Intracarotid urokinase with thromboembolic occlusion of the middle cerebral artery

Why do all drugs work in animals but none in stroke patients? 1. Drugs promoting cerebral blood flow

Medical treatments which presumably alter cerebral blood flow (CBF) have been quite unimpressive in their effect on stroke outcome. In considering experimental and clinical data from the use of haemodilution and of the antiplatelet agent prostacyclin in focal cerebral ischaemia, and the current work with fibrinolytic agents in acute stroke, several lessons are apparent. Often agents hypothesized to affect CBF receive an underserved reputation based on sparse experimental evidence. Significant even unsuspected differences between species limit application to the clinical setting. Limitations of CBF measurements in experimental models and in humans raise questions about apparent responses to those agents. The failure to confirm a relationship between CBF enhancement and reduction in infarct development experimentally has plagued these approaches. The need for early application of agents which may modulate CBF during cerebral ischaemia is critical. Attention to these general issues and careful application of appropriate models are necessary so that a potentially useful therapeutic intervention is not overlooked.

Thrombolysis in thromboembolic diseases

Thrombolysis in many manifestations of thromboembolic disease offers a valuable alternative to surgery. However, as thrombolysis is always associated with a bleeding hazard (though low) one should always weigh the risks against the expected benefits when the decision for or against this therapeutic option is made. Furthermore, in selecting the appropriate thrombolytic agent, one should be led by the urgency of reperfusion to maintain organ function. If one decides on an aggressive, high-dose, brief-duration regimen, reperfusion may be achieved more rapidly but may be incomplete in the majority of cases. On the other hand, by selecting an intermediate- or long-duration, low-dose regimen, reperfusion may happen too late to improve the patient's prognosis. Above all, one should keep in mind that the hazard of serious bleeding constantly increases with duration of thrombolysis. No matter which strategy is regarded as the best to resolve a clot in a particular patient with a particular type of thromboembolic disease, thrombolysis should be accompanied by high doses of i.v. heparin. Finally, if bleeding occurs in spite of all precautions taken, the new generation of fibrin-specific thrombolytic agents offers the advantage of short half-lives. In addition--in contrast to streptokinase--the hemostatic defect that they cause may be rapidly reversed by the infusion of antagonist drugs such as aprotinin, tranexamic acid, or epsilon-aminocaproic acid. This adds to the clinical safety profile of these thrombolytic agents.

Thrombolytic therapy in acute stroke

PURPOSE

To report the safety and efficacy of local, direct, intra-arterial and intravenous fibrinolysis treatment in selected cases of clinically symptomatic patients with acute occlusion of the intracranial cerebral arteries and dural sinuses.

METHODS

Patients with acute progressive neurological deterioration, in spite of systemic anticoagulation and/or antiplatelet medications, presenting with occlusion of a major intracranial cerebral artery or dural sinus were tested. From a transfemoral approach through a guiding catheter, a 2.5F microcatheter was guided directly into the intracranial cerebral circulation and embedded within the clot. Infusion of urokinase was then performed directly into the thrombus until lysis was attained.

RESULTS

In 36 total patients, 27 cases were treated for an acute arterial occlusion in 45 vascular territories. Clinically, there was neurological improvement in 18 (66.7%) cases. Complications directly related to therapy included symptomatic intracranial hemorrhage in three cases (11.1%), which included 1 case (3.7%) of vessel perforation. In 8 (29.6%) patients, there was no evidence of clinical improvement, and in long-term follow-up there were 9 (33.3%) patient deaths. Nine patients were treated for an intracerebral dural sinus thrombosis in ten vascular territories by local urokinase infusion. In 7 (77.8%) cases, there was angiographic evidence of clot lysis and clinical improvement of the patient's neurological condition. Minor complications including infection and noncerebral sites of bleeding occurred in 3 (33.3%) patients, requiring adjustment in urokinase infusion therapy.

CONCLUSION

Local, direct intra-arterial or intravenous infusion of thrombolytic drugs for treatment of stroke patients may improve overall patient morbidity and mortality related to acute thromboembolic disease in the central nervous system. Further clinical studies are warranted to evaluate this form of therapy.

