Effects of time delays on the therapeutic outcomes of intravenous thrombolysis for acute ischemic stroke in the posterior circulation: An observational study

Intravenous thrombolysis for ischemic stroke in the posterior circulation: A systematic review and meta-analysis

OBJECTIVES

Intravenous thrombolysis (IVT) is recommended in patients with ischemic stroke in the anterior and posterior circulation. Neurological outcomes due to posterior circulation strokes (PCS) without treatment remain poor. Our aim was to overview the literature on outcomes of IVT and conservative treatment in PCS, based on a systematic review and meta-analysis.

METHODS

A systematic literature search was performed on February 27th 2023. Outcome measures included favorable functional outcome at 90 days (modified Rankin Scale [mRS] 0-2), mortality at 90 days, and symptomatic intracranial hemorrhages (sICH). Weighted averages with DerSimonian-Laird approach was used to analyze the data. Subgroup analyses by time window were performed: standard time window (<4.5 hours after symptom onset) and extended time window (>4.5 hours). Analyses were performed using R.

RESULTS

Eight prospective and four retrospective cohort studies were included (n = 1589 patients); no studies with conservative treatment were eligible. The pooled weighted probability regarding favorable functional outcome after IVT was 63 % (95 %CI:0.45-0.78), for mortality 19 % (95 %CI:0.11-0.30), and for sICH 4 % (95 %CI:0.02-0.07). Subgroup analyses showed higher probabilities on achieving favorable functional outcomes for patients treated in the standard (77 %; 95 %CI:0.62-0.88) compared to the extended time window (38 %; 95 %CI:0.29-0.48) with RR = 1.93 (95 %CI:1.66-2.24). Lower probabilities regarding mortality at 90 days and sICH were seen in patients treated in standard compared to extended time window (RR = 0.42, 95 %CI:0.34-0.51 and RR = 0.27, 95 %CI:0.16-0.45, respectively).

CONCLUSIONS

IVT in patients with PCS seems to be safe and effective in standard and extended time window. The effect of IVT is higher in the standard time window.

Posterior circulation ischemic stroke: radiomics-based machine learning approach to identify onset time from magnetic resonance imaging

PURPOSE

Posterior circulation ischemic stroke (PCIS) possesses unique features. However, previous studies have primarily or exclusively relied on anterior circulation stroke cases to build machine learning (ML) models for predicting onset time. To date, there is no research reporting the effectiveness and stability of ML in identifying PCIS onset time. We aimed to build diffusion-weighted imaging-based ML models to identify the onset time of PCIS patients.

METHODS

Consecutive PCIS patients within 24 h of definite symptom onset were included (112 in the training set and 49 in the independent test set). Images were processed as follows: volume of interest segmentation, image feature extraction, and feature selection. Five ML models, naïve Bayes, logistic regression, tree ensemble, k-nearest neighbor, and random forest, were built based on the training set to estimate the stroke onset time (binary classification: ≤ 4.5 h or > 4.5 h). Relative standard deviations (RSD), receiver operating characteristic (ROC) curves, and the calibration plot was performed to evaluate the stability and performance of the five models.

RESULTS

The random forest model had the best performance in the test set, with the highest area under the curve (AUC, 0.840; 95% CI: 0.706, 0.974). This model also achieved the highest accuracy, sensitivity, specificity, positive predictive value, and negative predictive value (83.7%, 64.3%, 91.4%, 75.0%, and 86.5%, respectively). Furthermore, the model had high stability (RSD = 0.0094).

CONCLUSION

The PCIS case-based ML model was effective for estimating the symptom onset time and achieved considerably high specificity and stability.

Repeated Intravenous Thrombolysis in Patients with Recurrent Ischemic Stroke in the Vertebrobasilar Territory

Acute ischemic vertebrobasilar stroke (AIVBS) is usually associated with poor outcome and prognosis and in case of basilar artery occlusion (BAO) with high mortality. Intravenous thrombolysis (IVT), as a standard recanalization therapy of acute ischemic stroke (IS) within first 4.5 h, can be administrated beyond this therapeutic time window in case of symptomatic BAO. Repeated IVT is generally contraindicated in case of early recurrent IS, despite a risk of poor outcome or death after recurrent IS. The aim was to present 2 cases of repeated IVT for recurrent AIVBS and discuss specific situations where repeated IVT may be considered. Up to now, repeated IVT has been reported only in recurrent stroke in anterior circulation.

