Update on the natural history of intracranial atherosclerotic disease: A critical review

Adjunctive rescue therapy in acute large vessel occlusion secondary to underlying intracranial atherosclerotic disease

BACKGROUND

The optimal treatment for patients with acute large vessel occlusion (LVO) secondary to intracranial atherosclerotic disease (ICAD) is unclear. Adjunctive rescue therapy with balloon angioplasty or stenting may be necessary to ensure vessel patency. We aimed to compare the safety and clinical outcomes of adjunctive rescue therapy vs lone thrombectomy for ICAD-related-LVO.

METHODS

A retrospective propensity score matching analysis was performed in acute stroke patients who had endovascular thrombectomy between 2008-2021. We included patients with acute ICAD-related-LVO. The location of ICAD and exposure to thrombolysis were used to generate propensity score matching to estimate the likelihood of treatment by adjunctive rescue therapy. The primary clinical outcome (90-day modified rankin scale 0-2) and safety outcomes (symptomatic intracerebral hemorrhage) were assessed between the two groups.

RESULTS

One-hundred and forty-four patients were included. The median (IQR) age was 68(59-76) and 52(36%) were females. The baseline NIHSS was 12.5(8-19). Sixty-seven (47%) patients had ICAD in M1 or M2 segments. Forty-six patients (67%) had lone thrombectomy and twenty-one (28%) had adjunctive rescue therapy. Propensity score matching did not demonstrate significant differences in 90-day modified Rankin Score 0-2 between lone thrombectomy (38.8%) and adjunctive rescue therapy (39.3%) (p=0.3). Lone thrombectomy, compared to adjunctive rescue therapy, did not result in significantly more symptomatic intracerebral hemorrhages (2.8% vs 8.3%, p=0.6), nor progressive occlusion (17% vs 19%, p=0.8).

CONCLUSION

We did not find significant differences in clinical outcomes and safety between lone thrombectomy and adjunctive rescue therapy. Randomized controlled studies are required to resolve the equipoise in treatment of ICAD-related-LVO.

Application of drug-coated balloons for intracranial atherosclerosis disease: a systematic review

BACKGROUND

Although percutaneous transluminal angioplasty and stenting (PTAS) was an effective and safe alternative treatment for severe intracranial atherosclerosis disease (ICAD), the high rate of restenosis remained a major issue for this endovascular procedure. Recently, the application of drug-coated balloons (DCB) in ICAD was developed to reduce restenosis. This systematic review aimed to evaluate the efficacy and safety of DCB angioplasty for ICAD.

METHODS

We searched relevant databases for eligible studies enrolling ICAD patients treated with DCB. The event rates of restenosis and periprocedural complications in the follow-up period were pooled with random-/fixed-effect models using Freeman-Tukey double arcsine transformation. Heterogeneity tests and publication bias tests were performed.

RESULTS

Two hundred and twenty-four ICAD patients treated with DCB from 9 eligible studies were included. Rate of stenosis in the DCB arm before treatment was ranged from 62% to 90% and reported median follow-up was ranged from 3 to 10.7 months. The pooled incidence of restenosis were 5.7% (95% confidence interval [CI] 2.6%-9.7%; I² = 0%, p = 0.516) and 5.9% for periprocedural complications (95% CI: 2.5-10.3%; I² = 0%, p = 0.649) in follow-up term.

CONCLUSION

With the limitation of the low quality of the available evidence, angioplasty with DCB appears to be effective and safe in severe ICAD. Further larger randomized trials are needed to provide more definitive evidence and to address the ideal clinical context for their application.

Current Advances in Endovascular Treatment of Intracranial Atherosclerotic Disease and Future Prospective

OBJECTIVES/BACKGROUND

Medical therapy is the first line of treatment for intracranial atherosclerotic disease (ICAD). Percutaneous transluminal angioplasty and stenting (PTAS) are mainly considered for those patients with severe stenosis and recurrent events despite aggressive medical therapy. In this review, we discuss the application of PTAS as a treatment option for ICAD and its future prospect.

