to be determined. This article reviews established and emerging data from clinical trials evaluating the safety and efficacy of carotid endarterectomy, carotid angioplasty, and stenting.

Carotid endarterectomy versus angioplasty/stenting for carotid stenosis

Carotid occlusive disease remains an important cause of ischemic stroke. The results of large, randomized clinical trials have established the benefit of surgical revascularization in selected patients with symptomatic or asymptomatic carotid stenosis. The introduction of balloon angioplasty and stenting of the extracranial carotid artery as a potential alternative to surgery has been received with enthusiasm by patients and physicians alike. Whether or not this enthusiasm is fully justified has yet to be determined. This article reviews published data regarding the safety and clinical efficacy of carotid angioplasty and stenting. Particular focus is directed towards results from recently completed and ongoing prospective comparative trials of endarterectomy and carotid angioplasty and stenting.

Does carotid stent cell design matter?

BACKGROUND AND PURPOSE

Carotid stent cell design has recently been suggested to be a determinant of periprocedural and early postprocedural neurologic complications. We investigated the impact of closed- versus open-cell stent design on neurologic adverse events and mortality after carotid artery stenting.

METHODS

We studied 1684 consecutive patients (1010 asymptomatic, 674 symptomatic) from 10 European centers who underwent carotid artery stenting with either closed-cell (n=859, 51%) or open-cell (n=825, 49%) design stents. Rates of transient ischemic attack, stroke, and death on the day of the procedure (acute events) and from day 1 to day 30 after the procedure (subacute events) were analyzed (95% CIs).

RESULTS

Combined transient ischemic attack, stroke, or death rates, and stroke or death rates within 30 days of treatment were 6.1% (95% CI, 5.0 to 7.2) and 3.1% (95% CI, 2.3 to 3.9) for the closed-cell design versus 4.1% (95% CI, 3.2 to 5.0) and 2.4% (95% CI, 1.7 to 3.1) for the open-cell design stents (P=0.077, P=0.38), respectively, without significant differences in asymptomatic and symptomatic patients. By propensity-score-adjusted multivariable analysis, the open-cell carotid stent design was not associated with a differential risk for combined acute and subacute neurologic complications compared with closed-cell stents (adjusted odds ratio=0.84, P=0.53). When analyzed separately, the risk for acute events on the day of the procedure (adjusted odds ratio=0.83, P=0.57) and the risk for subacute events at days 1 to 30 (adjusted odds ratio=1.61, P=0.51) also were not significantly different between the groups.

CONCLUSIONS

Current data do not support the superiority of a specific carotid stent cell design with respect to neurologic complications, stroke, and mortality risk.

Carotid intervention 3: the evidence for cerebral protection

Carotid stenting is a safe alternative option to conventional carotid endarterectomy in the treatment of carotid artery stenosis in patients considered poor candidates for surgery or who choose not to have open surgery. During the stenting procedure, however, distal embolization may occur with neurological sequelae. To reduce the incidence of this, several cerebral-protection devices (CPDs) have been developed. Different types of CPDs are now commercially available: distal occlusion balloons, distal filters, and proximal protection devices with or without reversal of flow. But complications can occur with their use and are usually associated with an inability to cross the lesion, failure to capture the emboli, vasospasm, and vessel wall injury. Because protection devices are currently the focus of interest by manufacturers and physicians, several trials are going on worldwide to analyze the characteristics of each of them and to evaluate their efficacy in reducing the rate of distal embolization.

Carotid Artery Stent Placement with Embolic Protection: Single-Center Experience

PURPOSE

To evaluate the efficacy of carotid artery stent placement with embolic protection.

MATERIALS AND METHODS

During a 2-year period (May 2003 to April 2005), 232 patients underwent carotid artery stent placement with the Acculink RX stent-graft and an embolic protection device. There were 150 men (mean age,70 years; age range, 58-85 years) and 82 women (mean age, 76 years; age range, 56-82 years). One hundred sixty-five patients were symptomatic and 67 were asymptomatic. All patients were at high risk for carotid endarterectomy.

RESULTS

The procedure was technically successful in 231 patients. The procedure was stopped in one patient due to asystole. In three patients, a cervical approach was necessary owing to aortic arch anatomy. During the procedure,11 patients (4.74%) experienced bradycardia and two developed a major stroke (0.86%). The mean follow-up was 30 months (range, 12-36 months). Four patients died. No stent occlusion was observed. During the late follow-up period(>30 days), two patients (0.86%) had minor strokes, three (1.29%) had nonfatal transient ischemic attacks, and seven(3.01%) had myocardial infarctions.

CONCLUSION

Carotid artery stent placement with cerebral protection by using the specific devices compares favorably to previously reported surgical results.

