Role and Prognostic Implications of Venous Outflow Assessment in Acute Ischemic Stroke.

Introduction: The venous outflow profile (VOP) is a crucial yet often overlooked aspect affecting stroke outcomes. It plays a major role in the physiopathology of acute cerebral ischemia, as it accounts for both the upstream arterial collaterals and cerebral microperfusion. This enables it to circumvent the limitations of various arterial collateral evaluation systems, which often fail to consider impaired autoregulation and its impact on cerebral blood flow at the microcirculatory levels.

AM-PAC 6-Clicks Basic Mobility and Daily Activities Scores Predict 90-Day Modified Rankin Score in Patients with Acute Ischemic Stroke Secondary to Large Vessel Occlusion.

The relative level of functional impairment in stroke patients is a significant determinant of post-acute care. The Activity Measure for Post Acute Care 6-Clicks (AM-PAC) scores for basic mobility and daily activity are rapid standardized assessments whose utilities in predicting long-term stroke outcomes have not yet been studied. We performed a retrospective analysis of acute ischemic stroke patients and their outcomes.

Prolonged venous transit is associated with lower odds of excellent recovery after reperfusion in anterior large-vessel occlusion stroke.

Background And Purpose: Acute ischemic stroke due to anterior circulation large-vessel occlusion (AIS-LVO) remains a leading cause of disability despite successful reperfusion therapies. Prolonged venous transit (PVT) has emerged as a potential prognostic imaging biomarker in AIS-LVO. We aimed to investigate whether PVT is associated with a decreased likelihood of excellent functional outcome (modified Rankin Scale [mRS] score of 0-1 at 90 days) after successful reperfusion.

Prolonged Venous Transit on Perfusion Imaging is Associated with Longer Lengths of Stay in Acute Large Vessel Occlusions.

Background And Purpose: Prolonged venous transit (PVT+) is a marker of venous outflow; it is defined as the presence or absence of time-to-maximum ≥10 seconds timing in either the superior sagittal sinus or torcula. This novel perfusion imaging-based metric has been associated with higher odds of mortality and lower odds of functional recovery. This study aims to assess the relationship between PVT on admission perfusion imaging and length of hospital stay in large vessel occlusion strokes successfully reperfused with mechanical thrombectomy.

The Los Angeles Motor Scale is independently associated with cerebral blood flow < 30% volume in large vessel occlusions.

Background And Purpose: Mechanical thrombectomy (MT) is the treatment standard for large vessel occlusion (LVO) stroke. Under current guidelines, only patients with smaller ischemic core volumes (ICV) are eligible for MT. Thus, it is of interest to quickly estimate ICV in stroke patients.

Perfusion-Based Relative Cerebral Blood Volume Is Associated With Functional Dependence in Large-Vessel Occlusion Ischemic Stroke.

Background: Pretreatment computed tomography perfusion parameter relative cerebral blood volume (rCBV) lesion volume has been shown to predict 90-day modified Rankin Scale score in small-core strokes with Alberta Stroke Program Early Computed Tomography Score ≥5, including those with medium-vessel occlusions (mid and distal M2 segment occlusions). Hence, in this study we aim to assess the performance of different rCBV lesion volume thresholds (rCBV <42%, rCBV <38%, and rCBV <34%) with 90-day modified Rankin Scale score including patients with large core (Alberta Stroke Program Early Computed Tomography Score <5) and strictly including only patients with anterior circulation large-vessel occlusion.

Methods And Results: In this retrospective evaluation of our prospectively collected database, inclusion criteria were (1) Computed tomographic angiography confirmed anterior circulation large-vessel occlusion from September 1, 2017, to October 1, 2023; and (2) diagnostic computed tomography perfusion.

Mismatch Vs No Mismatch in Large Core-A Matter of Definition.

Background: Endovascular thrombectomy (EVT) has shown promise in randomized controlled trials (RCTs) for large ischemic core stroke patients, yet variability in core definition and onset-to-imaging time creates heterogeneity in outcomes. This study aims to clarify the prevalence and implications of core-perfusion mismatch (MM) versus no mismatch (No MM) in such patients, utilizing established imaging criteria.

Methods: A retrospective cohort study was conducted including patients from 7/29/2019 to 1/29/2023, with data extracted from a continuously maintained database.

Association of Pretreatment Perfusion Imaging Parameters With 90-Day Excellent Functional Outcomes in Anterior Circulation Distal Medium Vessel Occlusion Stroke.

