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  • Ovid Technologies (Wolters Kluwer Health)  (34)
  • Matouk, Charles  (34)
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  • Ovid Technologies (Wolters Kluwer Health)  (34)
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  • 1
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 53, No. Suppl_1 ( 2022-02)
    Abstract: Introduction: High blood pressure variability (BPV) after endovascular thrombectomy is associated with post-stroke complications and poor neurological outcomes. However, whether BPV is an epiphenomenon of the stroke itself or causally related to the outcome remains unknown. Objective: In this study we aimed to evaluate if a relationship exists between pre-and post-stroke BPV in patients with large vessel occlusions (LVO). Methods: From our prospective stroke registry, we identified patients who had an anterior circulation LVO, underwent EVT, and had at least three blood pressure measurements recorded in the electronic medical record in the six months prior to their stroke admission. All patients had repeated time-stamped blood pressure data recorded for the first 72 hours after thrombectomy. Using the standard deviation of systolic BP, we calculated BPV for each patient and separated patients into tertiles based on their post-EVT BPV. The relationship between pre-stroke BPV and post-EVT BPV was analyzed using an ordinal logistic regression and Spearman’s rank correlation analysis. Results: Two hundred fifty-two patients were included in our analysis (mean age 70±16.2 years, mean admission NIHSS 15±7, median pre-stroke BP measurements 14.5 (IQR 5.0-55.8)). Pre-stroke BPV gradually increased for patients with higher post-EVT BPV tertiles (tertile 1 = 13.2(±5.2) mmHg, tertile 2 = 15.0(±5.5) mmHg, tertile 3 = 16.7(±7.0) mmHg, p=0.001). A positive correlation was observed between pre-stroke BPV and post-EVT BPV (p 〈 0.001, R=0.21). After adjusting for age and admission NIHSS, pre-stroke BPV was significantly associated with post-EVT BPV tertile membership (OR 1.37, 95% CI 1.02-1.86, p=0.039). Conclusion: High pre-stroke BPV is correlated with high post-EVT BPV. Although larger, prospective studies are needed to provide definitive evidence of this relationship, our work suggests that high post-EVT BPV may be related to an underlying biological phenomenon and not merely a consequence of the stroke itself. Individuals with high BPV may benefit from more intensive blood pressure management in the acute phase after EVT.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2022
    detail.hit.zdb_id: 1467823-8
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  • 2
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 53, No. Suppl_1 ( 2022-02)
    Abstract: Introduction: Secondary inflammation is a well-established cause of injury in intracerebral hemorrhage (ICH). One potential treatment for ICH limits inflammation through targeted metabolic modulation of immune cells, but leukocyte activation states in ICH are poorly defined. Using single-cell RNA sequencing (scRNA-seq) of patient hematoma evacuates, we characterized the inflammatory and metabolic profile of over a dozen identifiable leukocyte populations. This research provides insight into the dynamics of immune activation in ICH. Methods: Evacuated hematoma and peripheral blood samples from 8 ICH patients (62 ± 2.1 years) were collected via minimally invasive surgery (n=5) or craniotomy (n=3) (Fig. 1a). Collection time ranged from 0 to 4 days after ICH onset (1.5 ± 0.5 days). scRNA-seq was done on the 10X Genomics platform and analyzed using Seurat. Human monocyte-derived macrophage cultures were stimulated with S100A9 and IL-1β, two ICH-relevant inflammatory molecules, or LPS. Echinomycin and 2-deoxy-D-glucose were used to inhibit HIF signaling and glycolysis respectively. Results: Clustering revealed over a dozen transcriptionally distinct CNS-resident and immune cell types, many of which have little prior study in ICH (Fig. 1b). 3,395 differentially expressed genes between hematoma and peripheral blood (p 〈 0.05) were found in CD14 + monocytes and 932 in CD4 + effector T cells. Pathway analysis found upregulation of HIF signaling, glycolysis, and correlated networks of cytokine expression in the hematoma. The findings were significant across all immune populations but most prominent in myeloid cells (Fig. 1c). Inhibition of HIF and glycolysis in human macrophages in-vitro abrogated inflammatory and reparative cytokine production following inflammatory stimulation. In conclusion, this work highlights the interplay of inflammation and metabolism at a single cell level in ICH, contributing to knowledge of the immune response to brain injury.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2022
