Intracarotid urokinase with thromboembolic occlusion of the middle cerebral artery

Evaluation of local intra-arterial fibrinolytic therapy for acute middle cerebral artery occlusion

SUMMARY

Fibrinolytic therapy for acute ischaemic stroke has been investigated in several clinical trials, with various protocols. This retrospective study was undertaken to evaluate the efficacy and limitation of local intra-arterial fibrinolytic therapy using urokinase (UK) in patients with acute middle cerebral artery occlusion. Fifty patients were treated with local intra-arterial fibrinolytic therapy within six hours after onset of symptoms. The median National Institutes of Health Stroke Scale (NIHSS) score was 17 (range, 6 to 28).Two hundred and forty thousand IU of UK was administered through a microcatheter for 20 minutes. When arterial recanalization was not achieved, a second or third infusion was performed. Maximum dosage of UK was 0.96 x 106 IU. Recanalization efficacy was evaluated at the end of fibrinolytic therapy and intracranial haemorrhage was assessed within 24 hours. Clinical outcome was evaluated three months after ictus with modified Rankin scale (RS). Thirty-nine patients (78%) obtained recanalization. Twenty-nine of 39 (74%) showed clinical improvement just after treatment. On the other hand, only 18% patients (2/11) who did not recanalize demonstrated improvement. Twenty-five of 50 (50%) patients recovered to RS score 0 or 1, however, only 28% of patients (5/18) with proximal M1 occlusion obtained good outcome and 39% of them (7/18) died. The mean time interval from onset to treatment did not affect outcome. The overall incidence of haemorrhagic event (HE) within 24 hours was 36%, however, 78% of patients with proximal M1 occlusion showed HE. Only one patient with HE clinically deteriorated. In conclusion, local intra-arterial fibrinolytic therapy could be a safe and effective method for acute middle cerebral artery occlusion, however, indication of this therapy for patients with proximal M1 occlusion should be carefully decided.

Advances in the vascular pathophysiology of ischemic stroke

The cerebral vascular supply is constructed to protect the cerebral hemispheres and brainstem from the consequences of blood flow cessation. Reversal of blood flow around local obstructions is a feature of the microvascular beds of the striatum and cerebral cortex. Cerebral capillaries of these beds consist of endothelial cells, basal lamina, and astrocyte end-feet that sit in close apposition. The interaction of astrocytes with neurons indicates the close relationship of microvessels to neurons. These relationships are altered when blood flow ceases in the supplying artery. Increased endothelial cell permeability and endocytoses lead to edema formation, and matrix degradation is associated with hemorrhage. Autoregulation is lost. Ischemia initiates leukocyte adhesion receptor expression, which is promoted by cytokine generation from the neuropil and activated monocytes. "Preactivation" may further augment the inflammatory responses to ischemia. The activation of cerebral microvessels by ischemia is heterogeneous, involving alterations in integrin-matrix interactions, leukocyte-endothelial cell adhesion, permeability changes, and the "no-reflow" phenomenon due to platelet activation, fibrin formation, and leukocyte adhesion. Ischemia produces swelling of the microvascular endothelium, and rapid detachment and swelling of the astrocyte end-feet. Ischemic injury targets the microvasculature, where the inflammatory responses are initiated and contribute to tissue injury.

Acute ischemic stroke therapy

Acute ischemic stroke is a medical emergency that requires rapid evaluation and treatment. Prehospital and emergency department care can be streamlined to meet those goals. Intravenous rt-PA therapy improves outcome in selected patients with ischemic stroke if given within 3 hours of stroke onset, but offers no benefit beyond that time window. Intra-arterial thrombolytic therapy and intravenous defibrogenating agents may also be beneficial in selected patients. Newer thrombolytic agents such as aspirin and heparin in acute ischemic stroke treatment have been clarified by recent trials.

Update on therapies for acute ischemic stroke

Acute ischemic stroke is now considered a neurological emergency for which there are new therapies. Neurosurgeons and neurologists need to remain apprised of advances in this field. The authors discuss approved and emerging therapies for patients suffering from acute ischemic stroke, based on a review of recent publications. Currently, intravenous tissue-type plasminogen activator is the only Food and Drug Administration–approved therapy for acute ischemic stroke. Intraarterial delivery of thrombolytics is a promising treatment and may be effective in selected patients. Other therapies for acute cerebral ischemia are intriguing but still in the investigational stages.

AR-R15896AR reduces cerebral infarction volumes after focal ischemia in cats

OBJECTIVE

The use of competitive and noncompetitive N-methyl-D-aspartate receptor antagonists to prevent neuronal death during ischemia has been comprehensively studied. This study was performed to examine the neuroprotective effects and pharmacokinetics of the noncompetitive N-methyl-D-aspartate receptor channel blocker (S)-alpha-phenylpyridine-ethanamine dihydrochloride, AR-R15896AR (formerly designated ARL 15896AR), using a gyrencephalic cat middle cerebral artery occlusion model.

METHODS

In a separate experiment, three cats were used for pharmacokinetic analysis, thus establishing the optimal dose of AR-R15896AR. Focal cerebral ischemia was induced in 21 cats. After 30 minutes of a 90-min ischemic insult, the cats received an intravenous infusion (total volume, 3 ml), in a 15-minute period, of either AR-R15896AR or normal saline solution (control). Physiological data were obtained after 40 and 80 minutes of ischemia and at 2, 4, and 6 hours after ischemia. At 6 hours after ischemia, each cat was positioned for both T2- and diffusion-weighted scans (eight slices, 5-mm thick). At 8 hours after ischemia, the animals were perfusion-fixed for histopathological analysis.

