Design of the Vitesse Intracranial Stent Study for Ischemic Therapy (VISSIT) trial in symptomatic intracranial stenosis

Treatment of Acute Ischemic Stroke: The Last 30 Years of Trials and Tribulations

The landscape of acute ischemic stroke management has undergone a substantial transformation over the past 3 decades, mirroring our enhanced comprehension of the pathology and progress in diagnostic techniques, therapeutic interventions, and preventive measures. The 1990s marked a pivotal moment in stroke care with the integration of intravenous thrombolytics. However, the most significant paradigm shift in recent years has undoubtedly been the advent of endovascular thrombectomy. This article endeavors to deliver an exhaustive analysis of this revolutionary progression.

Dual anti-platelet therapy for secondary prevention in intracranial atherosclerotic disease: a network meta-analysis

Background:

Intracranial arterial stenosis (ICAS) is a non-marginal cause of stroke/transient ischemic attacks (TIAs) and is associated with high stroke recurrence rate. Some studies have investigated the best secondary prevention ranging from antithrombotic therapy to endovascular treatment (ET). However, no direct comparison between all the possible treatments is currently available especially between single and dual anti-platelet therapies (SAPT and DAPT).

Aim:

To establish whether DAPT is more effective than SAPT in preventing the recurrence of ICAS-related stroke, by means of a network meta-analysis (NMA).

Design:

Systematic review and NMA in accordance to PRISMA guidelines.

Data sources and methods:

We performed a systematic review of trials investigating secondary prevention (SAPT or DAPT, anticoagulant treatment or ET) in patients with symptomatic ICAS available in MEDLINE, Scopus and Web of Science from January 1989 to May 2021. We defined our primary efficacy outcome as the recurrence of ischemic stroke/TIA. We analysed the extracted data with Bayesian NMA approach.

Results:

We identified 815 studies and included 5 trials in the NMA. Sequence generation was adequate in all the selected studies while the allocation concealment method was described in one study. All the included studies reported the pre-specified primary outcomes, and outcome assessment was blinded in all the studies. We used the fixed-effect approach as the heterogeneity was not significant (p > 0.1) according to the Cochran’s Q statistic. DAPT was superior to SAPT and DAPT + ET in preventing stroke/TIA recurrence [respectively, odds ratio (OR), 0.59; confidence interval (CI), 0.39–0.9; and OR, 0.49, CI, 0.26–0.88], while no difference was found between DAPT and oral anticoagulant therapy (OAC). DAPT was safer than OAC (OR, 0.48; CI, 0.26–0.89) and DAPT + ET (OR, 0.50; CI, 0.35–0.71), while no difference was found between DAPT and SAPT.

Conclusion:

DAPT is more effective than SAPT for secondary stroke prevention in patients with symptomatic ICAS, without increasing the risk of haemorrhage.

Registration:

Prospero/CRD42019140033.

Risk Factors of New Cerebral Infarctions After Endovascular Treatment for Basilar Artery Stenosis Based on High-Resolution Magnetic Resonance Imaging