    detail.hit.zdb_id: 1467823-8
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  • 3
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 53, No. Suppl_1 ( 2022-02)
    Abstract: Introduction: The precise interactions between collateral perfusion, hemodynamics, and infarct growth after large vessel occlusion (LVO) require further definition. This study examined whether patients with poor collateral circulation and rapid early infarct progression are more vulnerable to reductions in blood pressure (BP). Methods: We prospectively enrolled patients with LVO stroke who underwent thrombectomy. Volumes of arterial tissue delay and relative cerebral blood flow (CBF) were estimated with RAPID software; a poor collateral profile was defined by a hypoperfusion intensity ratio 〉 0.4. Early infarct growth rate (EIGR) was defined as ischemic core volume (CBF 〈 30%) divided by the time from symptom onset to imaging. A fast progressor profile was assigned to patients whose EIGR was 〉 10 mL/h. The final infarct growth rate (FIGR) was the quotient of final infarct volume (FIV) and time from symptom onset to reperfusion. BP reduction was measured as the difference between admission mean arterial pressure (MAP) and lowest MAP before reperfusion. Results: Fifty-five patients (mean age 69 + 15, mean NIHSS 13) with successful reperfusion (TICI 2B/3) were included in the analysis. The median MAP reduction was 17 (IQR 9, 32). Poor collateral perfusion and EIGR were independent predictors of FIV after adjusting for age and admission NIHSS (mean FIV 70 vs. 31 mL, p=0.012 and 60 vs. 29 mL, p=0.01, respectively). A significant interaction was found between MAP reduction and both collateral status (p=0.04) and progressor profile (p=0.01). For every 10 mmHg MAP reduction, patients with poor collaterals experienced an average increase in FIGR of 3.6 mL/h (Fig. 1A). Above a critical MAP reduction threshold of 30 mmHg, mean FIV was significantly larger in patients with rapidly progressing infarcts (p 〈 0.01, Fig. 1B). Conclusions: Patients with poor collaterals and rapid early infarct growth are at higher risk of accelerated infarct growth and larger FIV related to BP reductions.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2022
    detail.hit.zdb_id: 1467823-8
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  • 4
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 51, No. Suppl_1 ( 2020-02)
    Abstract: Background: Loss of cerebral autoregulation in the acute phase of ischemic stroke leaves patients vulnerable to blood pressure (BP) changes. Effective BP management after endovascular therapy (EVT) may protect the brain from hypo- or hyperperfusion. In this observational study, we compared personalized, autoregulation-guided BP management with two commonly used clinical approaches: (1) maintaining BP below a fixed, pre-determined value and (2) stratifying BP thresholds based on reperfusion status. Methods: We prospectively enrolled 90 patients undergoing EVT for stroke. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy-derived tissue oxygenation (a cerebral blood flow surrogate) in response to changes in mean arterial pressure (MAP). The resulting autoregulatory index was used to trend the BP range at which autoregulation was most preserved. Percent time that MAP exceeded the upper limit of autoregulation (ULA) or decreased below the lower limit of autoregulation (LLA) was calculated for each patient. Time above fixed SBP thresholds was computed in a similar fashion. Functional outcome was measured with the modified Rankin Scale (mRS) at 90 days. Results: Personalized limits of autoregulation (LA) were successfully computed in all 90 patients (mean age 72 + 16, 47% female, mean NIHSS 14, mean monitoring time 28 + 18 hours). Percent time with MAP above the ULA associated with worse 90-day outcomes (OR per 10% 1.84, 95% CI 1.3-2.7, P=0.002), and patients suffering from hemorrhagic transformation spent more time above the ULA (10.9% vs. 16.0%, P=0.042). While there appeared to be a non-significant trend towards worse outcome with increasing time above SBP thresholds of 140 mmHg and 160 mmHg, the effect sizes were smaller compared to the personalized approach. Conclusions: Non-invasive determination of personalized BP thresholds for stroke patients is feasible. Deviation from these limits may increase risk of further brain injury and poor functional outcome. This approach may present a better strategy compared to the classical approach of maintaining SBP below a pre-determined value, though a randomized trial is needed to determine the optimal approach for hemodynamic management.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2020
