Mechanisms of early Recurrence in Intracranial Atherosclerotic Disease (MyRIAD): Rationale and design

Evaluation of paclitaxel-coated balloon angioplasty for the treatment of symptomatic intracranial in-stent restenosis

Background

Symptomatic intracranial in-stent restenosis (sISR) poses a major challenge in the management of cerebrovascular diseases, often requiring effective and safe treatment options.

Objectives

This study aims to evaluate the efficacy and safety of paclitaxel-coated balloon (PCB) angioplasty for treating sISR.

Methods

We conducted a retrospective analysis of five patients aged 49-74 years, who were treated with PCB angioplasty between January 2017 and June 2022. Treatment procedures included pre-operative digital subtraction angiography, antiplatelet therapy, and the use of the SeQuent Please balloon. Patients received aspirin and clopidogrel prior to and after the procedure.

Results

The procedure achieved a 100% success rate. The degree of ISR was significantly reduced from an average pre-operative rate of 72±18.9% to a post-operative rate of 34±8.22%. Long-term follow-up showed that the majority of patients did not experience restenosis, confirming the long-term effectiveness of the treatment.

Conclusions

PCB angioplasty demonstrates significant potential as an effective and safe treatment option for patients with sISR, especially those considered to be at high risk. This study supports further investigation into PCB angioplasty as a standard treatment for sISR.

Development and validation of a clinical prediction model for ischemic stroke recurrence after successful stent implantation in symptomatic intracranial atherosclerotic stenosis

OBJECTIVE

This study aimed to analyze the risk factors for recurrent ischemic stroke in patients with symptomatic intracranial atherosclerotic stenosis (ICAS) who underwent successful stent placement and to establish a nomogram prediction model.

METHODS

We utilized data from a prospective collection of 430 consecutive patients at Jining NO.1 People's Hospital from November 2021 to November 2022, conducting further analysis on the subset of 400 patients who met the inclusion criteria. They were further divided into training (n=321) and validation (n=79) groups. In the training group, we used univariate and multivariate COX regression to find independent risk factors for recurrent stroke and then created a nomogram. The assessment of the nomogram's discrimination and calibration was performed through the examination of various measures including the Consistency index (C-index), the area under the receiver operating characteristic (ROC) curves (AUC), and the calibration plots. Decision curve analysis (DCA) was used to evaluate the clinical utility of the nomogram by quantifying the net benefit to the patient under different threshold probabilities.

RESULTS

The nomogram for predicting recurrent ischemic stroke in symptomatic ICAS patients after stent placement utilizes six variables: coronary heart disease (CHD), smoking, multiple ICAS, systolic blood pressure (SBP), in-stent restenosis (ISR), and fasting plasma glucose. The C-index (0.884 for the training cohort and 0.87 for the validation cohort) and the time-dependent AUC (>0.7) indicated satisfactory discriminative ability of the nomogram. Furthermore, DCA indicated a clinical net benefit from the nomogram.

CONCLUSIONS

The predictive model constructed includes six predictive factors: CHD, smoking, multiple ICAS, SBP, ISR and fasting blood glucose. The model demonstrates good predictive ability and can be utilized to predict ischemic stroke recurrence in patients with symptomatic ICAS after successful stent placement.

Epidemiology, Pathophysiology, and Imaging of Atherosclerotic Intracranial Disease

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of stroke worldwide. Among people with stroke, those of East Asia descent and non-White populations in the United States have a higher burden of ICAD-related stroke compared with Whites of European descent. Disparities in the prevalence of asymptomatic ICAD are less marked than with symptomatic ICAD. In addition to stroke, ICAD increases the risk of dementia and cognitive decline, magnifying ICAD societal burden. The risk of stroke recurrence among patients with ICAD-related stroke is the highest among those with confirmed stroke and stenosis ≥70%. In fact, the 1-year recurrent stroke rate of >20% among those with stenosis >70% is one of the highest rates among common causes of stroke. The mechanisms by which ICAD causes stroke include plaque rupture with in situ thrombosis and occlusion or artery-to-artery embolization, hemodynamic injury, and branch occlusive disease. The risk of stroke recurrence varies by the presumed underlying mechanism of stroke, but whether techniques such as quantitative magnetic resonance angiography, computed tomographic angiography, magnetic resonance perfusion, or transcranial Doppler can help with risk stratification beyond the degree of stenosis is less clear. The diagnosis of ICAD is heavily reliant on lumen-based studies, such as computed tomographic angiography, magnetic resonance angiography, or digital subtraction angiography, but newer technologies, such as high-resolution vessel wall magnetic resonance imaging, can help distinguish ICAD from stenosing arteriopathies.