MATERIALS AND METHODS

We did the literature review of the key articles and guidelines to elaborate on the role of PTAS in the management of ICAD based on the current data and expert opinion. We searched PubMed, Google Scholar, and Scopus up to August 2020, and included articles published only in the English language.

RESULTS

Since the publication of the results from SAMMPRIS and VISSIT trials, stenting is no longer recommended for secondary stroke prevention in patients with symptomatic ICAD. However, recent clinical studies on intracranial stenting for a subgroup of ICAD patients have shown promising results, likely due to better patient selection and continued advancement of endovascular techniques.

CONCLUSION

There exists a lack of consensus regarding the best endovascular treatment approach (e.g., angioplasty alone or balloon mounted stent vs. self-expanding stent with or without prior angioplasty) or management of in-stent restenosis. Another area of clinical controversy relates to the ideal use and duration of antiplatelet therapy.

Efficacy and safety of endovascular treatment for patients with acute intracranial atherosclerosis-related posterior circulation stroke: a systematic review and meta-analysis

The benefit of endovascular treatment (EVT) for patients with intracranial atherosclerosis-related large vessel occlusion (ICAS-LVO) in posterior circulation stroke (PCS) is inconsistent. This systematic review and meta-analysis were conducted to estimate the effect of ICAS-LVO in PCS treated by EVT. A systematic review was completed, tracking studies from their date of inception until February 2020. Clinical studies which compared outcomes after EVT for ICAS-LVO and non-ICAS-LVO in PCS were included. Data were synthesized and interpreted from meta-analysis. A total of 688 patients (352 ICAS-LVO and 336 non-ICAS-LVO) in the eight studies were included. The successful reperfusion rate (odds ratio [OR], 0.58; 95% confidence intervals [95% CIs], 0.37-0.93; P = 0.02) was lower in PCS with ICAS-LVO than non-ICAS-LVO. And for other clinical outcomes, there were no differences between both groups. Moreover, there were no statistical differences of any clinical outcome among subgroups stratified by nations and target vessel occlusion location. With respect to patients' characteristics, age (mean difference [MD], -2.75; 95% CI, -4.62--0.88; P = 0.004), pc-Alberta Stroke Program Early CT Score (MD, -0.49; 95% CI, -0.94--0.05; P = 0.03), distributions of sex (male) (OR, 2.34; 95% CI, 1.53-3.56; P < 0.001), prior or current smoking (OR, 1.85; 95% CI, 1.12-3.07; P = 0.02), hypertension (OR, 2.06; 95% CI, 1.32-3.22; P = 0.002), coronary artery disease (OR, 0.27; 95% CI, 0.11-0.66; P = 0.004) and general anesthesia (OR, 2.89; 95% CI, 1.54-5.45; P = 0.001) were statistically different between both groups. In conclusion, more targeted assessments are warranted for patients with ICAS-LVO-related PCS during clinical strategies, and the benefit of EVT for PCS with ICAS-LVO deserves further research.

Improvement of Cerebrovascular Reserve by Percutaneous Transluminal Angioplasty for Symptomatic Middle Cerebral Artery Stenosis

Objective

The purpose of this study was to investigate the efficacy of percutaneous transluminal angioplasty (PTA) for symptomatic middle cerebral artery stenosis by analyzing cerebral blood flow (CBF).

Methods

Between January 2016 and December 2018, six patients with symptomatic middle cerebral artery stenosis underwent CBF analysis by single-photon emission computed tomography (SPECT) with acetazolamide challenge before and after PTA for stenosis. They were retrospectively reviewed, and the blood flow in the area of the affected middle cerebral artery before and after angioplasty was compared.