Objective: The current study aims to analyze the risk factors of new cerebral infarctions in the distribution of basilar artery (BA) detected by diffusion-weighted imaging (DWI) after endovascular treatment in patients with severe BA stenosis. Methods: Data was collected from the electronic medical records of patients with severely atherosclerotic basilar artery stenosis (≥70%) who underwent endovascular treatment. The plaque characteristics, including the plaque distribution, plaque burden, plaque enhancement index, remodeling ratio, and stenosis degree, were evaluated qualitatively and quantitatively using high-resolution magnetic resonance imaging (HR-MRI) and digital subtraction angiography (DSA). The characteristics of the procedure, such as the type of treatment, balloon diameter, balloon length, stent diameter, and stent length, were analyzed. Results: A total of 107 patients with severe basilar artery stenosis (≥70%) who underwent endovascular treatment were enrolled. The study participants included 77 men and 30 women, with an average age of 61.6 ± 8.1 years. The rate of postoperative new cerebral infarctions was 55.1% (59/107), of which 74.6% (44/59) were caused by artery-to-artery embolism, 6.8% (4/59) due to perforator occlusion, and 18.6% (11/59) were caused by a mixed mechanism. Twelve of 59 patients had ischemic events, with nine cases of stroke and three cases of transient ischemic attacks (TIA). The plaque burden in the DWI-positive group was significantly larger than that in the DWI-negative group (3.7% vs. -8.5%, p = 0.016). Positive remodeling was more common in the DWI-positive group than in the DWI-negative group (35.6% vs. 16.7%, p = 0.028). Smoking was inversely correlated with the rate of new cerebral infarctions (odds ratio, 0.394; 95% confidence interval, 0.167-0.926; p = 0.033). Conclusion: The plaque characteristics are not associated with new cerebral infarctions in the distribution of BA, although a large plaque burden and positive remodeling are more likely to appear in patients with new cerebral infarctions after BA stenting, which warrants further studies with a larger sample size. As for smoking, the inverse correlation with new cerebral infarctions in the BA territory needs large-scale prospective randomized controlled trials to verify.

Long-Term Effects on Preventing Stroke after Endovascular Treatment or Bypass Surgery for Intracranial Arterial Stenosis

BACKGROUND

Intracranial arterial stenosis (ICAS) is an important cause of ischemic stroke worldwide due to its higher risk of recurrence with medical therapy. Although some large randomized studies failed to show the superiority of surgical treatment compared with medical therapy, the results of medical therapy are not sufficient. There are patients who still benefit from surgical treatment. This retrospective analysis aimed to evaluate the long-term efficacy of surgical therapy with percutaneous transluminal angioplasty and/or stenting (PTA/PTAS) or extracranial-intracranial (EC/IC) bypass surgery for patients with ICAS.

METHODS

Between October 2005 and December 2016, 55 ICAS patients were treated with PTA/PTAS or EC-IC bypass surgery. Their electronic medical records were retrospectively reviewed and analyzed. The primary outcome was all adverse events beyond 30 days after a revascularization procedure.

RESULTS

We performed 21 cases (35%) of PTA, 4 cases (7%) of PTAS, and 34 cases (58%) of EC-IC bypass surgery and the median follow-up duration was 66 months (range 1-144 months). The occurrence rate of the primary outcome was 10.2% and only 1 patient (1.8%) experienced ipsilateral disabling ischemic stroke beyond 30 days. The long-term functional independent survival rate was 83.6%.

CONCLUSIONS

We demonstrated a long-term favorable outcome of combined surgical intervention for ICAS patients with PTA/PTAS and EC-IC bypass surgery, and the result was better than previously reported outcomes of medical therapy. Additional multicenter studies are required to draw firm conclusions on the efficacy of reduction of recurrent stroke in patients with ICAS.

Endovascular Treatment of Intracranial Atherosclerotic Stenosis: Current Debates and Future Prospects

Intracranial atherosclerotic stenosis (ICAS) is a common cause of transient ischemic attack (TIA) and ischemic stroke. Endovascular treatment, including balloon angioplasty alone, balloon-mounted stents, and self-expandable stent placement with or without prior angioplasty, is an alternative to medical treatment for the prevention of recurrent TIA or ischemic stroke in patients with ICAS. Although the SAMMPRIS and VISSIT trials supported medical management alone against endovascular treatments, both randomized controlled trials (RCT) were criticized due to flaws relating to patient-, intervention-, and operator-related factors. In this review, we discuss the current debate regarding these aspects and suggest approaches to solve current controversies in the future. In our opinion, endovascular treatment in carefully selected patients, individualized choice of endovascular treatment subtypes, and an experienced multidisciplinary team managing the patient in the pre-, peri- and post-procedural period have the potential to provide safe and efficious treatment of patients with symptomatic ICAS.