Factors Influencing the Outcome of Symptomatic Intracranial Artery Stenosis With Hemodynamic Impairment After Short and Long-Term Stent Placement

Objective

Stent placement is a feasible approach worldwidely for patients with symptomatic intracranial artery stenosis (sICAS) and hemodynamic impairment (HI) who are at high risk of recurrent stroke after medical treatment. Exploration of factors associated with poor outcomes after stent placement could help develop better individualized therapeutic strategies.

Methods

This study conducted a post-hoc analysis of a prospective, multicenter registry study of stent use for sICAS with HI in China. Patient and clinical demographics, and stenotic lesion images were analyzed using univariate and multivariate Cox regression to the time until any endpoints or the end of the follow-up period. The short-term endpoint included any transient ischemic attack (TIA), stroke, or death within 1 month after stent placement. The long-term endpoints included the short-term endpoints and any TIA or stroke in the region of the affected artery that occurred more than 1 month after stent placement.

Results

Two hundred and ninety two patients were included, with 13 short-term and 39 long-term endpoints. Multivariate Cox regression analysis revealed that lesions at the arterial origin or bifurcation (Hazard Ratio (HR) = 7.52; 95% CI, 1.89-29.82; p = 0.004) were significantly associated with higher short-term risk. Baseline renal insufficiency reduced the risk (HR = 0.08; 95% CI: 0.01-0.68; p = 0.021). Factors significantly associated with higher long-term risk included irregular or ulcerated plaques at the lesion (HR = 2.15; 95% CI: 1.07-4.33; p = 0.031). Subgroup analyses indicated that higher risk occurred in the older age group (age>59 years, HR = 3.73, 95% CI: 1.27-10.97, p = 0.017), and not in the younger group (age≤59 years, HR = 1.12, 95% CI: 0.42-3.03, p = 0.822).

Conclusion

Irregular or ulcerated plaques in older patients and lesions at the arterial opening or bifurcation were more likely to result in adverse endpoints for stent placement during long or short -term follow-up. Investigation of these factors might facilitate the development of individualized therapeutic strategies for this population.

Clinical Trial Registration

http://www.clinicaltrials.gov, identifier: NCT01968122.

Vertebrobasilar Stroke: Association Between Infarction Patterns and Quantitative Magnetic Resonance Angiography Flow State

Background

Treatment and prognosis of vertebrobasilar atherosclerotic disease differs depending on stroke mechanism, such as artery‐to‐artery embolism, branch atheromatous disease, and hemodynamic ischemia. Our aim was to investigate the relationship between infarction pattern and flow status using quantitative magnetic resonance angiography (QMRA), to determine the validity of using infarction patterns to infer stroke mechanism.

Methods and Results

This is a retrospective study of patients with ischemic stroke with intra‐ or extracranial vertebrobasilar atherosclerotic stenosis, who underwent magnetic resonance imaging of the brain, neurovascular imaging, and QMRA, between 2009 and 2021. Patients with cerebral infarction predating or following QMRA by ≥1 year, or QMRA studies performed for basilar thrombosis, vertebral dissection, or only postangioplasty/stenting, were excluded. Poststenotic flow (basilar and posterior cerebral arteries) was dichotomized as low‐flow or normal‐flow based on published criteria. Of 1211 consecutive patients who underwent QMRA noninvasive optimal analysis, 69 met inclusion. Mixed patterns were most common (46.4%), followed by perforator (23.2%), borderzone (14.5%), and territorial (15.9%). Patients with low‐flow had a significantly higher rate of borderzone+ patterns (borderzone alone or in mixed pattern) compared with patients with normal‐flow (77.4% low‐flow versus 39.5% normal‐flow, P=0.002). Borderzone+ patterns were associated with 61.5% probability of low‐flow state, while no borderzone (perforator/territorial) patterns were associated with 76.7% probability of normal‐flow state.

Conclusions

Borderzone infarction pattern (alone or mixed) was associated with low poststenotic posterior circulation flow by QMRA. However, borderzone pattern only moderately predicted low‐flow state, and may be an unreliable flow marker. Therefore, infarct topography may complement, but should not replace hemodynamic studies to establish flow status.