RESULTS

Pharmacokinetic studies indicated that AR-R15896AR remained in the blood at elevated levels for the 6 hours studied, with a calculated half-life of approximately 6 hours. AR-R15896AR rapidly entered the brain and exhibited a brain/plasma ratio of approximately 8:1. The infarction volumes for the AR-R15896AR-treated group were 1138.5+/-363.1, 651.3+/-428.9, and 118.6+/-50.1 mm3, as calculated using diffusion- and T2-weighted MRI and histopathological data, respectively. The infarction volumes for the control group were 3866.3+/-921, 3536+/-995.7, and 359.9+/-80.2 mm3, as calculated using diffusion- and T2-weighted MRI and histopathological data, respectively. No significant changes were observed in the physiological parameters measured (mean arterial blood pressure, pH, arterial carbon dioxide pressure, arterial oxygen pressure, sodium, potassium, chloride, and glucose levels, hematocrit, and temperature) for either the control or AR-R15896AR-treated group. Postischemic calcium levels returned to normal in the AR-R15896AR-treated cats, whereas they decreased in the control cats.

CONCLUSION

When administered after ischemia, AR-R15896AR was effective in significantly reducing infarction volumes, as measured using diffusion- or T2-weighted magnetic resonance imaging data or quantitative histopathological data. This study also demonstrated that infarction volumes were greater in the diffusion- and T2-weighted magnetic resonance imaging scans than in the qualitative histopathological analyses, with the diffusion-weighted scans exibiting the largest infarction volumes.

Thrombolytic therapy for stroke: a review with particular reference to elderly patients

Clinical trials in the 1990s of intravenous thrombolysis for ischaemic stroke have involved over 3000 patients. Alteplase given within 3 hours of onset significantly reduces the combined end-point of death and disability. Although alteplase appears safe when given up to 6 hours after onset, individual trials have failed to confirm efficacy beyond 3 hours. Meta-analysis indicates that intravenous alteplase given up to 6 hours after stroke onset significantly reduces death or dependence 3 months after stroke. Two trials of intra-arterial pro-urokinase confirm benefits of treatment up to 6 hours in highly selected patients with angiographically confirmed proximal middle cerebral occlusion. Streptokinase increased the risk of early death significantly in 3 trials, with no overall reduction in eventual death and disability. Patients over 80 years have been excluded from most trials of alteplase, and experience in this age group is minimal. Increased incidence and poorer functional outcome in the elderly mean that thrombolysis may have greater absolute benefit in this group than in the young, but there is also a higher prevalence of absolute or relative potential contraindications to treatment (ranging from increased use of anticoagulant drugs to higher prevalence of atrial fibrillation). Further trials are necessary to address age restrictions and other important issues in the use of alteplase. Thrombolysis is likely to remain feasible for a minority of stroke patients of all ages, and there is a need for other acute treatment options.

Cerebral hemorrhagic complications of thrombolytic therapy

Thrombolytic therapy is well established in the management of a select group of atherothrombotic and thromboembolic diseases at the expense of definite but increased risk of intracranial hemorrhage. The incidence of intracranial hemorrhage is higher (6.4% to 20%) in the thrombolytic treatment of acute ischemic stroke, whereas the cerebral hemorrhagic complications of thrombolytic treatment in acute myocardial infarction, acute pulmonary embolism, deep venous thrombosis, and arterial and graft occlusion is less than 2%. Although systemic fibrinolysis after thrombolysis is responsible for hemorrhagic complications, many factors are implicated in predisposition to cerebral hemorrhagic complications such as old age, untreated or chronic hypertension, history of cardiac disease, hyperglycemia, patients with small body mass, previous stroke, longer therapeutic treatment window, increasing neurological deficit or severity of neurological deficit, higher thrombolytic dose and computed tomography findings of mass effect, edema, or extended infarct sign involving more than one third of the territory of the middle cerebral artery. Although the knowledge of different factors associated with intracranial hemorrhage is important, it is the judicious use and strict adherence of appropriate clinical protocols in different clinical settings of thrombolytic treatment and avoidance of the contra-indications that will minimize the rate of hemorrhagic complication to achieve good clinical outcome and desired benefit.

Angiographic Classification of Cerebral Embolism

Since 1994, we have treated 62 cases with hyperacute cerebral embolism with local intraarterial thrombolysis (LIT), but not all cases showed recanalization. We tried to classify these cases by angiographic results. Angiographically they could be classified into four types; tapering type, fading type, stump type, and edge type. The tapering and fading type had a significantly higher tendency to recanalize than the stump and edge type.

We think these classifications indicate the dissolubility of the cerebral emboli; the former two types dissoluble, the latter two types indissoluble. The tapering and fading type are the good indicators for LIT, but the stump and edge type may not be.

Thrombolysis for acute stroke

Thrombolysis for acute stroke is effective if administered according to the approved protocol. Since the initial report of success in 1995, a number of subsequent reports confirmed the safety and efficacy of this treatment. There is no particular subgroup of patients at increased likelihood of benefit or hemorrhage that can be identified at baseline. Unlike many expensive therapies, thrombolysis for acute stroke saves the health care system considerable long-term costs. The search for even safer and more effective thrombolytics continues.