DO STUDY RESULTS TRANSLATE INTO PRACTICE? INTRACRANIAL STENTING IN GERMANY

OBJECTIVES

Enrolment into the SAMMPRIS trial published in September 2011 had to be stopped due to a 2.5 higher 30-day stroke and death rate in patients with percutaneous transluminal angioplasty and stenting (PTAS) compared with the control group with only medical therapy. After these results were published, one would have expected a change toward a clearer definition of indications for intracranial stent implantation in patients with intracranial artery stenosis, using this treatment only in patients suffering from recurrent strokes despite aggressive medical management.

METHODS

The frequency of intracranial stenting and indication parameters in patients with intracranial artery stenosis were assessed from 2010 to 2013 using claims data for all inpatient episodes from Germany's largest provider of statutory health insurance.

RESULTS

The number of intracranial stenting procedures decreased slowly from 580 in 2010 to 375 in 2013. With a rate of 29 percent there was no change between 2010 and 2013 of patients who were admitted to hospital for stent implantation, without documentation of an acute stroke or transient ischemic attack (TIA). Before PTAS, one-third of patients were admitted twice because of a stroke or TIA over a period of 5 years, 17 percent of patients had been prescribed platelet aggregation inhibitors and at least two admissions to hospital were for an ischemic cerebrovascular event before PTAS.

CONCLUSIONS

Our analysis of German claims data provides little evidence of changed indications for stenting in cases of intracranial atherosclerotic disease which one might expect to be caused by the emergence of high-level evidence.

Stroke Caused by Atherosclerosis of the Major Intracranial Arteries

Our goal in this review is to discuss the pathophysiology, diagnosis, and treatment of stroke caused by atherosclerosis of the major intracranial arteries. References for the review were identified by searching PubMed for related studies published from 1955 to June 2016 using search terms intracranial stenosis and intracranial atherosclerosis. Reference sections of published randomized clinical trials and previously published reviews were searched for additional references. Intracranial atherosclerotic disease is a highly prevalent cause of stroke that is associated with a high risk of recurrent stroke. It is more prevalent among blacks, Hispanics, and Asians compared with whites. Diabetes mellitus, hypertension, metabolic syndrome, smoking, hyperlipidemia, and a sedentary lifestyle are the major modifiable risk factors associated with intracranial atherosclerotic disease. Randomized clinical trials comparing aggressive management (dual antiplatelet treatment for 90 days followed by aspirin monotherapy and intensive management of vascular risk factors) with intracranial stenting plus aggressive medical management have shown medical management alone to be safer and more effective for preventing stroke. As such, aggressive medical management has become the standard of care for symptomatic patients with intracranial atherosclerotic disease. Nevertheless, there are subgroups of patients who are still at high risk of stroke despite being treated with aggressive medical management. Future research should aim to establish clinical, serological, and imaging biomarkers to identify high-risk patients, and clinical trials evaluating novel therapies should be focused on these patients.

The contemporary management of intracranial atherosclerotic disease

Intracranial atherosclerotic disease is the most common cause of cerebral vasculopathy and an important stroke etiology worldwide, with a higher prevalence in Asian, Hispanic and African ethnicities. Symptomatic intracranial atherosclerotic disease portends a recurrent stroke risk as high as 18% at one year. The key to secondary prevention is an understanding of the underlying stroke mechanism and aggressive control of conventional cardiovascular risks. Contemporary treatment includes antiplatelet therapy, optimal glycemic and blood pressure control, statin therapy and lifestyle modifications. For patients with high-grade (70-99%) symptomatic steno-occlusion, short-term dual antiplatelet therapy with aspirin and clopidogrel followed by life-long single antiplatelet therapy may reduce the recurrent risk. Current evidence does not advocate percutaneous transluminal angioplasty and stenting as an initial treatment. External counterpulsation, encephaloduroarteriosynangiosis and remote limb ischemic preconditioning are treatments under investigation. Future studies should aim at predicting patients prone to recurrence despite of medical therapies and testing the efficacy of emerging therapies.

