Predictors of clinical improvement, angiographic recanalization, and intracranial hemorrhage after intra-arterial thrombolysis for acute ischemic stroke

Predictors for the extent of pial collateral recruitment in acute ischemic stroke

BACKGROUND

Pial arterioles can provide a variable degree of collateral flow to ischemic vascular territories during acute ischemic stroke. This study sought to identify predictive factors of the degree of pial collateral recruitment in acute ischemic stroke.

METHODS

Clinical information and arteriograms from 62 consecutive patients with stroke due to either middle cerebral artery (MCA) M1 segment or internal carotid artery (ICA) terminus occlusion within 6 h following symptom onset were retrospectively reviewed. Pial collaterals were defined based on the extent of reconstitution of the MCA territory. Patients with slow antegrade flow distal to the occlusion site were excluded and no anesthetics were used prior or during angiography. Results were analyzed using multivariate nominal logistic regression.

RESULTS

Better pial collateral recruitment was associated with proximal MCA versus ICA terminus occlusion (p = 0.005; odds ratio (OR) = 9.3; 95% confidence interval (CI), 2.16-53.3), lower presenting National Institutes of Health Stroke Scale Score (NIHSSS) (p = 0.023; OR = 6.51; 95% CI, 1.49-41.7), and lower diastolic blood pressure (p = 0.0411; OR = 5.05; 95% CI, 1.20-29.2). Age, gender, symptom duration, diabetes, laterality, systolic blood pressure, glucose level, hematocrit, platelet level, and white blood cell count at presentation were not found to have a statistically significant association with pial collateral recruitment.

CONCLUSIONS

Extent of pial collateral recruitment is strongly associated with the occlusion site (MCA M1 segment versus ICA terminus) and less strongly associated with presenting NIHSSS and diastolic blood pressure.

Significance of angiographic clot meniscus sign in mechanical thrombectomy of basilar artery stroke

Introduction

The relationship between the occlusive clot morphology and the efficacy of mechanical thrombectomy (MT) in basilar artery occlusion (BAO) is not well known. Our aim was to evaluate the clinical significance of the clot meniscus sign in patients with acute BAO.

Methods

89 patients with acute BAO who underwent MT were retrospectively analyzed. The clot meniscus sign was defined as meniscoid/tram-track like antegrade side-wall contrast opacification of the thrombus. Patients were assigned to two groups based on the presence of the clot meniscus sign. The treatment and clinical outcomes were compared.

Results

The clot meniscus sign was diagnosed in 62.9% (53/89) of the patients. The meniscus sign (+) group showed a shorter procedure time (55 vs 85 min; p=0.045), higher rate of successful recanalization (89.3% vs 63.6%, p=0.004), higher incidence of first pass effect (32.1% vs 6.1%, p=0.004), and lower number of passes (2 vs 3; p=0.042) when compared with the meniscus sign (−) group. The procedure time (OR 0.972, 95% CI 0.962 to 0.992; p=0.003) and clot meniscus sign (OR 7.920, 95% CI 1.769 to 35.452; p=0.007) were independent predictors of successful recanalization.

Conclusion

The clot meniscus sign is related to high first pass effect and short procedure time and is a reliable predictor of successful recanalization in patients with acute BAO.

In vitro characterization of sonothrombolysis and echocontrast agents to treat ischemic stroke

The development of adjuvant techniques to improve thrombolytic efficacy is important for advancing ischemic stroke therapy. We characterized octafluoropropane and recombinant tissue plasminogen activator (rt-PA)-loaded echogenic liposomes (OFP t-ELIP) using differential interference and fluorescence microscopy, attenuation spectroscopy, and electrozone sensing. The loading of rt-PA in OFP t-ELIP was assessed using spectrophotometry. Further, it was tested whether the agent shields rt-PA against degradation by plasminogen activator inhibitor-1 (PAI-1). An in vitro system was used to assess whether ultrasound (US) combined with either Definity or OFP t-ELIP enhances rt-PA thrombolysis. Human whole blood clots were mounted in a flow system and visualized using an inverted microscope. The perfusate consisted of either (1) plasma alone, (2) rt-PA, (3) OFP t-ELIP, (4) rt-PA and US, (5) OFP t-ELIP and US, (6) Definity and US, or (7) rt-PA, Definity, and US (n = 16 clots per group). An intermittent US insonation scheme was employed (220 kHz frequency, and 0.44 MPa peak-to-peak pressures) for 30 min. Microscopic imaging revealed that OFP t-ELIP included a variety of structures such as liposomes (with and without gas) and lipid-shelled microbubbles. OFP t-ELIP preserved up to 76% of rt-PA activity in the presence of PAI-1, whereas only 24% activity was preserved for unencapsulated rt-PA. The use of US with rt-PA and Definity enhanced lytic efficacy (p < 0.05) relative to rt-PA alone. US combined with OFP t-ELIP enhanced lysis over OFP t-ELIP alone (p < 0.01). These results demonstrate that ultrasound combined with Definity or OFP t-ELIP can enhance the lytic activity relative to rt-PA or OFP t-ELIP alone, respectively.

