Acute Recanalization Therapy Research Articles

Stroke in 2015: Acute endovascular recanalization therapy comes of age.

The past year has seen practice-changing findings in stroke research. Strong evidence now supports endovascular thrombectomy as the new gold standard of care in acute ischaemic stroke, and a pragmatic trial raised concerns over early intensive mobilization after stroke. Moreover, new insights were gained into the trajectory of stroke-associated cognitive decline.

急性期脳梗塞における，治療別に見た急性期血行再建術の成績の比較

要旨：急性期脳梗塞への治療は，血管内治療併用や閉塞血管別の治療方針など未確定な部分が多い．我々は2005 年4 月～2014 年10 月の間に急性期脳梗塞にてrt-PA 静注療法および血管内治療，あるいはその双方を施行した急性期脳梗塞患者191 例に対し，A 群（rt-PA 静注），B 群（ウロキナーゼ動注），C 群（機械的血栓除去），D 群（failed rt-PA 患者に血管内治療を追加）に分別し遡及的に検討した．治療開始までの時間が短いA，D 群は予後良好な傾向を認め，内頸動脈閉塞患者ではD 群で予後良好，C 群では不良傾向を認めた．今回の検討において，最大の予後改善因子は早期再開通と考えた．また，rt-PA 静注適応の内頸動脈閉塞患者においても血管内治療併用による予後改善の可能性が示唆された．急性期脳梗塞においては，再開通までの時間を可及的に短縮する必要があると思われる．

Abstract T P168: A Wake-up Call for Wake-up Strokes

INTRODUCTION: Studies suggest 8%-28% of ischemic strokes present as wake-up strokes (WUS). The unknown time of symptom onset precludes these patients from approved treatments for acute ischemic stroke, but a substantial proportion of patients may be deemed candidates for treatment if other factors are considered. The aim of this study was to identify characteristics associated with clinical outcomes of WUS patients. METHODS: We retrospectively reviewed the medical record of patients with ischemic stroke admitted to a large academic medical center between January 2011 and May 2012. We identified patients with stroke symptoms upon awakening or those who were found with stroke symptoms with an unknown time of onset. Baseline demographics, stroke mechanism, presenting NIHSS, Alberta Stroke Program Early Computed Tomography Score (ASPECTS), and modified Rankin Scale (mRS) scores on discharge and at 3-month follow-up were obtained. A good outcome was defined as mRS 0-2. RESULTS: WUS patients comprised 22% (162/731) of all patients with ischemic stroke at our institution during this time period. Median age was 74 years (range 15-100), median presenting NIHSS was 5 (range 0-28), and median initial ASPECTS 10 (range 0-10). A cardioembolic mechanism was identified in 68 patients (42%). Predictors of good outcome at hospital discharge were lower initial NIHSS (3.5 versus 12.0, p<0.0001) and higher ASPECTS (9.8 versus 8.1, p=0.0002). The predictors of good outcomes at 3 months were younger age (69.1 versus 75.8, p=0.009), lower initial NIHSS (5.0 versus 12.6, p<0.0001), and higher ASPECTS (9.5 versus 8.1, p=0.0006). One hundred and eleven patients (68.5%) had initial ASPECTS of 10. Of those, 19 had NIHSS≥10 and 7 were treated with acute recanalization therapies. Four of the 7 treated patients had good outcomes, and 2 of the 12 untreated patients had good outcomes. CONCLUSIONS: Few patients with strokes of unknown onset and severe deficits have good outcomes without acute stroke treatment. Patients with NIHSS≥10 and ASPECTS 10 may be candidates for acute recanalization therapy.

Abstract W P18: Evaluating Clot Burden and the Vascular Basis of Pial Collaterals with a Bimodal Angiographic Score

Treatment decision for endovascular recanalization in acute ischemic stroke is based on validated outcome predictors such as age, initial infarct size, collaterals and clot burden. The CTA-based Clot Burden Score (CBS) only considers occlusions of the A1-segment of the anterior cerebral artery (ACA), but patency of the ipsilateral A2-segment is mandatory for collateral formation in a typical middle cerebral artery (MCA) occlusion. Secondly, CTA often cannot differentiate between an extra- or intra-cranial internal carotid artery (ICA) occlusion due to non-contrasting of the whole ICA in both. Thirdly, a 4-vessel angiogram, necessary to grasp the vascular basis of all pial collaterals, is often not done during acute recanalization therapy for reasons of time. To bypass these inadequacies, we propose a combined CTA/DSA score (ALITA) to assess pre-therapeutic thrombus load. We hypothesized a good outcome prediction of this score. We evaluated the ALITA score in a retrospective study including consecutive patients of the years 2010-12, who received endovascular therapy for acute stroke in the ICA-territory. Final outcome was measured with the modified Rankin Scale score (mRS) at 90 days. Reperfusion (mTICI), collaterals (CT-CS), clot burden (CBS), and the ALITA score were independently assessed. ALITA evaluates patency of the ACA and MCA in CTA and of the ICA in DSA. Data-driven ordinal regression analysis modeled outcome prediction of all scores. Of 99 patients 60% had a good reperfusion (mTICI 2b/3) and 29% had a good outcome (mRS 0-2), mortality was 23%. Age and reperfusion were independent predictors of good outcome (p<.001). CT-CS (p<.01), CBS (p<.01) and ALITA (p<.05) were significant predictors, but showed interaction regarding outcome. In the considered model CBS was a stronger predictor than ALITA. Although ALITA assesses all vessels of the anterior circulation contributing to collaterals the score was statistically different from CT-CS. This is consistent with results that describe pial collaterals as genetically determined. In conclusion, the combined CTA/DSA clot burden score better depicts the vascular basis of pial collaterals and predicts outcome in acute stroke patients.