Acute stroke intervention with intraarterial urokinase infusion

PURPOSE

A preliminary evaluation of the efficacy and safety of treating patients with acute stroke with intraarterial urokinase infusions was performed.

PATIENTS AND METHODS

Twelve patients with acute stroke were treated within 8 hours of symptom onset (average, 5 hours). Thrombolysis was performed within the middle cerebral (n = 10), internal carotid (n = 1), and basilar (n = 1) arteries. Urokinase (160,000-500,000 IU) was infused through microcatheters placed into or adjacent to the thrombi.

RESULTS

Thrombolysis was angiographically successful in nine patients (75%), all of whom had long-term neurologic improvement. No or minimal neurologic deficits were present in six patients (50%). Thrombolysis failed in three patients (25%); one patient died and two developed severe permanent neurologic deficits. No hemorrhagic complications occurred.

CONCLUSION

Preliminary results suggest that intraarterial urokinase infusion may be effective and safe for treating patients with acute stroke. Potentially devastating neurologic damage was averted or lessened in nine patients (75%). No additional neurologic damage was caused by intervention in the remaining three patients (25%).

Febrile reaction associated with urokinase

Urokinase is an endogenously produced human proteolytic enzyme used to treat many thrombotic disorders. A 54-year-old man with recurrent myocardial infarction experienced fever during intracoronary urokinase infusion into a saphenous vein graft; the fever resolved after discontinuation of the infusion. After excluding all other possible etiologies of fever, urokinase was determined to be the cause. Several studies indicated that this reaction may be associated with urokinase infusion, but it is actually recognized by few individuals. This is the first published case report of the adverse event to our knowledge.

"Brain attack": the rationale for treating stroke as a medical emergency

Stroke is the third leading cause of death in the United States, behind only heart disease and cancer. With an estimated three million survivors of stroke in the United States, the cost to society, both directly in health care and indirectly in lost income, is staggering. Despite recent advances in basic and clinical neurosciences, which have the potential to improve the treatment of acute stroke, the general approach to the acute stroke patient remains one of therapeutic nihilism. Most basic science studies show that to be effective, acute intervention to reperfuse ischemic tissue must take place within the first several hours, as is the case with ischemic myocardium. In addition, most neuroprotective agents must also be administered within a short time frame to be effective at salvaging at-risk tissue. Recent studies have suggested that the outcome after intracerebral and subarachnoid hemorrhage is improved with early intervention. However, most stroke patients fail to present to medical attention within this short "window of opportunity." The public's knowledge about stroke is woefully inadequate. However, clinicians who deal with stroke can use the dramatic changes in the treatment of acute myocardial infarction over the last 2 decades as a guide for shaping changes in the management of acute stroke. Comprehensive educational efforts aimed at clinicians and the public at large have dramatically reduced the time from symptom onset to presentation and treatment for acute myocardial infarction, enabling treatment methods such as thrombolysis to be effective. The Decade of the Brain offers a unique opportunity to all concerned with the treatment of the patient with acute stroke to engage in a concerted effort to bring patients with a "brain attack" to specialized neurological attention within the same timeframe that the "heart attack" patient is handled. Such an effort is justified because, although at the present time there are few therapeutic interventions of "proven" value in the treatment of acute stroke, there is more than sufficient suggestive evidence that a number of approaches may be beneficial within the first few hours after the onset of the stroke.

Thrombolysis and stroke management

Up to 90% of patients (those with occlusive stroke) may be candidates for clot lysis. Fears that lysis might cause hemorrhage appear to be unwarranted. The most important clinical lesson learned to date is that the earlier the intervention, the better the outcome. Issues such as the most efficient diagnosis, most amenable sites, and IV versus intra-arterial administration are under study.