Efficacy of carotid thrombus penetration with a balloon guiding catheter to fast recanalization of acute extra- and intra-cranial carotid artery tandem occlusion - a preliminary report

Acute ischemic stroke with ipsilateral Internal carotid artery (ICA) stenosis presents a great management dilemma. We present our preliminary report of retrograde retrieval of clot from middle cerebral artery (MCA) followed by delayed carotid artery stenting (CAS) with dual anti platelet therapy (DAPT).

Acute Ischaemic Stroke: Management, Recent Advances and Controversies

Acute ischaemic stroke is a major cause of death and disability. It may become an enormous burden to the patients themselves, their families as well as the health care systems. Patients at risk of airway, breathing and circulatory compromise should receive prompt resuscitation. Vital parameters and neurological status should be closely monitored. Attentions to blood pressure, temperature and sugar profile are important. The significance of early and correct diagnosis and subsequent treatment cannot be over-emphasised. There have been tremendous recent advances in different treatment modalities in acute stroke management. Various recanalisation modalities include intravenous and/or intra-arterial thrombolysis, acute defibrinogenation, anti-platelet treatment and anticoagulation. Carotid endarterectomy and endovascular strategies are recommended in selected patients. Advanced neuro-imaging techniques and neuroprotectants are being evaluated. Multidisciplinary stroke teams have been shown to improve patient survival and functional outcome. Pre-defined algorithms and protocols should be in place to expedite smooth and effective delivery of stroke service. Future directions should be aimed at exploring safer recanalisation modalities and extending the limit of the current 3-hour treatment window for thrombolysis.

Comparative lytic efficacy of rt-PA and ultrasound in porcine versus human clots

Introduction

Porcine thrombi are employed routinely in preclinical models of ischemic stroke. In this study, we examined the differential lytic susceptibility of porcine and human whole blood clots with and without the use of microbubbles and ultrasound (US) as an adjuvant.

Materials and methods

An in vitro system equipped with time-lapse microscopy was used to evaluate recombinant tissue-plasminogen activator (rt-PA) lysis of porcine and human clots in the same species or cross species plasma. Human and porcine whole blood clots were treated with rt-PA and an echo contrast agent, Definity^®, and exposed to intermittent 120 kHz US.

Results and conclusions

The rt-PA lytic efficacy observed for porcine clots in porcine plasma was 22 times lower than for human clots in human plasma reported previously. Further, porcine clots did not exhibit increased lysis with adjuvant Definity^® and US exposure. However, the rt-PA lytic susceptibility of the porcine clots in human plasma was similar to that of human clots in human plasma. Human clots perfused with porcine plasma did not respond to rt-PA, but adjuvant use of Definity^® and US enhanced lysis. These results reveal considerable differences in lytic susceptibility of porcine clots and human clots to rt-PA. The use of porcine clot models to test new human thrombolytic therapies may necessitate modulation of coagulation and thrombolytic factors to reflect human hemostasis accurately.

Update on Endovascular Treatment of Cerebrovascular Diseases

Several developments in endovascular technology have greatly expanded the application of these techniques to treat extra- and intracranial cerebrovascular diseases. This review explores the indications, techniques, and clinical results for endovascular treatment of ischemic stroke and intracranial stenoses, aneurysms, and arteriovenous malformations.

Intravenous versus intra-arterial thrombolysis in ischemic stroke: a systematic review and meta-analysis

BACKGROUND

Reperfusion following ischemic stroke can be attained by either intravenous thrombolysis (IVT) or intra-arterial thrombolysis (IAT). Only a limited number of randomized prospective studies have compared the efficacy and safety of IVT and IAT. This meta-analysis investigated possible clinical benefits of IAT relative to IVT in patients with acute ischemic stroke.

METHODS

We searched the PubMed, Cochrane, and Google Scholar databases through October 2013 for manuscripts that describe the findings of randomized controlled or prospective studies that evaluated the outcomes of patients with ischemic stroke who were treated with IVT or IAT. The clinical outcome measures were score on the modified Rankin scale (mRS) and mortality at 90 days. A favorable outcome was defined as an mRS score of 0 to 2.

RESULTS

For the mRS, the combined odds ratio (OR) of 3.28 (95% confidence interval (CI), 1.91 to 5.65, P < 0.001) indicated that patients who received IAT had a significantly higher chance for a favorable outcome than did those who received IVT. For mortality, the OR indicated that IAT therapy significantly reduced the proportion of patients who died within 90 days of the procedure (combined OR, 0.40; 95%CI, 0.17 to 0.92; P = 0.032).

