HITS in internal carotid dissections

Antithrombotic drugs for carotid artery dissection: Updated systematic review

INTRODUCTION

Extracranial internal carotid artery dissection (eICAD) is a leading cause of stroke in younger patients. In this Cochrane Review update we compared benefits and harms of eICAD-patients treated with either antiplatelets or anticoagulants.

PATIENTS AND METHODS

Eligible studies were identified through Cochrane Stroke Group Trials Register, CENTRAL, MEDLINE, and EMBASE and personal search until December 2023. We included randomized-controlled trials (RCTs) and non-randomized studies comparing anticoagulants with antiplatelets in eICAD-patients. Co-primary outcomes were (i) death (all causes) and (ii) death or disability. Secondary outcomes were ischemic stroke, symptomatic intracranial hemorrhage, and major extracranial hemorrhage. Odds ratios (OR) with 95% CIs were calculated for (i) all studies and (ii) separately for RCTs and non-randomized studies.

RESULTS

We meta-analyzed a total of 42 studies (2624 patients) including 2 RCTs (213 patients) for the primary outcome of death and 31 studies (1953 patients) including 1 RCT (115 patients) for the primary outcome of death or disability. Antiplatelet-treated patients had higher odds for death (ORall-studies 2.70, 95% CI 1.27-5.72; ORRTCs 6.80, 95% CI 0.14-345; ORnon-randomized studies 2.60, 95% CI 1.20-5.60) and death or disability (ORall-studies 2.1, 95% CI 1.58-2.66; ORRTCs 2.2, 95% CI 0.29-16.05; ORnon-randomized studies 2.1, 95% CI 1.58-2.66) than anticoagulated patients. Antiplatelet-treated patients had also higher odds for ischemic stroke, though this reached statistical significance only in the subgroup of RCTs (ORRTC 4.60, 95% CI 1.36-15.51). In turn, antiplatelet-treated patients had less symptomatic intracranial hemorrhage (ORall-studies 0.25, 95% CI 0.07-0.86) and a tendency toward less major extracranial hemorrhage (ORall-studies 0.17, 95% CI 0.03-1.03).

DISCUSSION AND CONCLUSION

The evidence considering antiplatelets as standard of care in eICAD is weak. Individualized treatment decisions balancing risks versus harms seem recommendable.

Micro-Embolic Signals and Dissection: Association or Causation for Stroke? A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE

Although the mechanism of stroke in cervical artery dissection (CAD) has been hypothesized to be embolization rather than hemodynamic compromise, there are a limited number of studies supporting this hypothesis. Detection of micro-embolic signals (MESs) using transcranial Doppler (TCD) helps in understanding the mechanism in these patients. A systematic review and meta-analysis were performed to estimate the prevalence of MES and its association with stroke outcomes in patients with acute stroke/TIA secondary to dissection.

METHODS

A comprehensive literature search was conducted for studies before January 26, 2021, in PubMed, Embase, Google Scholar, Cochrane Library, and ClinicalTrials.gov. Studies were identified that used TCD to detect MES in stroke/TIA patients secondary to CAD. Pooled prevalence was calculated. Entire statistical analysis was conducted in R version 3.6.2.

RESULTS

Eleven studies involving 112 patients (50 MES+, 62 MES-) were included in our meta-analysis. The pooled prevalence of MES among acute stroke/TIA patients secondary to dissection was 46.0% (95% CI 26.0-67.0%). The presence of MES was associated with an increased risk of early ischemic recurrence in patients with CAD. We could not estimate the functional outcome and mortality associated with the presence of MES due to the scarcity of data.

CONCLUSIONS

Our meta-analysis showed 46% prevalence of MES in the studies which looked at acute stroke/TIA secondary to CAD using TCD. This finding supports the assumption that embolism may be a major cause of stroke in patients with dissection although this could be determined only in a small population.

Relationship of spontaneous microembolic signals to risk stratification, recurrence, severity, and mortality of ischemic stroke: a prospective study

Introduction

The presence of microembolic signals (MES) during the acute phase of stroke is poorly understood, and its role and clinical application in relation to risk stratification and prognosis in patients remain uncertain. We assessed the prevalence of spontaneous MES in acute stroke and their relationship with risk stratification, stroke recurrence, morbidity, and mortality.

Patients and methods

This was a prospective cohort study conducted in the Stroke Unit. The MES presence was evaluated by transcranial Doppler (TCD) in patients with ischemic stroke within 48 h. The outcomes (risk stratification, morbidity, mortality, and recurrence of a stroke) were followed up for 6 months. The relationship between risk stratification and MES was obtained by odds ratios and that between MES and stroke recurrence, morbidity, and mortality using multiple logistic regression; considering statistical significance at P < 0.05.

Results

Of the 111 patients studied, 70 were men (63.1%) and 90 were white (81.1%), with a median age of 68 years. The MES frequency was 7%. There was a significant relationship between MES and symptomatic carotid disease (OR = 22.7; 95% CI 4.1–125.7; P < 0.001), a shorter time to monitoring (OR = 12.4; 95% CI  1.4–105.4; P = 0.02), and stroke recurrence (OR = 16.83; 95% CI 2.01–141; P = .009).

