Stroke prevention: anti-platelet and anti-thrombolytic therapy

Treatment of chronic internal carotid artery occlusion by ipsilateral external carotid endarterectomy

Chronic complete occlusion of the internal carotid artery (ICA) is a common and important cause of ischemic cerebrovascular disease, which can be treated in many ways: antithrombotic and anticoagulant agents, direct or indirect procedure for revascularization. However, there is still no evidence to prove which method is the most effective. Here we reported a case showed the successful endarterectomy of the external carotid artery (ECA) for a chronic complete occlusion of ICA patient. A 50-year-old male patient presented with progressively aggravated left-sided limb weakness and limb cold feeling. Digital subtraction angiography (DSA) showed ICA occlusion and ipsilateral ECA stenosis. The right ECA compensated for blood supply to the middle cerebral artery (MCA) through the accessory meningeal artery and ophthalmic artery. The patient was treated by endarterectomy of ipsilateral ECA (ECEA). In the second day after operation, the symptom was improved significantly. Surprisingly, both ICA and ECA were recanalized and the metabolism of the affected brain tissue was also increased. In conclusion, patients with chronic complete occlusion, ECEA would also be an effective therapeutic method.

Surgical treatment and perioperative management of intracranial aneurysms in Chinese patients with ischemic cerebrovascular diseases: a case series

BACKGROUND

Patients with ischemic cerebrovascular diseases are more likely to suffer from intracranial aneurysms, and their surgical treatment has a growing controversy in this condition. The current case series was aimed at exploring surgical treatment and perioperative management of intracranial aneurysms in Chinese patients with ischemic cerebrovascular diseases.

METHODS

Minimally invasive surgical approach through small pterion or inferolateral forehead was applied in 31 patients. Anti-platelet drugs were withdrawn 1 week before surgical operation. Systolic blood pressure was controlled to be more than 110 mmHg and increased by 20% after the clipping of intracranial aneurysms. Branches of external carotid artery were spared to ensure collateral circulation. Temporary blocking was minimized and ischemic time was shortened during surgical operation.

RESULTS

Patients had an average age of 66 (46-78) years, and proportion of males was 39% (12 males). There were 35 unruptured intracranial aneurysms with a diameter more than 5 mm. There were 20 posterior communicating and anterior choroidal aneurysms (57%), seveb middle cerebral aneurysms (20%), and eight anterior communicating aneurysms (23%), with 21 lobular aneurysms (60%). Twenty-nine patients had normal neurological function (Glasgow Outcome Scale [GOS] 5), one patient with mild neurological defect (GOS 4), and one patient with severe neurological defect (GOS 3) at discharge. Meanwhile, there were 26 patients with modified Rankin Scale (MRS) 0-1, 4 patient with MRS 2, and one patient with MRS 3 at discharge. There were four patients lost during the follow-up. During the follow-up, 26 patients had normal neurological function (GOS 5), and one patient with severe neurological defect (GOS 3). Meanwhile, there were 25 patients with MRS 0-1, one patient with MRS 2, and one patient with MRS 3. All patients had no recurrence of intracranial aneurysms after operation.

CONCLUSIONS

The current case series found that minimally invasive surgical approach and intraoperative monitoring, supplemented by effective management of cerebrovascular perfusion, circulation and coagulation, can promote the treatment of intracranial aneurysms and prevent the development of cerebral ischemia and aneurysm rupture in Chinese patients with ischemic cerebrovascular diseases. Future studies with large sample size will be needed to confirm the results from the current case series.

Carotid occlusion is associated with more frequent neurovascular events than moderately severe carotid stenosis

OBJECTIVE

Asymptomatic internal carotid artery occlusion (CO) presents a clinical dilemma, and presently, the natural history, stroke risk, and optimal management remain ill defined. This study compared outcomes, including neurovascular events (NVEs) and health care costs, between patients with CO and patients with asymptomatic carotid artery stenosis (CS).

METHODS

A prospectively maintained database was queried to identify patients with CO and CS with at least >50% carotid stenosis by duplex. We identified and reviewed 622 consecutive patients with asymptomatic carotid artery disease at one academic medical center between 2011 and 2013. Patients with CO (n = 97) were identified and propensity matched by age and gender in a 1:2 ratio with CS patients (n = 194) for further analyses. Univariate and multivariate models were used to analyze baseline characteristics, clinical variables, and 1-year follow-up data from the date of diagnosis. Multivariate analysis was performed by multiple linear regression modeling. Institutional Review Board approval was obtained.