Lipid Levels and Short-Term Risk of Recurrent Brain Infarcts in Symptomatic Intracranial Stenosis

OBJECTIVES

Hyperlipidemia is a strong risk factor for intracranial atherosclerotic disease (ICAD) and clinical stroke recurrence. We explored the effect of serum lipid levels on subclinical infarct recurrence in the Mechanisms of earlY Recurrence in Intracranial Atherosclerotic Disease (MYRIAD) study.

MATERIALS AND METHODS

We included enrolled MYRIAD patients with lipid measurements and brain MRI at baseline and brain MRI at 6-8 weeks. Infarct recurrence was defined as new infarcts in the territory of the symptomatic artery on brain MRI at 6-8 weeks compared to baseline brain MRI. We assessed the association between baseline total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG) levels and recurrent infarct at 6-8 weeks using multivariable logistic regression.

RESULTS

Among 74 patients (mean age 64.2±12.9 years, 59.5% were white, 60.8% men), 20 (27.0%) had new or recurrent infarcts. Mean HDL-C (37.2 vs. 43.9 mg/dL, P=0.037) was lower and TG (113.5 vs. 91.3 mg/dL, P=0.008) was higher while TC (199.8 vs. 174.3 mg/dL, P=0.061) and LDL-C (124.3 vs. 101.2 mg/dL, P=0.053) were nominally higher among those with recurrent infarcts than those without. LDL-C (adj. OR 1.022, 95% CI 1.004-1.040, P=0.015) and TG (adj. OR 1.009, 95% CI 1.001-1.016, P=0.021) were predictors of recurrent infarct at 6-8 weeks adjusting for other clinical and imaging factors.

CONCLUSIONS

Baseline cholesterol markers can predict early infarct recurrence in patients with symptomatic ICAD. More intensive and rapid lipid lowering drugs may be required to reduce risk of early recurrence.

Risk Factors Control and Early Recurrent Cerebral Infarction in Patients with Symptomatic Intracranial Atherosclerotic Disease

BACKGROUND

The risk of early recurrent cerebral infarction (RCI) is high in patients with symptomatic intracranial atherosclerotic disease (IAD). We sought to determine the relationship between risk factor control and early RCI risk among patients with symptomatic IAD.

METHODS

We analyzed participants with symptomatic IAD in the multi-center prospective observational MYRIAD study. Risk factor control was assessed at 6-8-week follow-up. Optimal risk factor control was defined by target systolic blood pressure, being non-smoker, target physical activity, and antiplatelet and antilipidemic therapy compliance. Age-adjusted associations were calculated between risk factor control and RCI determined by MRI-evident new infarcts in the territory of the stenotic vessel at 6-8 weeks from the index event.

RESULTS

Among 82 participants with clinical and brain MRI information available 6-8 weeks after the index event (mean age 63.5 ±12.5 years, 62.2% men), RCI occurred in 21 (25.6%) cases. At 6-8-week follow-up, 37.8% had target systolic blood pressure, 92.7% were non-smokers, 51.2% had target physical activity, and 98.8% and 86.6% were compliant with antiplatelet and antilipidemic therapy, respectively. Optimal risk factor control increased from 4.9% at baseline to 19.5% at 6-8-week follow-up (p=0.01). None of the participants with optimal risk factor control at follow-up had RCI (0% vs. 31.8%, p<0.01).

CONCLUSIONS

Only one-fifth of MYRIAD participants had optimal risk factor control during early follow-up. Approximately half and two-thirds had physical inactivity and uncontrolled systolic blood pressure, respectively. These risk factors may represent important therapeutic targets to prevent early RCI in patients with symptomatic IAD.

Intracranial dolichoectasia in patients with symptomatic intracranial atherosclerotic disease: Results from the MYRIAD study

BACKGROUND AND PURPOSE

It is unknown whether intracranial atherosclerotic disease (ICAD), in addition to causing stenosis, also associates with abnormal arterial enlargement, a condition known as intracranial dolichoectasia (IDE). Across symptomatic ICAD patients, we aim to determine IDE prevalence and IDE impact on cerebral hemodynamics and recurrent cerebral ischemia.