Intra-arterial thrombolysis for carotid circulation ischemia

Recanalization of acutely occluded arteries in the carotid territory, particularly the middle cerebral artery, by intra-arterial delivery of thrombolytic drugs, has advanced dramatically over the last decade. Randomized prospective studies have begun to show the potential impact of this form of intervention. Still, patient selection, therapeutic window, critical care support, and experience of the management team are clearly the determining features for the success of intra-arterial thrombolysis. The use of thrombolytic agents currently available, and research involving the next generation of these agents, open a field that shows promise for the improvement of outcomes of patients whose typical prognosis is poor.

Embolectomy for acute embolic occlusion of the internal carotid artery bifurcation

BACKGROUND

Acute occlusion of the distal intracranial segment of the internal carotid artery (ICA) causes sudden severe hemispheric ischemia. A low rate of recanalization and a high mortality rate for this condition have been noted, even with endovascular treatment.

METHODS

We report the results of emergency embolectomy in six patients with acute embolic occlusion of the internal carotid artery (ICA) bifurcation. All six patients were admitted to our institute within 2 h of the onset of symptoms. Computed tomography (CT) scans on admission revealed no low-density or high-density regions in any patients. The time between onset of symptoms and completion of angiography ranged from 2 to 4 h (2.8 +/- 0.7 h).

RESULTS

Emergency embolectomy was performed for each patient. Recanalization was confirmed angiographically in four of the patients. In the remaining two patients, massive infarction in the territory of the ICA was detected on the CT scans obtained the day of the operation, and postoperative angiography was not performed in these two cases. These two patients died of uncal herniation 6 days after onset. Two of the six patients were able to walk with a cane 2 months after surgery. The remaining two patients were unable to walk or attend to their own bodily needs without assistance. The time elapsed between onset of symptoms to reopening of the occluded vessel was within 6 h in the four surviving patients. The recanalization rate was 66.7% (4/6) for the embolectomy procedure, significantly higher than that (12.5%) of the thrombolytic therapy reported in a previous study.

CONCLUSIONS

In summary, open embolectomy can be performed when the time after onset of symptoms is less than 6 h.

The simple indicator for revascularization of acute middle cerebral artery occlusion using angiogram and ultra-early embolectomy

BACKGROUND

The purpose of the study was: (1) to find a clinical indicator for revascularization of acute middle cerebral artery (MCA) occlusion using angiograms of 100 patients examined immediately after onset and treated medically and (2) to investigate 10 ultra-early MCA embolectomies.

METHODS

Quantity of collateral circulation, based on time required for conduction of contrast media to the insular portion of the MCA from the anterior cerebral artery, MCA conduction time (MCT) was graded as: Grade 1: In the arterial phase, there was conduction not only to the insular portion of the MCA but also to proximal M2; Grade 2: Conduction to the insular portion was present in late arterial phase; Grade 3: Conduction was present in capillary phase; Grade 4: Conduction was present in venous phase; Grade 5: No conduction was seen. The results of embolectomy are discussed.

RESULTS

MCT can predict the extent of resultant low-density area on computed tomographic scan. For Grades 3, 4, or 5, embolectomy could be considered superior to medical treatment, if the low-density area was localized in the basal ganglia or centrum semiovale after surgery. Consequently, embolectomy was effective in four cases recanalized within 6 hours of onset. Except for one Grade 5 case, the remaining nine cases showed neither lethal hemorrhagic infarction nor brain edema. Overall outcome was significantly better than cases treated medically (p < 0.05), but some cases did not recover from hemiparesis due to infarcts in the area of the lenticulostriate arteries.

CONCLUSIONS

MCT helps to predict the applicability of revascularization of acute MCA occlusion. Efficacy of embolectomy depends on revascularization within 6 hours of onset. Even after complete MCA flow restoration, infarcts in the area of the lenticulostriate arteries cannot always be prevented.

Carotid endarterectomy and intracranial thrombolysis: simultaneous and staged procedures in ischemic stroke

PURPOSE

The feasibility and safety of combining carotid surgery and thrombolysis for occlusions of the internal carotid artery (ICA) and the middle cerebral artery (MCA), either as a simultaneous or as a staged procedure in acute ischemic strokes, was studied.

METHODS

A nonrandomized clinical pilot study, which included patients who had severe hemispheric carotid-related ischemic strokes and acute occlusions of the MCA, was performed between January 1994 and January 1998. Exclusion criteria were cerebral coma and major infarction established by means of cerebral computed tomography scan. Clinical outcome was assessed with the modified Rankin scale.

RESULTS

Carotid reconstruction and thrombolysis was performed in 14 of 845 patients (1.7%). The ICA was occluded in 11 patients; occlusions of the MCA (mainstem/major branches/distal branch) or the anterior cerebral artery (ACA) were found in 14 patients. In three of the 14 patients, thrombolysis was performed first, followed by carotid enarterectomy (CEA) after clinical improvement (6 to 21 days). In 11 of 14 patients, 0.15 to 1 mIU urokinase was administered intraoperatively, ie, emergency CEA for acute ischemic stroke (n = 5) or surgical reexploration after elective CEA complicated by perioperative intracerebral embolism (n = 6). Thirteen of 14 intracranial embolic occlusions and 10 of 11 ICA occlusions were recanalized successfully (confirmed with angiography or transcranial Doppler studies). Four patients recovered completely (Rankin 0), six patients sustained a minor stroke (Rankin 2/3), two patients had a major stroke (Rankin 4/5), and two patients died. In one patient, hemorrhagic transformation of an ischemic infarction was detectable postoperatively.

