Lin, Michelle

Introduction: Carotid revascularization is known to prevent stroke in patients with high-grade carotid stenosis, but whether carotid revascularization may slow the progression of hemispheric WMD in patients with carotid stenosis to prevent cognitive decline have not been well described. Methods: We conducted a longitudinal study involving patients age ≥40 years with carotid stenosis on ultrasound from 2011-2015 with serial brain MRI scans at least 1 year apart followed for radiographic and clinical outcomes to 2020. Severity of carotid stenosis was defined as moderate 50-69%, high-grade 70-99%, or occluded. Hemispheric WMD volume was quantified from axial T2 FLAIR images. Patients were stratified by revascularization status. Primary outcome was change in WMD volume per year ipsilateral or contralateral to the index carotid. Hemispheric differences in the annual rate of WMD progression (cc/yr) were compared between revascularized vs not revascularized using multivariable linear regression analysis adjusted for variables that differed between revascularization status. Results: Of the 150 patients, moderate stenosis was present in 37.3%, high-grade stenosis in 42.0%, and carotid occlusion in 20.7%. Mean age was 71±10 years, 36.7% were female. Seventy-three (48.7%) had carotid revascularization with a median follow-up of 5.1 years. Baseline WMD volume was 4.86cc ipsilateral and 4.39cc contralateral to the index carotid. Patients who underwent revascularization trended to have slower WMD progression in the hemisphere ipsilateral to the index carotid compared to those not revascularized (0.32cc/yr vs 0.63 cc/yr, p=0.340). The same trend was not observed in the contralateral hemisphere. In adjusted models, carotid revascularization was associated with a 0.33 cc per year decrease in WMD progression between hemispheres compared to those not revascularized (β= -0.33, p=0.070). Conclusions: In this study with a median follow-up of 5 years, we found that carotid revascularization resulted in a 50% reduction in the annual rate of WMD progression. Intervention trials should test whether carotid revascularization slows WMD progression in patients with cognitive impairment to prevent further cerebrovascular events and cognitive decline.

Introduction: Collateral circulation plays a crucial role in determining the extent of brain tissue ischemia and functional outcome in large vessel occlusive (LVO) stroke. Heart failure (HF) is known to cause cerebral hypoperfusion, yet the relationship between HF and robustness of collateral flow has not been well described. Here we hypothesized that HF is associated with poor collateral flow and functional outcome in patients presenting with LVO treated with mechanical thrombectomy (MT). Methods: A single center retrospective study of patients presenting with LVO ischemic stroke who underwent MT between 2012-2020 was done. Single-phase CTA of head prior to MT was used to assess collateral status with poor status defined as ≤ 50% filling and good status as >50% filling. Classification of HF by left ventricular ejection fraction (LVEF) on echocardiogram was used where HF with reduced ejection fraction (HFrEF) had LVEF ≤40%, HF with preserved EF (HFpEF) had LVEF ≥50% with evidence of structural heart disease, and no HF was LVEF≥50% without structural heart disease. Functional outcome was modified Rankin scale (mRS) at 90 days with scores of 0-2 representing good outcome and 3-6 representing poor outcome. Multivariable logistic regression analyses were performed to evaluate the association between HF and poor collaterals after adjusting for vascular risk factors. Results: We identified 235 patients, mean age was 69 ±15 years, median NIHSS was 18, and 45.5% had HF (HFrEF 12.8%, HFmrEF 4.7%, HFpEF 28.1%) while 54.5% had no HF. Poor collaterals were seen in 47.7%, and those with HF were likely to have poor collaterals compared to those without HF (56.1% vs 35.1%, P=.001). There was a dose-dependent relationship between severity of HF and poor collaterals: adjusted odds of poor collaterals were 1.63 and 2.45 in HFpEF and HFrEF, compared to those without HF (trend p=.018). Patients with poor collaterals were likely to have poor outcome at 3 months compared to those with good collaterals (75.0% vs 57.8%; p=.015). Conclusion: Patients with HFrEF were twice as likely to have poor collaterals. This study demonstrated a likely mechanism for poor outcomes seen in ischemic stroke with HF, future studies may explore whether optimization of HF may augment collaterals to improve outcomes.