Background And Purpose: Acute ischemic strokes caused by distal medium vessel occlusions (DMVO) represent a significant proportion of all stroke cases, yet the predictors of excellent functional outcomes in these patients remain poorly understood. This study aims to identify pretreatment computed tomography perfusion (CTP) parameters associated with excellent functional outcomes, defined as a modified Rankin Scale (mRS) score of 0-1 at 90 days, in patients with anterior circulation DMVO.

Materials And Methods: We conducted a retrospective multicenter study involving patients with anterior DMVO, from three stroke centers within the Johns Hopkins Medical Enterprise.

CT perfusion derived relative cerebral blood volume < 42 % is negatively associated with poor functional outcomes at discharge in anterior circulation large vessel occlusion stroke.

Background And Aim: Recent studies have shown that the CT Perfusion (CTP) parameter of rCBV < 42 % lesion volume can predict 90-day functional outcomes in stroke patients. However, its correlation with discharge outcomes, including functional dependence, has not been investigated. Our study aims to evaluate the relationship between rCBV < 42 % and poor functional outcomes at discharge, defined as a modified Rankin score (mRS) of 3 or higher.

Prolonged venous transit is associated with worse neurological recovery in successfully reperfused large vessel strokes.

Objective: Venous outflow (VO) impairment predicts unfavorable outcomes in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO). Prolonged venous transit (PVT), a visual qualitative VO marker on CT perfusion (CTP) time to maximum (Tmax) maps, has been associated with unfavorable 90-day functional outcomes despite successful reperfusion. This study investigates the association between PVT and percent change on the National Institutes of Health Stroke Scale (NIHSS) among AIS-LVO patients who have undergone successful reperfusion.

Role of Hypoperfusion Intensity Ratio in Vessel Occlusions: A Review on Safety and Clinical Outcomes.

The hypoperfusion intensity ratio (HIR) is a quantitative metric used in vascular occlusion imaging to evaluate the extent of brain tissue at risk due to hypoperfusion. Defined as the ratio of tissue volume with a time-to-maximum (Tmax) of >10 seconds to that of >6 seconds, HIR assists in differentiating between the salvageable penumbra and the irreversibly injured core infarct. This review explores the role of HIR in assessing clinical outcomes and guiding treatment strategies, including mechanical thrombectomy and thrombolytic therapy, for patients with large vessel occlusions (LVOs).

The Los Angeles motor scale (LAMS) and ASPECTS score are independently associated with DSA ASITN collateral score.

Background: Mechanical thrombectomy (MT) is the treatment standard in eligible patients with acute ischemic stroke (AIS) secondary to large vessel occlusions (LVO). Studies have shown that good collateral status is a strong predictor of MT efficacy, thus making collateral status important to quickly assess. The Los Angeles Motor Scale is a clinically validated tool for identifying LVO in the field.

The single-phase computed tomographic angiography clot burden score is independently associated with digital subtraction angiography derived American Society of Interventional and Therapeutic Neuroradiology collateral score.

Objectives: The variation in quality and quantity of collateral status (CS) is in part responsible for a wide variability in extent of neural damage following acute ischemic stroke from large vessel occlusion (AIS-LVO). Single-phase CTA based clot burden score (CBS) is a promising marker in estimating CS. The aim of this study is to assess the relationship of pretreatment CTA based CBS with the reference standard Digital subtraction angiography (DSA) based American Society of Interventional and Therapeutic Neuroradiology (ASITN) CS.

Simplifying venous outflow: Prolonged venous transit as a novel qualitative marker correlating with acute stroke outcomes.

Background: Prolonged venous transit (PVT), defined as presence of time-to-maximum 10 s within the superior sagittal sinus (SSS) and/or torcula, is a novel, qualitatively assessed computed tomography perfusion surrogate parameter of venous outflow with potential utility in pretreatment acute ischemic stroke imaging for neuroprognostication. We aim to characterize the correlation between PVT and neurological functional outcomes in thrombectomy-treated patients.

Methods: A prospectively-collected database of large vessel occlusion acute ischemic stroke patients treated with thrombectomy was retrospectively analyzed.

The Los Angeles motor scale (LAMS) is independently associated with CT perfusion collateral status markers.