CONCLUSION

This meta-analysis determined that IAT conferred a significantly greater probability of achieving a favorable outcome compared with IVT. There was also a significant difference in mortality rates between IAT and IVT. The studies included in this analysis were small and heterogeneous; therefore, larger randomized prospective clinical studies are necessary to further investigate this issue.

4D-CTA in neurovascular disease: a review

CT angiography is a widely used technique for the noninvasive evaluation of neurovascular pathology. Because CTA is a snapshot of arterial contrast enhancement, information on flow dynamics is limited. Dynamic CTA techniques, also referred to as 4D-CTA, have become available for clinical practice in recent years. This article provides a description of 4D-CTA techniques and a review of the available literature on the application of 4D-CTA for the evaluation of intracranial vascular malformations and hemorrhagic and ischemic stroke. Most of the research performed to date consists of observational cohort studies or descriptive case series. These studies show that intracranial vascular malformations can be adequately depicted and classified by 4D-CTA, with DSA as the reference standard. In ischemic stroke, 4D-CTA better estimates thrombus burden and the presence of collateral vessels than conventional CTA. In intracranial hemorrhage, 4D-CTA improves the detection of the "spot" sign, which represents active ongoing bleeding.

Acute combined revascularization in acute ischemic stroke with intracranial arterial occlusion: self-expanding solitaire stent during intravenous thrombolysis

PURPOSE

To investigate the safety and efficacy of the self-expanding Solitaire stent used during intravenous thrombolysis (IVT) for intracranial arterial occlusion (IAO) in acute ischemic stroke (AIS).

MATERIALS AND METHODS

Consecutive nonselected patients with AIS with IAO documented on computed tomographic angiography or magnetic resonance angiography and treated with IVT were included in this prospective study. Stent intervention was initiated and performed during administration of IVT without waiting for any clinical or radiologic signs of potential recanalization. Stroke severity was assessed by National Institutes of Health Stroke Scale (NIHSS), and 90-day clinical outcome was assessed by modified Rankin scale (mRS), with a good outcome defined as an mRS score of 0-2. Recanalization was rated by thrombolysis in cerebral infarction (TICI) scale.

RESULTS

Fifty patients (mean age, 66.8 y ± 14.6) had a baseline median NIHSS score of 18.0. Overall recanalization was achieved in 94% of patients, and complete recanalization (ie, TICI 3 flow) was achieved in 72% of patients. The mean time from stroke onset to maximal recanalization was 244.2 minutes ± 87.9, with a median of 232.5 minutes. The average number of device passes was 1.5, with a mean procedure time to maximal recanalization of 49.5 minutes ± 13.0. Symptomatic intracerebral hemorrhage occurred in 6% of patients. The median mRS score at 90 days was 1, and 60% of patients had a good outcome (ie, mRS score 0-2). The overall 3-month mortality rate was 14%.

CONCLUSIONS

Combined revascularization with the Solitaire stent during IVT appears to be safe and effective in the treatment of acute IAO.

Advances in revascularization for acute ischemic stroke treatment

Intravenous thrombolysis with recombinant tissue plasminogen activator is the established treatment for acute ischemic stroke patients presenting within 3 h after stroke onset. In a significant number of patients, however, intravenous thrombolysis with recombinant tissue plasminogen activator remains ineffective. New thrombolytic agents, such as reteplase, tenecteplase or desmoteplase, offer pharmacokinetic and dynamic advantages over recombinant tissue plasminogen activator and have been or are currently being tested for safety and efficacy in clinical trials. Endovascular revascularization is an evolving treatment option enabling mechanical clot disruption or extraction in combination with thrombolysis. Several new endovascular devices have been successfully tested for safety in acute ischemic stroke patients and are now being tested for efficacy in larger clinical trials. Continued innovation and refinement of endovascular technology and techniques is expected to increase technical success with a minimal procedure-related morbidity in the treatment of acute ischemic stroke.

Intra-arterial thrombolysis in acute ischemic stroke: a review of pharmacologic approaches

Ischemic stroke is a major public health problem worldwide. The potential to cure stroke patients with intravenous thrombolytic therapy has evolved to the use of intra-arterial thrombolytic agents. Fewer than 200 patients have been enrolled in randomized trials of intra-arterial therapy. In this article the authors have reviewed the literature listed in MEDLINE and EMBase, and searched relevant articles to examine the role of fibrinolytic agents in acute interventional stroke therapy. Only English language articles reporting five or more patients were included. Outcomes were defined at 90 days. Good outcome was defined on the modified Rankin Scale. Symtpomatic hemorrhage was defined as hemorrhage in the setting of clinical deterioration in the first 24 to 48 h. The search identified 57 studies of which 44 reported usable data. Only three randomized trials were reported. Of a total of 1140 patients, most (73%) were treated open-label with urokinase (Abbokinase, Abbott Laboratories). The best outcomes were reported in case series and slightly worse outcomes were reported in clinical trials. Overall, it was not possible to distinguish whether one agent was superior to the others. There is a paucity of published evidence on intra-arterial therapy for acute ischemic stroke. Alteplase (Activase, Genentech Inc.) is currently the drug of choice simply because it is available and it is the current intravenous standard. Further trials and developments are anticipated.