METHODS

We analyzed 98 participants (mean age 63.8 ± 11.9 years, 56.1% men) of the prospective observational study MYRIAD. Participants were enrolled within 21 days of an ischemic stroke or transient ischemic attack caused by moderate-to-severe ICAD. Semi-automatic vessel segmentation was used to determine diameters, length, and tortuosity-index of proximal intracranial arteries. Either ectasia (increased diameter) or dolichosis (increased length or TI) defined IDE. We assessed IDE association with new infarcts during 12-month follow-up, and IDE correlation with cerebral hemodynamics determined by quantitative MR-angiography (QMRA), MR-perfusion weighted-imaging, and transcranial Doppler breath-holding index.

RESULTS

IDE was present in 35.7% of patients and 10.2% of symptomatic arteries. Basilar stenosis was associated with higher IDE prevalence (27.8% vs. 8.8%, p = 0.04), whereas other symptomatic arteries showed no association with IDE. Symptomatic arteries with IDE had lower hypoperfusion prevalence on MR-PWI (11.1% vs. 28.4%, p = 0.03). Increased diameter (r = 0.33, p<0.01) and tortuosity-index (r = 0.29, p = 0.01) showed positive correlation with QMRA flow rate. IDE was not associated with new infarcts during follow-up.

CONCLUSIONS

IDE was common among symptomatic ICAD patients. IDE was not associated with stroke recurrence. Instead, increased diameter and tortuosity correlated with improved blood flow across the stenotic artery, suggesting that IDE may originate as an adaptive mechanism in ICAD.

Predictors of Early Infarct Recurrence in Patients With Symptomatic Intracranial Atherosclerotic Disease

BACKGROUND AND PURPOSE

While prior studies identified risk factors for recurrent stroke in patients with symptomatic intracranial atherosclerotic disease, few have assessed risk factors for early infarct recurrence.

METHODS

We performed a post hoc analysis of the MYRIAD study (Mechanisms of Early Recurrence in Intracranial Atherosclerotic Disease) of intracranial atherosclerotic disease patients with recent (<21 days) stroke/transient ischemic attack, 50% to 99% stenosis and who underwent 6- to 8-week magnetic resonance imaging (MRI) per protocol. Infarct recurrence was defined as new infarcts in the territory of the symptomatic artery on brain MRI at 6 to 8 weeks compared to index brain MRI. Qualifying events and clinical and imaging outcomes were centrally ascertained by 2 independent reviewers. We assessed the association between baseline clinical and imaging variables and recurrent infarct in bivariate models and multivariable logistic regression to identify independent predictors of infarct recurrence.

RESULTS

Of 105 enrolled patients in MYRIAD, 89 (84.8%) were included in this analysis (mean age, 64±12 years, 54 [60.7%] were male, and 53 [59.6%] were White). The median time from qualifying event to MRI was 51+16 days, on which 22 (24.7%) patients had new or recurrent infarcts. Younger age (57.7 versus 66.0 years; P<0.01), diabetes (32.6% versus 14.6%, P=0.05), index stroke (31.3% versus 4.6%, P=0.01), anterior circulation location of stenosis (29.7% versus 12.0%, P=0.08), number of diffusion-weighted imaging lesions (>1: 40.0%, 1: 26.9% versus 0: 4.4%, P<0.01), and borderzone infarct pattern (63.6% versus 25.0%, P=0.01) on baseline MRI were associated with new or recurrent infarcts. Age (adjusted odds ratio, 0.93 [95% CI, 0.89-0.98], P<0.01) and number of diffusion-weighted imaging lesions (adjusted odds ratio, 3.24 [95% CI, 1.36-7.71], P<0.01) were independently associated with recurrent infarct adjusting for hypertension, diabetes, and stenosis location (anterior versus posterior circulation).

CONCLUSIONS

An index multi-infarct pattern is associated with early recurrent infarcts, a finding that might be explained by plaque instability and artery-to-artery embolism. Further investigation of plaque vulnerability in intracranial atherosclerotic disease is needed. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02121028.