CONCLUSION

Combining carotid surgery with thrombolysis (simultaneous or staged procedure) offers a new therapeutic approach in the emergency management of an acute carotid-related stroke. Its efficacy should be evaluated in interdisciplinary studies.

The effect of reperfusion therapy on cerebral blood flow in acute stroke

The effect of reperfusion therapy on cerebral blood flow (CBF) in acute cerebral ischemia was studied using xenon-enhanced computed tomography (XeCT). The XeCT CBF studies of 10 patients were evaluated before and after thrombolytic therapy. CBF evidence of reperfusion was evaluated in relation to the angiographic results and the clinical outcomes. Six patients had occlusions of the middle cerebral artery and four of the internal carotid artery. The mean CBF of the ischemic areas before attempted reperfusion was 9 +/- 3 mL/100g/min compared with 34 +/- 9 mL/100g/min in the contralateral asymptomatic region (P<.001). Intra-arterial-thrombolysis was performed in nine patients, and in one patient the intravenous route was used. Reperfusion of the ischemic region was shown in 9 of 10 patients, both angiographically and with the XeCT CBF studies (the mean CBF increased from 9 +/- 3 mL/100g/min to 32 +/- 10 mL/100g/min, P<.001). Among the nine successfully reperfused patients, seven were neurologically improved, one was unchanged, and one died. The mean National Institutes of Health stroke scale in the eight reperfused survivors was 12 on admission and decreased to 6 on discharge. XeCT CBF measurements are correlated with the angiographic results and can assist in the understanding of the effects of thrombolytic therapy on CBF in acute stroke. Re-establishment of CBF is associated with an improved clinical outcome but exceptions can be found. Reperfusion can occur in ischemic brain regions even with very low CBF (approaching 0 mL/100g/min) although it is not associated with prevention of infarction.

Outcome in acute stroke with successful intra-arterial thrombolysis and predictive value of initial single-photon emission-computed tomography

This study investigates retrospectively, in selected patients, the ischemic outcome (reversible ischemia, infarction, and hemorrhage) and neurologic outcome of acute stroke treated with intra-arterial thrombolysis and the predictive value of pretreatment single-photon emission-computed tomography (SPECT). Thirty patients with complete recanalization within 12 hours were analyzed. The extent of ischemia was outlined on SPECT, and two CBF parameters were calculated: the ratio of ischemic regional activity to CBF in the cerebellum and the asymmetry index. Reversible ischemia, infarction, and hemorrhage were identified by comparing SPECT and follow-up computed tomography. Nine patients (30%) had no or small infarction, 14 (47%) had medium or large infarction, and seven (23%) had hemorrhage. Forty-two lesions were identified (22 reversible ischemia, 13 infarction, and 7 hemorrhage). Duration of ischemia, urokinase dose, disease type, and occlusion site were nonsignificant factors, whereas neurologic outcome and CBF parameters were significant among the three patient groups and three types of ischemic lesions. Ischemic tissue with CBF greater than 55% of cerebellar flow still may be salvageable, even with treatment initiated 6 hours after onset of symptoms. Ischemic tissue with CBF greater than 35% of cerebellar flow still may be salvageable with early treatment (less than 5 hours). Ischemic tissue with with CBF less than 35% of cerebellar flow may be at risk for hemorrhage within the critical time window. Pretreatment SPECT can provide useful parameters to increase the efficacy of thrombolysis by reducing hemorrhagic complications and improving neurologic outcome.

Relationship between cerebral blood flow and the development of swelling and life-threatening herniation in acute ischemic stroke

OBJECT

The purpose of this study was to determine whether cerebral blood flow (CBF) measurements in acute stroke could be correlated with the subsequent development of cerebral edema and life-threatening brain herniation.

METHODS

Twenty patients with aggressively managed acute middle cerebral artery (MCA) territory strokes who underwent xenon-enhanced computerized tomography (Xe-CT) CBF scanning within 6 hours of onset of symptoms were retrospectively reviewed. The relationship among CBF and follow-up CT evidence of edema and clinical evidence of brain herniation during the 36 to 96 hours following stroke onset was analyzed. Initial CT scans displayed abnormal findings in 11 patients (55%), whereas the Xe-CT CBF scans showed abnormal findings in all patients (100%). The mean CBF in the symptomatic MCA territory was 10.4 ml/100 g/minute in patients who developed severe edema compared with 19 ml/100 g/minute in patients who developed mild edema (p < 0.05). The mean CBF in the symptomatic MCA territory was 8.6 ml/100 g/minute in patients who developed clinical brain herniation compared with 18 ml/100 g/minute in those who did not (p < 0.01). The mean CBF in the symptomatic MCA territory that was 15 ml/100 g/minute or lower was significantly associated with the development of severe edema and herniation (p < 0.05).

CONCLUSIONS

Within 6 hours of acute MCA territory stroke, Xe-CT CBF measurements can be used to predict the subsequent development of severe edema and progression to clinical life-threatening brain herniation. Early knowledge of the anatomical and clinical sequelae of stroke in the acute phase may aid in the triage of such patients and alert physicians to the potential need for more aggressive medical or neurosurgical intervention.

