Venous Flow Profiles on Perfusion CT are Associated with Futile Recanalization After Thrombectomy

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.

MATERIALS AND METHODS

Patients with acute ischemic stroke with large vessel occlusions in the anterior circulation successfully treated with thrombectomy between January 2017 and September 2022 were retrospectively reviewed. The primary outcome was length of stay in the hospital due to the acute stroke event. Univariable and forward stepwise multivariable linear regressions were performed for the primary outcome.

RESULTS

Of 109 patients meeting inclusion, median age was 71 (interquartile range [IQR] 62-80) years. Median hospital length of stay was significantly greater in PVT+ patients (9 [IQR 6-18] days) compared with PVT- patients (6 [IQR 4-12] days, P = .03). In multivariable regression, PVT+ was significantly associated with length of stay, and PVT+ was associated with approximately 2 additional days of hospital stay compared with PVT- (P = .03).

CONCLUSIONS

In successfully reperfused large vessel occlusion strokes, PVT+ was associated with an additional 2 days of hospital stay on average compared with PVT- patients, when adjusting for other clinical covariables. This simple, novel imaging metric is robust in correlating with a range of short- and long-term clinical outcomes.

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). PVT+ was defined as Tmax ≥10 s timing on CTP Tmax maps in at least one of the following: superior sagittal sinus (proximal venous drainage) and/or torcula (deep venous drainage). PVT- was defined as lacking this in both regions. The primary outcome was mortality at 90 days. In a 1:1 propensity score-matched cohort, regressions were performed to determine the effect of PVT on 90-day mortality.

RESULTS

In 127 patients of median (IQR) age 71 (64-81) years, mortality occurred in a significantly greater proportion of PVT+ patients than PVT- patients (32.5% vs 12.6%, P=0.01). This significant difference persisted after matching (P=0.03). PVT+ was associated with a significantly increased likelihood of 90-day mortality (OR 1.22 (95% CI 1.02 to 1.46), P=0.03) in the matched cohort.

CONCLUSIONS

PVT+ was significantly associated with 90-day mortality despite successful reperfusion therapy in patients with AIS-LVO. PVT is a simple VO profile marker with potential as an adjunctive metric during acute evaluation of AIS-LVO patients. Future studies will expand our understanding of using PVT in the evaluation of patients with AIS-LVO.

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. Spearman's rank correlation coefficient and point-biserial correlations were performed between PVT status (i.e., no region, either SSS or torcula, or both), 90-day modified Rankin score (mRS), mortality (mRS 6), and poor functional outcome (mRS 4-6 vs 0-3).

RESULTS

Of 128 patients, correlation between PVT and 90-day mRS (ρ = 0.35, p < 0.0001), mortality (r = 0.26, p = 0.002), and poor functional outcome (r = 0.27, p = 0.002) were significant.

CONCLUSION

There is a modest, significant correlation between PVT and severity of neurological functional outcome. Consequently, PVT is an easily-ascertained, qualitative metric that may be useful as an adjunct for anticipating a patient's clinical course. Future analyses will determine the significance of incorporating PVT in clinical decision-making.

Impact of Microcirculatory Dysfunction on Persistent Global Cerebral Edema After Aneurysmal Subarachnoid Hemorrhage: An Age-Stratified Analysis

BACKGROUND

Microcirculatory dysfunction is one of the most important pathophysiology mechanisms of global cerebral edema (GCE) after aneurysmal subarachnoid hemorrhage (aSAH). Data regarding the impact of microcirculatory dysfunction on persistent GCE following aSAH are currently lacking. The aim of our study was to investigate whether microcirculatory dysfunction is correlated with persistent GCE in patients with aSAH across different age groups.

METHODS

The study was conducted in Beijing Tiantan Hospital from October 2020 to July 2023. Patients with aSAH who underwent computed tomographic perfusion (CTP) within 24 h after ictus were enrolled prospectively. The difference value of arteriovenous peak time (DV), which serves as an indicator of microcirculatory impairment, was derived from the time-density curve of CTP. Persistent GCE was defined as selective sulcal volume ≤ 11.3 mL at both admission and 7 ± 1 days after ictus. Age-stratified multivariable analyses were applied to identify the association between microcirculatory dysfunction and persistent GCE.

RESULTS

A total of 390 patients with aSAH were enrolled; the mean age was 56.5 ± 12.1 years old, and 245 (65.1%) patients were female. On multivariable analysis, prolonged DV was significantly associated with increased risk of persistent GCE after aSAH in patients older than 60 years (adjusted odds ratio 1.350, 95% confidence interval 1.025-1.778), whereas this similar independent association was not observed in patients younger than 60 years after adjusting for confounding factors (adjusted odds ratio 1.002, 95% confidence interval 0.817-1.229).