Precision Medicine for Intracranial Atherosclerotic Disease

Diagnostic and therapeutic strategies for intracranial atherosclerotic disease (ICAD) have vastly expanded within the last several years. Challenges and concrete initiatives have emerged in the implementation of precision medicine for ICAD, focusing personalized treatment for the prevention of stroke and cognitive impairment around pathophysiology. Theranostics for ICAD incorporates an integrated diagnostic and therapeutic approach tailored to a specific individual. The ICAS 2019 meeting provided a roadmap for accelerating global innovation, underscoring the epidemiology, prior scientific evidence from trials, diagnostic tools or imaging, novel biomarkers, management approaches, and a broad range of treatments including many new medications, endovascular, and surgical strategies. This thematic overview provides perspective on current definitions for arterial stenosis, symptomatic lesions and outcomes or endpoints in clinical trials. Imaging correlates are reviewed, from routine multimodal CT or MRI to advanced angiographic techniques. The temporal features of ICAD and longitudinal observation are considered with respect to management and risk factor modification. The evolving science of multivariable interactions in ICAD and use of big data are explored, followed by an overview of recently launched clinical trials.

Imaging Patterns of Recurrent Infarction in the Mechanisms of Early Recurrence in Intracranial Atherosclerotic Disease (MyRIAD) Study

Introduction: While much is known about recurrent clinical events in patients with intracranial atherosclerotic disease (ICAD), there is limited data on characteristics of recurrent infarcts.

Methods: The NIH-funded MyRIAD prospective, observational study was designed to identify mechanisms of ischemia and predictors of recurrence in ICAD. Recurrent infarction was assessed on MRI at 6–8 weeks. We reviewed the DWI/ADC and FLAIR sequences in patients with recurrent stroke and characterized the number of infarcts, infarct location, size, and patterns based on whether they were borderzone (BZ), perforator (SC/P), cortical or territorial (C/T), and mixed. Temporal characteristics were delineated by ADC/FLAIR correlation.

Results: Of the 89 patients with 6–8 weeks MRI, 22 (24.7%) had recurrent infarcts in the territory of the symptomatic artery. Recurrent infarcts were evident on DWI in 63.6% and single infarcts in 54.5%. The median recurrent infarct volume was 2.0 cm³ compared to median index infarct volumes of 2.5 cm³. A mixed infarct pattern was most common (40.9%), followed by borderzone (22.7%), cortical or territorial (27.3%), while only 9.1% were in a perforator artery distribution. Amongst those with a mixed pattern, 8/9 had a borderzone distribution infarct as part of their mixed infarct pattern.

Conclusion: These findings provide novel data on the characteristics of early recurrent infarcts in patients with symptomatic ICAD.

Infarct Recurrence in Intracranial Atherosclerosis: Results from the MyRIAD Study

BACKGROUND

Intracranial atherosclerotic disease (ICAD) is a common cause of ischemic stroke with a high risk of clinical stroke recurrence. Multiple mechanisms may underlie cerebral ischemia in this condition. The study's objective is to discern the mechanisms of recurrent ischemia in ICAD through imaging biomarkers of impaired antegrade flow, poor distal perfusion, abnormal vasoreactivity, and artery-to-artery embolism.

METHODS

This prospective multicenter observational study enrolled patients with recent (≤21 days) ischemic stroke or transient ischemic attack (TIA) caused by ICAD with 50-99% stenosis treated medically. We obtained baseline quantitative MRA (QMRA), perfusion MRI (PWI), transcranial Doppler vasoreactivity (VMR), and emboli detection studies (EDS). The primary outcome was ischemic stroke in the territory of the stenotic artery within 1 year of follow-up; secondary outcomes were TIA at 1 year and new infarcts in the territory on MRI at 6-8 weeks.

RESULTS

Amongst 102 of 105 participants with clinical follow-up (mean 253±131 days), the primary outcome occurred in 8.8% (12.7/100 patient-years), while 5.9% (8.5/100 patient-years) had a TIA. A new infarct in the territory of the symptomatic artery was noted in 24.7% at 6-8 weeks. A low flow state on QMRA was noted in 25.5%, poor distal perfusion on PWI in 43.5%, impaired vasoreactivity on VMR in 67.5%, and microemboli on EDS in 39.0%. No significant association was identified between these imaging biomarkers and primary or secondary outcomes.

CONCLUSIONS

Despite intensive medical management in ICAD, there is a high risk of clinical cerebrovascular events at 1 year and an even higher risk of new imaging-evident infarcts in the subacute period after index stroke. Hemodynamic and plaque instability biomarkers did not identify a higher risk group. Further work is needed to identify mechanisms of ischemic stroke and infarct recurrence and their consequence on long-term physical and cognitive outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02121028.