Results

The mean stenosis rate and length of lesion before angioplasty were 76.4 ± 5.4% and 6.5 ± 2.1 mm, respectively. Balloon angioplasty without stenting was performed on all patients. The mean residual stenosis rate just after angioplasty was 45.4 ± 9.3%. No periprocedual complications developed, and there were no notable cerebral ischemic events during the postprocedural follow-up period. One patient underwent repeat angioplasty for restenosis. Although there was only a mild decrease in blood flow at rest, the cerebrovascular reserve (CVR) in the area of the affected middle cerebral artery was markedly decreased before angioplasty (mean, 3.6 ± 4.3%). After angioplasty, the CVR was significantly improved (mean, 18.0 ± 4.7%, p <0.01).

Conclusions

PTA for symptomatic middle cerebral artery stenosis can be safely performed using appropriate interventional techniques for select patients. Reduced CVR due to stenosis can be improved after angioplasty, which may reduce the risk of cerebral ischemic events.

Comparison of Risk Factors, Treatment, and Outcome in Patients with Symptomatic Intracranial Atherosclerotic Disease in India and the United States

BACKGROUND AND AIMS

Intracranial atherosclerotic disease (ICAD) is common in the Asian population, but less studied in South Asians compared to East Asians. We compared risk factors, treatments, and outcomes among consecutive patients with symptomatic ICAD from India with a mixed-ethnic cohort from Chicago, Illinois.

METHODS

Consecutive patients with symptomatic ICAD were enrolled at 2 academic medical centers in Kerala, India and Chicago, United States. Data on demographics, risk factors, initial stroke severity (National Institute of Health Stroke Scale score [NIHSS]), recurrent stroke, and 3-month functional outcome (modified Rankin Scale [mRS]) were prospectively collected. Recurrent stroke was defined as symptomatic recurrence of focal neurologic deficits associated with radiographic evidence of new cerebral infarction within 3 months of index admission.

RESULTS

329 patients (117 from Kerala, 212 from Chicago) were included. Indian patients were younger (61 vs. 68, P < 0.001), less frequently had prior stroke history (15.4 vs. 32.5%, P = 0.001) and coronary artery disease (11.1 vs. 22.2%, P = 0.013) but had higher initial NIHSS score (median 6 vs. 3, P < 0.001). Both groups received reperfusion therapy in similar proportions (8.5 vs. 7.1%, P = 0.630) but at discharge, 90.6% of Indian patients compared to 59.0% of Chicago patients were treated with dual antiplatelet therapy. More recurrent strokes occurred in Chicago patients (21.7 vs. 1.9%, P < 0.001) but functional outcome did not differ significantly.

CONCLUSION

Compared to patients in US with symptomatic ICAD, Indian patients were younger and had more severe strokes. However, Indian patients had lower rates of recurrent stroke, perhaps due to greater use of dual antiplatelet therapy.

Microembolic Signals Predict Recurrence of Ischemic Events in Symptomatic Patients with Middle Cerebral Artery Stenosis

Middle cerebral artery (MCA) stenosis is a common cause of ischemic stroke in Asian populations. We sought to determine whether microembolic signals (MESs) can predict the occurrence or recurrence of ischemia in symptomatic and asymptomatic patients with MCA stenosis. The symptomatic group had a significantly higher incidence of MES (30% vs. 16.2%, p < 0.05), as well as higher incidences of cerebral infarction and transient ischemic attack (TIA) (infarction, 13.0% vs. 4.4%, OR 3.123 [95% CI, 1.049-9.294], p < 0.05; TIA, 21.0% vs. 2.9%, OR = 7.108 [95% CI, 1.808-27.949], p < 0.001) than the asymptomatic group. After a follow-up period of 0.5-4.5 y, the subgroup of MES-positive (MES+) symptomatic patients had a significantly higher incidence of TIA (36.7% vs. 14.3%, OR = 1.623 [95% CI, 1.166-2.258]; p < 0.001) than the subgroup of MES-negative (MES-) symptomatic patients. The likelihood of the early occurrence of an endpoint event was also higher in the subgroup of MES+ symptomatic patients. In the group of asymptomatic patients with MCA stenosis, no significant differences were identified between the MES+ and MES- subgroups.