CONCLUSIONS

An age-dependent association between microcirculatory dysfunction and increased risk of persistent GCE following aSAH was found, which offers promising insight into future research to investigate tailored treatments across different ages.

Early Microcirculatory Dysfunction on Perfusion CT Is Related to Prognosis After Aneurysmal Subarachnoid Hemorrhage

Microcirculatory dysfunction is an important pathophysiology mechanism of early brain injury after aneurysmal subarachnoid hemorrhage (aSAH), which contributes to poor outcomes. The study was performed in Beijing Tiantan Hospital from October 2020 to July 2023. Patients with aSAH who underwent computed tomographic perfusion (CTP) within 24 h after ictus were enrolled prospectively. The peak time of arterial inflow (PTA), peak time of venous outflow (PTV), total venous outflow time (TVT), and difference value of arteriovenous peak time (DV) were collected from the time-density curve of CTP. Primary outcome was 3-month unfavorable functional outcome (modified Rankin Scale score of 4-6). Secondary outcomes included 3-month all-cause death and delayed cerebral ischemia. Multivariable logistic regression analysis and restricted cubic splines were performed to explore the relationship between cerebral hemodynamic parameters and outcomes. We also assessed the prognostic performance of incorporating hemodynamic parameters into previous nomogram models for 3-month poor clinical outcomes. A total of 612 patients were enrolled, among whom the mean age was 56.9 ± 12.3 years old and 391 (63.9%) were female. On multivariable analysis, prolonged TVT could significantly predict 3-month poor functional outcome (adjusted OR 1.074, 95%CI 1.013-1.139), while prolonged PTA was an independent predictor of 3-month all-cause death (adjusted OR 1.293, 95%CI 1.099-1.521). The addition of TVT or PTA to previous nomogram models led to improvements in C-statistics, net reclassification (NRI), and integrated discrimination improvement (IDI). Our study underscores the vital role of arterial inflow and venous outflow in sustaining microcirculation during the acute phase after aSAH, thereby offering new directions for future investigations into therapeutic targets.

CTP-Derived venous outflow profiles correlate with tissue-level collaterals regardless of arterial collateral status

BACKGROUND AND PURPOSE

Tissue-level collaterals (TLC), which quantify the state of arterial blood flow transiting through cerebral ischemic tissue, have been shown to be related to the clinical outcomes of acute ischemic stroke (AIS), regardless of the arterial collateral status on computed tomography angiography(CTA). Herein, we investigated whether venous outflow (VO) profiles on computed tomographic perfusion (CTP) were linked to TLC, regardless of the arterial collateral status.

METHODS

Consecutive anterior circulation AIS patients with large vessel occlusion(LVO) undergoing thrombectomy in a retrospective cohort were evaluated between January 2021 and August 2023 at two comprehensive stroke centers. All patients underwent pretreatment noncontrast computed tomography (NCCT), computed tomography perfusion (CTP) and follow-up NCCT or head magnetic resonance imaging (MRI) within 72 h of endovascular treatment (EVT). The VO profile parameters were recorded based on time-density curve derived from the CTP, including the peak time of VO (PTV) and total VO time (TVT). As the quantitative index of TLC, hypoperfusion intensity ratio (HIR) ≦0.4 was considered favorable for TLC. The primary outcome was tissue-level collaterals (TLC), defined by the HIR. Logistic regression analysis was used to assess the association between VO characteristics and TLC, whereas receiver operating characteristic (ROC) analysis was used to evaluate the value of VO parameters in predicting favorable TLC.

RESULTS

This study enrolled 221 eligible patients, among whom patients with favorable TLC were found to have a shorter PTV than patients with unfavorable TLC (12 s vs.16.5 s, P < 0.001) in univariable analysis. A shorter PTV was significantly associated with a favorable TLC (odds ratio [OR], 0.811; 95% confidence interval [CI], 0.709 to 0.927; P=0.002). Multivariable binary logistic stepwise regression analysis revealed that PTV was negatively correlated with TLC, regardless of the arterial collateral status was good (Good: OR, 0.777; 95%CI, 0.660-0.914; P=0.002; Poor: OR,0.729; 95%CI, 0.569-0.932; P=0.012). ROC analysis revealed that the PTV threshold for predicting favorable TLC was ≤13s, with an area under the curve (AUC), sensitivity, and specificity of 0.754, 0.728, and 0.699, respectively. The comprehensive predictor combined with PTV had an optimal predictive ability for TLC with an AUC of 0.894 (sensitivity=0.839, specificity=0.864).