    detail.hit.zdb_id: 1467823-8
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  • 5
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 54, No. Suppl_1 ( 2023-02)
    Abstract: Introduction: Conventional MRI (cMRI) is not routinely available post-mechanical thrombectomy (MT), which can preclude accurate infarction assessment. Our objective was to evaluate the use of low-field portable MRI (pMRI) for bedside evaluation post-MT, including its use as a post-procedural baseline monitor. Methods: Low-field pMRI was used to obtain bedside imaging in post-MT patients between December 2021 to August 2022 at Yale-New Haven Hospital. All pMRI exams were conducted in the standard ferromagnetic environment of the IR suite. Volumetric analyses were performed by a neuroradiologist using 3D Slicer software. If cMRI was not available for comparison, a CT was used. Patients’ charts were reviewed for pre-revascularization MAP and occurrences of MAP dropping by 10% and 20% from individual baselines between the time of pMRI and delayed imaging. Results: A total of 25 patients (64% females, median age 77 years-old [IQR 69.5-84.5]) underwent bedside pMRIs in the IR suite post-MT. The median time from last known normal to access was 6 hours [IQR 4-17] . The median pMRI examination time was 30 minutes [IQR 17-32]. Of the 24 patients with available delayed imaging, 7 (29.2%) had infarct progression compared to immediate post-MT pMRI, while 15 patients (62.5%) had stable/decreased stroke volume. Two patients (8.3%) had parenchymal hemorrhage type 2 and were excluded from further analysis. There was no statistically significant difference between the proportions of favorable TICI scores (85.7% in the infarct progression group vs. 92.3% in the stable/decreased infarct group, p=1.00). Patients with infarct progression had comparable pre-revascularization MAP compared to those with stable/decreased delayed infarct volume (mean of 100.3±4.6 vs. 101.9±15.9 respectively, p=0.727) but had more occurrences of MAP dropping by 10% and 20% of their baseline between the time of pMRI and delayed imaging (mean of 35.0±23.3 vs. 14.7±11.3 occurrences, p=0.011; and mean of 21.7±16.5 vs. 8.5±9.5 occurrences, p=0.026, respectively). Conclusions: The use of low-field MRI in the post-MT setting can facilitate benchmark brain monitoring and serial examinations to evaluate the impact of potential physiological perturbations that may impact ongoing brain injury.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2023
    detail.hit.zdb_id: 1467823-8
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  • 6
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 54, No. Suppl_1 ( 2023-02)
    Abstract: Background: Optimal level blood pressure (BP) targets in acute stroke remain elusive. Tailored hemodynamic management after endovascular thrombectomy (EVT) may reduce the risk of reperfusion injury and promote penumbral recovery. Our study aimed to evaluate the relationship between personalized autoregulation-based BP targets, secondary brain injury, and functional outcomes. Methods: We prospectively enrolled 200 patients with acute ischemic stroke who underwent EVT. Autoregulatory function was continuously measured for 〉 =24 hours using simultaneous recordings of near-infrared spectroscopy and mean arterial pressure (MAP). The resulting autoregulatory index was used to calculate and trend the BP range at which autoregulation was most preserved. Percent time and “dose” that MAP exceeded the upper limit or dropped below the lower limit of autoregulation (ULA, LLA) were calculated for each patient. Hemodynamic parameters were correlated with short-term clinical endpoints (symptomatic ICH), biomarkers of secondary brain injury (net water uptake, hemorrhagic transformation (HT), infarct