Endovascular recanalization of basilar artery occlusion 80 days after symptom onset

Delayed revascularization in acute ischemic stroke patients

Stroke shares a significant burden of global mortality and disability. A significant decline in the quality of life is attributed to the so-called post-stroke cognitive impairment including mild to severe cognitive alterations, dementia, and functional disability. Currently, only two clinical interventions including pharmacological and mechanical thrombolysis are advised for successful revascularization of the occluded vessel. However, their therapeutic effect is limited to the acute phase of stroke onset only. This often results in the exclusion of a significant number of patients who are unable to reach within the therapeutic window. Advances in neuroimaging technologies have allowed better assessment of salvageable penumbra and occluded vessel status. Improvement in diagnostic tools and the advent of intravascular interventional devices such as stent retrievers have expanded the potential revascularization window. Clinical studies have demonstrated positive outcomes of delayed revascularization beyond the recommended therapeutic window. This review will discuss the current understanding of ischemic stroke, the latest revascularization doctrine, and evidence from clinical studies regarding effective delayed revascularization in ischemic stroke.

Endovascular Treatment of Acute Ischemic Stroke Due to Isolated Proximal Posterior Artery Occlusion

Background

Acute ischemic stroke (AIS) due to isolated proximal posterior cerebral artery (PPCA) occlusion is rare but associated with high morbidity and mortality rates. However, the optimal treatment strategy for patients with AIS caused by PPCA remains unclear. We discuss our single-center experience with endovascular treatment (EVT) in patients with PPCA.

Methods

Data from patients with AIS due to PPCA occlusion were retrospectively analyzed. We analyzed procedural details, the degree of reperfusion, functional outcomes, and complications. Functional outcomes were determined using the modified Rankin Scale (mRS) at 90 days, and good outcome was defined as mRS 0–2 at 90 days. Successful reperfusion was defined as modified treatment in cerebral ischemia (mTICI) 2b−3 after endovascular therapy. Safety variables included symptomatic hemorrhage (defined as an increase of four or more points in the National Institute of Health Stroke Scale score), vessel perforation or dissection, and new ischemic stroke in different territories.

Results

Seven patients were included in this study. The mean age of the patients was 64 ± 12.4 years. Successful reperfusion was achieved in all seven patients (100%). Good outcomes were achieved at 90 days in 2 patients (28.6%), and favorable outcomes were observed in five patients (71.4%). One patient underwent angioplasty as rescue therapy after three attempts. One patient died because of severe gastrointestinal bleeding 24 h after EVT, which was probably a complication of intravenous alteplase. One patient had an embolism in the basilar artery and achieved complete reperfusion after rescue thrombectomy. Another patient had a complication of vessel dissection in the PPCA and underwent stent implantation as rescue therapy. We observed no recurrence of ischemic stroke or any intracranial hemorrhage on non-contrast computed tomography 24 h after the procedure.

Conclusion

EVT may represent an alternative treatment strategy for patients with acute ischemic stroke caused by PPCA.

Delayed Recanalization-How Late Is Not Too Late?

Stroke has become the second most prevalent cause of mortality in the world. Currently, the treatment of ischemic stroke is based on thrombolytic and thrombectomy therapy shortly after the ischemic event (≤ 4.5 h for thrombolytic strategies; ≤ 6 h for thrombectomy strategies). However, the majority of patients are unable to receive prompt treatment, particularly in undeveloped countries. Alternative solutions are lacking for those patients that miss the optimal window of opportunity for treatment. Recently, new developments in imaging techniques and intravascular interventional devices enable the expansion of the window of opportunity for treating stroke patients. Clinical studies have reported that delayed recanalization at 24 h, or even more than 1 month, was beneficial for some patients. However, the mechanisms of neuroprotection that underly the delayed recanalization in these ischemic stroke patients remain unclear. In this review, we will summarize the clinical studies of delayed recanalization, and organize them according to the duration of occlusion. Additionally, we will discuss the changing guidelines and possible mechanisms based on animal research, and attempt to draw conclusions and future perspectives.

Cerebral Hemodynamic Changes After Endovascular Recanalization of Symptomatic Chronic Intracranial Artery Occlusion

Objective: We performed this study to evaluate the hemodynamic changes over time after successful endovascular recanalization in patients with symptomatic chronic intracranial artery occlusion (CIAO).