RESULTS

Follow-up data were available for 99% of matched patients. CO patients were younger (72 vs 75 years; P < .01) and more likely male (67% vs 53%; P = .01) compared with CS patients. After propensity matching, baseline characteristics were similar between groups, with a trend toward higher use of statin therapy among patients with CO. Antiplatelet therapy was used in 79% of patients with CS and in 74% of patients with CO (P = .45). The rate of NVE among CO patients was higher than among CS patients at 1 year of follow-up (14% vs 7%; P = .03). Among those with NVE, neither antiplatelet therapy (64% vs 77%; P = .49) nor statin therapy (86% vs 77%; P = .58) appeared to have a significant effect. Health care costs ($14,361 vs $12,142; P = .44) and hospital admission rate (63% vs 71%; P = .18) were similar between groups. Not surprisingly, the rate of vascular procedures was higher in the CS group (55% vs 27%; P = .04).

CONCLUSIONS

Patients with asymptomatic CO experience more NVEs compared with similar patients with moderately severe CS. Further study of preventative strategies, including intensity of medical therapy, is warranted.

[Incremental cost-effectiveness of dipyridamole + acetylsalicylic acid in secondary prevention of ischemic noncardioembolic stroke]

BACKGROUND AND PURPOSE

The aim of secondary prevention in stroke is to avoid restrokes. The current standard treatment in Germany is a lifelong therapy with low-dose acetylsalicylic acid (ASA). As the incidence of restrokes remains relatively high from a health-care payer's perspective, the question arises, whether the combination of dipyridamole + acetylsalicylic acid (Dip + ASA) is cost-effective in comparison with a therapy based on ASA only.

METHODS

A decision-analytic cross-sectional epidemiologic steady-state model of the German population compares the effects of two strategies of secondary prevention with Dip + ASA (12 months vs. open end) and with ASA monotherapy.

RESULTS

The model predicts the following estimates: the annual incidence of initial ischemic strokes in Germany is estimated at 130,000 plus an extra 34,000 restrokes (base year 2005). Additionally, there are 580,000 people that experienced a stroke > 12 months earlier, of whom 135,000 had a restroke. Every year, nearly 89,000 Germans die of the consequences of an ischemic stroke. If Dip + ASA would have been the standard therapy in secondary prevention of ischemic stroke, an additional 7,500 persons could have been saved in 2005. Statutory health insurance would have to spend 33,000 Euro for every additional life year gained with Dip + ASA as secondary prevention strategy. If secondary prevention with Dip + ASA would be limited to the first 12 months after an initial stroke, which is the time of the highest risk for a restroke, the incremental cost-effectiveness ratio is about 7,000 Euro per life year gained. The results proved to be robust in sensitivity analyses.

CONCLUSION

Secondary prevention with Dip + ASA is cost-effective in comparison to treatment with ASA in monotherapy, because its incremental cost-effectiveness ratio is within common ranges of social willingness to pay. From the standpoint of the patient as well as the health-care payer, focusing on the first 12 months after the initial incident for intensified preventive drug treatment with Dip + ASA should be valuable from a medical as well as a health-economic perspective.

Complete occlusion of extracranial internal carotid artery: clinical features, pathophysiology, diagnosis and management

A complete occlusion of the internal carotid artery (ICA) is an important cause of cerebrovascular disease. A never-symptomatic ICA occlusion has a relatively benign course, whereas symptomatic occlusion increases future risk of strokes. Ultrasonography, magnetic resonance imaging and contrast angiography are useful diagnostic tests, and functional imaging of the brain (eg, with positron emission tomography) helps to understand haemodynamic factors involved in the pathophysiology of brain ischaemia. Recently, there has been a resurgence of interest in the role of extracranial-intracranial bypass surgery for the treatment of completely occluded ICA. With advances in the measurement of cerebral haemodynamics, it may be possible to identify high-risk patients who could benefit from the bypass surgery.