AbstractThe authors illustrate the use of through-and-through brachio/radio-femoral access technique in two patients who presented with subclavian steal syndrome. This is an additional tool in the armamentarium of the endovascular specialist to improve management of complex cases with subclavian steal syndrome. This technique provides several advantages to improve efficiency and precision of the procedure while reserving the open surgical bypass option if needed.

Introduction: Patients with carotid stenosis may have silent cerebrovascular disease due to chronic hypoperfusion and atheroembolism. If so, progression of silent disease may be preventable through revascularization. We aim to evaluate the association between carotid stenosis/occlusion and cerebral small vessel disease (SVD) burden ipsilateral to the cervical carotid stenosis. Methods: Patients age ≥40 years with carotid stenosis or occlusion on carotid ultrasound who underwent MRI brain and intracranial angiogram with gradable SVD on MRI from 2011-2015 were included. Severity of carotid stenosis was defined using NASCET criteria as 50-69% (moderate), 70-99% (high-grade), or occluded. WMH volume was quantified using an automated artificial intelligence algorithm applied to axial T2 FLAIR images. Images were also scored for presence of chronic lacune, cerebral microbleeds (CMB), and silent infarcts using STRIVE criteria. Differences in WMD volume between hemispheres ipsilateral and contralateral to the carotid stenosis were calculated, and prevalence of SVD and silent infarct were compared across severities of carotid stenosis. Results: Of the 183 patients, mean age was 71±10 years and 38% were female. Moderate and severe stenosis was present in 36% and 46.5%, respectively, and 18% had carotid occlusion. Mean WMH volume was 7271±522mm 3 . Patients with carotid stenosis had greater WMH volume ipsilateral to the side of carotid stenosis than the contralateral side (mean difference 224±206mm 3 ), and higher severity of stenosis was associated with greater hemispheric difference in WMH volume (moderate vs high; 164±274mm 3 vs 743±309 mm 3 , p=0.009). Silent infarcts were more prevalent in high-grade carotid stenosis than moderate grade (moderate vs high, 10.8% vs 36.5%; p=0.002). There were no differences in either lacunae or CMBs across severities. Conclusions: Greater than one third of patients with high-grade carotid stenosis had ipsilateral silent brain infarction, and the volume of WMH was greater on the side of carotid stenosis. Future analyses should consider the potential yield of screening for carotid atherosclerosis in patients with varying degrees of hemispheric WMH asymmetry.

Mechanical thrombectomy (MT) represents the mainstay of treatment for patients with acute ischemic stroke due to large-vessel occlusion (LVO). Intravenous thrombolysis has been associated with worse clinical outcome in patients presenting with high blood glucose levels at admission; to date the true effect of hyperglycemia in the setting of MT has not been fully elucidated. In this meta-analysis, we analyzed the influence of high blood glucose levels at admission on clinical outcome after MT. Ovid EMBASE, PubMed, Scopus, and Cochrane Library databases were searched from their dates of inception up to March 2021. An initial search identified 2118 articles representing 1235 unique studies. After applying selection criteria, three prospective and five retrospective studies were analyzed, yielding a pooled cohort of 5861 patients (2041 who presented with hyperglycemia, and 3820 who presented with normal blood glucose levels). Patients in the hyperglycemia group were less likely to have a modified Ranking Scale (mRS) score <3 (risk ratio (RR): 0.65; 95% CI 0.59 to 0.72; p<0.0001; I 2=13%), and had an increased risk of symptomatic intracranial hemorrhage (sICH) (RR: 2.07; 95% CI 1.65 to 2.60; p<0.0001; I 2=0%) and mortality (RR: 1.73; 95% CI 1.57 to 1.91; p<0.0001; I 2=0%). Patients who present with hyperglycemia and undergo MT for treatment of LVO have an increased risk of unfavorable clinical outcome, sICH, and mortality. Glucose levels at admission appear to be a prognostic factor in this subset of patients. Further studies should focus on evaluating control of the glucose level at admission as a modifiable risk factor in patients undergoing MT for LVO.