Discussion

It was observed that the stroke recurrence adjusted for prior stroke was higher and earlier among patients with MES detection. In conclusion, MES demonstrated a significant correlation with symptomatic carotid disease and a shorter DELAY until monitoring, and could be a predictor for the early recurrence of stroke in the long term.

Diagnosis and treatment of cervical artery dissection

Cervical artery dissection (CAD) is a major cause of stroke in the young. A mural hematoma is detected in most CAD patients. The intramural blood accumulation should not be considered a reason to withhold intravenous thrombolysis in patients with CAD-related stroke. Because intravenous-thrombolyzed CAD patients might not recover as well as other stroke patients, acute endovascular treatment is an alternative. Regarding the choice of antithrombotic agents, this article discusses the findings of 4 meta-analyses across observational data, the current status of 3 randomized controlled trials, and arguments and counterarguments favoring anticoagulants over antiplatelets. Furthermore, the role of stenting and surgery is addressed.

[Detection of micro-embolic signals: a review of the literature]

BACKGROUND

The detection of micro-embolic signals (MES), by transcranial Doppler sonography might be useful for risk stratification in patients with symptomatic and asymptomatic carotid or cerebral artery stenosis, dissections, aortic atheroma, interventional procedures, and right to left cardiac shunts.

AIM

Review of the technique and clinical situations of MES detection.

METHODS

PubMed search from 1990 to 2012.

RESULTS

MES were found in 0,19, 48% versus 0,3, and 12% of patients with symptomatic and asymptomatic inferior than 30, 30 to 69, and 70 to 99% carotid stenosis, respectively. MES were related to the risk of recurrent stroke or transient ischemic attack (TIA). In the ACES study, the absolute annual risk of stroke or TIA after 2 years was 7% with vs 3% without MES. In patients with intracranial stenosis, the risk of stroke recurrence was 48% with vs 7% without MES at 13.6 months follow-up. MES were reported in 25% of the symptomatic versus none of the asymptomatic patients with intracranial stenosis.

CONCLUSION

Detection of MES is feasible and reproducible for multicenter studies, using rigourous methodology and long lasting recordings. It may contribute to risk stratification, especially in patients with extra- or intracranial stenosis.

Antithrombotic drugs for carotid artery dissection

BACKGROUND

Extracranial internal carotid artery dissection (eICAD) is a leading cause of stroke in younger patients.

OBJECTIVES

1. To determine whether, in patients with eICAD, treatment with anticoagulants, antiplatelet agents or control was associated with a better functional outcome. 2. To compare, among patients treated with either anticoagulants or antiplatelet agents, the risk of ischaemic strokes and major bleeding episodes.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched 3 October 2009). In addition, we performed comprehensive searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2009), MEDLINE (January 1966 to November 2009) and EMBASE (January 1980 to November 2009), checked all relevant papers for additional eligible studies and contacted authors and researchers in the field.

SELECTION CRITERIA

Randomised controlled trials, controlled clinical trials and non-randomised studies (if they reported on outcome stratified by antithrombotic treatment and included at least four patients) of anticoagulants or antiplatelet agents for the treatment of extracranial internal carotid artery dissection. Two review authors independently extracted data.

DATA COLLECTION AND ANALYSIS

Primary outcomes were death (all causes) and death or disability. Secondary outcomes were ischaemic stroke, symptomatic intracranial haemorrhage, and major extracranial haemorrhage during the reported follow-up period. The first choice treatment was taken for analyses.

MAIN RESULTS

We did not find any completed randomised trials. Comparing antiplatelets with anticoagulants across 36 observational studies (1285 patients), there were no significant differences in the odds of death (Peto odds ratio (Peto OR) 2.02, 95% CI 0.62 to 6.60), or the occurrence of ischaemic stroke (OR 0.63, 95% CI 0.21 to 1.86) (34 studies, 1262 patients). For the outcome of death or disability, there was a non-significant trend in favour of anticoagulants (OR 1.77, 95% CI 0.98 to 3.22; P = 0.06) (26 studies, 463 patients). Symptomatic intracranial haemorrhages (5/627; 0.8%) and major extracranial haemorrhages (7/425; 1.6%) occurred only in the anticoagulation group; however, for both these outcomes, the estimates were imprecise and indicated no significant difference between the two treatment modalities.

AUTHORS' CONCLUSIONS

There were no randomised trials comparing either anticoagulants or antiplatelet drugs with control, thus there is no evidence to support their routine use for the treatment of extracranial internal carotid artery dissection. There were also no randomised trials that directly compared anticoagulants with antiplatelet drugs and the reported non-randomised studies did not show any evidence of a significant difference between the two.

Antiplatelets Versus Anticoagulation in Cervical Artery Dissection

Background and Purpose— The widespread preference of anticoagulants over antiplatelets in patients with cervical artery dissection (CAD) is empirical rather than evidence-based.