Added Value of Vessel Wall Magnetic Resonance Imaging for Differentiation of Nonocclusive Intracranial Vasculopathies

BACKGROUND AND PURPOSE

Our goal is to determine the added value of intracranial vessel wall magnetic resonance imaging (IVWI) in differentiating nonocclusive vasculopathies compared with luminal imaging alone.

METHODS

We retrospectively reviewed images from patients with both luminal and IVWI to identify cases with clinically defined intracranial vasculopathies: atherosclerosis (intracranial atherosclerotic disease), reversible cerebral vasoconstriction syndrome, and inflammatory vasculopathy. Two neuroradiologists blinded to clinical data reviewed the luminal imaging of defined luminal stenoses/irregularities and evaluated the pattern of involvement to make a presumed diagnosis with diagnostic confidence. Six weeks later, the 2 raters rereviewed the luminal imaging in addition to IVWI for the pattern of wall involvement, presence and pattern of postcontrast enhancement, and presumed diagnosis and confidence. Analysis was performed on per-lesion and per-patient bases.

RESULTS

Thirty intracranial atherosclerotic disease, 12 inflammatory vasculopathies, and 12 reversible cerebral vasoconstriction syndrome patients with 201 lesions (90 intracranial atherosclerotic disease, 64 reversible cerebral vasoconstriction syndrome, and 47 inflammatory vasculopathy lesions) were included. For both per-lesion and per-patient analyses, there was significant diagnostic accuracy improvement with luminal imaging+IVWI when compared with luminal imaging alone (per-lesion: 88.8% versus 36.1%; P<0.001 and per-patient: 96.3% versus 43.5%; P<0.001, respectively). There was substantial interrater diagnostic agreement for luminal imaging+IVWI (κ=0.72) and only slight agreement for luminal imaging (κ=0.04). Although there was a significant correlation for both luminal and IVWI pattern of wall involvement with diagnosis, there was a stronger correlation for IVWI finding of lesion eccentricity and intracranial atherosclerotic disease diagnosis than for luminal imaging (κ=0.69 versus 0.18; P<0.001).

CONCLUSIONS

IVWI can significantly improve the differentiation of nonocclusive intracranial vasculopathies when combined with traditional luminal imaging modalities.

Intracranial Atherosclerosis: From Microscopy to High-Resolution Magnetic Resonance Imaging

Intracranial atherosclerosis is one of the leading causes of ischemic stroke and occurs more commonly in patients of Asian, African or Hispanic origin than in Caucasians. Although the histopathology of intracranial atherosclerotic disease resembles extracranial atherosclerosis, there are some notable differences in the onset and severity of atherosclerosis. Current understanding of intracranial atherosclerotic disease has been advanced by the high-resolution magnetic resonance imaging (HRMRI), a novel emerging imaging technique that can directly visualize the vessel wall pathology. However, the pathological validation of HRMRI signal characteristics remains a key step to depict the plaque components and vulnerability in intracranial atherosclerotic lesions. The purpose of this review is to describe the histological features of intracranial atherosclerosis and to state current evidences regarding the validation of MR vessel wall imaging with histopathology.

Early middle cerebral artery stenosis following stent-assisted thrombectomy

Stent-assisted thrombectomy (SAT) is an extensively used endovascular treatment method for stroke in which the thrombectomy stents come into direct contact with the vascular intimal surface and entrap the thrombus causing the arterial occlusion. Although there are a few studies that demonstrate that the vessel wall changes in the arteries where stroke intervention is performed, we observed progressive stenosis in early follow-up imaging studies in a case. We present a middle cerebral artery (MCA) stroke patient who had four repetitive stent passes during SAT and developed distal MCA stenosis 2 months after SAT at the control magnetic resonance angiography (MRA). Inclusion of early follow-up MRA studies would be helpful in defining the silent vascular changes in patients who have undergone repetitive SAT.