Background And Aim: The Los Angeles Motor Scale (LAMS) is an objective tool that has been used to rapidly assess and predict the presence of large vessel occlusion (LVO) in the pre-hospital setting successfully in several studies. However, studies assessing the relationship between LAMS score and CT perfusion collateral status (CS) markers such as cerebral blood volume (CBV) index, and hypoperfusion intensity ratio (HIR) are sparse. Our study therefore aims to assess the association of admission LAMS score with established CTP CS markers CBV Index and HIR in AIS-LVO cases.

CT Perfusion Derived rCBV < 42% Lesion Volume Is Independently Associated with Followup FLAIR Infarct Volume in Anterior Circulation Large Vessel Occlusion.

Pretreatment CT Perfusion (CTP) parameter rCBV < 42% lesion volume has recently been shown to predict 90-day mRS. In this study, we aim to assess the relationship between rCBV < 42% and a radiographic follow-up infarct volume delineated on FLAIR images. In this retrospective evaluation of our prospectively collected database, we included acute stroke patients triaged by multimodal CT imaging, including CT angiography and perfusion imaging, with confirmed anterior circulation large vessel occlusion between 9 January 2017 and 10 January 2023.

The Relative Cerebral Blood Volume (rCBV) < 42% Is Independently Associated with Collateral Status in Anterior Circulation Large Vessel Occlusion.

The pretreatment CT perfusion (CTP) marker the relative cerebral blood volume (rCBV) < 42% lesion volume has recently been shown to predict 90-day functional outcomes; however, studies assessing correlations of the rCBV < 42% lesion volume with other outcomes remain sparse. Here, we aim to assess the relationship between the rCBV < 42% lesion volume and the reference standard digital subtraction angiography (DSA)-derived American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN) collateral score, hereby referred as the DSA CS. In this retrospective evaluation of our prospectively collected database, we included acute stroke patients triaged by multimodal CT imaging, including CT angiography and perfusion imaging, with confirmed anterior circulation large vessel occlusion between 1 September 2017 and 1 October 2023.

CT perfusion based rCBF <38% volume is independently and negatively associated with digital subtraction angiography collateral score in anterior circulation large vessel occlusions.

Background: Collateral status (CS) is an important biomarker of functional outcomes in patients with acute ischemic stroke secondary to large vessel occlusion (AIS-LVO). Pretreatment CT perfusion (CTP) parameters serve as reliable surrogates of collateral status (CS). In this study, we aim to assess the relationship between the relative cerebral blood flow less than 38% (rCBF <38%), with the reference standard American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score (CS) on DSA.

Follow-up infarct volume on fluid attenuated inversion recovery (FLAIR) imaging in distal medium vessel occlusions: the role of cerebral blood volume index.

Background: Distal medium vessel occlusions (DMVOs) contribute substantially to the incidence of acute ischemic strokes (AIS) and pose distinct challenges in clinical management and prognosis. Neuroimaging techniques, such as Fluid Attenuation Inversion Recovery (FLAIR) imaging and cerebral blood volume (CBV) index derived from perfusion imaging, have significantly improved our ability to assess the impact of strokes and predict their outcomes. The primary objective of this study was to investigate relationship between follow-up infarct volume (FIV) as assessed by FLAIR imaging in patients with DMVOs.

Prolonged venous transit on perfusion imaging is associated with higher odds of mortality in successfully reperfused patients with large vessel occlusion stroke.

Background: Poor venous outflow (VO) profiles are associated with unfavorable outcomes in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO), despite achieving successful reperfusion. The objective of this study is to assess the association between mortality and prolonged venous transit (PVT), a novel visual qualitative VO marker on CT perfusion (CTP) time to maximum (Tmax) maps.

Methods: We performed a retrospective analysis of prospectively collected data from consecutive adult patients with AIS-LVO with successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b/2c/3).

Implementation of low-intensity thrombolysis monitoring care in routine practice: process evaluation of the Optimal Post rtPA-IV Monitoring in Acute Ischemic Stroke (OPTIMISTmain) study in the United States.

Introduction: The ongoing OPTIMISTmain study, an international, multicenter, stepped-wedge cluster randomized trial, aims to determine effectiveness and safety of low-intensity versus standard monitoring in thrombolysis-treated patients with mild-to-moderate acute ischemic stroke (AIS). An embedded process evaluation explored integration and impact of the intervention on care processes at participating US sites.

Methods: A mixed-methods approach with quantitative and qualitative data were collected between September 2021 and November 2022.