MRI in Patients with Acute Basilar Artery Occlusion – DWI Lesion Scoring is an Independent Predictor of Outcome

We analyzed early diffusion-weighted magnetic resonance imaging of patients with acute basilar artery occlusion by applying different lesion scoring systems and determined their predictive value for favorable outcome. Between 1998 and 2010, patients with confirmed basilar artery occlusion were entered in a local database. magnetic resonance imaging angiography was performed for diagnosis of basilar artery occlusion and/or during initiated recanalization therapy. We analyzed the patients' clinical and radiological baseline data, recanalization, and favorable outcome modified Rankin Scale 0-2 after three-months. Diffusion weighted imaging findings were categorized into lesions in vascular territories as well as by two previously published scores for ischemic damage in the posterior circulation, the Renard score and posterior circulation Acute Stroke Prognosis Early computed tomography Score. Fifty patients with basilar artery occlusion received an early MRI, and in 30 of those, a follow-up MRI was performed. Median time to baseline MRI was 5·5 h (one-hour to 24 h). Median baseline Renard score and posterior circulation Acute Stroke Prognosis Early CT Score were 2·75 (0-10) and 7 (0-10), respectively. Of the patients, 82% received an acute recanalization therapy and in 78% of those, the basilar artery recanalized. Median time to therapy was five-hours (1·25-20 h). 24% of all patients had a favorable outcome (mRS 0-2). Patients with a favorable outcome had a lower Renard score and higher pcASPECTS, a lower rate of complete basilar artery occlusion, a higher Glasgow coma scale on admission, and a higher rate of successful recanalization (all P < 0·05). After logistic regression, the only independent predictor for favorable outcome was a posterior circulation Acute Stroke Prognosis Early CT Score of 8 or more points (odds ratio 3·9, 95% confidence interval 1·4-11·7, P < 0·05). In patients with acute basilar artery occlusion, posterior circulation Acute Stroke Prognosis Early CT Score of 8 or more points on early diffusion weighted imaging is an independent predictor for favorable outcome.

Acute endovascular recanalization therapy in wake-up stroke

Background and Purpose Up to 15–25% of patients with ischemic stroke wake up with their deficits. Because of the uncertainty about the time of onset, these patients are generally not offered thrombolytic therapy. Some of these wake-up stroke patients may be eligible for acute endovascular stroke therapy based on hyperacute CT or MR imaging independent of the time window. Report We report two patients with acute ischemic stroke whose symptoms were present upon awakening and who were successfully treated with endovascular interventions. Results The first patient was discharged with complete neurological recovery on second day after endovascular intervention. The second patient went home on fifth day with a mild left facial paresis and left arm drift. Both these patients did not have any neurological deficit on 18-month follow up. Conclusions Some patients who present with stroke on awakening may be candidates for thrombolytic therapy or recanalization techniques irrespective of mode of therapy (intravenous, intravenous + intra-arterial or intra-arterial tPA alone). Further randomized, controlled studies are warranted to safely identify those candidates who would benefit from thrombolysis and endovascular interventions in ischemic wake-up strokes.

Using Advanced MRI Techniques for Patient Selection Before Acute Stroke Therapy

Results of acute MRI studies may help guide the management of acute stroke. Patients with a malignant MRI pattern may be poor candidates for reperfusion therapies yet may benefit from hemicraniectomy. Preliminary data suggest that patients with a carefully identified diffusion weighted imaging (DWI)/perfusion weighted imaging (PWI) mismatch may benefit from intravenous recombinant tissue plasminogen activator in a 3- to 6-hour time window; however, confirmatory studies with larger sample sizes are required before clinical use of this strategy can be generally recommended. Post hoc analyses of recent studies suggest that PWI techniques that use a threshold to exclude benign oligemia from penumbra and DWI techniques that use apparent diffusion coefficient thresholds to exclude reversible DWI lesions to distinguish the ischemic core from penumbra appear to provide more accurate determinations of the volume of salvageable tissue. New automated software programs are now implementing these techniques to generate quantitative PWI and DWI maps within minutes. Prospective trials are in progress to investigate these new techniques. The results of these studies will further refine the application of MRI to select patients for acute recanalization therapies.