Anticoagulant and Platelet-Antiaggregating Therapy in Stroke and Threatened Stroke

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 treated. 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.

Conclusions:

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.

OCCIPITAL ARTERY-TO-POSTERIOR INFERIOR CEREBELLAR ARTERY BYPASS FOR TREATMENT OF BILATERAL VERTEBRAL ARTERY OCCLUSION: THE ROLE OF QUANTITATIVE MAGNETIC RESONANCE ANGIOGRAPHY NONINVASIVE OPTIMAL VESSEL ANALYSIS

OBJECTIVE

Patients with partial or complete bilateral vertebral artery occlusion often present with signs and symptoms of transient ischemic attacks or infarction. Advances in phase contrast magnetic resonance imaging have led to noninvasive assessment of volumetric blood flow rates and direction that help in the workup and management of these patients.

CLINICAL PRESENTATION

We present the case of a patient with symptoms of vertebrobasilar insufficiency without previous transient ischemic attacks or stroke. Quantitative magnetic resonance angiography (QMRA) demonstrated bilateral vertebral artery occlusion with reversal of flow in the basilar and vertebral arteries to the level of the posterior inferior cerebellar arteries bilaterally. A prominent right posterior communicating artery filled the basilar artery and proximal vertebral arteries.

INTERVENTION

The presence of reversal and diminished flow in the basilar and vertebral arteries suggested that occipital artery-to-posterior inferior cerebellar artery bypass would improve posterior circulation, relieve symptoms, and reduce the risk of infarction. Postoperative QMRA and angiography confirmed revascularization, and QMRA confirmed correction of blood flow direction.

CONCLUSION

This case illustrates the potential of QMRA as part of a comprehensive cerebrovascular assessment, operative planning, and follow-up of patients with vertebrobasilar insufficiency.

Interventional neurovascular techniques in the treatment of stroke--state-of-the-art therapy

Interventional neurovascular techniques for the treatment of patients presenting with symptoms of acute or impending stroke, are now being utilized with increasing frequency in three major areas. (i) For patients presenting with cerebrovascular ischaemic symptoms due to haemodynamically significant stenosis from atherosclerosis, vasculitis, intimal hyperplasia, and dissection, cerebral percutaneous transluminal angioplasty has been shown to be beneficial for both extracranial and intracranial disease. (ii) Patients with acute, embolic occlusion of the internal carotid, middle cerebral, distal vertebral, and basilar arteries have been successfully treated by placement of microcatheters directly into the thrombus with successful thrombolysis, recanalization, and reperfusion to the distal ischemic brain. (iii) Acute arterial vasospasm secondary to subarachnoid haemorrhage is now being managed by balloon angioplasty in those instances where conventional medical therapy has failed. These techniques are altering our current management and broadening the therapeutic alternatives for patients who present with acute cerebrovascular insufficiency and stroke in evolution. As wider experience is gained in these techniques, the clinical indications for their use will also broaden.

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.

Endarterectomy of the intradural vertebral artery via the far lateral approach

Transient ischemic attacks (TIAs) of the posterior circulation are associated with a significant risk of subsequent infarction, particularly when caused by stenotic lesions in the intracranial portion of the vertebral artery (VA). Eight patients who had persistent posterior circulation TIAs despite receiving maximal medical therapy (including anticoagulation) and who had angiographic evidence of severe stenosis of the proximal intracranial VA with poor collateral flow were treated by endarterectomy of the intradural VA. Their ages ranged from 52 to 65 years. Five of these operations were performed via the far lateral approach. In all patients, the contralateral VA was hypoplastic or occluded, or ended in the posterior inferior cerebellar artery. Postoperative angiograms showed that the arteries of five of the patients were widely patent, one was improved but still stenotic, and two were occluded. The latter two patients subsequently underwent thrombectomy, after which the artery was patent in one patient and remained occluded in the other. After surgery, the TIAs of seven patients were relieved completely, and the patients were neurologically intact. The patient with persistent occlusion ultimately had moderate disability. Complications included the two cases of thrombotic occlusion that required a second operation, three cases of communicating hydrocephalus that required lumboperitoneal shunts, and two cases of transient dysfunction of the 9th and 10th cranial nerves. Suitable patients with persistent posterior circulation TIAs refractory to medical therapy who have appropriate angiographic evidence of proximal VA stenosis and poor collateral flow may benefit from endarterectomy of the intradural VA.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis of occipital artery to anterior inferior cerebellar artery with interposition of superficial temporal artery. Case report