Practical approach to management of intracranial atherosclerosis

OPINION STATEMENT

Intracranial atherosclerosis (ICAS) is one of the most frequent causes of stroke worldwide and has a high incidence of recurrent stroke. The therapeutic approaches for treating this high-risk disease have been evolving over time. The most recent, evidence-based approach is to focus on aggressive medical management of vascular risk factors and includes short-term dual antiplatelet treatment for 90 days followed by antiplatelet monotherapy. The role of endovascular therapy in the treatment of ICAS has not been established and is currently reserved only for patients who have failed aggressive medical management with recurrent ischemic events. There are no currently recommended surgical options to treat ICAS; however, investigational treatments such as encephaloduroarteriosynagiosis (EDAS) may hold promise. Despite aggressive medical management with short-term dual antiplatelet therapy, there remains a subset of patients with severe ICAS who will have recurrence of ischemic events. Further research is needed to better identify this high-risk subset and develop novel treatments to prevent further stroke and death.

The technique of endovascular intracranial revascularization

Intracranial atherosclerosis was traditionally believed to carry a risk of stroke of 8% to 22% per annum. The annualized stroke rate in the recent stenting and aggressive medical management for preventing stroke in intracranial stenosis (SAMMPRIS) trial medical management arm was 12.2%. This trial was halted due to excessive periprocedural events in the stent arm. This stroke rate is still unacceptably, high and a treatment strategy is still needed. SAMMPRIS has no bearing on angioplasty alone. Angioplasty alone has always been our primary intervention for intracranial atherosclerosis and remains so to this day due to its relative simplicity, low complication rate, and efficacy. We have, however, made adjustments to our patient management regimen based on the results of SAMMPRIS. This paper outlines our current patient selection, procedural technique, and post-procedure management. The complications we have encountered while developing our technique are described along with how to avoid them and how to manage them. Our most recent results (since previous publications) are also discussed.

Intracranial Angioplasty and Stenting before and after SAMMPRIS: "From Simple to Complex Strategy - The Chinese Experience"

Intracranial atherosclerotic disease (ICAD) accounts for 33–50% of all ischemic strokes in the Asian population (1) and represents an important public health issue in China. The results of the SAMMPRIS trial alarmed most experienced interventionalists in China for two reasons. Firstly, the high complication rate in the stenting arm (20% the first year) was higher than expected. Secondly, the recurrent stroke rate in the aggressive medical treatment arm at 12.2% during the first year was unacceptably high, not to mention the fact that such tight vascular risk factor control is difficult to achieve for many patients in real life clinical experience, at least in China. The experience of treating ICAD in China, gained over the last two decades, is very rich and promising. We intend to highlight these past experiences and address future trials and trends in China. We will also address our criticism of the SAMMPRIS trial design in order to better design a future trial.

Routine clinical evaluation of cerebrovascular reserve capacity using carbogen in patients with intracranial stenosis

BACKGROUND AND PURPOSE

A promising method for identifying hemodynamic impairment that may serve as a biomarker for stroke risk in patients with intracranial stenosis is cerebrovascular reactivity (CVR) mapping using noninvasive MRI. Here, abilities to measure CVR safely in the clinic using hypercarbic hyperoxic (carbogen) gas challenges, which increase oxygen delivery to tissue, are investigated.

METHODS

In sequence with structural and angiographic imaging, blood oxygenation level-dependent carbogen-induced CVR scans were performed in patients with symptomatic intracranial stenosis (n=92) and control (n=10) volunteers, with a subgroup of patients (n=57) undergoing cerebral blood flow-weighted pseudocontinuous arterial spin labeling CVR. Subjects were stratified for 4 substudies to evaluate relationships between (1) carbogen and hypercarbic normoxic CVR in healthy tissue (n=10), (2) carbogen cerebral blood flow CVR and blood oxygenation level-dependent CVR in intracranial stenosis patients (n=57), (3) carbogen CVR and clinical measures of disease in patients with asymmetrical intracranial atherosclerotic (n=31) and moyamoya (n=29) disease, and (4) the CVR scan and immediate and longer-term complications (n=92).