Summary of Review— This article summarizes pathophysiological considerations, clinical experiences, and the findings of a systematic metaanalysis about antithrombotic agents in CAD patients. As a result, there are several putative arguments in favor as well as against immediate anticoagulation in CAD patients.

Conclusions— A randomized controlled trial comparing antiplatelets with anticoagulation is needed and ethically justified. However, attributable to the large sample size which is required to gather meaningful results, such a trial represents a huge venture. This comprehensive overview may be helpful for the design and the promotion of such a trial. In addition, it could be used to encourage both participation of centers and randomization of CAD patients. Alternatively, antithrombotic treatment decisions can be customized based on clinical and paraclinical characteristics of individual CAD patients. Stroke severity with National Institutes of Health Stroke Scale score ≥15, accompanying intracranial dissection, local compression syndromes without ischemic events, or concomitant diseases with increased bleeding risk are features in which antiplatelets seem preferable. In turn, in CAD patients with (pseudo)occlusion of the dissected artery, high intensity transient signals in transcranial ultrasound studies despite (dual) antiplatelets, multiple ischemic events in the same circulation, or with free-floating thrombus immediate anticoagulation is favored.

Clinical application of transcranial Doppler monitoring for embolic signals

A major advantage of transcranial ultrasound is its suitability for continuous monitoring. Microembolic signals (MES) are brief, high-intensity transients that occur when particulate microemboli or gaseous microbubbles pass through the ultrasound beam. These MES have been detected in several clinical scenarios, but rarely in age-matched controls. The detection of MES provides important pathophysiological information in a variety of disorders, but their clinical importance and possible therapeutic implications are still under debate. The present article summarizes the significance of MES in different clinical settings and outlines some of the problems to be resolved so that transcranial ultrasound can be applied in clinical practice.

Antithrombotic drugs for carotid artery dissection

BACKGROUND

Extracranial internal carotid artery dissection can lead to occlusion of the artery and hence cause an ischaemic stroke. It is the underlying stroke mechanism in approximately 2.5% of all strokes. It is the second leading cause of stroke in patients younger than 45 years of age. Anticoagulants or antiplatelets may prevent arterial thrombosis in extracranial internal carotid artery dissection, but these benefits may be offset by increased bleeding.

OBJECTIVES

To determine whether antithrombotic drugs (antiplatelet drugs, anticoagulation) are effective and safe in the treatment of patients with extracranial internal carotid artery dissection, and which is the better treatment.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched 3 October 2002). In addition we performed comprehensive searches of the Cochrane Central Register of Controlled Trials (Cochrane Library Issue 2, 2002), MEDLINE (January 1966 to May 2002) and EMBASE (January 1980 to June 2002), and checked all relevant papers for additional eligible studies.

SELECTION CRITERIA

Randomised controlled trials, controlled clinical trials assessing the efficacy of anticoagulants or antiplatelets for the treatment of extracranial internal carotid artery dissection, and non-randomised trials, e.g. case series (studies), that reported on any antithrombotic treatment with at least 4 patients, were eligible for inclusion. Data from all eligible studies were extracted independently by two reviewers. Disagreements were resolved by discussion.

DATA COLLECTION AND ANALYSIS

Data on the primary outcome measures were extracted systematically. These were: death (all causes) and death or disability. Secondary outcomes were: first stroke occurrence, stroke recurrence, any stroke during reported follow-up, extracranial haemorrhage, and intracranial haemorrhage. The first choice treatment was taken for analyses.

MAIN RESULTS

No randomised trials were identified. No reliable comparisons of antiplatelet drugs or anticoagulants with control were available. Twenty-six eligible studies including 327 patients (who either received antiplatelet drugs or anticoagulants) were to be included in the comparative analysis. There was no significant difference in odds of death comparing antiplatelet drugs with anticoagulants (Peto odds ratio (Peto OR) 1.59, 95% CI 0.22-11.59). There was also no significant difference in the odds of being dead or disabled (Peto OR 1.94, 95% CI 0.76-4.91). Few intracranial haemorrhages (0.5%) were reported for patients on anticoagulants, none for patients on antiplatelets.

REVIEWER'S CONCLUSIONS

There were no randomised trials comparing either anticoagulants or antiplatelet drugs with control. There is, therefore, no evidence to support their routine use for the treatment of extracranial internal carotid artery dissection. There were also no randomised trials that directly compared anticoagulants with antiplatelet drugs, and the reported non-randomised studies did not show any evidence of a significant difference between the two. We suggest that a randomised trial including at least 1400 patients in each treatment arm with this condition is clearly needed.

Microembolus detection by transcranial doppler sonography

Microembolic signals can be detected by transcranial ultrasound as signals of high intensity and short duration. These signals represent circulating gaseous or solid particles. To optimize the differentiation from artefacts and the background signal and to facilitate the clinical use, several attempts have been made to automatize the detection of microemboli. Microemboli occur spontaneously in various clinical situations but their clinical impact and possible therapeutical implications are still under debate. This article provides a review of the actual literature concerning the current state of technical and clinical aspects of microembolus detection.