Intra-arterial fibrinolytic therapy in central retinal artery occlusion

We have treated 23 patients with central retinal artery occlusion by intra-arterial fibrinolysis, a method already in use for treatment of thromboembolic occlusion of the cerebral arteries. Fibrinolysis was carried out through a microcatheter placed in the origin of the ophthalmic artery. When ophthalmic artery cannot be catheterised, treatment can be carried out indirectly via the maxillary-ophthalmic anastomoses. In 18 cases urokinase was used in doses of 200,000-1,200,000 units; in 5 patients recombinant tissue plasminogen activator was used. Six patients showed marked improvement or total recovery, and six partial recovery, with improvement of visual acuity or a field defect. The worst results were obtained in six patients where the mean delay between the appearance of symptoms and initiation of treatment was more than 20 h. Intra-arterial thrombolysis led to a better outcome in acute occlusion of the central retinal artery than might have been expected with conservative treatment. A good prognosis is to be expected when treatment starts within the first 6-8 h, when some vision remains and when there is less retinal oedema.

Evaluation of critically perfused area in acute ischemic stroke for therapeutic reperfusion: a clinical PET study

To evaluate critically perfused areas in the acute ischemic brain, 9 patients were studied by positron emission tomography (PET) within 7-32 hours after the onset. The cerebral blood flow (CBF) and oxygen metabolic rate (CMRO2) were evaluated and compared with sequential change in CT findings. In all the regions developing subsequent necrosis on CT, CBF dropped below 17 ml/100 g/min. But in some of these lesions, CMRO2 remained above the minimum value for regions in which infarction did not develop, and the tissue density on CT obviously remained normal for several hours after PET scan. The mean CBF in these lesions (14.0 ml/100 g/min, range: 9.9-17.3 ml/100 g/min) was significantly higher than that in ischemic areas with low density on CT before or just after PET study (approximately 10 ml/100 g/min, range: 7.7-14.1 ml/100 g/min). These findings suggest that a part of the tissue with CBF between 10-17 ml/100 g/min is still viable at least 7 hours after the onset of ischemia, but becomes non-viable in a longer period of ischemia. These lesions should respond to effective treatment, including therapeutic reperfusion.

Thrombolytic Therapy: A Comprehensive Review of Its Use in Clinical Medicine. Part II

The second part of this comprehensive review of thrombolytic therapy in clnical medicien focuses on its use in a wide renge of thrombotic disorders, including pulmonary embolism, deep venous thrombosis, arterial thrombocmbolism, catheter-related thrombosis, arterial thrombocmbolism, catheter-relted thrombosis, and prosthetic valve occlusion. New experimental applications in the management of unstable angina and cerebrovascular disease are also discussed.

Stroke rates in patients with lacunar and large vessel cerebral infarctions

A stroke registry was developed to determine the value of various clinical data in distinguishing lacunar from large vessel infarctions. Adequate localization was achieved in 98% of 246 patients with brain infarcts. These and 30 transient ischemic attack patients were followed for a median of 1082 days (range 2-1657). Follow-up data on TIA patients were invalidated by evidence of serious underreporting of TIAs in our general population. Among 212 male patients with cerebral infarcts not due to cardiogenic embolism, syphilis, migraine, vasculitis, or other unusual etiologies, 1-, 12-, and 36-month recurrence rates were 23%, 31% and 39% among patients with large vessel anterior circulation infarcts; 15%, 20% and 28% among patients with large vessel posterior circulation infarcts; and 8%, 16% and 21% among patients with lacunar anterior circulation infarcts, respectively. Six patients with posterior circulation lacunes did not experience recurrence. Comparative case fatality data were also compiled. Large vessel infarcts tended to be followed by further large vessel infarcts, usually in the same vascular distribution, whereas lacunar infarcts were not predictive of the type or location of subsequent events.

