Thrombolysis in Large Diffusion-Weighted Imaging Lesions: Lower Chance but Still a Chance

Association of Bun/Cr ratio-based dehydration status with infarct volumes and stroke severity in acute ischemic stroke

BACKGROUND

Only a few clinical research had previously investigated the dehydration status to predict the evolution of the ischemic core. The aim of this study is to clarify the association between blood urea nitrogen (BUN)/creatinine (Cr)ratio-based dehydration and infarct volume measured using DWI (Diffusion-weighted imaging) at admission in patients with AIS (Acute Ischemic Stroke).

METHODS

We retrospectively recruited a total of 203 consecutive patients who were hospitalized through emergency or outpatient services within 72 h of acute ischemic stroke onset between October 2015 and September 2019. Stroke severity was measured by assessing the National Institutes of Health Stroke Scale (NIHSS) on admission. Infarct volume was measured using DWI with MATLAB software.

RESULTS

In this study, 203 patients who met the study criteria were enrolled. Patients in the dehydration group (Bun/Cr ratio>15) had a higher median NIHSS score (6(IQR:4-10) VS. 5(3-7); P = 0.0015)and larger DWI infarct volume (1.55 ml (IQR:0.51-6.79) VS. (0.37 ml (0.05-1.22); P < 0.001) on admission compared with patients in normal group. Further, a statistically significant correlation was found between DWI infarct volumes and NIHSS score with nonparametric Spearman rank correlation (r = 0.77; P < 0.001). The median NIHSS scores for the DWI infarct volumes quartiles were 3 ml (IQR, 2-4), 5 ml (4-7), 6 ml (5-8), and12 ml (8-17) from lowest to highest. However, the second quartile group did not show any significant correlation with the third quartile group (P = 0.4268). Multivariable linear and logistic regression analyses were used to test dehydration (Bun/Cr ratio>15), representing a predictor of infarct volume and stroke severity.

CONCLUSION

Bun/Cr ratio-based dehydration is associated with larger volumes of ischemic tissue measured using DWI and worse neurological deficit assessed by the NIHSS score in acute ischemic stroke.

Outcomes of Mechanical Thrombectomy in Patients with Large Diffusion-Weighted Imaging Lesions

Objective

Despite many advancements in endovascular treatment, the benefits of mechanical thrombectomy (MT) in patients with large infarctions remain uncertain due to hemorrhagic complications. Therefore, we aimed to investigate the efficacy and safety of recanalization via MT within 6 hours after stroke in patients with large cerebral infarction volumes (>70 mL).

Methods

We retrospectively reviewed the medical data of 30 patients with large lesions on initial diffusion-weighted imaging (>70 mL) who underwent MT at our institution within 6 hours after stroke onset. Baseline data, recanalization rate, and 3-month clinical outcomes were analyzed. Successful recanalization was defined as a modified treatment in cerebral ischemia score of 2b or 3.

Results

The recanalization rate was 63.3%, and symptomatic intracerebral hemorrhage occurred in six patients (20%). The proportion of patients with modified Rankin Scale (mRS) scores of 0-3 was significantly higher in the recanalization group than in the non-recanalization group (47.4% vs. 9.1%, p=0.049). The mortality rate was higher in the non-recanalization group, this difference was not significant (15.8% vs. 36.4%, p=0.372). In the analysis of 3-month clinical outcomes, only successful recanalization was significantly associated with mRS scores of 0-3 (90% vs. 50%, p=0.049). The odds ratio of recanalization for favorable outcomes (mRS 0-3) was 9.00 (95% confidence interval, 0.95-84.90; p=0.055).

Conclusion

Despite the risk of symptomatic intracerebral hemorrhage, successful recanalization via MT 6 hours after stroke may improve clinical outcomes in patients with large vessel occlusion.