A 56-year-old man with vertebrobasilar insufficiency and associated findings including quadriparesis, dysarthria, cerebellar ataxia, nystagmus, and somnolence underwent left occipital artery (OA) to anterior inferior cerebellar artery (AICA) anastomosis with interposition of a superficial temporal artery (STA) graft. This procedure was chosen because cerebral angiograms demonstrated occlusion of the right vertebral artery (V3) and severe stenosis of the V4 segment of the left vertebral artery, with perfusion of the territory of the left posterior inferior cerebellar artery via the ipsilateral AICA, and because dissection of the OA is a relatively difficult and time-consuming procedure. Dissection of the STA, on the other hand, is much easier. Preoperative measurements of local cerebral blood flow in the vertebrobasilar circulation before and after intravenous administration of acetazolamide (500 mg) were obtained, and demonstrated low flow and hemodynamic compromise in the posterior circulation. The patient's hemodynamic and neurological status improved following surgery. In this report, we present a new and simplified method of OA-AICA anastomosis with interposition of STA graft.

Transluminal angioplasty for atherosclerotic disease of the vertebral and basilar arteries

Transluminal angioplasty for hemodynamically significant stenosis (> 70%) involving the posterior cerebral circulation is now being performed by the authors in selected cases. A total of 42 lesions affecting the vertebral or basilar artery have been successfully treated by percutaneous transluminal angioplasty techniques in 41 patients. The lesions involved the proximal vertebral artery in 34 cases, the distal vertebral artery in five, and the basilar artery in three. Patients were examined clinically at 1 to 3 and 6 to 12 months after angioplasty. Three (7.1%) permanent complications occurred, consisting of stroke in two cases and vessel rupture in one. There were four (9.5%) transient complications (< 30 minutes): two cases of vessel spasm and two of cerebral ischemia. Clinical follow-up examination demonstrated improvement of symptoms in 39 cases (92.9%). Radiographic follow-up studies demonstrated three cases (7.1%) of restenosis involving the proximal vertebral artery; two were treated by repeat angioplasty without complication, and the third is being followed clinically while the patient remains asymptomatic. In patients with significant atherosclerotic stenosis involving the vertebral or basilar artery territories, transluminal angioplasty may be of significant benefit in alleviating symptoms and improving blood flow to the posterior cerebral circulation.

Vertebrobasilar insufficiency: stable xenon computed tomography-cerebral blood flow study in posterior circulation revascularization

Preoperative and postoperative local cerebral blood flow were measured by the stable xenon computed tomography-cerebral blood flow technique in 15 patients with vertebrobasilar insufficiency. The surgery included end-arterectomy or angioplasty of the vertebral artery (five cases), superficial temporal artery-superior cerebellar artery anastomosis (eight cases), and superficial temporal artery-posterior cerebral artery anastomosis (two cases). Fourteen (93.3%) of the 15 patients improved in the post-operative period. Low local cerebral blood flow in the ischemic area without infarction manifested a constant and significant increase postoperatively. In summary, the stable xenon computed tomography-cerebral blood flow technique is thought to be a simple and useful method for assessing local cerebral blood flow in posterior circulation perioperatively.

Treatment of ischemic stroke. Lessons from clinical trials

The tools and methods of epidemiology, particularly the clinical trial, help guide the clinical practice of medicine. Dr Gorelick reviews the results of major clinical trials for prevention of transient cerebral ischemia and atherothrombotic stroke and assesses the effect of these findings on treatment.