Materials and Methods: We included 20 patients with symptomatic CIAO in a high-volume stroke center from June 2014 to June 2019. All subjects were evaluated with CT perfusion (CTP) studies before and after the recanalization. The relative cerebral blood flows (rCBFs) in perforating artery territory (PAT) and cortical artery territory (CAT) of occluded arteries were compared before and after the recanalization. The patients were categorized into subgroups based on the time interval from revascularization to post-procedural CTP, occlusion sites, and restenosis status. The proportion of rCBF change (rCBFc%) was compared in variable subgroups.

Results: The rCBF increased significantly from 0.52 to 0.71 in PAT (P < 0.001) and from 0.59 to 0.85 in CAT (P < 0.001) after recanalization, and there were also statistical differences in variable subgroups except for those with restenosis. The median and interquartile range (IQR) of rCBFc% were 35.2 and 18.6–56.6%. For patients with short-term follow-up (55.2%), the rCBFc% was relatively higher than that in patients with mid-term (35.4%) and long-term follow-up (32.7%), although without statistical difference (P = 0.273). For patients with restenosis, the rCBFc% was significantly lower than that in patients without restenosis (18.5 vs. 37.3%, P = 0.008).

Conclusions: In patients with symptomatic CIAO, the CBF may increase and be relatively stable over time after successful recanalization except for restenosis.

Delayed recanalization after MCAO ameliorates ischemic stroke by inhibiting apoptosis via HGF/c-Met/STAT3/Bcl-2 pathway in rats

The activation of tyrosine kinase receptor c-Met by hepatocyte growth factor (HGF) showed an anti-apoptotic effect in numerous disease models. This study aimed to investigate the neuroprotective mechanism of the HGF/c-Met axis-mediated anti-apoptosis underlying the delayed recanalization in a rat model of middle cerebral artery occlusion (MCAO). Permanent MCAO model (pMCAO) was induced by intravascular filament insertion. Recanalization was induced by withdrawing the filament at 3 days after MCAO (rMCAO). HGF levels in the blood serum and brain tissue expressions of HGF, c-Met, phosphorylated-STAT3 (p-STAT3), STAT3, Bcl-2, Bax, cleaved caspase-3(CC3) were assessed using ELISA and western blot, respectively. To study the mechanism, HGF small interfering ribonucleic acid (siRNA) and c-Met inhibitor, su11274, were administered intracerebroventricularly (i.c.v.) or intranasally, respectively. The concentration of HGF in the serum was increased significantly after MCAO. Brain expression of HGF was increased after MCAO and peaked at 3 days after recanalization. HGF and c-Met were both co-localized with neurons. Compared to rats received permanent MCAO, delayed recanalization after MCAO decreased the infarction volume, inhibited neuronal apoptosis, and improved neurobehavioral function, increased expressions of p-STAT3 and its downstream Bcl-2. Mechanistic studies indicated that HGF siRNA and su11274 reversed the neuroprotection including anti-apoptotic effects provided by delayed recanalization. In conclusion, the delayed recanalization after MCAO increased the expression of HGF in the brain, and reduced the infarction and neuronal apoptosis after MCAO, partly via the activation of the HGF/c-Met/STAT3/Bcl-2 signaling pathway. The delayed recanalization may serve as a therapeutic alternative for a subset of ischemic stroke patients.

Endovascular Recanalization for Symptomatic Subacute to Chronic Atherosclerotic Basilar Artery Occlusion

Background: The prognosis is poor for patients with symptomatic subacute to chronic atherosclerotic basilar artery occlusion (BAO) refractory to medical therapy. There has been no consensus on the optimal treatment for these patients until now.

Objectives: To assess the feasibility of endovascular recanalization for patients with symptomatic subacute to chronic atherosclerotic BAO refractory to medical therapy.

Methods: Consecutive patients who underwent endovascular recanalization for symptomatic subacute to chronic symptomatic atherosclerotic BAO from May 2015 to October 2018 were enrolled in our stroke center. Demographic, clinical, angiographic, procedural, and follow-up data were collected and analyzed.

