Stroke prevention in women: role of aspirin versus ticlopidine

Is Carotid Stenosis in Women a Gender-Related Condition?

BACKGROUND

We set out to study, through ultrasound examinations, the carotid bifurcation in men and women with/without carotid stenosis to look for anatomical and electrophysiologic differences. We evaluated other variables to look for differences that might explain the dissimilar behavior of this disease in the two sexes and the presence and impact of risk factors.

METHODS

We examined 974 subjects aged 25 to 88 years (478 men and 496 women) in whom we considered heart rate, smoking status, and the presence of hypertension, diabetes, hypercholesterolemia, and hypertriglyceridemia. Ultrasound examination of the neck vessels included measurement of intimal medial thickness (IMT), vessel diameter, and outflow area/inflow area ratio. We established plaque location, echogenicity and echostructure, and the percentage of stenosis owing to plaque and measured systolic velocity, flow direction, and the depth of detection of these parameters. We used the apnea and hyperpnea test to assess cerebrovascular reactivity.

RESULTS

Hypertension and hypercholesterolemia were the most frequent risk factors. Women had a higher heart rate, whereas men had significantly greater IMT. The presence of atheromatous plaque was significantly correlated with age in both sexes, with men having a higher prevalence of carotid plaques. The sexes differed significantly with regard to plaque location, echogenicity, echostructure, and intracranial circulation. Women had a slightly higher blood flow velocity in the intracranial arteries. Risk factors affected plaque formation and extent more in men than in women.

CONCLUSIONS

These findings suggest that carotid stenosis is a gender-related trait.

Retrospective analysis of aspirin and ticlopidine in preventing recurrent stroke following an initial lacunar infarct

Of 73 patients with initial lacunar stroke subsequently treated with aspirin, 13 (18%) developed recurrent stroke (11 lacunar infarcts and 2 nonlacunar infarcts), and 4 (5%) died within 1 year. Of the aspirin-treated lacunar infarct patients, 58 received 325 mg or lower-dose aspirin, and 15 received 600-1,300 mg of aspirin. Thirteen aspirin-treated patients who developed recurrent ischemic stroke received 80 mg or 325 mg of aspirin, whereas recurrent stroke did not occur in 15 patients treated with 600-1,300 mg of aspirin daily. Of 25 patients with lacunar stroke who were subsequently treated with 250 mg of ticlopidine twice daily, 1 patient (4%) developed recurrent lacunar infarct, and none died within 1 year. Of 10 patients who had an initial lacunar stroke and subsequently received no antiplatelet medication, 4 (40%) developed recurrent lacunar stroke, and 1 (10%) died within 1 year.

Transient ischemic attack and risk of stroke recurrence: The Lehigh Valley Recurrent Stroke Study

We investigated the effect of transient ischemic attack occurring both before and after an initial stroke on risk of recurrent stroke in a population-based study. In the Lehigh Valley Recurrent Stroke Study, patients were enrolled between July 1987 and August 1989 and followed up regularly at about 6-month intervals for up to 4 years (mean, 2 years). In addition to history of transient ischemic attack before and after the initial stroke, information on comorbidities including hypertension, myocardial infarction, cardiac arrhythmia, and diabetes mellitus was collected at the baseline visit and at follow-up visits. The 621 patients with an initial ischemic stroke constituted the cohort analyzed in this report. A history of transient ischemic attack was present at enrollment in 114 (18.4%) patients. During follow-up, 20 patients experienced a transient ischemic attack, and 77 had a recurrent stroke. Using a Cox proportional hazards model taking comorbidities, sex, and age into account, we analyzed the relationship between transient ischemic attack and recurrent stroke in the 503 patients with at least one follow-up visit. History of transient ischemic attack before the initial stroke was associated with a decreased risk of recurrent stroke (Hazards ratio, 0.3; 95% confidence interval, 0.08 to 0.86; P=.03), whereas a new transient ischemic attack after the initial stroke was associated with an increased risk of recurrent stroke (Hazards ratio, 11.7; 95% C.I. confidence interval=3.45 to 39.83; P=.0001).

Allogeneic bone marrow stromal cells promote glial-axonal remodeling without immunologic sensitization after stroke in rats

We evaluated the effects of allogeneic bone marrow stromal cell treatment of stroke on functional outcome, glial-axonal architecture, and immune reaction. Female Wistar rats were subjected to 2 h of middle cerebral artery occlusion. Rats were injected intravenously with PBS, male allogeneic ACI--or syngeneic Wistar--bone marrow stromal cells at 24 h after ischemia and sacrificed at 28 days. Significant functional recovery was found in both cell-treated groups compared to stroke rats that did not receive BMSCs, but no difference was detected between allogeneic and syngeneic cell-treated rats. No evidence of T cell priming or humoral antibody production to marrow stromal cells was found in recipient rats after treatment with allogeneic cells. Similar numbers of Y-chromosome+ cells were detected in the female rat brains in both groups. Significantly increased thickness of individual axons and myelin, and areas of the corpus callosum and the numbers of white matter bundles in the striatum were detected in the ischemic boundary zone of cell-treated rats compared to stroked rats. The areas of the contralateral corpus callosum significantly increased after cell treatment compared to normal rats. Processes of astrocytes remodeled from hypertrophic star-like to tadpole-like shape and oriented parallel to the ischemic regions after cell treatment. Axonal projections emanating from individual parenchymal neurons exhibited an overall orientation parallel to elongated radial processes of reactive astrocytes of the cell-treated rats. Allogeneic and syngeneic bone marrow stromal cell treatment after stroke in rats improved neurological recovery and enhanced reactive oligodendrocyte and astrocyte related axonal remodeling with no indication of immunologic sensitization in adult rat brain.