Evolution of thrombectomy approaches and devices for acute stroke: a technical review

While intravenous administration of tissue plasminogen activator (tPA) remains the only FDA-approved treatment modality for acute ischemic stroke, many patients do not meet the criteria for intravenous tPA and are offered intra-arterial therapy. Rapid advances in devices and approaches have marked the evolution of thrombectomy over the past decade from rudimentary mechanical disruption, followed by intra-arterial thrombolytic infusions to increasingly effective thrombectomy devices. We review the critical advancements in thrombectomy technique that have evolved and the key anatomic and technical challenges they address, from first-generation Merci retrieval systems to second-generation Penumbra aspiration systems and third-generation stent retrievers, as well as nuances of their uses to maximize their effectiveness. We also highlight more recent advances that offer patients hope for more expedient vessel recanalization.

The safety and efficacy of bridging full-dose IV-IA thrombolysis in acute ischemic stroke patients with MCA occlusion: a comparison with IV thrombolysis alone

AIMS

Early recanalization of the occluded cerebral artery is substantial for clinical improvement in acute ischemic stroke (IS) patients. The rate of achieved recanalizations using IVT is low. The aim of this study was to compare the safety and efficacy of bridging full-dose intravenous-intraarterial (IV-IA) thrombolysis to IVT alone in acute IS patients with occluded MCA.

METHODS

Seventy-nine consecutive IS patients with MCA occlusion were treated either with IVT alone (historic controls, Group 1) or with full-dose IV-IA thrombolysis (Group 2). Stroke severity was evaluated using NIHSS, achieved recanalizations using transcranial Doppler (Group 1) or angiography (Group 2). Occurrence of ICH including SICH was evaluated after 24 hours. 90-day clinical outcome was evaluated using modified Rankin Scale (mRS).

RESULTS

Group 1 consisted of 50 patients (24 males, mean age 70.8±10.2 years) and Group 2 of 29 patients (14 males, mean age 67.8±10.0 years). No difference was found in the initial NIHSS (median 16 vs. 17) and other baseline parameters including time from stroke onset to IVT. Patients treated with bridging therapy had a higher number of achieved MCA recanalization (75.9 vs. 32.0%, P=0.0002), similar number of SICH (6.0 vs. 6.9%, P=1.000) and 34.5% of them achieved mRS 0-2 versus 28.0% of patients treated with IVT (P=0.546). Patients with shorter TR had significantly better clinical outcome (P=0.019).

CONCLUSION

Bridging IV-IA thrombolysis seems to be safe and more effective than IVT alone in acute stroke patients with MCA occlusion.

Development of endovascular vibrating polymer actuator probe for mechanical thrombolysis: in vivo study

In this study, we propose a new method for the enhancement of intraarterial thrombolysis by use of an endovascular vibrating polymer actuator probe (VPAP), which is fabricated from an ionic polymer metal composite (IPMC) actuator. The endovascular VPAP was fabricated by combining 0.8 × 0.8 × 10 mm3 IPMC samples, 0.22 mm × 50 cm copper wires, and 40 cm of Teflon tube. The purpose of this study was to evaluate the thrombolysis efficiency of an endovascular VPAP in a dog model. Both renal arteries of the enrolled dogs (n = 5) were used in the current study. A distal portion of the renal artery in a mongrel dog was occluded by a blood clot from autologous venous whole blood. Intraarterial thrombolysis was performed by use of a VPAP without the actuation force (control group), by a VPAP-only (VPAP-only group), or with a combination of recombinant tissue plasminogen activator (rtPA) and a VPAP (VPAP + rtPA group). The thrombolysis efficiency was evaluated by the modified Thrombolysis in Myocardial Infarction (TIMI) grading system based on the consensus between two radiologists. The grading scales were compared according to each intraarterial thrombolysis method. The VPAP + rtPA and VPAP-only groups showed a significantly higher thrombolysis efficiency than did the control group (p < 0.05). The VPAP-only group also showed a significantly higher thrombolysis efficiency than did the control group (p < 0.05). The VPAP+ rtPA group showed a significantly higher thrombolysis efficiency than did the VPAP-only group (p < 0.05). The use of an endovascular VPAP was a feasible and useful method for intraarterial thrombolysis, and it enhanced the thrombolysis efficiency when combined with the thrombolytic agent rtPA.