Introduction: Left ventricular assist device (LVAD) is known to extend survival in patients with advanced heart failure but it is associated with intracranial cranial hemorrhage (ICH). In the last decade, the use of LVAD substantially increased along with advances in LVAD technology, but there is limited data regarding the trends of ICH risk and predictors in patients with LVAD. Methods: We included the patients aged≥18 years with primary diagnosis of LVAD hospitalized in the US from 2005 to 2014 using the National Inpatient Sample. We computed the survey weighted percentages with ICH across the 10-year study period and assessed whether the proportions changed over time. Predictors of ICH were evaluated using the multivariable logistic regression model. All analyses were appropriately adjusted for the survey design variables to account for the complex survey design. Results: Of 33,246 hospitalizations, 568 (1.7%) had ICH. The number of LVAD placement has increased from 873 in year 2005 to 5,175 in year 2014. However, the risk of ICH remained largely unchanged from 1.7% to 2.3% (linear trend: p=0.604). The adjusted odds of ICH was increased with the presence one of the following variables: female sex (odds ratio [OR]: 1.58, 95% confidence interval [CI] 1.03-2.43), history of ischemic stroke (OR: 3.13, 95% CI 1.86-5.28), and Charlson Comorbidity Index (CCI) of ≥3 (OR: 77.40, 95% CI 10.03-597.60). Conclusions: Despite advances in LVAD technology and its increased use in patients with advanced heart failure, the risk of ICH has remained relatively unchanged. High CCI and history of ischemic stroke were associated with higher odds of ICH in patients with LVAD. With the advent of magnetically levitated centrifugal-flow LVAD, future trend of ICH may change and further research efforts are needed to prevent ICH in patients with LVAD.

Introduction: Robust leptomeningeal collaterals protect the brain from ischemia, yet the determinants of poor collaterals have not been established. We aimed to identify predictors of poor collaterals in patients with large vessel occlusive stroke. Methods: Consecutive patients with large vessel occlusive stroke who underwent thrombectomy at 2 academic medical centers (derivation cohort/validation cohort) from 2012-2017 were included. Poor collaterals were defined as ≤50% filling on CT angiogram. Pre-specified predictors of poor collaterals were analyzed with adjusted logistic regression models: demographics (age, sex, race), risk factors (hypertension, diabetes, atrial fibrillation, smoking), hemodynamics (blood pressure, cardiac output, troponin), metabolic (hyperglycemia, hyponatremia, uremia), hematologic (anemia, leukocytosis, thrombocytosis) and neuroimaging evidence of chronic cerebral small-vessel disease and chronic steno-occlusive arterial disease. Results: Of the 248 total patients, poor collaterals were detected in 107 (43%). Mean age was 71±14y vs. 63±16y in patients with poor vs good collaterals, respectively (p<.001). There were 136 patients in the derivation cohort; 54 (48%) patients with poor collaterals. Multivariable modeling identified that older age (OR 1.8, p<.001), hyperglycemia (OR 2.4, p=.029) and white matter hyperintensities (WMH) (OR 6.1, p=.003) were independent predictors of poor collaterals in the derivation cohort. The validation cohort consisted of 136 patients; 53 (39%) had poor collaterals, of which older age (OR 1.4, p=.015), thrombocytosis (OR 24.0, p=.012), and WMH (OR 6.7, p=.018) were significant predictors of poor collaterals. Age and WMH were the only significant predictors of poor collaterals across the derivation and validation cohorts. When pooled the cohorts, older age (OR=1.5, p<.001), thrombocytosis (OR=7.6, p=.001) and WMH (OR=6.4, p<.001) were significant predictors of poor collaterals. Conclusions: We have identified that advanced age, WMH, and thrombocytosis are predictors of poor collaterals. Future studies to explore the effect of vascular aging on collateral therapeutics are indicated.

Introduction: Cilostazol has promise as an alternative to aspirin for secondary stroke prevention given its vasodilatory and anti-inflammatory properties in addition to platelet aggregation inhibition. We conducted a systematic review and meta-analysis to estimate the comparative effectiveness and safety of cilostazol compared to aspirin for stroke prevention in patients with previous stroke or TIA. Hypothesis: Cilostazol is more effective than aspirin in preventing recurrent ischemic stroke with lower risk of intracranial hemorrhage and bleeding. Methods: We searched PubMed and the Cochrane Central Register of Controlled Trials from inception to 2019. Randomized clinical trials that compared cilostazol vs aspirin and reported the endpoints of ischemic stroke, intracranial hemorrhage and bleeding were included. A random-effects estimate was computed based on Mantel-Haenszel methods. The pooled estimates with 95% confidence intervals were compared between cilostazol and aspirin and displayed as forest plots (Figure). Results: The search identified 5 randomized clinical trials comparing cilostazol vs aspirin for secondary stroke prevention that enrolled 7,240 patients from primarily Asian countries (3,615 received cilostazol and 3,625 received aspirin). The pooled results from the random-effects model showed that cilostazol was associated with significantly lower risk of recurrent ischemic stroke (Hazard ratio [HR] 0.70; 95%CI, 0.54-0.89), intracranial hemorrhage (HR 0.41; 95%CI, 0.25-0.65) and bleeding (HR 0.71; 95%CI, 0.55-0.91). See forest plots. Conclusion: This meta-analysis suggests cilostazol is more effective than aspirin in the prevention of recurrent ischemic stroke with lower risk of intracranial hemorrhage and bleeding. Confirmatory randomized trials of cilostazol for secondary stroke prevention to be performed in more generalizable populations are needed.