Results: Twenty-one patients were enrolled in this study [mean age 57.9 years; 90.5% male; median pretreatment National Institutes of Health Stroke Scale (NIHSS) score 10; median time from image-documented BAO to treatment 15 days]. The success rate of the procedure was 81.0% (17/21). Periprocedural perforator strokes occurred in two patients (9.5%, 2/21). At 90 days, there was one death due to pneumonia (unrelated to the procedure), and there were no recurrent cases of TIA or stroke in the other 16 patients. At 90 days, 76.5% (13/17) of patients achieved a good clinical outcome [mRS: modified Rankin Scale (mRS) scores 0–2], and 94.1% (16/17) of patients achieved an acceptable outcome (mRS scores 0–3). During the 17.4 ± 8.0-month clinical follow-up period, one patient suffered from Wallenberg syndrome at 29 months.

Conclusions: Our study suggests that endovascular recanalization for subacute to chronic symptomatic atherosclerotic BAO appears to be feasible in selected patients.

Endovascular recanalization for symptomatic subacute and chronic intracranial large artery occlusion of the anterior circulation: initial experience and technical considerations

PURPOSE

This study aimed to report the clinical findings and initial clinical experience of endovascular recanalization for symptomatic subacute/chronic intracranial large artery occlusion (ILAO) of the anterior circulation.

METHODS

From October 2015 to December 2017, 13 patients with symptomatic subacute/chronic ILAO of the anterior circulation were enrolled in this study and underwent endovascular recanalization. We collected the initial procedural results, including the rate of successful recanalization and periprocedural complications, and data pertaining to angiographic and clinical follow-up.

RESULTS

Recanalization was successful in 11 of 13 patients (84.6%). Intraoperative complications occurred in four cases, including symptomatic distal embolism in three cases; one of which was simultaneously complicated with artery dissection. Intracerebral hemorrhage occurred in one case. Eleven patients underwent angiographic follow-up, and 12 patients underwent clinical follow-up. The results of the angiography follow-up (mean 6 ± 3.29 months) showed that in-stent restenosis occurred in one of the 11 successfully recanalized patients. However, the artery was occluded again in the patient who achieved thrombolysis in cerebral infarction (TICI) grade of 2a after treatment. Clinical follow-up (mean 5.8 ± 2.25 months) showed no recurrence of transient ischemic attack (TIA) or stroke in ten successfully recanalized cases. However, the patient who developed in-stent stenosis suffered TIA.

CONCLUSIONS

Endovascular recanalization for symptomatic subacute/chronic ILAO of anterior circulation is feasible, relatively safe, and efficacious in highly selected cases, improving patients' symptoms in the short-term. However, further larger scale pilot studies are needed to determine the efficacy and long-term outcome associated with this treatment.

Implications of Mechanical Endovascular Thrombectomy for Acute Basilar and Posterior Cerebral Artery Occlusion

Objective

Protocols for posterior circulation ischemic stroke have not been established by randomized clinical trials. Mechanical endovascular thrombectomy (MET) devices are evolving, and many of these devices already developed or in development are suitable for posterior circulation MET.

Materials and Methods

We investigated the medical records of patients who underwent MET for posterior circulation ischemic stroke from January 2012 to August 2016. Fifteen patients were included. MET was performed in patients with or without injected intravenous tissue plasminogen activator. MET was considered in patients with a National Institute of Health Stroke Scale score of 4 or more, older than 18 years, with definite occlusion of the basilar artery or posterior cerebral artery (PCA), and who arrived at the hospital within 24 hours from onset.

Results

The direct catheter aspiration technique was used in five cases, and the stent retrieval technique was used in seven cases. The stent retrieval technique with the direct aspiration technique was used in three cases. Recanalization failed in two cases. Basilar occlusion without PCA involvement is the only effective factor of successful recanalization (p = 0.03). Successful recanalization (p = 0.005) and the presence of a posterior communicating artery (p = 0.005) affected the good outcome at discharge.

Conclusion

An early diagnosis and active MET may improve the patient outcome. MET may help recanalization and good flow restoration and the potential for a good outcome.