Therapeutic interventions in acute stroke

1. Potential therapies for ischaemic stroke include agents to reduce oedema, to improve cerebral perfusion, to reduce excitotoxic damage, to minimise free-radical induced injury and to reduce complications such as deep venous thrombosis. 2. Of the anti-oedema drugs, steroids are ineffective and possibly dangerous; intravenous glycerol is unproven. 3. Haemodilution to reduce whole blood viscosity and improve perfusion is ineffective. Thrombolytic drugs have not been adequately tested but several randomised multicentre trials are now commencing. Early treatment and CT scanning are essential. 4. Anticoagulants and antiplatelet drugs may have wide applicability but have not been tested in the acute phase of stroke. A multi-centre trial will address this issue. 5. Neuronal cytoprotection offers exciting prospects for acute stroke treatment. Antagonists of glutamate at the NMDA receptor, calcium and sodium channel blocking agents and free radical scavenging drugs have potent effects experimentally. Several agents are now reaching clinical trials. The calcium antagonist nimodipine has been disappointing in large scale trials but some studies were flawed by late treatment. 6. Successful treatment of acute stroke is likely to combine several approaches. 7. Therapeutic trials in stroke must include CT scanning, early treatment and a multicentre approach to achieve large numbers of patients.

Clinical, radiological, and functional evaluation following acute stroke

1. There are currently no proven treatments for cerebral infarction or intracerebral haematoma. Drug testing is at an exciting phase, however, and thrombolytic and neuroprotective agents appear to have the potential to rescue ischaemic cerebral tissue. The heterogeneous nature of stroke demands adequate patient assessment by clinical and radiological study, with standardised approaches to the measurement of recovery. 2. Previous studies have not fulfilled these stringent criteria, impairing interpretation and inter-study comparison. The needs of drug studies in the acute phase following stroke are discussed in this review.

Selective and superselective infusion of urokinase for embolic stroke

Intraarterial administration of urokinase using Tracker microcatheter was performed in 11 patients with acute cerebral infarction caused by embolic occlusion of the internal carotid or the middle cerebral artery. Recanalization was observed in seven cases (64%) following the fibrinolytic therapy, and the time until recanalization from the start of the treatment was on the average 2.8 hours. Recanalization was seen in five out of six cases that received superselective infusion of urokinase, while it was seen in two out of five cases that received selective infusion. This study suggests that superselective infusion of urokinase is an excellent therapeutic method for embolic occlusion of the cerebral artery.

Local intraarterial thrombolysis for acute stroke in the carotid artery territories

We have tested the feasibility of local intraarterial thrombolytic therapy in ischemic stroke in the carotid artery territories observed within 5 h of the onset of symptoms. Only 5 of 615 consecutive patients were enrolled. They were 1 man and 4 women aged 50 to 75 years. Angiography disclosed occlusion of the M2 tract in one, of the M3 tract in one, of the carotid siphon in one of M4 tract in two. Intraarterial urokinase was infused at a mean dosage of 560,000 units close to the site of occlusion. Four of them had partial or complete recanalisation at early angiographic control and were independent at 6th month control. The one who did not demonstrate recanalisation was confined to a wheelchair. One patient, who had recanalisation, sustained a hemorrhagic transformation of the brain ischemia not interfering with outcome. Our experience, at the light of the low rate of enrollment, despite the results, suggest that intraarterial thrombolysis may be a therapeutic tool for selected patients with stroke in the carotid artery territories and not a routinary treatment for them.

Recombinant tissue plasminogen activator in acute thrombotic and embolic stroke

An open angiography-based, dose rate escalation study on the effect of intravenous infusion of recombinant tissue plasminogen activator (rt-PA) on cerebral arterial recanalization in patients with acute focal cerebral ischemia was performed at 16 centers. Arterial occlusions consistent with acute ischemia in the carotid or vertebrobasilar territory in the absence of detectable intracerebral hemorrhage were prerequisites for treatment. After the 60-minute rt-PA infusion, arterial perfusion was assessed by repeat angiography and computed tomography scans were performed at 24 hours to assess hemorrhagic transformation. Of 139 patients with symptoms of focal ischemia, 80.6% (112) had complete occlusion of the primary vessel at a mean of 5.4 +/- 1.7 hours after symptom onset. No dose rate response of cerebral arterial recanalization was observed in 93 patients who completed the rt-PA infusion. Middle cerebral artery division (M2) and branch (M3) occlusions were more likely to undergo recanalization by 60 minutes than were internal carotid artery occlusions. Hemorrhagic infarction occurred in 20.2% and parenchymatous hematoma in 10.6% of patients over all dose rates, while neurological worsening accompanied hemorrhagic transformation (hemorrhagic infarction and parenchymatous hematoma) in 9.6% of patients. All findings were within prospective safety guidelines. No dose rate correlation with hemorrhagic infarction, parenchymatous hematoma, or both was seen. Hemorrhagic transformation occurred significantly more frequently in patients receiving treatment at least 6 hours after symptom onset. No relationship between hemorrhagic transformation and recanalization was observed. This study indicates that site of occlusion, time to recanalization, and time to treatment are important variables in acute stroke intervention with this agent.