CONCLUSION

Cerebral VO profiles in patients with anterior circulation AIS with LVO were related to TLC regardless of arterial collateral status, while PTV≤13s was a good predictor of favorable TLC.

Larger Perfusion Mismatch Volume Is Associated With Longer Hospital Length of Stay in Medium Vessel Occlusion Stroke

BACKGROUND AND PURPOSE

Prolonged length of stay (LOS) following a stroke is associated with unfavorable clinical outcomes. Factors predicting LOS in medium vessel occlusion (MeVO), impacting up to 40% of acute ischemic stroke (AIS) cases, remain underexplored. This study aims to investigate the predictors of LOS in AIS-MeVO.

METHODS

We conducted a retrospective analysis of prospectively maintained stroke databases, comprising AIS cases with MeVO in the anterior circulation, assessed by adequate CT perfusion (CTP). Baseline and clinical data were obtained from electronic health records. Alberta Stroke Program Early CT Scores (ASPECTS) were calculated from non-contrast head CT. The perfusion mismatch volume (time to maximum > 6 s minus relative cerebral blood flow <30%) volume was reported from CTP. Multiple regression was employed to examine the relationship between baseline parameters and hospital LOS.

RESULTS

A total of 133 patients (median age 71 [interquartile range 63-80] years, 59.4% females) were included in the study cohort. The perfusion mismatch volume significantly positively correlated with LOS (r = 0.264, p = 0.004). After adjusting for age, sex, hypertension, diabetes, prior stroke or transient ischemic attack, admission NIHSS, ASPECTS, Tan score, intravenous thrombolysis, mechanical thrombectomy (MT), and hemorrhagic transformation, a larger mismatch volume remained independently associated with longer hospital stays (β = 0.209, 95% confidence interval [CI] 0.006-0.412, p = 0.045). Additional significant determinants of longer hospital stay included admission NIHSS (β = 0.250, 95% CI: 0.060-0.440, p = 0.010) and MT (β = 0.208, 95% CI: 0.006-0.410, p = 0.044). Among patients who underwent MT (n = 83), multiple regression analysis incorporating both perfusion mismatch volume and admission NIHSS revealed that perfusion mismatch volume remained independently associated with LOS (β = 0.248, 95% CI: 0.019-0.471, p = 0.033), while admission NIHSS did not retain significance (β = 0.208, 95% CI: 0.019-0.433, p = 0.071).

CONCLUSIONS

In our cohort of AIS patients with MeVO in the anterior circulation, and particularly in those who underwent MT, the perfusion mismatch volume serves as an independent predictor of LOS. These findings offer critical valuable insights in clinical assessments and decision-making protocols of MT in AIS-MeVO.

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.

METHODS

We performed a retrospective analysis of prospectively collected data from consecutive adult AIS-LVO patients with successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b/2c/3). PVT+ was defined as Tmax ≥10 s in the superior sagittal sinus, torcula, or both. The primary outcome was continuous NIHSS percent change and dichotomous NIHSS percent change ≥70%. Regression analyses were performed to assess the effect of PVT on NIHSS percent change.

RESULTS

In 119 patients of median (IQR) age 71 (63-81) years, the admission and discharge NIHSS scores were significantly higher in PVT+ patients compared to PVT- patients (17 [14-23.5] vs. 13 [9.5-19], p = 0.011, and 7.5 [4-12] vs. 3 [1-7], p < 0.001, respectively). After adjusting for age, sex, hypertension, diabetes, atrial fibrillation, administration of intravenous thrombolysis (IVT), Alberta Stroke Program Early CT Scores (ASPECTS), mTICI 2c and/or 3, Tmax >6 s volume, and hemorrhagic transformation, PVT+ was significantly associated with lower NIHSS percent change (B = -0.163, 95%CI -0.326 to -0.001, p = 0.049) and was less likely to achieve higher than 70% NIHSS improvement (OR = 0.331, 95% CI 0.127-0.863, p = 0.024).

INTERPRETATION

PVT+ was significantly associated with reduced neurological improvement despite successful reperfusion in AIS-LVO patients, highlighting the critical role of VO impairment in short-term functional outcomes. These findings further validate PVT as a valuable adjunct imaging biomarker derived from CTP for assessing VO profiles in AIS-LVO.