progression), and 90-day functional outcomes. Results: Personalized BP targets were successfully computed in 195 patients (mean age 70 ± 16, 45% female, mean NIHSS 14, mean monitoring time 31 ± 28 hours). Time above the ULA was associated with worse functional outcomes at 90-days after adjusting for age, sex, NIHSS, ASPECTS and TICI (adjusted OR per 10% increase 1.4, 95% CI 1.1-1.6, P=0.004). The burden of hyperperfusion was significantly greater among patients with HT (median 2.7 vs. 3.2 mmHg*min, p=0.01) and sICH (median 2.8 vs. 4.8 mmHg*min, p=0.05) than in those without it. Furthermore, time spent above the ULA was significantly correlated with net water uptake at 72 hours (r=0.37, p=0.03). Among patients with unsuccessful reperfusion, there was a non-significant correlation between time below the LLA and infarct progression (r=0.35, p=0.064). Conclusions: In the largest study conducted to date, deviations from personalized BP targets were associated with an increased risk of secondary brain injury and worse functional outcomes. Autoregulation-oriented BP management represents a promising strategy for maximizing recovery after ischemic stroke.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2023
    detail.hit.zdb_id: 1467823-8
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  • 7
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 50, No. Suppl_1 ( 2019-02)
    Abstract: Background: After large-vessel occlusion (LVO), blood flow to the ischemic penumbra largely depends on collateral perfusion. Blood pressure (BP) reductions during endovascular therapy (EVT) have been associated with increased infarct size and unfavorable functional outcome. We hypothesized that patients with poor collateral circulation assessed using CT perfusion imaging are at increased risk for infarct progression associated with intraprocedural BP reductions. Methods: We prospectively enrolled 90 patients with LVO stroke who underwent perfusion imaging and EVT at two comprehensive stroke centers. Volumes of arterial tissue delay 〉 10 seconds (ATD10) were estimated with RAPID software; a malignant profile was defined as ADT10 〉 100 ml. BP reduction was defined as the difference between baseline mean arterial pressure (MAP) at the start of EVT and the lowest MAP during the procedure. Sustained relative hypotension was calculated as the area between baseline MAP and continuous measurements of intraprocedural MAP. Results: Sixty-seven patients (mean age 67 ± 15, 38 F, mean NIHSS 16) who were successfully revascularized (TICI 2B/3) were included in analysis. Mean baseline MAP was 119 ± 23 mmHg and median BP reduction was 28 (IQR 20 - 53). These values did not differ significantly among those with malignant (n=19) and non-malignant (n=48) collateral profiles, yet average infarct volume on follow-up was significantly greater among patients with poor collaterals (65 mL vs 32 ml) after adjusting for age and admission NIHSS (p=0.029). A significant interaction was found between the malignant collateral profile and intraprocedural BP reduction (p=0.02, Figure 1A & B). Conclusions: Patients with malignant collateral profiles are more sensitive to BP reductions during EVT, leading them to develop significantly larger infarcts. These results emphasize the importance of intraprocedural blood pressure management for this at-risk group.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2019
    detail.hit.zdb_id: 1467823-8
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  • 8
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 50, No. Suppl_1 ( 2019-02)
    Abstract: Background: Effective blood pressure (BP) management after endovascular stroke therapy (EVT) is critical for maintaining optimal cerebral perfusion and to protect the brain from hyperperfusion. A single, universal BP target below 180/105 mmHg is likely inadequate in this highly heterogeneous patient population. We calculated individualized BP thresholds at which cerebral autoregulation was best preserved and analyzed how exceeding these limits correlates with hemorrhagic transformation (HT) and functional outcome. Methods: 51 patients with large-vessel occlusion (LVO) stroke who underwent EVT were prospectively enrolled. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy and mean arterial pressure (MAP). The resulting autoregulatory index was used to identify and trend the BP range at which autoregulation was most preserved (Figure 1A). The percent time that MAP exceeded the upper limit of autoregulation (ULA) was calculated for each patient. HT was identified on CT imaging at 24 hours. Functional outcome was assessed using the modified Rankin Scale (mRS). Associations among percent time above ULA, HT and mRS were analyzed using ordinal or logistic regression, adjusting for age, TICI score and baseline NIHSS. Results: Personalized limits of autoregulation could be computed in 36 patients (mean age 71±15, 12 F, mean admission NIHSS 15±6, average monitoring time 26±19 hours, HT=17). Optimal BP and limits of autoregulation were calculated for 83±11% of the total monitoring period. Percentage of time with MAP above ULA was associated with HT (p=0.016, OR 1.15, 95% CI 1.02-1.29) and worse functional outcome at discharge (p 〈 0.004, OR 1.13, 95% CI 1.04-1.22) and 90 days (p=0.003, OR 1.22, 95% CI 1.06-1.38) (Figure 1B - D). Conclusions: Non-invasive determination of personalized BP thresholds for LVO stroke patients is feasible; exceeding these limits may increase the risk of HT and worse clinical outcomes.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2019
    detail.hit.zdb_id: 1467823-8
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  • 9
    In: Neurology, Ovid Technologies (Wolters Kluwer Health), Vol. 100, No. 22 ( 2023-05-30), p. 1067-1071
    Abstract: In the 20th century, the advent of neuroimaging dramatically altered the field of neurologic care. However, despite iterative advances since the invention of CT and MRI, little progress has been made to bring MR neuroimaging to the point of care. Recently, the emergence of a low-field ( 〈 1 T) portable MRI (pMRI) is setting the stage to revolutionize the landscape of accessible neuroimaging. Users can transport the pMRI into a variety of locations, using a standard 110–220 V wall outlet. In this article, we discuss current applications for pMRI, including in the acute and critical care settings, the barriers to broad implementation, and future opportunities.
    Type of Medium: Online Resource
    ISSN: 0028-3878 , 1526-632X
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2023
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  • 10
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 52, No. Suppl_1 ( 2021-03)
    Abstract: Introduction: Decreases in blood pressure (BP) during thrombectomy are associated with infarct progression and worse outcomes. Many patients present first to a primary stroke center (PSC) and are later transferred to a comprehensive stroke center (CSC) to undergo thrombectomy. During this period, important BP variations might occur. We evaluated the association of BP reductions with neurological worsening and functional outcomes. Methods: We prospectively collected hemodynamic, clinical, and radiographic data on consecutive patients with LVO ischemic stroke who were transferred from a PSC for possible thrombectomy between 2018 and 2020. We assessed systolic BP (SBP) and mean arterial pressure (MAP) at five time points: earliest recorded, average pre-PSC, PSC admission, average PSC, and CSC admission. We measured neurologic worsening as a change in NIHSS (ΔNIHSS) from PSC to CSC 〉 3 and functional outcome using the modified Rankin Scale (mRS) at discharge and 90 days. Relationships between variables of interest were evaluated using linear regression. Results: Of 91 patients (mean age 70±16 years, mean NIHSS 12) included, 13 (14%) experienced early neurologic deterioration (ΔNIHSS 〉 3), and 34 (37%) achieved a good outcome at discharge (mRS 〈 3). We found that patients with good outcome had significantly lower SBP at all five assessed time points compared to patients with poor outcome (Figure 1, p 〈 0.05). Percent change in MAP from initial presentation to CSC arrival was independently associated with ΔNIHSS after adjusting for age, sex, and transfer time (p=0.03, β=0.27). Conclusions: Patients with poor outcomes have higher BP throughout the pre-CSC period, possibly reflecting an augmented hypertensive response. Reductions in SBP and MAP before arrival at the CSC are associated with neurologic worsening. These results suggest that BP management strategies in the pre-CSC period to avoid large reductions in BP may improve outcomes in patients affected by LVO stroke.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2021
    detail.hit.zdb_id: 1467823-8
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