OBJECTIVE: The mortality of acute type A aortic dissection (ATAAD) with malperfusion syndrome (MPS) is high. However, the management strategy remains controversial. We aimed to evaluate the strategy for MPS at our institution.
METHODS: Among 724 patients with ATAAD, 167 patients with MPS were treated with immediate central repair (1st stage) or an optimized strategy (2nd stage). In 2nd stage, the optimized strategy used was based on 6-hour threshold from symptom onset. For MPS with symptom onset within 6 hours, immediate central repair was performed followed by endovascular reperfusion if malperfusion persisted. With symptom onset beyond 6 hours, individualized delayed central repair was performed. We compared outcomes between the 1st and 2nd stage.
RESULTS: The in-hospital mortality of ATAAD was significantly decreased when the optimized strategy was used (4.3% in 2nd stage vs. 12.5% in 1st stage, P<0.01). In 2nd stage, the in-hospital mortality for MPS was decreased (10.2% vs. 33.9%, P<0.01). Moreover, the in-hospital mortality for MPS with symptom onset within or beyond 6 hours decreased from 24% to 7.5% and from 41.2% to 11.8%, respectively. The operative mortality of MPS in 2nd stage was comparable with patients without MPS (4.0% vs. 2.4%, P>0.05).
CONCLUSIONS: The optimized strategy significantly improved the outcomes of MPS. The 6-hour threshold from symptom onset could be very useful in determining the timing of central repair. For MPS with symptom onset within 6 hours, immediate central repair is reasonable. For those with symptom onset beyond 6 hours, individualized delayed central repair should be considered.

The cerebral collateral circulation is an increasingly important consideration in the management of acute ischemic stroke and is a key determinant of outcomes. Growing evidence has demonstrated that better collaterals can predict the rate of infarct progression, degree of recanalization, the likelihood of hemorrhagic transformation and various therapeutic opportunities. Collaterals can also identify those unlikely to respond to reperfusion therapies, helping to optimize resources. More randomized trials are needed to evaluate the risks and benefits of endovascular reperfusion with consideration of collateral status. This reviews our current understanding of the pathophysiologic mechanisms, effect on outcomes and strategies for improvement of the collateral system.

BACKGROUND: The hyperdense middle cerebral artery sign on computed tomography indicates proximal middle cerebral artery occlusion. Recent reports suggest an association between the hyperdense sign and successful reperfusion. The prognostic value of the hyperdense middle cerebral artery sign in patients receiving mechanical thrombectomy has not been extensively studied.
OBJECTIVE: Our study aims to evaluate the association between the hyperdense middle cerebral artery sign and functional outcome in patients with M1 occlusions that had undergone mechanical thrombectomy.
METHODS: We conducted a single-center retrospective observational cohort study of 102 consecutive patients presenting with acute M1 occlusions that had undergone mechanical thrombectomy. Patients were stratified into cohorts based on the presence of hyperdense middle cerebral artery sign visually assessed on computed tomography by two readers. The outcomes of interests were functional disability measured by the ordinal Modified Rankin Scale (mRS) at 90 days, mortality, reperfusion status and hemorrhagic conversion.
RESULTS: Out of the 102 patients with M1 occlusions, 71 had hyperdense middle cerebral artery sign. There was no significant difference between the cohorts in age, baseline mRS, NIHSS, ASPECTS, and time to reperfusion. The absence of hyperdense middle cerebral artery sign was associated with increased odds of being dependent or dying (higher mRS) (OR: 3.24, 95% CI: 1.30-8.06, p = 0.011) after adjusting for other significant predictors, including age, female sex, hypertension, presenting serum glucose, ASPECTS, CTA collateral score, and successful reperfusion.
CONCLUSIONS: The absence of hyperdense middle cerebral artery sign is associated with worse functional outcome in patients presenting with M1 occlusions undergoing thrombectomy.

BACKGROUND: Effectiveness of mechanical thrombectomy for mild-deficit stroke due to large-vessel occlusion is controversial. We present a single-center consecutive case series on thrombectomy for large-vessel occlusion mild stroke. We evaluated various thrombectomy parameters to better understand disagreement in the literature.
METHODS: Data from a retrospective cohort of large-vessel occlusion mild stroke patients (National Institutes of Health Stroke Scale <6) treated with mechanical thrombectomy over 6 years and 2 months were analyzed. Patients were divided into 2 groups: successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b or 3) and failed reperfusion (modified Thrombolysis in Cerebral Infarction 0,1, or 2a). Ninety-day modified Rankin Scale in-hospital mortality, and symptomatic hemorrhage rates were compared between groups. Multivariate logistic regression was performed to evaluate reperfusion status as a predictor of 90-day favorable (modified Rankin Scale 0-2) and excellent (modified Rankin Scale 0-1) outcomes.
RESULTS: We identified 61 patients with large-vessel occlusion mild stroke who underwent thrombectomy. Reperfusion was successful in 49 patients and a failure in 12. The successful group exhibited significantly higher rates of favorable outcome (83.7% vs. 25.0%; p < 0.001) and excellent outcome (69.4% vs.16.7%; p = 0.002) at 90 days. In-hospital mortality was significantly higher in the failure group (41.7% vs.10.2%; p = 0.019). Multivariate logistic regression identified successful reperfusion as a significant predictor (p = 0.001) of 90-day favorable outcome.
CONCLUSIONS: Reperfusion success was significantly associated with improved functional outcomes in large-vessel occlusion mild stroke mechanical thrombectomy. Future studies should consider reperfusion rates when evaluating the effectiveness of thrombectomy against that of medical management in these patients.

OBJECTIVE: Diffusion-weighted imaging (DWI) lesion volume is associated with poor outcome after thrombolysis, and it is unclear whether endovascular therapies are beneficial for large DWI lesion. Our aim was to assess the impact of pretreatment DWI lesion volume on outcomes after endovascular therapy, with a special emphasis on patients with complete recanalization.
METHODS: We analyzed data collected between April 2007 and November 2011 in a prospective clinical registry. All acute ischemic stroke patients with complete occlusion of internal carotid artery or middle cerebral artery treated by endovascular therapy were included. DWI lesion volumes were measured by the RAPID software. Favorable outcome was defined by modified Rankin Scale of 0 to 2 at 90 days.
RESULTS: A total of 139 acute ischemic stroke patients were included. Median DWI lesion volume was 14 cc (interquartile range, 5-43) after a median onset time to imaging of 110 minutes (interquartile range, 77-178). Higher volume was associated with less favorable outcome (adjusted odds ratio, 0.55; 95% confidence interval, 0.31-0.96). A complete recanalization was achieved in 65 (47%) patients after a median onset time of 238 minutes (interquartile range, 206-285). After adjustment for volume, complete recanalization was associated with more favorable outcome (adjusted odds ratio, 6.32; 95% confidence interval, 2.90-13.78). After stratification of volume by tertiles, complete recanalization was similarly associated with favorable outcome in the upper 2 tertiles (P<0.005).
CONCLUSIONS: Our results emphasize the importance of initial DWI volume and recanalization on clinical outcome after endovascular treatment. Large DWI lesions may still benefit from recanalization in selected patients.