Developing practice recommendations for endovascular revascularization for acute ischemic stroke

Guidelines have been established for the management of acute ischemic stroke; however, specific recommendations for endovascular revascularization therapy are lacking. Burgeoning investigation of endovascular revascularization therapies for acute ischemic stroke, rapid device development, and a diverse training background of the providers performing the procedures underscore the need for practice recommendations. This review provides a concise summary of the Society of Vascular and Interventional Neurology endovascular acute ischemic stroke roundtable meeting. This document was developed to review current clinical efficacy of pharmacologic and mechanical revascularization therapy, selection criteria, periprocedure management, and endovascular time metrics and to highlight current practice patterns. It therefore provides an outline for the future development of multisociety guidelines and recommendations to improve patient selection, procedural management, and organizational strategies for revascularization therapies in acute ischemic stroke.

Assessment of recanalization after intra-arterial thrombolysis in patients with acute ischemic stroke : proposed modification of the qureshi grading system

OBJECTIVE

We aimed to investigate the correlation between the success of recanalization and a modified version of the Qureshi grading system in acute ischemic stroke patients.

METHODS

We retrospectively analyzed the intra-arterial thrombolysis (IAT) records of 37 patients who were evaluated by Thrombolysis in Myocardial Infarction (TIMI) and a modified version of the Qureshi grading systems as follows : 1) post-IAT Qureshi grade, 2) modified Δ Qureshi grade : pre-IAT group grade - post-IAT group grade (grade 1 : Qureshi grades 0-2 and grade 2 : Qureshi grade 3-5) and 3) Δ Qureshi grade (post-IAT Qureshi grade - pre-IAT Qureshi grade). Successful recanalization was defined as follows : 1) post-IAT TIMI grades 2 and 3, 2) post-IAT Qureshi grade 0-2, 3) modified Δ Qureshi grade=1, and 4) Δ Qureshi grade of ≥2 and/or post-IAT Qureshi grade=0. We investigated the correlation between the post-IAT TIMI grade and the modified Qureshi grade and also compared the various grading systems with modified Rankin Scale scores for evaluating the clinical outcome at 3 months.

RESULTS

The post-IAT Qureshi grade and Δ Qureshi grade and/or post-IAT Qureshi grade were significantly correlated with the TIMI grade (γ=0.976 and, 0.942, respectively). Further, post-IAT Qureshi grade and Δ Qureshi grade and/or post-IAT Qureshi grade showed a significantly stronger association with clinical outcome than did the post-IAT TIMI grade (p=0.001 and, 0.000 vs. 0.083, respectively).

CONCLUSION

Our preliminary results suggest that the modified Qureshi grading system is a useful tool for assessing the success of recanalization after IAT.

Endovascular treatment strategies for acute ischemic stroke

The limitations of intravenous thrombolysis therapy have paved the way for the development of novel endovascular technologies for use in the setting of acute stroke. These technologies range from direct intraarterial thrombolysis to various thrombus disruption or retrieval devices to angioplasty and stenting. The tools in the armamentarium of the neuroendovascular interventionalist enable fast, effective revascularization to be offered to a wider population of patients that may otherwise have few therapeutic options available to them. In this paper, we review the current state-of-the-art in neuroendovascular intervention for acute ischemic stroke. Particular emphasis is placed on delineating the indications and outcomes for use of these various technologies.

CT perfusion imaging in acute stroke

Computed tomographic perfusion (CTP) imaging is an advanced modality that provides important information about capillary-level hemodynamics of the brain parenchyma. CTP can aid in diagnosis, management, and prognosis of acute stroke patients by clarifying acute cerebral physiology and hemodynamic status, including distinguishing severely hypoperfused but potentially salvageable tissue from both tissue likely to be irreversibly infarcted ("core") and hypoperfused but metabolically stable tissue ("benign oligemia"). A qualitative estimate of the presence and degree of ischemia is typically required for guiding clinical management. Radiation dose issues with CTP imaging, a topic of much current concern, are also addressed in this review.

Hemorrhage rates and outcomes when using up to 100 mg intra-arterial t-PA for thrombolysis in acute ischemic stroke

This work presents a unique single center experience with intra-arterial delivery of tissue plasminogen activator (t-PA) doses as high as 100mg for thrombolysis. Hemorrhage volumes, hemorrhage rates, clinical outcomes and radiographic outcomes were assessed. Prospectively collected angiographic, clinical and laboratory information on 67 consecutive patients with acute ischemic stroke involving either the m1 segment of the middle cerebral artery, the intracranial internal carotid artery or the basilar artery were retrospectively analyzed. Patients who received more than 50 mg t-PA were compared with those patients receiving 50 mg or less. Outcome measures included: symptomatic hemorrhage, significant hemorrhage volume (greater than 25 ml), hemorrhage rate, change in National Institutes of Health stroke scale score at 24 hours and at hospital discharge, modified Rankin score at 90 days, in-hospital deaths, death within 90 days, reperfusion rate, and infarct volume. Multivariate logistic regression analysis demonstrated that t-PA dose over 50 mg was associated with higher rates of hemorrhage and larger hemorrhages. Poor pial collateral formation, poor reperfusion (less than 50% of the territory involved), and platelet count below 200 K/μL influenced hemorrhage. Limiting t-PA dose to 100mg rather than 50mg improved documented reperfusion rates from 37% to 61%. Restricting intra-arterial t-PA administration to 100mg rather than 50mg, is associated with higher overall reperfusion rates and improves overall outcomes, however, the hemorrhage rate is also elevated. Poor pial collateral formation and platelet count less than 200 K/μL may be reasons to curtail the use of higher t-PA dose to reduce hemorrhage rate.