Delayed Recanalization Promotes Functional Recovery in Rats Following Permanent Middle Cerebral Artery Occlusion

Most large vessel stroke patients have permanent occlusion, for which there are no current treatment options. Recent case studies have indicated delayed recanalization, that is recanalization outside of the 6-h treatment window, may lead to improved outcome. We hypothesized that delayed recanalization will restore cerebral blood flow, leading to improved function in rats. Male SD rats were subjected to pMCAO or sham surgery. Delayed recanalization was performed on either day 3, 7, or 14 after pMCAO in a subset of animals. Cerebral blood flow was monitored during suture insertion, during recanalization, and then at sacrifice. Neurological function was evaluated for 1 week after delayed recanalization and at 4 weeks post-ictus. After sacrifice, cerebral morphology was measured. Compared to no treatment, delayed recanalization restored cerebral blood flow, leading to sensorimotor recovery, improved learning and memory, reduced infarct volume, and increased neural stem/progenitor cells within the infarction. The data indicate that earlier delayed recanalization leads to better functional and histological recovery. Yet, even restoring cerebral blood flow 14 days after pMCAO allows for rats to regain sensorimotor function. This exploratory study suggests that delayed recanalization may be a viable option for treatment of permanent large vessel stroke.

Precision Stroke Animal Models: the Permanent MCAO Model Should Be the Primary Model, Not Transient MCAO

An argument for preclinical stroke research to make more use of the permanent middle cerebral artery occlusion (MCAO) model, rather than transient MCAO, is presented. Despite STAIR recommending permanent MCAO as the primary model, preclinical stroke research has not been listened. In 2012, Hossmann reported that 64% of the treatment studies for MCAO used prompt transient MCAO models and only 36% of the studies used permanent MCAO or gradual transient MCAO (i.e., embolic stroke model). Then, in 2014 and 2015, 88% of published basic science studies on large vessel occlusion used the transient MCAO model. However, this model only represents 2.5-11.3% of large vessel stroke patients. Therefore, the transient MCAO model, which mimics stroke with reperfusion, does not accurately reflect the majority of clinical stroke cases. Thus, once again, the argument for studying permanent MCAO as a primary model is made and supported.

The use of mechanical thrombectomy in the treatment of basilar artery occlusion--case report

Occlusion of the basilar artery (BAO) is a rare cause of stroke, making up approximately 1% of all cases. Ischemic stroke within the basilar artery is associated with serious complications and high mortality (75-91%). BAO may occur initially in the form of mild prodromal symptoms with neurological disorders, the consequences of which can lead to death. For these reasons, BAO requires rapid diagnosis and treatment. We report the case of a 26-year-old man who suffered basilar artery occlusion and was treated with endovascular therapy. The patient was disqualified from intra-venous thrombolysis and endovascular treatment due to exceeding the therapeutic time window. Despite this, due to the location of ischemia and age of the patient, it was decided to proceed with a mechanical thrombectomy (TM). Vessel patency was restored using the Solitaire FR stent. Treatment continued with antiplatelet therapy. Despite a significant overshoot of the time window the procedure was successful and complete recanalization was achieved. During hospitalization, significant neurological symptom reductions were observed. There is no accurate data on which method of treatment of ischemic stroke is best for BAO. Expectations about the effectiveness of endovascular techniques are high.

Perioperative complications of recanalization and stenting for symptomatic nonacute vertebrobasilar artery occlusion

BACKGROUND

Endovascular recanalization and stenting has been used to treat patients with symptomatic nonacute intracranial vertebrobasilar artery occlusion (VBAO) refractory to aggressive medical treatment. This study was performed to analyze the perioperative complications of the procedures.

METHODS

Between February 2010 and March 2012, 27 consecutive patients (24 men, 3 women; age: 57 ± 10 years) with symptomatic, nonacute intracranial VBAO including 12 basilar artery occlusions and 15 vertebral artery occlusions were collected and retrospectively analyzed.

RESULTS

The median time between symptom onset and recanalization was 1.5 months (interquartile range [IQR]: 0.7-3.4) and between imaging-documented occlusion and recanalization was 9.5 days (IQR: 6-18 days). Recanalization was achieved in 96% of patients (26/27). Five (5/27; 19%) perioperative complications occurred. Two patients had dissections: 1 dissection resulted in termination of the procedure without successful recanalization, and the other was handled by the placement of 2 stents. There was 1 intraprocedural acute thrombosis that was successfully treated with balloon angioplasty. One patient experienced thrombus disruption and translocation during the procedure: thrombus was dislodged after disruption by the guidewire. There was 1 acute reocclusion after procedure: while recanalization was achieved again, there was no improvement in clinical outcome.