Glycoprotein IIb/IIIa antagonist, murine 7E3 F(ab') 2, and tissue plasminogen activator in focal ischemia: evaluation of efficacy and risk of hemorrhage with combination therapy

Tissue hypoperfusion during cerebral ischemia results from occlusion of large and small vessels. Combination treatment strategies using fibrinolytics to thrombolyse an embolic clot and antiplatelet agents to prevent reocclusion and the formation of new platelet thrombi in the microcirculation may offer advantages over single-agent therapy. The authors report on the effects of tissue plasminogen activator (rt-PA), a glycoprotein (GP) IIb/IIIa receptor antagonist, 7E3 F(ab') 2, or a combination of the two agents in a focal embolic model of cerebral ischemia in Wistar rats. Focal ischemia was produced by introducing an autologous thrombus into the right side middle cerebral artery. Forty-six male Wistar rats were randomly divided into 6 groups: control (n = 8), 7E3 F(ab') 2 (n = 9, 6 mg/kg), rt-PA (n = 9, 10 mg/kg), rt-PA (n = 6, 20 mg/kg), and 7E3 F(ab') 2 with either 10 mg/kg (n = 10) (low-dose combination) or 20 mg/kg (n = 6) (high-dose combination) rt-PA. Evaluation of neurobehavioral scores, cerebral angiography, bleeding time, and measurement of brain infarction volume were used to determine efficacy. All actively treated groups showed a significant reduction in the infarct volume. Animals treated with 7E3 F(ab') 2 showed reduced infarction volumes (24.0 +/- 5.1%) compared with controls (42.43 +/- 5.6%, P < 0.02). Treatment with rt-PA significantly reduced infarction volume (20.7 +/- 3.3, = 0.01) at 10 mg/kg and at 20 mg/kg (19.5 +/- 8.2%, P < 0.05). Compared with vehicle-treated animals, the low-dose combination (16.4 +/- 5.5, P < 0.003) and high-dose combination (23.7 +/- 6.2%, P < 0.05) showed significant reduction in infarction volume. Cerebral angiography revealed significantly better recanalization in the combination group (5/6 animals in the high dose and 4/6 in low dose) compared with animals treated with 7E3 F(ab') 2 (3/10) or rt-PA alone (2/6). Bleeding time significantly increased from 11.25 +/- 1.9 minutes in the control group to 17 +/- 3.1 minutes in the rt-PA group, 24.5 +/- 2.6 minutes in the 7E3 F(ab') 2 group, 25.7 +/- 3.1 minutes in the low-dose combination group, and 32.5 +/- 4.7 minutes in the high-dose combination group. The incidence of intercerebral hemorrhage was highest in the high-dose combination group (6 of 6 animals) and lowest in the single treatment with 7E3 F(ab') 2 alone (1 of 10 animals) ( P < 0.05). Our data show that murine 7E3 F(ab') 2 alone has therapeutic effects when used after cerebral ischemia. Although this study suggests that higher doses of thrombolytic combined with anti-GPIIb/IIIa therapy may increases the risk of intracranial hemorrhage, the data also support the notion that anti-GPIIb/IIIa agents can safely be combined with low doses of thrombolytic agent to produce significant attenuation of neuronal damage with no increase in the incidence of cerebral hemorrhage.

Recent advances in the diagnosis and treatment of stroke

Stroke is defined as an abnormality in brain function resulting from disruption of cerebral circulation. It is the third leading cause of death in the United States and the primary cause of long-term disability. The economic burden of stroke will only increase as the population ages, making prevention and treatment of stroke one of the most important public health issues of the upcoming millennium. New therapies for the treatment of acute stroke, especially thrombolysis, have turned what was once considered an inevitable deficit into a potentially treatable illness. It is increasingly important for all physicians to be able to identify symptoms of cerebral ischemia. Neurons have a very limited tolerance for ischemia, making the rapid evaluation and diagnosis of stroke critical. This is particularly relevant for the ophthalmologist, who may be the first physician to see individuals presenting with visual deficits. Trials are underway to look specifically at central retinal artery and basilar artery ischemia and their response to thrombolytic therapy. This review will focus on description of recent advances in treatment and diagnosis of stroke, including thrombolytic trials and the expanding role of neuroimaging.