Intravenous rt-PA versus endovascular therapy for acute ischemic stroke

The influence of baseline stroke severity on outcome makes comparisons between nonrandomized studies of intravenous and intra-arterial (IA) therapy problematic. Using pooled data from the placebo arms of randomized trials in acute ischemic stroke, we derived predictive functions for outcome. We then compared the outcomes from published trials to these functions. Net benefit was calculated by comparison of the individual study with the predicted outcome based on the therapeutic time window. Similar net benefit for IA therapy and intravenous therapy was found at 3 hours and 6 hours; a slight advantage for IA therapy was mitigated by an increase in mortality at 6 hours and by publication bias. No net benefit for IA therapy was shown in the time window greater than 6 hours. Conclusive evidence for the superiority of either therapy awaits prospective randomized trials.

Safety and efficacy of alteplase in the treatment of acute ischemic stroke

After publication of the results of the National Institute of Neurological Disorders and Stroke study, the application of intravenous thrombolysis for ischemic stroke was launched and has now been in use for more than 10 years. The approval of this drug represented only the first step of the therapeutic approach to this pathology. Despite proven efficacy, concerns remain regarding the safety of recombinant tissue-type plasminogen activator for acute ischemic stroke used in routine clinical practice. As a result, a small proportion of patients are currently treated with thrombolytic drugs. Several factors explain this situation: a limited therapeutic window, insufficient public knowledge of the warning signs for stroke, the small number of centers able to administer thrombolysis on a 24-hour basis and an excessive fear of hemorrhagic complications. The aim of this review is to explore the clinical efficacy of treatment with alteplase and consider the hemorrhagic risks.

Intra-arterial stroke therapy: an assessment of demand and available work force

Intra-arterial therapy is currently applicable to a small subset of patients with ischemic stroke, but it will likely have an expanding role as new devices are introduced. This review evaluates the demand for such therapy and the physician work force available to provide such therapy in the United States. The available literature was reviewed to assess how many patients might need intra-arterial therapy annually and how many skilled neurointerventionalists are available to provide intra-arterial therapy for acute stroke. The number of acute ischemic strokes in the United States that will be amenable to intra-arterial therapy can only be crudely estimated, but it is certainly less than 126,000 per year and will quite likely be no more than 20,000 cases per year. The future demand for intra-arterial reperfusion techniques may change, but the number of patients who require intra-arterial thrombolysis is currently quite low. The overall number of neurointerventionists is currently adequate, though there might be local shortages.

Intra-arterial thrombolysis within three hours of stroke onset in middle cerebral artery strokes

BACKGROUND AND PURPOSE

The Prolyse in Acute Cerebral Thromboembolism II (PROACT II) trial showed improved outcomes in patients with proximal middle cerebral artery (MCA) occlusions treated with intra-arterial (IA) thrombolysis within 6 h of stroke onset. We analyzed outcomes of patients with proximal MCA occlusions treated within 3 h of stroke onset in order to determine the influence of time-to-treatment on clinical and angiographic outcomes in patients receiving IA thrombolysis.

METHODS

Thirty-five patients from three academic institutions with angiographically demonstrated proximal MCA occlusions were treated with IA thrombolytics within 3 h of stroke onset. Outcome measures included outcomes at 30-90 day follow-up, recanalization rates, incidence of symptomatic intracranial hemorrhage, and mortality in the first 90 days. The endpoints were compared to the IA treated and control groups of the PROACT II trial.

RESULTS

The median admission National Institutes of Health Stroke Scale (NIHSS) score was 16 (range 4-24). The mean time to initiation of treatment was 106 min (range 10-180 min). Sixty-six percent of patients treated, had a modified Rankin Scale (mRS) score of 2 or less at 1-3 month follow-up compared to 40% in the PROACT II trial. The recanalization rate was 77% (versus 66% in PROACT II). The symptomatic intracranial hemorrhage rate was 11% (versus 10% in PROACT II) and the mortality rate was 23% (versus 25% in PROACT II).

CONCLUSION

Time-to-treatment is just as important in IA thrombolysis as it is in IV thrombolysis, both for improving clinical outcomes and recanalization rates as well.