Emergency embolectomy for embolic occlusion of the middle cerebral artery after internal carotid artery balloon test occlusion. Case report

Balloon test occlusion of the internal carotid artery (ICA) is useful in preoperatively assessing the risk of temporary occlusion or permanent sacrifice of the carotid artery. The incidence of symptomatic complications from this procedure is 1.7%. The case is reported of a 57-year-old woman in whom a balloon test occlusion of the left ICA was attempted. She developed a left ICA dissection/occlusion with subsequent embolization to the left middle cerebral artery, leading to right-sided hemiplegia and expressive aphasia. She was successfully treated by an emergency embolectomy followed by surgical repair of the left ICA, with an excellent outcome. This case represents the most serious complication encountered by the authors in more than 300 balloon test occlusions. Means of avoiding this complication during balloon test occlusion as well as the important factors in managing this problem are emphasized.

The efficacy and safety of tissue plasminogen activator in acute ischemic strokes

Over the past decade there has been an increasing use of thrombolytic agents in the treatment of coronary artery disease, pulmonary embolism, and thromboembolic strokes. The use of thrombolytic agents has been most successful in treating acute myocardial infarction. When treatment with intravenous streptokinase or tissue plasminogen activator (tPA) is initiated within the first 3 to 4 hours from the onset of symptoms, the rate of reperfusion ranges from 60% to 90%, as compared to a rate of 13% to 21% for placebo control. Both streptokinase and tPA have been extensively studied as therapies for acute myocardial infarction, and in general, a higher initial rate of reperfusion is achieved in tPA-treated patients than in streptokinase-treated patients, although the final arterial patency rate may not be different in the two groups due to a higher rate of reocclusion in the tPA-treated population. Furthermore, time dependency for efficacy from the onset of symptoms to the initiation of treatment is less for tPA than for streptokinase. However, the role of thrombolytic agents in the treatment of thromboembolic strokes is more experimental than clinical at the present time. Of all agents, tPA is the most promising and the most extensively studied. This paper will review the experimental data on the use of tPA in acute thromboembolic strokes as well as the existing clinical data on stroke reperfusion.

What have drugs to offer the patient with acute stroke?

1. Drug treatment for acute stroke is designed to salvage neuronal tissue, and to prevent complications of stroke, which are often non-neurological. This review addresses the areas of recent advance in treatment designed to reduce the size of the cerebral infarct. With the exception of cardiac-source embolism, for which anticoagulation in the acute phase is sometimes considered, prevention of recurrent events is not discussed. 2. It is to be hoped that pharmaceutical developments will improve the current bleak picture in which there are no proven treatments for ischaemic stroke or intracerebral haemorrhage. To meet this challenge will require careful, controlled evaluation of treatment early after acute stroke in large scale clinical studies.