CONCLUSIONS

This study revealed that recanalization and stenting for nonacute VBAO may be technically feasible but that it is accompanied by a high risk of complication. The causative factors for perioperative complications need future study.

Endovascular mechanical thrombectomy in basilar artery occlusion: initial experience

Objective

This study was conducted to assess the efficacy and safety of endovascular mechanical thrombectomy (EMT) for patients diagnosed with basilar artery (BA) occlusion.

Materials and Methods

We retrospectively analyzed clinical and imaging data of 16 patients diagnosed with BA occlusion who were treated with endovascular intervention from July 2012 to February 2013. Direct suction using the Penumbra system and thrombus retrieval by the Solitaire stent were the main endovascular techniques used to restore BA flow. The outcomes were evaluated based on rate of angiographic recanalization, rate of improvement of National Institutes of Health Stroke Scale (NIHSS) score, rate of modified Rankin Scale (mRS) at discharge and after 3 months, and rate of cerebral hemorrhagic complications. Successful recanalization was defined as achieving Thrombolysis In Cerebral Infarction (TICI) of II or III.

Results

Sixteen patients received thrombectomy. The mean age was 67.8 ± 11 years and the mean NIHSS score was 12.3 ± 8.2. Eight patients treated within 6 hours of symptom onset were grouped as A and the other 8 patients treated beyond 6 hours (range, 6-120) were grouped as B. Successful recanalization was met in six patients (75%) for group A and 7 (87.5%) for group B. Favorable outcome occurred in 4 patients (50%) for group A and 5 (62.5%) for group B.

Conclusion

Our study supports the effectiveness and safety of endovascular mechanical thrombectomy in treating BA occlusion even 6 hours after symptom onset.

Endovascular revascularization of chronic symptomatic vertebrobasilar occlusion

BACKGROUND AND PURPOSE

Acute basilar artery occlusion is associated with a high risk of stroke, mortality, and poor outcome in survivors. Timely vessel revascularization is critical to improve the clinical outcome in this condition. A subset of patients survives acute occlusion with mild or no disability and some of these individuals develop recurrent ischemic events despite optimal medical therapy. The strategy for management of these patients is unknown.

CASE SUMMARY

We described 3 patients with chronic intracranial vertebrobasilar occlusions who presented with recurrent ischemic symptoms and progressive disability. All 3 patients were treated successfully with angioplasty and stenting. One patient experienced headache postprocedure and was found to have subarachnoid hemorrhage, which was self-limiting without need for intervention or result in permanent neurological sequela. All 3 patients have been free of recurrent symptoms for up to 30 months.

CONCLUSIONS

Revascularization of chronic vertebrobasilar occlusions is technically feasible. Due to the high-risk nature, it should be reserved as an option only for selected group of patients with recurrent ischemic symptoms and progressive disability despite maximal medical therapy. Further prospective study is helpful to clarify the role of this intervention.

Intraarterial thrombolysis and stent placement for acute basilar artery occlusion

PURPOSE

To study retrospectively the prognostic factors for acute basilar artery occlusion treated with intraarterial thrombolysis and stent placement.

MATERIALS AND METHODS

Within 3-48 hours of disease onset, 52 patients with basilar artery occlusion were treated with emergency intraarterial thrombolysis with recombinant tissue plasminogen activator (rtPA) or urokinase (UK) or intraarterial thrombolysis combined with stent placement. Sixteen patients simultaneously received stent placement for the partial recanalization of basilar artery occlusion after intraarterial thrombolysis. The National Institutes of Health Stroke Scale (NIHSS) scores and the modified Rankin Scale (mRS) scores of the patients were estimated.

RESULTS

A favorable clinical outcome occurred in 22 patients (42.3%), and 20 patients (38.5%) died. The survival rate was 61.5% (32 patients). Successful recanalization of basilar artery occlusion was achieved in 24 patients (46.2%), and partial recanalization was achieved in 16 patients (30.7%). The rate of recanalization was 76.9%. NIHSS scores less than 14, treatment time window less than 24 hours, and a good recanalization were markedly correlated with good clinical prognosis. NIHSS scores less than 14 and treatment time window less than 24 hours were significantly correlated with recanalization. NIHSS scores less than 14 and good recanalization could act as independent predictors for clinical prognosis.