Predictors of hemorrhage following intra-arterial thrombolysis for acute ischemic stroke: the role of pial collateral formation

BACKGROUND AND PURPOSE

The extent of pial collateral formation during acute ischemic stroke has been shown to influence outcomes. This study examines whether angiographic assessment of pial collateral formation is predictive of hemorrhagic transformation following intra-arterial thrombolysis (IAT) for acute ischemic stroke.

MATERIALS AND METHODS

Rates of any hemorrhage and significant hemorrhage (>25 mL) were reviewed in 104 consecutive patients who underwent IAT following acute ischemic stroke. The influence of the anatomic extent of pial collateral formation on the rates of hemorrhage and significant hemorrhage relative to known predictors for hemorrhagic transformation (presenting systolic blood pressure, blood glucose level, platelet level, and National Institutes of Health Stroke Scale [NIHSS] score, history of diabetes, time to treatment, age, sex, occlusion site, and extent of reperfusion) was analyzed by using logistic regression models.

RESULTS

Rates of any hemorrhage and significant hemorrhage were 25.2% (26/104) and 9.7% (10/104), respectively. The rate of significant hemorrhage was 25.0% (8/32) in patients with poor pial collaterals and 2.78% (2/72) in those with good pial collaterals (P = .0004, Pearson correlation). The rate of any hemorrhage was also significantly higher in patients with poor pial collaterals (40.6% versus 18.1%; P = .0142, Pearson correlation). Logistic regression analyses revealed that pial collateral formation (odds ratio [OR] = 3.04), history of diabetes (OR = 4.83), platelets <200,000/microL (OR = 2.95), and time to treatment <3 hours (OR = 12.0) were statistically significant predictors of hemorrhage, whereas pial collateral formation (OR = 13.1) and platelets <200,000/microL (OR = 8.1) were statistically significant predictors of significant hemorrhage.

CONCLUSIONS

Poor pial collateral formation is associated with higher incidence and larger size of hemorrhage following IAT.

Role of recanalization in acute stroke outcome: rationale for a CT angiogram-based "benefit of recanalization" model

BACKGROUND AND PURPOSE

In acute middle cerebral artery (MCA) stroke, CT angiographic (CTA) source images (CTA-SI) identify tissue likely to infarct despite early recanalization. This pilot study evaluated the impact of recanalization status on clinical and radiologic predictors of patient outcomes.

MATERIALS AND METHODS

Of 44 patients undergoing CT/CTA within 6 hours of developing symptoms of proximal MCA ischemia, 19 patients achieved complete proximal MCA (MCA M1) recanalization. Admission National Institutes of Health Stroke Scale (NIHSS) score, onset-to-imaging time, CTA-SI Alberta Stroke Program Early CT Score, MCA M1 occlusion, cerebrovascular collaterals score, and CTA-SI lesion volume were correlated with 3- to 6-month follow-up modified Rankin Scale (mRS). We developed 2 stepwise regression models: one for patients with complete MCA M1 recanalization and one for patients without complete recanalization.

RESULTS

Complete and incomplete recanalization groups had similar median admission NIHSS scores (19 versus 19) and mean onset-to-imaging times (2.3 versus 1.9 hours) but different proportions of patients achieving mRS scores 0-2 (74% versus 40%; P = .04). The only independent predictors of clinical outcome in patients with complete recanalization were onset-to-imaging time and admission CTA-SI lesion volume (total model R(2) = 0.75; P = .01). The only independent predictors of outcome in patients with incomplete recanalization were admission CTA-SI lesion volume and NIHSS score (total model R(2) = 0.66; P = .007).

CONCLUSION

Regardless of recanalization status, admission CTA-SI lesion volume was associated with clinical outcome. Recanalization status did, however, affect which variables in addition to CTA-SI volume significantly impacted clinical outcome: time with complete recanalization and NIHSS with incomplete recanalization. This finding may support the development of a model predicting the potential clinical benefit expected with early successful recanalization.

Comparison of combined venous and arterial thrombolysis with primary arterial therapy using recombinant tissue plasminogen activator in acute ischemic stroke

OBJECTIVE

We sought to compare the safety and efficacy of combined intravenous (IV) and intra-arterial (IA) thrombolysis with primary IA therapy using tissue plasminogen activator for acute ischemic stroke presenting within 6 hours of symptom onset.

METHODS

We performed quasirandomization of a single institution's prospectively collected stroke database, comparing IV/IA (0.6 mg/kg IV < or = 60 mg, followed by 0.3 mg/kg IA < or = 30 mg) versus primary IA. Outcome measures include 90-day modified Rankin scale score, mortality, symptomatic intracerebral hemorrhage, and recanalization rates. Statistical analysis was performed using bivariate and propensity score methods.