Introduction: Left atrial enlargement (LAE) is associated with atrial fibrillation, a frequent cause of large vessel occlusion (LVO) leading to ischemic stroke. Leptomeningeal collaterals protect tissue from ischemia, but the association between collaterals and structural heart disease is not well described. We aim to investigate the association between LAE and cerebral collaterals during acute LVO when microvasculature, vasodilation, and chronotropic competence are critically important. Hypothesis: Left atrial enlargement is associated with poor collaterals. Methods: We reviewed consecutive patients presenting with middle cerebral and internal carotid LVO who underwent thrombectomy from 2012 to 2017. Patients with CT angiogram of the head and echocardiogram were included. Poor collaterals were defined as ≤ 50% filling on CT angiogram. LAE was defined as left atrial volume index ≥ 35 mL/m 2 . Multivariate logistic regression analysis was performed to evaluate the relationship between LAE and poor collaterals with adjustment for age and hypertension. Results: There were 128 eligible patients. The mean age was 68± 15 years, median NIHSS was 17, and 51 (39.8%) had LAE. Baseline characteristics are described in the table. Poor collaterals were observed in 50 (39%) patients. Patients with LAE were more likely to have poor collaterals compared to those with normal left atrial size (52.9% vs. 29.9%, p=0.009). After adjusting for age and hypertension, a trend towards association remained (OR 2.00, p=0.089). Conclusion: Our results indicate that patients with LVO and LAE were more likely to have poor collaterals. Further research is warranted to determine the cause of the association. One possibility is shared pathophysiology affecting both cardiac and cerebral vasculature such as microvascular disease or endothelial dysfunction. Alternatively, structural heart disease causing chronotropic incompetence may lead to poor collateral filling.

Background: Perfusion weighted imaging on MRI (MRP) and computerized tomography perfusion (CTP) are increasingly required to manage large vessel disease. Computerized algorithms can quantify perfusion data, but the programs are expensive and not widely used outside acute stroke evaluation. We aimed to determine how well human observers can identify asymmetries in cerebral perfusion images compared with an automated computer algorithm. Methods: Ten clinicians experienced in treating carotid artery disease (4 vascular neurologists, 3 neuroradiologists, 1 vascular surgeon, 1 neurosurgeon, 1 interventional radiologist) were given 28 post-processed, color-coded, axial-slice MRP scans from patients in the Carotid Revascularization Endovascular versus Stenting Trial - Hemodynamics (CREST-H) study. All patients had >70%, unilateral, asymptomatic carotid artery stenosis and had varying degrees of time-to-peak (TTP) delay on the side of stenosis, ranging from 0 to 2 secs, quantified by a semi-automated system that computes quantitative perfusion maps, using deconvolution of tissue and arterial signals (Olea, Cambridge, MA). A minimum volume of 10cc was required for a given TTP delay. Clinicians were asked to determine asymmetry (y/n) and side of occlusion for each case. Number of correct responses that matched the computer output were tallied. Results: We averaged correct responses by the 10 clinicians for cases at each increment of TTP delay; (Figure). At TTP delays ≥1.5 seconds, accuracy was ≥80%. At 1.25 sec accuracy fell to 60%, and at ≤ 1 sec, accuracy was ≤50%. For TTP=0 (no asymmetry), accuracy was 71%. Conclusions: Visual impression of hemodynamic asymmetry among experienced clinicians was reasonably accurate for TTP delays ≥1.5 seconds, but declined with more subtle asymmetries. Depending on the clinical impact of TTP delays (for CREST-H: correlation with cognitive decline), experienced clinicians may perform as well as an automated algorithm.