Ischemic stroke

Acute ischemic stroke is a neurological emergency that requires ultra-rapid intervention. Stroke teams and stroke protocols can be devised to expediate evaluation and treatment. In carefully selected patients, thrombolytic therapy offers a significant benefit but must be initialized within 3 hours of stroke onset. Emerging alternative strategies for reperfusion and neuroprotection must also be initiated during the hyperacute period. The role of more traditional therapies, such as antiplatelet agents and anticoagulants, have been better defined through several recent major clinical trials.

Thrombolysis and angioplasty for acute occlusion of intracranial vertebrobasilar arteries. Report of three cases

Three cases of intracranial vertebrobasilar occlusion were successfully treated in the acute stage by thrombolysis and angioplasty. All three patients were admitted to the hospital because of consciousness disturbance and other brainstem signs. Initial angiography revealed intracranial vertebrobasilar occlusions. At first, a microcatheter was introduced into the distal site of the occlusion and thrombolysis was attempted by using urokinase. Recanalization was achieved in all cases but severe stenosis of the intracranial vertebral and basilar arteries was found. The recanalization was followed by transluminal balloon angioplasty and the stenosis was successfully resolved. Marked neurological improvement was achieved in each case. Follow-up cerebral angiography demonstrated sufficient patency at the angioplasty site after 3 to 6 months. Residual severe stenosis of vertebrobasilar arteries after thrombolytic therapy carries the possibility of reocclusion. Combining angioplasty with thrombolysis to avoid rethrombosis and obtain sufficient distal blood flow is of significant benefit in treating vertebrobasilar occlusion.

Interventional use of plasminogen activators in central nervous system diseases

Still an experimental approach, the direct intra-arterial infusion of plasminogen activators in the setting of acute thrombotic stroke has received impetus from successful clinical trials of intravenous infusion therapy. Direct therapy, employing catheter delivery, has successfully produced evidence of recanalization in carotid artery territory and vertebrobasilar artery territory thrombotic occlusions. One very recent prospective randomized study has demonstrated the success and limitations of this approach. Attention to safety concerns will be important to the future success of direct intra-arterial delivery of plasminogen activators in acute thrombotic stroke.

Thrombolytic therapy in the treatment of stroke

Approximately 80 to 90% of cerebral ischaemic events that occur within 24 hours of symptom onset are due to atherothrombotic or thromboembolic occlusions. This forms the rationale for the use of thrombolytic agents in patients with acute ischaemic stroke. Early studies determined that recanalisation occurred in approximately 21 to 72% of patients with occluded cerebral arteries after intra-arterial or intravenous administration of streptokinase, urokinase, alteplase (recombinant tissue-type plasminogen activator; rt-PA) or duteplase (a 2-chain rt-PA). Initial reports suggested that frequencies of haemorrhagic transformation and parenchymatous haematoma in the carotid territory were similar whether patients with middle cerebral artery stroke received thrombolysis via intra-arterial or intravenous administration. The Multicentre Acute Stroke Trial-Europe (MAST-E), the Australia Streptokinase (ASK), and the Multicentre Acute Stroke Trial-Italy (MAST-I) trials, which evaluated intravenous streptokinase 1.5 x 10(6) IU in patients with acute ischaemic stroke, were terminated prematurely because of excessive early mortality and symptomatic intracranial haemorrhage in streptokinase recipients compared with those treated with placebo. However, those studies had not been preceded by dose-ranging trials. Intravenous administration of alteplase 0.9 mg/kg within 3 hours [National Institute of Neurological Disorders and Stroke (NINDS) trial], or 1.1 mg/kg within 6 hours [European Cooperative Acute Stroke Study (ECASS)], of symptom onset in patients with acute ischaemic stroke resulted in an absolute 11 to 13% treatment-associated improvement in clinical measurement scales; such as the modified Rankin scale and Barthel index, compared with placebo recipients. In the ECASS trial, those results were limited to a 'target population' restricted to those who satisfied all entry criteria. In both trials, the frequency of symptomatic haemorrhage was greater in patients treated with alteplase than with placebo and reinforced the importance of careful patient selection. Strict patient selection remains central to the success of this approach.

Angioplasty of Acute Occluded Cerebral Arteries

22 cases of stenosed or occluded cerebral arteries were treated by percutaneous transluminal angioplasty (PTA) in acute stage. There were 10 internal carotid lesions, 4 middle cerebral artery lesions, 5 intracranial vertebral artery lesions, and 3 basilar artery lesions. 14 cases were treated for residual stenosis after recanalization using urokinase.

Successful dilatation (over 50%) was achieved in 16 cases (73%). 3 lesions were inaccessible due to atherosclerotic change. There were no major complications. Restenosis was observed in 4 internal carotid lesions and 1 middle cerebral lesion. 7 (50%) cases with internal carotid lesions and 5 (63%) cases with vertebrobasilar lesions returned to their previous life.

The results suggest that PTA in acute stage is feasible for occlusive disease of cerebral arteries.

Intra-arterial thrombolysis in acute basilar artery thromboembolism: the initial Mayo Clinic experience

OBJECTIVE

To investigate the feasibility of intra-arterial thrombolysis in acute basilar artery thrombosis.

DESIGN

We reviewed a consecutive series of patients in whom intra-arterial thrombolysis was performed during the period from 1994 to 1996.

MATERIAL AND METHODS

Intra-arterial thrombolysis with urokinase was done in an attempt to recanalize the basilar artery in a series of nine patients with basilar artery thrombosis admitted to the neurologic intensive care unit. At the time of initial assessment, all nine patients had major neurologic deficits attributable to brain-stem ischemia, including two patients with locked-in syndrome.