Thrombolytic therapy in cerebrovascular disorders

The knowledge obtained from the ongoing investigational trials of tPA for acute ischemic stroke will not only help establish the appropriate dose range and complication rates but will also further develop the clearly mandatory rapid, aggressive team approach needed to truly treat acute ischemic strokes successfully. Experimental cerebral ischemia data have pointed to the need to treat acute clinical stroke within only a few hours or less to effectively reduce stroke morbidity and mortality. Specifically, with reversible MCA occlusion models of focal cerebral ischemia (dogs and cats), the animals uniformly survive without neurological deficit if the occlusion is for less than 2 to 3 hours. Similarly in primates, MCA occlusion for 3 hours or less will lead to clinical improvement and a decrease in infarct size, with complete recovery generally associated with less than 2 hours of MCA occlusion. Therefore, it appears unlikely that ischemic brain can be salvaged if vascular occlusion persists longer than 4 to 6 hours (similar to the pathophysiology of myocardial ischemia). Further, at least one third of ischemic stroke patients reperfuse spontaneously (and obviously too late) within 48 hours of stroke onset. Several factors believed to be related to successful outcome after thrombolytic therapy are summarized in Table 16. A schematic approach to determining the response to thrombolytic agents in acute ischemic stroke is outlined in Table 17. Zivin succinctly reviews thrombolysis for stroke, both experimental and clinical, and summarizes some of the difficulties of the early clinical stroke trials with thrombolytic agents and speculates about future prospects. He believes tPA may prove valuable in the treatment of some forms of thromboembolic stroke. Its usefulness may depend in part on how quickly the drug can be initiated and the risk of side effects; factors that will require further study. The currently used doses of tPA may be too low to lyse large cerebral arterial clots and, therefore, if current trials do not show a positive treatment response, further trials with higher doses may be indicated. The implications of a potentially effective treatment for truly acute stroke are enormous: stroke will need to be considered by all (lay public through to caregivers) as a true medical emergency, analogous to MI and trauma.(ABSTRACT TRUNCATED AT 400 WORDS)

Thrombolysis with recombinant tissue plasminogen activator in acute ischemic stroke: evaluation with rCBF-SPECT

We treated five patients with hemispheric ischemic stroke with intravenous recombinant tissue plasminogen activator (rtPA), within 3-6 h after stroke onset. Regional cerebral blood flow was evaluated with single photon emission computed tomography (rCBF-SPECT) before and after treatment. One patient with aphasia and a moderately severe hemiparesis, who had a small flow deficit, was treated 5 h and 30 min after the onset of his stroke and had a prompt and complete recovery. The post treatment rCBF-SPECT showed normal flow. One patient with a very large flow deficit died of transtentorial herniation. In three other patient clinical condition remained unchanged, in one of them despite restoration of flow, demonstrated by transcranial doppler examination. In all these patients the rCBF-SPECT remained abnormal. rCBF-SPECT is a valuable tool in the explanatory analysis of fibrinolytic treatment in ischemic stroke.

Thrombolytic therapy and posterior circulation extracranial-intracranial bypass for acute basilar artery thrombosis. Case report

Basilar artery thrombosis has a very poor prognosis. A 56-year-old comatose man with acute basilar artery occlusion was successfully treated with local urokinase infusion which reopened the basilar artery and revealed a midbasilar stenotic plaque. This procedure was followed by a superficial temporal artery to superior cerebellar artery anastomosis for protection of the posterior circulation.

Clinical and instrumental evaluation of patients with ischemic stroke within the first six hours

The development of fibrinolytic agents such as streptokinase and recombinant tissue type plasminogen activator (r-TPA) and other modalities of treatment in acute ischemic stroke, has raised the need for a more precise knowledge of the pathophysiology of the acute phases of ischemic stroke as it pertains to prediction of clinical outcome. In a prospective analysis, 80 patients were studied within less than 6 h from the onset of symptoms by means of a detailed protocol including clinical evaluation, cerebral computed tomography, digital angiography and ultrasound transcranial Doppler sonography. Early angiography revealed a complete arterial occlusion in 76% of cases, the majority of which were intracranial (66%). Seventy percent of the occlusions that were retested were removed within 1 week. Potential embolic sources were found in more than 80% of cases. Patients with documented intracranial occlusion and scarce or absent collateral filling at early angiography, had the worst clinical outcome (P less than 0.05), based on mortality data and the Canadian Neurological Scale. The 30-day mortality rate was 25%. Survival was significantly better (P less than 0.01) in patients with a Canadian Neurological Score on entry of greater than or equal to 6.5 than in patients with a less than 6.5 value. Our data indicate that early pathophysiological studies augment the clinical information and should be taken into account in the design and analysis of therapeutic trials of acute ischemic stroke.