RESULTS

Noninvasive blood oxygenation level-dependent carbogen-induced CVR values correlate with (1) lobar hypercarbic normoxic gas stimuli in healthy tissue (R=0.92; P<0.001), (2) carbogen-induced cerebral blood flow CVR in patients with intracranial stenosis (R=0.30-0.33; P<0.012), and (3) angiographic measures of disease severity both in atherosclerotic and moyamoya patients after appropriate processing. No immediate stroke-related complications were reported in response to carbogen administration; longer-term neurological events fell within the range for expected events in this patient population.

CONCLUSIONS

Carbogen-induced CVR elicited no added adverse events and provided a surrogate marker of cerebrovascular reserve consistent with intracranial vasculopathy.

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

BACKGROUND AND PURPOSE

Analysis of procedural results and 30-day outcome after intracranial angioplasty and stenting (ICAS) with the balloon-expandable Pharos Vitesse stent system in carefully selected high-risk patients in two high-volume neurovascular centers.

MATERIALS AND METHODS

92 patients scheduled for elective ICAS using Pharos Vitesse between August, 2008 and August, 2011 were included. All patients showed high-grade intracranial stenosis and recurrent ischemic events despite best medical treatment at that time. The stroke rates and complications were divided into procedural and 30-day short-term events.

RESULTS

Successful stent placement was achieved in all but one patient. Ischemic procedural complications occurred in three subjects. 30-Day complications and strokes were seen in four patients: two minor ischemic strokes, one fatal hemorrhage and one non-stroke-related death. Overall, strokes occurred in 6 out of 92 patients (6.5%, 95% CI 3.0% to 13.5%). The total stroke and death rate was 7.6% (95% CI 3.7% to 14.9%). No significant correlation with previously reported risk factors could be found, although a higher rate of ischemic strokes (four out of five) in the posterior circulation was recorded.

CONCLUSIONS

In patients with intracranial stenosis who experience recurrent ischemic events despite best medical treatment, ICAS, using the balloon-expandable Pharos Vitesse stent, may still be considered as an individual treatment option in high-volume neurovascular centers.

Atherosclerotic intracranial arterial stenosis: risk factors, diagnosis, and treatment

Intracranial atherosclerosis is one of the most common causes of stroke worldwide and is associated with a high risk of recurrent stroke. New therapeutic approaches to treat this high-risk disease include dual antiplatelet treatment, intensive management of risk factors, and endovascular therapy. Early data from randomised trials indicate that aggressive medical therapy is better than stenting for prevention of recurrent stroke in high-risk patients with atherosclerotic stenosis of a major intracranial artery. Nevertheless, there are subgroups of patients who remain at high risk of stroke despite aggressive medical therapy. Further research is needed to identify these high-risk subgroups and to develop more effective treatments. Non-invasive vascular imaging methods that could be used to identify high-risk patients include fractional flow on magnetic resonance angiography (MRA), quantitative MRA, and high-resolution MRI of the atherosclerotic plaque. Alternative therapies to consider for future clinical trials include angioplasty alone, indirect surgical bypass procedures, ischaemic preconditioning, and new anticoagulants (direct thrombin or Xa inhibitors).

The challenge of stroke prevention with intracranial arterial stenosis

Patients with symptomatic intracranial atherosclerotic disease have a high risk of recurrent stroke, and secondary prevention in these patients remains a challenge. Aggressive medical management of vascular risk factors is safe and effective for most high risk patients, but the role of endovascular and surgical therapies still remain uncertain. Future studies may identify novel therapeutic strategies for patients with intracranial atherosclerotic disease, but aggressive risk factor control remains the mainstay of evidenced-based treatment at this time.