Study protocol: asymptomatic intracranial atherosclerotic disease in pakistanis

BACKGROUND

Intracranial atherosclerotic disease (ICAD) is the most frequent subtype of ischemic stroke globally. It is important to describe the determinants of early ICAD as a strategy to prevent strokes from clinically evident and progressive ICAD. Our objective is to report the determinants of asymptomatic ICAD by linking the presence or absence of ICAD on magnetic resonance angiogram (MRA) with detailed risk assessment in asymptomatic adults.

METHODS

This is an observational cross-sectional analytical study. We plan to recruit 200 adult participants from the radiology departments of two tertiary care centers of Karachi, Pakistan. The participants will first be screened for the absence of stroke symptoms via the Questionnaire for Verifying Stroke Free Status (QVSFS). QVSFS negative will be participants will be eligible. After written informed consent, participants will undergo detailed medical, sociodemographic, lifestyle, and anthropometric evaluation by a detailed interview. They will, in addition, undergo MRA to study the presence, degree, and distribution of asymptomatic ICAD. All MRA scans will be reviewed centrally by vascular neurologists blinded to clinical information. These images would be reviewed on DICOM Viewer 3.0 used for calculating the degree of stenosis using Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) study defined criteria employing electronic calipers. A sample size of 200 will achieve 80% power for detecting a minimum difference of 20% in the prevalence of exposure factors (medical and lifestyle) between asymptomatic ICAD positive and ICAD negative persons. This study will generate regional data on risks for ICAD development and prevention in a high-risk susceptible population. Study ID: NCT02072876.

Natural history of intracranial atherosclerotic disease

Intracranial atherosclerotic disease was very common among stroke patients of Asians, Blacks, and Hispanics ancestry. Furthermore, stroke patients with intracranial atherosclerosis (ICAS) have higher recurrence rate of cerebral ischemia and death than those without ICAS. However, the natural history of intracranial atherosclerotic disease is still in controversy. Most of the studies were retrospective and randomized controlled trial of drugs. This review summarized the prognosis of symptomatic and asymptomatic intracranial atherosclerotic disease in order to guide clinical decision-making and further clinical research.

Microembolic signals detected with transcranial doppler sonography differ between symptomatic and asymptomatic middle cerebral artery stenoses in Northeast China

Although microembolus monitoring has been widely used for ischemic cerebrovascular disease, the clinical significance of microembolic signal (MES) in asymptomatic middle cerebral artery (MCA) stenosis remains unclear. We aim to investigate the frequency of MES and the value of MES in predicting ischemic stroke secondary to asymptomatic MCA stenosis. From June 2011 to December 2012, microembolus monitoring was performed in 83 asymptomatic and 126 symptomatic subjects. By comparing the demographics and risk factors between the symptomatic and asymptomatic subjects, we found that the ratio of male sexuality and smoking history differed (101/126 vs 43/83, and 88/126 vs 38/83, respectively, p<0.01). The frequency of MES was significantly higher in the symptomatic group than in the asymptomatic group (49/126 vs 2/108, p<0.01). Specifically, the frequency of MES in the symptomatic and asymptomatic groups with mild stenosis, moderate stenosis, severe stenosis and occlusion groups was 4/18 (22.22%) vs 0/30 (0), 13/31 (41.94%) vs 1/28 (3.57%), 30/62 (48.39%) vs 1/39 (2.56%), 2/15 (13.33%) vs 0/11 (0), respectively. Except for the occlusive group, the frequency of MES is correlated with stenosis degree and symptom. Two patients in the asymptomatic group were found positive for MES, and the MES number was 1 for both. During the one-year follow-up, neither of them developed ischemic stroke. In conclusion, MES detected with TCD differs between symptomatic and asymptomatic MCA stenoses. Due to the low frequency, the value of MES as a predictor of subsequent ischemic stroke in patients with asymptomatic MCA stenosis might be limited.