RESULTS

Recanalization of the basilar artery system was successful in seven of the nine patients (a range of 2 to 13 hours after the ictus). Failure to recanalize the basilar artery occurred in two patients, who died after progressing to coma. Complete recovery or only minimal neurologic deficits were demonstrated in five of the nine patients. Despite recanalization of the basilar artery, two patients had no major change in their neurologic function, and both ultimately had severe ataxia and were fully dependent on others. A cerebellar hemorrhage occurred in one patient but without clinical worsening. Two patients had a retroperitoneal hematoma.

CONCLUSION

Intra-arterial thrombolysis with urokinase in acute basilar artery occlusion resulted in recanalization in seven of the nine patients (78%). Five of the nine patients recovered fully, including two patients who had had locked-in syndrome. In light of the devastating natural course of acute basilar artery occlusion, these initial results are encouraging and indicate that intra-arterial thrombolysis may be a useful emergency treatment, even in patients with prolonged symptoms of ischemia (up to 12 hours).

Intraoperative high-dose regional urokinase infusion for cerebrovascular occlusion after carotid endarterectomy

Operative stroke complicating carotid endarterectomy is traditionally treated by reexploration of the operative site to correct a potentially causative lesion; however, attempts are not made to diagnose or treat the intracranial arterial occlusion. A 65-year-old man had a right hemiplegia during a left carotid endarterectomy that was caused by premature reversal of heparin, which resulted in thrombosis of his left anterior cerebral artery. On reexploration, the patient was treated with a 1-hour infusion of 1 million U urokinase through an indwelling carotid shunt. A repeat arteriogram demonstrated patency of the left anterior cerebral artery, with complete clot dissolution and resolution of the right hemiplegia on awakening. Natural history studies of stroke and prospective, angiographically controlled clinical trials of intraarterial thrombolytic therapy for acute stroke support the use of intraoperative intraarterial infusion of urokinase as part of a therapeutic approach to patients who have an ischemic stroke during carotid endarterectomy.

Hemorrhagic transformation and microvascular integrity during focal cerebral ischemia/reperfusion

Hemorrhagic transformation after cerebral ischemia is a well known clinical concern. The frequency of intact basal lamina (BL), identified by laminin antigen, in hemorrhagic and nonhemorrhagic zones after middle cerebral artery occlusion (MCA:O) and 3-h MCA:O with reperfusion in adolescent male baboons was assessed. Parenchymal hemoglobin was not detected prior to 24-h reperfusion. A significant decrease in the density of laminin (BL) in hemorrhagic zones (6.2 +/- 2.4) compared with nonhemorrhagic ischemic zones (10.5 +/- 2.4) (p < 0.05) and nonischemic basal ganglia (17.0 +/- 2.7) (p < 0.01) was observed. Time-dependent changes in BL integrity appear linked to the extravasation of blood components.

Vertebrobasilar thrombosis: diagnosis, management, and the use of intra-arterial thrombolytics

OBJECTIVES

To review the diagnosis and management of vertebrobasilar thrombosis and to discuss the use of thrombolytics in the treatment of this disease.

DATA SOURCES

Selected references discussing epidemiology, anatomy, pathophysiology, diagnosis, therapy, and rehabilitation of vertebrobasilar occlusive disease.

STUDY SELECTION

Studies addressing acute intervention and outcome in the therapy of vertebrobasilar thrombosis were reviewed.

DATA EXTRACTION

Only those studies with angiographic documentation of arterial thrombosis and, in the case of thrombolysis, recanalization, were considered valid.

DATA SYNTHESIS

Thrombosis of the vertebrobasilar system is a highly fatal disease and should be treated as a neurologic emergency. The key to effective management depends on early recognition of the symptom complex and a thorough understanding of the anatomy and pathophysiology of the disease process.

CONCLUSIONS

A timely, integrated, multidisciplinary approach to the patient with vertebrobasilar thrombosis can improve outcome. The use of thrombolytics in the treatment of vertebrobasilar occlusion holds promise but the benefits have not yet been proven in a controlled, randomized study.

Thrombolytic therapy for cerebral infarction

Until recently, no clinically effective therapy for acute ischemic stroke has been available. Recent advances in the use of thrombolytic therapy for ischemic stroke appear promising in clinical care. As the use of thrombolytic therapy in acute stroke progress, emergency physicians (EPs) will become increasingly involved in its implementation. The EP must be cognizant of both prior and ongoing investigations in acute ischemic stroke therapy. To that end, this article reviews research in the field of thrombolytic therapy for acute ischemic stroke.

Radiologic intervention in the acute stroke patient

Overall, stroke is a common disease that can have devastating results. Treatment of stoke has been, for the most part, supportive in nature. Recently, more aggressive intervention has been used, particularly thrombolysis. Although such intervention can have devastating consequences, it has shown some promise, particularly in the arena of intraarterial administration. Although much work is needed to find the ideal agents and methods of administration, screening of patients may hold the key to success and the limitations of complications. Determination of exactly which patients will benefit and which will not and which will have complications and which will not, remains for the most part an enigma. Only through further investigation in a controlled, collaborative manner can such information be obtained.

Evaluation of time-dependent thresholds of cerebral blood flow and transit time during the acute stage of cerebral embolism: a retrospective study

BACKGROUND

Neurons within the ischemic penumbra are thought to be in a potentially reversible state of ischemic challenge. One therapeutic approach that is being actively explored is the recovery of function of cells within the ischemic penumbra through endovascular recanalization of cerebral arteries occluded with embolus. The purpose of this study was to determine the time-dependent hemodynamic threshold for the prevention of irreversible ischemia in patients with acutely symptomatic internal and middle cerebral artery (MCA) embolism.