RESULTS

Of 1057 patients, 41 patients were treated with IV/IA, and 55 with IA. There was significant difference in time to treatment (mean of 151 minutes for the combined group and 261 minutes for the IA, P < .0001) and arterial tissue plasminogen activator dose (17.5 mg for IV/IA v 22.8 mg for IA only, P = .05). Propensity score matching yielded 25 patients in each group. Symptomatic intracerebral hemorrhage rate was 12% in each group. Mortality was 20% in the IV/IA group versus 16% in the IA group (relative risk 1.3 [0.4-4.1], P = .7). More patients in IV/IA group had modified Rankin scale score less than or equal to 2 (odds ratio 1.6 [0.5-5.8], P = .3). Recanalization was 64% with IV/IA versus 48% with IA (odds ratio 1.9 [0.5-7.0], P = .3).

CONCLUSION

This study demonstrates that both combined IV/IA and primary IA recombinant tissue plasminogen activator therapy is feasible and safe in the treatment of acute ischemic stroke. Combined IV/IA therapy may be associated with an improvement in clinical outcome without a significant increase in the risk of symptomatic intracerebral hemorrhage and mortality compared with IA therapy.

Intra-arterial thrombolysis of occluded middle cerebral artery by use of collateral pathways in patients with tandem cervical carotid artery/middle cerebral artery occlusion

BACKGROUND AND PURPOSE

Cervical internal carotid artery (ICA) occlusion with middle cerebral artery (MCA) embolic occlusion is associated with a low rate of recanalization and poor outcome after intravenous thrombolysis. Prompt revascularization is required to prevent disabling stroke. We report our experience on acute ischemic stroke patients with tandem ICA or MCA occlusions treated with microcathether navigation and intra-arterial thrombolysis by use of collateral pathways including the posterior or anterior communicating arteries, or both pathways.

MATERIALS AND METHODS

We retrospectively identified 8 patients with proximal ICA occlusion associated with MCA embolic occlusions treated with intra-arterial thrombolysis (IA rtPA). Access to the occluded MCA was obtained via catheter navigation through intact collateral pathways, including posterior communicating (PcomA) or anterior communicating (AcomA) arteries, without passing a microcathether through the acutely occluded ICA. We assessed clinical outcomes using modified Rankin scale (mRS) and National Institutes of Health Stroke Scale (NIHSS).

RESULTS

Eight patients with a mean age of 57 +/- 4 years and median NIHSS of 14 were identified. Mean time from stroke onset to intra-arterial thrombolysis was 292 +/- 44 minutes. The MCA was revascularized completely in 5 of the 8 patients via collateral intra-arterial rtPA administration. All of the patients had a favorable outcome defined as a mRS of < or =2 or more at 1 and 3 months' follow-up after thrombolytic therapy. One patient had an asymptomatic petechial hemorrhage.

CONCLUSION

In this small number of patients with tandem occlusions of the ICA and MCA, intra-arterial thrombolysis and recanalization of the MCA by use of collateral pathways to bypass the occluded ICA is a safe and efficacious therapeutic option.

Angiographic analysis of intravascular thrombus volume in patients with acute ischemic stroke

PURPOSE

To investigate the role that intravascular thrombus volume plays in mechanical thrombectomy and dose-titrated algorithms using pharmaceutical thrombolytic therapies.

METHODS

The angiographic studies of 33 consecutive patients (19 women; mean age 66+/-11 years) who underwent endovascular treatment for acute ischemic stroke were reviewed. A double-injection technique was utilized that involved 2 catheters for simultaneous injection of contrast proximal and distal to the thrombus to delineate its boundaries. The thrombus volume was calculated using the formula for cylindrical objects after measuring its length and diameter.

RESULTS

The volume of the 36 thrombi measured in the study group was 46+/-59 mm3. The mean length and diameter were 10+/-6 and 2+/-1 mm, respectively. The time between symptom onset and acquisition of angiographic images ranged from 167 to 589 minutes (mean 336+/-109). In a multivariate analysis, thrombus volume was not associated with any recanalization (odds ratio 2.4, 95% CI 0.02-191) after adjusting for initial occlusion grade, time between symptom onset and angiography, and previous intravenous use of thrombolytic agents. Volume capacities for retrieval devices to retain 50% and 75% of the thrombi were estimated as 29.2 mm3 and 55.3 mm3, respectively.

CONCLUSION

The large variation in thrombi volume must be considered in designing retrieval devices to optimize their performance.

Combined intravenous and intra-arterial approach in acute stroke treatment

Despite the significant improvement in the outcome of ischaemic stroke with the use of intravenous recombinant tissue plasminogen activator, experience has shown limitations of the sole use of this approach in acute stroke treatment. This has encouraged the search for alternative managements for acute stroke. The combined use of intravenous/intra-arterial therapy is one such alternate treatment, if used in the right setting. In this review, the authors discuss the advantages and limitations of using this approach, together with an overview of the available therapies used through each route. The authors discuss the process of patient selection using clinical, as well as state of the art imaging modalities.