A randomized trial comparing ticlopidine hydrochloride with aspirin for the prevention of stroke in high-risk patients. Ticlopidine Aspirin Stroke Study Group

We report the results of the Ticlopidine Aspirin Stroke Study, a blinded trial at 56 North American centers that compared the effects of ticlopidine hydrochloride (500 mg daily) with those of aspirin (1300 mg daily) on the risk of stroke or death. The medications were randomly assigned to 3069 patients with recent transient or mild persistent focal cerebral or retinal ischemia. Follow-up lasted for two to six years. The three-year event rate for nonfatal stroke or death from any cause was 17 percent for ticlopidine and 19 percent for aspirin--a 12 percent risk reduction (95 percent confidence interval, -2 to 26 percent) with ticlopidine (P = 0.048 for cumulative Kaplan-Meier estimates). The rates of fatal and nonfatal stroke at three years were 10 percent for ticlopidine and 13 percent for aspirin--a 21 percent risk reduction (95 percent confidence interval, 4 to 38 percent) with ticlopidine (P = 0.024 for cumulative Kaplan-Meier estimates). Ticlopidine was more effective than aspirin in both sexes. The adverse effects of aspirin included diarrhea (10 percent), rash (5.5 percent), peptic ulceration (3 percent), gastritis (2 percent), and gastrointestinal bleeding (1 percent). With ticlopidine, diarrhea (20 percent), skin rash (14 percent), and severe but reversible neutropenia (less than 1 percent) were noted. The mean increase in total cholesterol level was 9 percent with ticlopidine and 2 percent with aspirin (P less than 0.01). The ratios of high-density lipoprotein and low-density lipoprotein to total cholesterol were similar in both treatment groups. We conclude that ticlopidine was somewhat more effective than aspirin in preventing strokes in this population, although the risks of side effects were greater.

Complications of intracranial bypass for vertebrobasilar insufficiency

The authors' initial experience with intracranial revascularization of vertebrobasilar insufficiency, reported previously, fortunately yielded reasonably good results with high patency rates but in some cases there were significant, albeit temporary, complications. Since that time, major brain-stem strokes have occurred in two patients following superficial temporal to superior cerebellar artery bypass procedures. This occurrence has caused the authors to reassess their experience with this procedure and review the published literature with regard to complications. This review and the results of the international bypass study on anterior circulation ischemia suggest that a very cautious and conservative approach should be taken prior to considering intracranial bypass to the superior cerebellar or posterior cerebral artery.

Ticlopidine-pentoxifylline combination in the treatment of atherosclerosis and the prevention of cerebrovascular accidents

This randomized, double-blind study on 79 patients reported the efficacy of ticlopidine-pentoxifylline combination in the treatment of atherosclerosis and the prevention of cerebrovascular accidents. Comparisons were made with aspirin-dipyridamole-buflomedil and buflomedil-placebo combinations as controls. Global symptoms, sensorimotor disorders and vertigo were improved in all treatment groups, although improvement tended to be more pronounced with ticlopidine-pentoxifylline. None of the groups showed any change in stenosis or vessel wall rigidity although ticlopidine-pentoxifylline reduced flow irregularity. This combination therapy also normalized the direction of flow in the ophthalmic artery in 46.2% of patients with retrograde flow prior to treatment, compared with 30.0% following aspirin-dipyridamole-buflomedil and 28.6% following buflomedil-placebo administration. Significantly fewer cerebrovascular accidents occurred after treatment with ticlopidine-pentoxifylline. In conclusion, ticlopidine-pentoxifylline showed good therapeutic efficacy against atherosclerosis and a preventative effect against new cerebrovascular accidents. This therapy was well tolerated.

Sex difference in antithrombotic effect of aspirin

A number of clinical trials suggest that the antithrombotic effect of aspirin is limited to men. To test the possibility that this is due to a sex difference in the inhibitory effect of aspirin on platelet behavior, we studied whole-blood platelet aggregation in men and women and in male patients with carcinoma of the prostate receiving hormone therapy. The in vitro inhibitory effect of aspirin on so-called spontaneous platelet aggregation induced by stirring whole blood and monitored by the decrease in the number of singleton platelets was greater in men (mean +/- SD inhibitory ratio 1.54 +/- 0.30 in men, 1.23 +/- 0.22 in women; p less than 0.001). The inhibitory effect of aspirin was reduced in orchiectomized male patients and was restored by the addition of testosterone to blood samples. Estradiol had no detectable influence on the inhibitory effect of aspirin. Testosterone thus seems to influence platelet aggregation and its inhibition by aspirin as assessed by whole-blood in vitro aggregometry. Possible mechanisms for this effect of testosterone and its relevance to the choice of antithrombotic therapy are discussed.

Medical treatment of transient ischemic attacks: does it influence mortality?