Carotid Artery Stenting Versus Carotid Endarterectomy: Current Status

As operator experience and device technology continue to improve, the theoretic advantages of endovascular approaches to treat carotid occlusive disease may be closer to realization. Currently, data from controlled trials of CAS is minimal, but several multicenter RCTs comparing CAS to CEA are recruiting patients actively and preliminary results show procedural morbidity and mortality rates for CAS that compare favorably to CEA. Community-based experience with CAS continues to grow and further refinements in patient selection based on plaque morphology and other variables offer further hope that endovascular approaches to carotid occlusive disease may benefit selected patients. Given the proved efficacy and durability of CEA for treatment of extracranial carotid stenosis, surgical revascularization remains the recommended standard of care for most patients. CAS will have to be proved equivalent or superior to surgery and as cost-effective to facilitate its widespread acceptance as a treatment alternative for carotid occlusive disease.

Techniques in cerebral protection

Carotid angioplasty and stenting is a valid alternative option to conventional carotid endarterectomy in the treatment of carotid artery stenosis. During the stenting process, however, distal embolization can occur with neurological consequences. To avoid this, cerebral protection devices have been introduced. Three principal types of protection system have been developed: distal balloon occlusion, distal filters and proximal protection with or without reversal of flow. As protection devices became the focus of interest by manufactures and physicians, several trials are going on worldwide to analyze the characteristics of each of them and to evaluate their efficacy to reduce the rate of distal embolization.

The evidence for cerebral protection: An analysis and summary of the literature

It has been considered likely that the majority of cerebral ischaemic episodes following carotid artery stenting are due to cerebral embolisation. It is intuitive therefore, to attempt to prevent these presumptive emboli, whether they are comprised of air or formed elements, from reaching the brain. Various pharmacological and mechanical solutions are being used. The available literature is hampered by comparisons against historical controls of unprotected CAS with many confounding variables that may influence outcome. There is no clinical Level-I evidence to support the use of protection devices but Level-III and Level-IV evidence suggest benefit.

Plaque Echolucency Is Not Associated With the Risk of Stroke in Carotid Stenting

Background and Purpose— Plaque characteristics are suggested to play a potentially important role as risk factors for poor outcome after carotid artery stenting (CAS). We therefore correlated objectively and subjectively determined carotid plaque morphology with neurological complications after CAS.

Methods— We enrolled 698 consecutive patients undergoing elective CAS from a prospective single-center registry database and classified the preinterventional plaque status according to gray-scale median levels and the standardized Beletsky and Gray-Weale plaque scores. Patients were followed for 30-day neurological complications.

Results— Neurological complications including transient ischemic attack, minor and major stroke occurred in 5.9% (41/698) of the patients. Median gray-scale median, Beletsky and Gray-Weale scores were 45 (interquartile range [IQR] 25 to 70), 3.0 (IQR 2.0 to 3.0) and 2.0 (IQR 2.0 to 3.0), respectively. None of the scores was significantly associated with adverse outcome adjusting for traditional risk factors, medication, preinterventional symptoms, degree of stenosis, contralateral occlusion and use of cerebral protection, neither with respect to all neurological complications nor with respect to stroke and death (all P >0.05).

Conclusions— Plaque echolucency measured by objective and subjective grading did not identify patients with an increased risk of peri-interventional neurological events. Evaluation of plaque echolucency therefore cannot be recommended for risk stratification in CAS patients.

Covered Versus Bare Self-Expanding Stents for Endovascular Treatment of Carotid Artery Stenosis:A Stopped Randomized Trial

PURPOSE

To investigate whether filter-protected carotid artery stenting (CAS) using a covered self-expanding stent reduces the risk of cerebral embolization.

METHODS

Fourteen asymptomatic patients (13 men; median age 77 years, IQR 73-83) were enrolled in a randomized pilot trial comparing the rates of cerebral microembolism during and after filter-protected CAS using either a self-expanding covered (n=8) or a bare (n=6) carotid stent. Transcranial Doppler (TCD) monitoring was done during and for 90 minutes after the procedure. Diffusion-weighted magnetic resonance imaging (DW-MRI) was performed before and 24 hours after CAS. Patients were followed for 6 months for neurological events and occurrence of restenosis.

RESULTS

A significant reduction in ipsilateral microembolic signals by TCD was observed with the covered (median 1, IQR 0-4) versus the bare stent (median 6, IQR 3-8; p=0.043). Comparison of the preprocedural and 24-hour postprocedural DW-MRI images showed no new ipsilateral lesions but 1 new lesion in the contralateral hemisphere in the covered stent group, resulting in an overall 7% (95% CI 0%-20%) rate of new ischemic lesions. No neurological complications occurred up to 6 months. Restenosis (>70%) occurred in 3 (38%) of 8 patients with the covered versus none of the bare stents (p=0.21). The trial was stopped when the third restenosis of a covered stent was detected.

CONCLUSION

Self-expanding covered stents potentially reduce the risk of cerebral microembolism during and after carotid stenting. However, the problem of in-stent restenosis has to be resolved before these devices can be considered for further investigation.