DWI lesions reversal in posterior circulation stroke after reperfusion: Two illustrative cases and review of the literature

Rapid Successful Reperfusion of Basilar Artery Occlusion Strokes With Pretreatment Diffusion-Weighted Imaging Posterior-Circulation ASPECTS <8 Is Associated With Good Outcome

Background

The association between time to reperfusion and clinical outcome is well known in anterior circulation strokes, whereas the impact of main time metrics remains unknown in posterior circulation strokes. We investigated the clinical effect of different time intervals from symptom onset to reperfusion on the 90‐day clinical outcome in acute ischemic stroke patients with basilar artery occlusion, and especially in the subset population presenting a low stroke volume on baseline diffusion‐weighted imaging.

Methods and Results

We studied patients included in the prospective, multicenter, observational ETIS (Endovascular Treatment in Ischemic Stroke) registry who had had basal artery occlusion and had achieved successful reperfusion (modified Thrombolysis In Cerebral Infarction 2b‐3). Three time intervals (onset to reperfusion, onset to imaging, and imaging to reperfusion) were considered in all patients and separately in patients with pc‐ASPECTS (posterior‐circulation Alberta Stroke Program Early Computed Tomography Score) <8 and ≥8 on baseline diffusion‐weighted imaging. The primary end point was good outcome defined as 90‐day modified Rankin Scale scores of 0 to 2. Among the 95 included patients, 38 (40%) achieved a good outcome. In all patients, no significant association was found between the different time intervals and outcome. In patients evaluated with diffusion‐weighted imaging (n=61) at baseline, a significant negative association was found between imaging‐to‐reperfusion time for patients with pc‐ASPECTS <8 (adjusted odds ratio=0.4 per 30‐minute increase; 95% CI 0.18‐0.85; P=0.02) compared with those with pc‐ASPECTS ≥8.

Conclusions

In patients with basilar artery occlusion and pc‐ASPECTS <8 at baseline diffusion‐weighted imaging, clinical outcome is highly dependent on the time from imaging to reperfusion, which suggests that rapid endovascular reperfusion should be performed after imaging in these patients.

Association of pretreatment pontine infarction with extremely poor outcome after endovascular thrombectomy in acute basilar artery occlusion

BACKGROUND

The association between pretreatment brain stem infarction and thrombectomy outcomes remains to be elucidated in patients with acute basilar artery occlusion (BAO). We aimed to assess the association between pretreatment pontine infarction and extremely poor outcome in patients who underwent endovascular thrombectomy due to acute BAO.

METHODS

We retrospectively reviewed data from a stroke database to identify patients with acute BAO who underwent thrombectomy between January 2011 and August 2019. Patient characteristics, pretreatment diffusion-weighted imaging (DWI) data, and outcomes were evaluated. The largest infarct core was expressed as the percentage of infarct core area in each brain stem region on the DWI slice displaying the largest lesion. Extremely poor outcome was defined as a 90-day modified Rankin Scale score of 5 or 6.

RESULTS

A total of 113 patients were included, 37 of whom had extremely poor outcome. Among the 15 patients with extensive pontine infarction (largest pontine infarct core of ≥70%), 93.3% had extremely poor outcome. Multivariate logistic regression analysis revealed that the following variables were independent predictors of extremely poor outcome: extensive pontine infarction (adjusted OR 22.494; 95% CI 2.335 to 216.689; p=0.007), posterior circulation ASPECTS on DWI (adjusted OR per 1-point decrease 1.744; 95% CI 1.197 to 2.541; p=0.004), age (adjusted OR per 1-year increase 1.067; 95% CI 1.009 to 1.128; p=0.023), and baseline NIHSS (adjusted OR per 1-point increase 1.105; 95% CI 1.004 to 1.216; p=0.040).

CONCLUSION

Our results showed that a large pontine infarct core of ≥70% on pretreatment DWI was strongly associated with extremely poor outcome among patients treated with endovascular thrombectomy for acute BAO.

Diffusion-weighted magnetic resonance imaging reflects activation of signal transducer and activator of transcription 3 during focal cerebral ischemia/reperfusion

Signal transducer and activator of transcription (STAT) is a unique protein family that binds to DNA, coupled with tyrosine phosphorylation signaling pathways, acting as a transcriptional regulator to mediate a variety of biological effects. Cerebral ischemia and reperfusion can activate STATs signaling pathway, but no studies have confirmed whether STAT activation can be verified by diffusion-weighted magnetic resonance imaging (DWI) in rats after cerebral ischemia/reperfusion. Here, we established a rat model of focal cerebral ischemia injury using the modified Longa method. DWI revealed hyperintensity in parts of the left hemisphere before reperfusion and a low apparent diffusion coefficient. STAT3 protein expression showed no significant change after reperfusion, but phosphorylated STAT3 expression began to increase after 30 minutes of reperfusion and peaked at 24 hours. Pearson correlation analysis showed that STAT3 activation was correlated positively with the relative apparent diffusion coefficient and negatively with the DWI abnormal signal area. These results indicate that DWI is a reliable representation of the infarct area and reflects STAT phosphorylation in rat brain following focal cerebral ischemia/reperfusion.

Mechanical thrombectomy for basilar artery thrombosis: a comparison of outcomes with anterior circulation occlusions

Background and purpose

The benefits of mechanical thrombectomy (MT) in basilar artery occlusions (BAO) have not been explored in recent clinical trials. We compared outcomes and procedural complications of MT in BAO with anterior circulation occlusions.

Methods

Data from the Madrid Stroke Network multicenter prospective registry were analyzed, including baseline characteristics, procedure times, procedural complications, symptomatic intracranial hemorrhage (SICH), modified Rankin Scale (mRS), and mortality at 3 months.

Results

Of 479 patients treated with MT, 52 (11%) had BAO. The onset to reperfusion time lapse was longer in patients with BAO (median (IQR) 385 min (320–540) vs 315 min (240–415), p<0.001), as was the duration of the procedures (100 min (40–130) vs 60 min (39–90), p=0.006). Moreover, the recanalization rate was lower (75% vs 84%, p=0.01). A trend toward more procedural complications was observed in patients with BAO (32% vs 21%, p=0.075). The frequency of SICH was 2% vs 5% (p=0.25). At 3 months, patients with BAO had a lower rate of independence (mRS 0–2) (40% vs 58%, p=0.016) and higher mortality (33% vs 12%, p<0.001). The rate of futile recanalization was 50% in BAO versus 35% in anterior circulation occlusions (p=0.05). Age and duration of the procedure were significant predictors of futile recanalization in BAO.

Conclusions

MT is more laborious and shows more procedural complications in BAO than in anterior circulation strokes. The likelihood of futile recanalization is higher in BAO and is associated with greater age and longer procedure duration. A refinement of endovascular procedures for BAO might help optimize the results.