All randomized studies published on the medical treatment of transient ischemic attacks in which controls received no treatment or placebo and in which mortality was reported were reviewed. Using the odds ratio method, we analyzed the results to determine if treatment had an effect on expected mortality. Studies were analyzed separately according to the treatment modality used. Chronic anticoagulation was used in four studies and platelet inhibitors in 12 (14 trials). This meta-analysis showed that neither treatment modality significantly reduces mortality. Chronic anticoagulation may have an adverse effect, and even though platelet inhibitors appeared to reduce mortality, no significance can be demonstrated, and the 95% confidence intervals did not allow us to rule out the possibility, albeit small, of an adverse effect or no effect at all.

Failure of heparin to prevent progression in progressing ischemic infarction

Anticoagulation with heparin is frequently recommended for patients with progressing ischemic cerebral infarction, yet little data is available detailing the acute results of treatment with this agent. We report the results of continuous intravenous heparin treatment in 36 consecutive patients admitted with progressing ischemic infarction, all of whom had computed tomography scans to exclude the diagnosis of hemorrhage prior to treatment. Overall, 18 of 36 (50%) had continued neurologic worsening despite treatment. The incidence of further worsening was greater in carotid territory infarctions (14 of 19, 74%) than in either vertebrobasilar (2 of 8, 25%) or lacunar (2 of 9, 22%) infarctions (p less than 0.05, Fisher's exact test). These observations suggest that additional controlled studies of the efficacy of heparin in progressing ischemic infarction are warranted.

Vertebrobasilar insufficiency. Part 2. Microsurgical treatment of intracranial vertebrobasilar disease

Posterior circulation transient ischemic attacks have an associated risk of subsequent infarction of approximately 5% per year. Intracranial vertebrobasilar thrombo-occlusive lesions appear particularly likely to result in repetitive ischemic symptoms and in infarction due to hemodynamic insufficiency. The authors present their experience with 45 patients with symptomatic intracranial vertebrobasilar vascular disease despite maximal medical therapy. The specific operative approaches for intracranial vertebral artery endarterectomy and extracranial to intracranial posterior circulation revascularization procedures are outlined.

Vertebrobasilar insufficiency. Part 1: Microsurgical treatment of extracranial vertebrobasilar disease

Extracranial vertebrobasilar artery thrombo-occlusive disease may cause repetitive transient ischemic episodes and, less frequently, brain-stem or cerebellar infarction. This report describes 40 patients who experienced repetitive vertebrobasilar ischemic symptoms despite maximal medical therapy. The natural history, pathogenesis, and treatment options for each causative lesion are reviewed. The operative approaches to symptomatic disease of the proximal vertebral arteries, arterial compression by cervical osteophytes, traumatic lesions of the vertebral arteries, and thrombo-occlusive pathology of the distal extracranial vertebral arteries are outlined. Specific anesthetic and surgical techniques that have proved successful while achieving zero operative mortality and low perioperative morbidity rates are reported.

Microsurgical endarterectomy under barbiturate protection: a prospective study

Carotid endarterectomy has the potential to improve on the natural history of untreated carotid artery disease with respect to subsequent infarction in symptomatic patients with causative angiographic lesions. This benefit of a reduced risk of stroke can be realized only if the perioperative morbidity and mortality rates are kept low. An approach to symptomatic carotid artery bifurcation disease is outlined, with a defined protocol of microsurgical endarterectomy utilizing barbiturate protection during the period of potential focal temporary cerebral ischemia. This protocol includes preoperative antiplatelet therapy, barbiturate anesthesia, the avoidance of an internal shunt, the use of the operating microscope, and strict control of postoperative hypertension. A series of 200 consecutive endarterectomies performed within this protocol in 180 patients and the resultant combined permanent morbidity and mortality rate of 1.5% are reported.

Transient ischemic attacks. Strategies for minimizing stroke risk

In patients with transient ischemic attack (TIA), the risk of stroke increases greatly, especially in the months immediately following the initial attack. Diagnosis of TIA is based primarily on the patient's cerebrovascular history, since results of neurovascular examination are usually normal. TIA is often related to atherosclerotic arterial disease but can have numerous causes. Migraine, focal seizures, and other neurologic conditions can closely mimic TIA. Surgical and medical therapies help minimize the risk of stroke. The choice of therapy depends on the vascular territory of ischemia, the cause of the attack, the patient's medical and neurologic condition, the availability of a skilled surgeon, and other factors.