CONCLUSIONS

NIHSS scores less than 14 on admission and successful recanalization can predict favorable outcome for patients with basilar artery occlusion. This study shows that intraarterial thrombolysis and stent placement may be a useful treatment for acute basilar artery occlusion.

Endovascular Recanalization of the Subacute to Chronically Occluded Basilar Artery

INTRODUCTION

Occlusion of the basilar artery (BA) has a poor prognosis. We evaluated technical considerations and complications associated with reopening subacute to chronically occluded BAs.

METHODS

Duration of BA occlusion before revascularization, symptoms and medical management before treatment, and postprocedural antiplatelet regimen and anticoagulation protocols of 9 patients were analyzed. All patients underwent endovascular low-volume balloon angioplasty followed by Wingspan stenting.

RESULTS

The median time between onset of symptoms and treatment was 5 days (range, 2 days to 3.5 years). The median time between documentation of BA occlusion by cerebral angiography or computed tomography angiography and treatment was 3 days (range, 1 day to 8 months). Recanalization was successful in 8 of the 9 patients. Immediately after the procedure, 4 patients were stable, 3 patients improved, and 2 patients were worse. Four patients had periprocedural complications. Four of the 9 patients died, 2 from periprocedural complications. The mean clinical duration of follow-up was 11 months. At latest follow-up, the modified Rankin Scale scores for the 5 surviving patients were 0, 0, 2, 2, and 3, respectively. During the follow-up period, 4 patients improved, 1 patient remained stable, and 1 patient died. The mean angiographic follow-up was 8.6 months. Two patients developed significant in-stent stenosis during this period.

CONCLUSION

With current endovascular techniques, recanalization of chronically occluded BAs is feasible. The procedure carries substantial risks and should be reserved for patients with medically refractory symptoms. Careful postprocedural medical management and radiographic follow-up are warranted to prevent in-stent restenosis.

Spontaneous recanalization of the basilar artery with conservative management months after symptom onset

Basilar artery occlusion may be associated with a poor prognosis in the absence of recanalization. Choices in aggressive treatment for this potentially fatal condition vary from intra-arterial or intravenous thrombolysis, endovascular removal, or a combination of the two, with adjunct anti-coagulation therapy. These therapies have proven to be effective in recanalization, whereas conservative management with anti-coagulants alone has had more limited success in the literature. We report a case of basilar artery occlusion managed conservatively with unfractionated heparin, resulting in complete recanalization 3.5 months after symptom onset. Conservative management of basilar artery occlusion with unfractionated heparin was associated with complete recanalization long after symptom onset.

Delayed treatment of basilar thrombosis in a patient with a basilar aneurysm: a case report

Introduction

Acute occlusion of the basilar artery is a neurological emergency that has a high risk of severe disability and mortality. Delayed thrombolysis or endovascular therapy has been performed with some success in patients who present after 3 hours of symptom onset. Here we present the first case of delayed intra-arterial thrombolysis of a basilar artery thrombosis associated with a large saccular aneurysm.

Case presentation

A 73-year-old Caucasian man with a history of smoking and alcohol abuse presented to the Emergency Department complaining of diplopia and mild slurred speech and who progressed over 12 hours to coma and quadriparesis. He was found to have a large basilar tip aneurysm putting him at high risk for hemorrhage with lytic treatment.

Conclusion

The treatment options for basilar thrombosis are discussed. Aggressive treatment options should be considered despite long durations of clinical symptoms in basilar thrombosis, even in extremely high risk patients.

Vertebrobasilar recanalization after 12 h of onset using balloon expandable stent and thrombolysis

Basilar artery (BA) thrombosis is a severe condition that has a high percentage of mortality if no treatment is performed. Recanalization is the most successful way of reducing mortality and improving outcome in patients with BA thrombosis. We present a case of a patient that presented to our hospital 12 h after onset of symptoms in which a combination of techniques were used to perform a vertebrobasilar recanalization.