METHODS

Thirty-six patients admitted within 6 hours of the onset of symptoms of acute cerebral ischemia, due to embolic occlusion of the major trunk of one of the arteries of the anterior cerebral circulation, were studied. On admission, both cerebral blood flow (CBF) and mean transit time (MTT) measurements were obtained following plain computed tomography (CT). All patients were treated by intraarterial administration of urokinase. MTT in the territory of the affected MCA divided by that in the territory of the unaffected MCA was defined as %MTT.

RESULTS

A significant negative correlation was found between MTT and CBF. In patients with at least 19 mL/100 g/minute CBF and a maximum of 1.6 %MTT, no cortical infarction occurred whether or not recanalization was obtained. Cortical infarction did not appear in patients with 9 mL/100 g/minute residual CBF and infinite %MTT in whom recanalization was achieved within 2 hours of onset, in patients with 13 mL/100 g/minute residual CBF and 3.7 %MTT in whom recanalization was achieved within 2.5 hours of onset, and in patients with 14 mL/100 g/minute residual CBF and 2.8 %MTT in whom recanalization could be achieved within 3.5 hours of onset.

CONCLUSIONS

CBF and MTT thresholds for conversion of reversible to irreversible ischemia can be rapidly determined by CT-based technologies. This type of information should be clinically relevant to guiding the management of patients with cerebral embolism.

Effects of acute percutaneous transluminal recanalization on cerebral embolism

The effects of percutaneous transluminal recanalization (PTR) on critical hemodynamics of cerebral embolism were studied using stable xenon-enhanced computed tomography in patients within 6 hours after onset. PTR was conducted in 10 cases (PTR group) and not conducted 8 cases (non-PTR group). The development of infarction was followed by CT scan. In the cortical arterial regions, the lowest cerebral blood flow (CBF) value in regions of interests (ROIs) without development of infarction was 12.9 ml/100 g/min in the PTR group and 17.0 ml/100 g/min in the non-PTR group. In ROIs with a cerebrovascular reserve capacity (CRC) less than 0 ml/100 g/min, even with a CBF greater than 12.9 ml/100 g/min, 3 of 4 ROIs underwent cerebral infarction. PTR conducted within 6 hours after onset of cerebral embolism would prevent the cortical regions with a CBF greater than 12.9 ml/100 g/min and with a CRC greater than 0 ml/100 g/min from undergoing cerebral infarction.

Intra-arterial thrombolysis in acute ischaemic stroke: experience with a superselective catheter embedded in the clot

OBJECTIVES

To report experience of intra-arterial thrombolysis for acute stroke, performed with a microcatheter navigated into the intracranial circulation to impale the clot.

METHODS

Patients were selected on the following criteria: (1) clinical examination suggesting a large vessel occlusion in stroke patients between 18 and 75 years; (2) no radiographic signs of large actual ischaemia on CT at admission; (3) angiographically documented occlusion of the middle cerebral artery (MCA) stem or of the basilar artery (BA), without occlusion of the ipsilateral extracranial internal carotid artery or of both the vertebral arteries; (4) end of the entire procedure within six hours of stroke. 12 patients with acute stroke were recruited, eight of whom had occlusion of the MCA stem and four of the BA. Urokinase was used as the thrombolytic agent.

RESULTS

Complete recanalisation in six MCA stem and in two BA occurred, and partial recanalisation in two MCA stem and one BA. There was no recanalisation in one BA. A clinically silent haemorrhage occurred in two patients, and a parenchymal haematoma in one patient, all in MCA occlusions. At four months five patients achieved self sufficiency (four with MCA and one with BA occlusion). Six patients were dependent (three totally), and one died.

CONCLUSIONS

The strict criteria of eligibility allowing the enrollment of very few patients and the procedure itself, requiring particular neuroradiological expertise, make this procedure not routine. Nevertheless, the approach can be considered a possible option for patients with acute ischaemic stroke.

Intracranial intraarterial thrombolysis facilitated by microcatheter navigation through an occluded cervical internal carotid artery

This report covers a series of four patients with acute cervical carotid occlusion and profound neurological deficits who were treated with intracranial intraarterial thrombolysis. All of the patients presented with arm plegia with variable leg involvement and two of them had global aphasia. Angiography identified occlusion of the proximal internal carotid artery (ICA) in each case and intracranial thromboembolus of the supraclinoid ICA and/or its branches. Catheter navigation through the occluded ICA segment was straightforward in three patients and somewhat difficult in one patient with an 80% ICA stenosis. Intraarterial urokinase infusion along with mechanical clot disruption was performed at the clot site in the middle cerebral artery, supraclinoid ICA, and/or anterior cerebral artery. All patients had recanalization of the treated artery after urokinase infusion. Antegrade flow through the ICA was reestablished in two patients, and good collateral filling across the anterior communicating artery was established in the other two. All patients had major pretreatment deficits (mean National Institutes of Health (NIH) Stroke Score 24 +/-4) with significant improvement noted at 3 months posttreatment (NIH Stroke Score 7 +/-6;p=0.03). Two patients made a dramatic early recovery. Postprocedure computerized tomography revealed no abnormality in one and asymptomatic basal ganglia high density from repeated local contrast injections in two patients. On the basis of their findings in this small study group the authors suggest that catheter navigation through a presumably occluded carotid artery is feasible and possibly effective in thrombolytic therapy of intracranial thrombolysis. Further study with clinical trials is necessary to determine the safety and efficacy of this technique.