Multiphase MR Angiography Collateral Map: Functional Outcome after Acute Anterior Circulation Ischemic Stroke

Background Collateral circulation determines tissue fate and affects treatment result in acute ischemic stroke. A precise method for collateral estimation in an optimal imaging protocol is necessary to make an appropriate treatment decision for acute ischemic stroke. Purpose To verify the value of multiphase collateral imaging data sets (MR angiography collateral map) derived from dynamic contrast material-enhanced MR angiography for predicting functional outcomes after acute ischemic stroke. Materials and Methods This secondary analysis of an ongoing prospective observational study included data from participants with acute ischemic stroke due to occlusion or stenosis of the unilateral internal carotid artery and/or M1 segment of the middle cerebral artery who were evaluated within 8 hours of symptom onset. Data were obtained from March 2016 through August 2018. The collateral grading based on the MR angiography collateral map was estimated by using six-scale MR acute ischemic stroke collateral (MAC) scores. To identify independent predictors of favorable functional outcomes, age, sex, risk factors, baseline National Institutes of Health Stroke Scale (NIHSS) score, baseline diffusion-weighted imaging (DWI) lesion volume, site of steno-occlusion, collateral grade, mode of treatment, and early reperfusion were evaluated with multiple logistic regression analyses. Results One hundred fifty-four participants (mean age ± standard deviation, 69 years ± 13; 99 men) were evaluated. Younger age (odds ratio [OR], 0.45; 95% confidence interval [CI]: 0.29, 0.70; P < .001), lower baseline NIHSS score (OR, 0.85; 95% CI: 0.78, 0.94; P < .001), MAC score of 3 (OR, 27; 95% CI: 4.0, 179; P < .001), MAC score of 4 (OR, 17; 95% CI: 2.1, 134; P = .007), MAC score of 5 (OR, 27; 95% CI: 2.5, 306; P = .007), and successful early reperfusion (OR, 7.5; 95% CI: 2.6, 22; P < .001) were independently associated with favorable functional outcomes in multivariable analysis. There was a linear negative association between collateral perfusion grades and functional outcomes (P < .001). Conclusion An MR angiography collateral map was clinically reliable for collateral estimation in patients with acute ischemic stroke. This map provided patient-specific pacing information for ischemic progression. © RSNA, 2020.

Meta-analysis of the Smoker’s Paradox in Acute Ischemic Stroke Patients Receiving Intravenous Thrombolysis or Endovascular Treatment

Introduction

The existence of the smoker’s paradox is controversial and potential mechanisms have not been explained. We aimed to explore the association between cigarette smoking and functional outcome at 3 months in patients with acute ischemic stroke who were treated with intravenous thrombolysis (IVT) or endovascular treatment (EVT).

Methods

This meta-analysis was conducted in accordance with the PRISMA guidelines. Studies exploring the association between smoking and good functional outcome (modified Rankin Scale score ≤ 2) following IVT or EVT were searched via the databases of PubMed, Embase, and the Cochrane Library from inception to August 8, 2018. Information on the characteristics of included studies was independently extracted by two investigators. Data were pooled using a random-effects or fixed-effects meta-analysis according to the heterogeneity of included studies.

Results

Among 20 identified studies, 15 reported functional outcomes following IVT, and five reported functional outcomes following EVT. Unadjusted analyses showed that smoking increased the odds of good functional outcomes with a pooled odds ratio (OR) of 1.48 (95% confidence interval [CI]: 1.36–1.60) after IVT and 2.10 (95% CI: 1.47–3.20) after EVT. Of IVT studies, only eight reported outcomes adjusted for covariates and none of the EVT studies reported adjusted outcomes. After adjustment, the relation between smoking and good functional outcome following IVT lost statistical significance (OR 1.14 [95% CI: 0.81–1.59]).

Conclusion

Our meta-analysis suggested that smoking was not associated with good functional outcome (mRS ≤ 2) at 3 months in patients with acute ischemic stroke who were treated with intravenous thrombolysis.

Implications

The existence of the smoker’s paradox is controversial. A previous letter by Plas et al. published in 2013 reported a positive result for the association between smoking and good functional outcome at 3 months in acute ischemic stroke patients who received intravenous thrombolysis (IVT). However, a major limitation of their meta-analysis was that the process of data synthesis was based on unadjusted data. Therefore, we conducted this meta-analysis to investigate the association based on adjusted data and a larger sample size. Our meta-analysis suggested that smoking was not associated with good functional outcome after adjusting for covariates.