Predictors for affected stroke territory and outcome of acute stroke treatments are different for posterior versus anterior circulation stroke

Distinct patient characteristics have been proposed for ischaemic stroke in the anterior versus posterior circulation. However, data on functional outcome according to stroke territory in patients with acute stroke treatment are conflicting and information on outcome predictors is scarce. In this retrospective study, we analysed functional outcome in 517 patients with stroke and thrombolysis and/or thrombectomy treated at the University Hospital Zurich. We compared clinical factors and performed multivariate logistic regression analyses investigating the effect of outcome predictors according to stroke territory. Of the 517 patients included, 80 (15.5%) suffered a posterior circulation stroke (PCS). PCS patients were less often female (32.5% vs. 45.5%, p = 0.031), received thrombectomy less often (28.7% vs. 48.3%, p = 0.001), and had lower median admission NIHSS scores (5 vs. 10, p < 0.001) as well as a better median three months functional outcome (mRS 1 vs. 2, p = 0.010). Predictors for functional outcome were admission NIHSS (OR 0.864, 95% CI 0.790–0.944, p = 0.001) in PCS and age (OR 0.952, 95% CI 0.935–0.970, p < 0.001), known symptom onset (OR 1.869, 95% CI 1.111–3.144, p = 0.018) and admission NIHSS (OR 0.840, 95% CI 0.806–0.876, p < 0.001) in ACS. Acutely treated PCS and ACS patients differed in their baseline and treatment characteristics. We identified specific functional outcome predictors of thrombolysis and/or thrombectomy success for each stroke territory.

Effects of time delays on the therapeutic outcomes of intravenous thrombolysis for acute ischemic stroke in the posterior circulation: An observational study

OBJECTIVES

We aim to demonstrate the effects of time delays on the therapeutic outcomes of intravenous thrombolysis (IVT) in acute posterior circulation stroke (PCS) patients.

METHODS

Consecutive PCS cases treated with IVT alone were retrospectively examined. The primary end point was set to be a favorable outcome (modified Rankin Scale [mRS] ≤2) at 3 months, and angiographic recanalization was set to be the secondary outcome.

RESULTS

A total of 95 PCS cases with IVT were recruited. The patients with favorable outcomes and those without favorable outcomes had similar baseline characteristics, except for significantly lower National Institute of Health Stroke Scale (NIHSS) scores (5 vs. 12, respectively; p < 0.001) and less hyperdense basilar artery signs in head CTs (26.5% vs. 70.4%, respectively; p < 0.001) for those with favorable outcomes. For patients with an onset-to-treatment time (OTT) of 0-90 min (n = 5), 91-180 min (n = 38), 181-270 min (n = 37), or ≧271 min (n = 15), the rate of favorable outcome was 100.0%, 71.1%, 67.6%, or 73.3%, respectively, and the Cochran-Armitage trend test showed no linear trend between the OTT and the clinical prognosis of IVT in PCS (p = 0.501) patients. In addition, the rates of recanalization were 100.0%, 68.4%, 64.9%, and 46.7%, and the Cochran-Armitage trend test suggested a linear trend between the OTT and recanalization (p = 0.046); that is, the proportion of PCS patients who underwent recanalization decreased with increasing OTTs. In the multivariate logistic regression analysis, after adjusting for confounding factors with p ≦ 0.20 in the univariate analysis, baseline NIHSS scores and hyperdense basilar artery signs were negatively associated with favorable outcomes, with odds ratios (OR) of 0.884 (95% confidence interval [CI], 0.804-0.971; p = 0.010) and 0.208 (95% CI, 0.062-0.693; p = 0.011), respectively. In addition, there was a negative association between recanalization, OTTs (OR, 0.993, 95% CI, 0.987-0.999; p = 0.029), and baseline NIHSS scores (OR, 0.881, 95% CI, 0.802-0.967; p = 0.008).

CONCLUSION

Irrespective of stroke severity, the therapeutic effects of recanalization after IVT decreased significantly with longer time delays in PCS patients.