Lys-plasminogen as an adjunct to local intra-arterial fibrinolysis for carotid territory stroke: laboratory and clinical findings

To improve the efficacy of local intraarterial fibrinolysis (LIF), we compared different fibrinolytic drugs in a cerebral circulation model in the laboratory. The technical efficacy of fibrinolysis, defined as the clot volume lysed per unit time, was found to be optimal with r-tissue plasminogen activator (TPA) activated lys-plasminogen (= plasmin). Subsequently, 20 patients with stroke due to carotid artery territory occlusion were treated by local intraarterial fibrinolysis using the plasmin regimen. The angiographic data and clinical outcome of these patients were compared with those of 40 patients who received plasminogen activators (urokinase or r-TPA) only. Laboratory and clinical data confirmed that plasmin lysis is superior to treatment using only plasminogen activators.

Transcranial duplex monitoring discloses hemorrhagic complication following rt-PA thrombolysis

INTRODUCTION

Transcranial color-coded sonography (TCCS) allows imaging of basal cerebral arteries as well as brain parenchyma. It may therefore serve to monitor thrombolysis in acute stroke.

CASE DESCRIPTION

rt-PA thrombolysis was performed in a patient, suffering from paradoxical embolism causing MCA occlusion. Hemorrhage immediately after completion of rt-PA infusion as well as delayed MCA recanalization could be monitored by TCCS.

CONCLUSION

TCCS is useful to improve monitoring and safety of systemic thrombolytic treatment.

Local thrombolytic therapy for cerebrovascular disease: current Oregon Health Sciences University experience (July 1991 through April 1995)

PURPOSE

This report details experience with local intraarterial or intradural sinus thrombolytic therapy for cerebrovascular thromboembolic occlusions in 40 patients.

PATIENTS AND METHODS

Between July 1991 and April 1995, intracranial local thrombolytic therapy with urokinase was used to treat 40 patients with occlusive vascular disease. Twenty-six patients had acute occlusions of the central retinal artery, middle cerebral artery, basilar artery, or combined internal carotid and middle cerebral arteries. Three patients had embolic complications related to cerebral vascular embolization procedures. Five patients were undergoing intracranial angioplasty procedures for occlusive atheromatous disease. Six patients had dural sinus thrombosis.

RESULTS

Local intraarterial thrombolytic therapy for acute thromboembolic arterial occlusions resulted in excellent restoration of perfusion in 18 patients, partial restoration of flow in four patients, and no effect in five patients. Fourteen of these patients had excellent clinical outcomes, seven made moderate improvements, and six died. In the two patients with central retinal arterial occlusions, no angiographic or clinical response to thrombolytic therapy could be ascertained. There was no angiographic improvement response from thrombolytic therapy in five patients with primary intracranial atheromatous stenosis, and one patient may have had an embolic complication related to this therapy. Three of six patients with dural sinus thrombosis had clearing of the thrombus and an excellent clinical result. The remaining three with extensive dural thrombosis did not have clearing of the thrombus; one patient became blind, and two patients died. Among the 40 patients treated, significant cerebral hemorrhage occurred after therapy in four.

CONCLUSION

Local thrombolytic therapy for thromboembolic occlusive cerebrovascular disease is useful in restoring perfusion of acutely occluded vessels. Further experience is needed to fully identify the most appropriate patients for therapy, dose of thrombolytic agent, timing and length of therapy, and risk factors for hemorrhage.

Interventional neuroradiology

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Intrathrombus administration of tissue plasminogen activator in acute cerebrovascular occlusion

Intraarterial thrombolysis for acute cerebrovascular occlusion has achieved recanalization at a 50-90% rate. Clinical outcome has been unpredictable. The authors sought to test the hypothesis that intrathrombus administration of recombinant tissue plasminogen activator (rt-PA) would improve recanalization rate and to assess the possibility that clinical outcome would be predicted by the extent of collateral flow. Seven patients with acute cerebrovascular occlusion (less than six hours in 6, twenty-four hours in 1) were treated with intrathrombus rt-PA at 1 mg/minute. Examinations were scored on a five-point motor scale. Collateral flow was assessed angiographically. Vessels recanalized in 5 patients, 3 of whom had good outcomes. Vessels failed to recanalize in 2 patients, 1 of whom had good outcome. Good collateral flow was evident in all 4 patients with good outcome and in none of those with poor outcome. Intrathrombus administration of rt-PA is technically feasible. Favorable clinical outcome is more likely in the presence of good collateral flow. In the absence of good collateral flow, ultra-early intervention may be necessary.

Intraoperative urokinase infusion for embolic stroke during carotid endarterectomy

Embolic stroke is an infrequent complication of carotid endarterectomy. Somatosensory evoked potential monitoring detected delayed acute neurological deterioration during endarterectomy performed on a 71-year-old woman. Intraoperative arteriography performed via an indwelling shunt revealed thrombus within the middle cerebral artery and distal branches. A microcatheter was placed into the internal carotid artery via the arteriotomy and advanced into the middle cerebral artery. Urokinase was infused into and around the thrombus until almost complete thrombolysis had been achieved. The patient recovered quickly and was discharged without neurological deficit.