Prevalence and outcomes of symptomatic intracranial large artery stenoses and occlusions in China: the Chinese Intracranial Atherosclerosis (CICAS) Study

BACKGROUND AND PURPOSE

We aimed to establish the prevalence, characteristics, and outcomes of intracranial atherosclerosis (ICAS) in China by a large, prospective, multicenter study.

METHODS

We evaluated 2864 consecutive patients who experienced an acute cerebral ischemia<7 days after symptom onset in 22 Chinese hospitals. All patients underwent magnetic resonance angiography, with measurement of diameter of the main intracranial arteries. ICAS was defined as ≥50% diameter reduction on magnetic resonance angiography.

RESULTS

The prevalence of ICAS was 46.6% (1335 patients, including 261 patients with coexisting extracranial carotid stenosis). Patients with ICAS had more severe stroke at admission and stayed longer in hospitals compared with those without intracranial stenosis (median National Institutes of Health Stroke Scale score, 3 versus 5; median length of stay, 14 versus 16 days; both P<0.0001). After 12 months, recurrent stroke occurred in 3.27% of patients with no stenosis, in 3.82% for those with 50% to 69% stenosis, in 5.16% for those with 70% to 99% stenosis, and in 7.27% for those with total occlusion. Cox proportional hazards regression analyses showed that the degree of arterial stenosis, age, family history of stroke, history of cerebral ischemia or heart disease, complete circle of Willis, and National Institutes of Health Stroke Scale score at admission were independent predictors for recurrent stroke at 1 year. The highest rate of recurrence was observed in patients with occlusion with the presence of ≥3 additional risk factors.

CONCLUSIONS

ICAS is the most common vascular lesion in patients with cerebrovascular disease in China. Recurrent stroke rate in our study was lower compared with those of previous clinical trials but remains unacceptably high in a subgroup of patients with severe stenosis.

Distribution, Severity and Radiologic Features of Intracranial Stenosis in Asymptomatic Pakistanis

BACKGROUND

Intracranial atherosclerotic disease (ICAD) is the most common ischemic stroke subtype globally. It accounts for 30-50% of all ischemic strokes in Asians.

AIMS

The aim of the study is to report the frequency of asymptomatic ICAD and its associated Magnetic Resonance Imaging (MRI) findings.

METHODS

200 adult participants were recruited from the Radiology Departments of two major diagnostic centers in Karachi. Eligible participants were confirmed for the absence of stroke symptoms via the Questionnaire for Verifying Stroke Free Status (QVSFS). QVSFS negative subjects underwent MRI on a 1.5 Tesla scanner. Images were centrally reviewed on Di com Viewer 3.0 with electronic calipers to calculate the degree of ICAD.

RESULTS

Mean age of subjects was 37.1 years (S.D 15.1) with 50.5% men (n=101) and 49.5% women (n=99). Asymptomatic ICAD was found in 34.5% (n=69) subjects. Of the 3800 intracranial arteries studied, 2.2% (n=88) had biological disease. 20.5% (n=18) of these vessels had atherosclerotic irregularities, 43.2% (n=38) had mild stenos is, 11.4% (n=10) had moderate stenos is, 5.7% (n=5) had severe stenos is while 19.3% (n=17) were completely occluded. The posterior cerebral artery (42% of stenosed arteries, n=37) was most affected. 23.5% (n=47) of subjects had peri-ventricular lucencies, 10.5% (n=21) had brain atrophy while 3.5% (n=7) had silent brain infarcts. There was a significant association between asymptomatic ICAD and peri ventricular lucencies (PR 1.59; 95% CI 1.35-1.99).

CONCLUSION

Asymptomatic ICAD is common in young Pakistanis, with no gender predilection; it preferentially affects the posterior circulation. Silent infarcts are rare compared to peri ventricular lucencies and atrophy.