Effects of clomethiazole on radial-arm maze performance following global forebrain ischemia in gerbils

The functional and neuroanatomical protective effects of clomethiazole (CMZ) were examined in an animal model of global forebrain ischemia. Gerbils underwent sham-surgery or were rendered ischemic by the application of aneurysm clips to both carotid arteries for 6 min. Three treatment groups received CMZ (50 mg/kg, 100 mg/kg, or 150 mg/kg) 30 min before ischemia, and one group was given 150 mg/kg of CMZ 30 min after ischemia. Following recovery, the gerbils were tested in a radial-arm maze to assess memory functions. Histological evaluation was assessed blindly using a percentile scoring system. The results indicate that pre-ischemic treatment with 100 mg/kg and 150 mg/kg of CMZ reduced brain damage and working memory errors significantly. Treatment dosage of 150 mg/kg of CMZ was the most effective in preventing neuronal damage in the hippocampus and eliminating the working memory deficit typically induced by ischemia.

Stroke is an emergency

Stroke is an emergency. Ischemic stroke is similar to myocardial infarction in that the pathogenesis is loss of blood supply to the tissue, which can result in irreversible damage if blood flow is not restored quickly. Public education is needed to emphasize the warning signs of stroke. Patients should seek medical help immediately, using emergency transport systems. Therapy geared toward minimizing the damage from an acute stroke should be started without delay in the emergency room. This includes measures to protect brain tissue, support perfusion pressure, and minimize cerebral edema. Strategies for improving recovery should also begin immediately. All major medical centers need stroke teams and stroke units. Stroke prevention should be given high priority as a public health strategy. Risk factor management should be part of general health care and should begin in childhood, with emphasis on nutrition, exercise, weight control, and avoidance of tobacco. Health screening and early treatment of hypertension and hypercholesterolemia has decreased the incidence of stroke and heart disease, but these efforts need to be expanded to reach all segments of the population. Basic research has opened the door to new therapies aimed at re-establishing blood flow and limiting tissue damage. Clinical trials have already led to changes in stroke prevention, including studies of carotid endarterectomy and ticlopidine and warfarin therapy (for patients with atrial fibrillation). Trials in progress are testing the usefulness of ancrod, neuroprotective agents, antioxidant agents, anti-inflammatory agents, low-molecular-weight heparin, thrombolytic drugs, and angioplasty. Any delay starting therapy after an acute stroke will result in progressive, irreversible loss of brain tissue. Clinicians should remember that for a stroke patient, time is brain tissue.

Gender influences the magnitude of the inflammatory response within embolic cerebral infarcts in young rats

BACKGROUND AND PURPOSE

The inflammatory response within cerebral infarcts may have an influence on tissue damage. Since old animals with an impaired immune response have decreased inflammation after experimental cerebral infarction, we postulated that female animals with an increased immune response will have an increased inflammatory response after cerebral infarction.

METHODS

Embolic cerebral infarcts were produced by photochemical irradiation of the right carotid artery in 12 female Fischer rats. The inflammatory response within 4-day-old infarcts was quantitated by histology with the use of computer-assisted image analysis and compared with that in 12 male rats from a previous series.

RESULTS

Severe infarcts had the most pronounced inflammatory response. Female rats had an increased inflammatory response in infarcts of all severity, which was statistically significant in severe cerebral infarcts even after adjustment for infarct size. Severe infarcts in males were significantly larger than those in females.

CONCLUSIONS

Gender influences the outcome of embolic cerebral infarcts after photochemical damage to the carotid artery, both in terms of the magnitude of the inflammatory response and infarct size. There are numerous gender-related differences in neurochemicals, cytokine production, and drug metabolism that may influence tissue damage after stroke and responsiveness to therapeutic intervention. The preponderance of male animals in stroke research may produce results not applicable to female stroke patients. The use of female animals will be required to provide adequate models for the study of stroke in women.

Drugs and surgery in the prevention of ischemic stroke

Randomized clinical trials have proved that warfarin therapy decreases the risk of stroke in patients with nonvalvular atrial fibrillation and in those who have had a myocardial infarction. In patients who are not candidates for long-term anticoagulant therapy, aspirin is beneficial, but the reduction in risk is smaller with aspirin than with warfarin. In patients with cerebral ischemic symptoms of noncardiac origin, aspirin and ticlopidine reduce the risk of stroke, but the benefit is modest. Given alone, neither dipyridamole nor sulfinpyrazone prevents stroke. The question remains whether either of these drugs plus aspirin is better than aspirin alone. The optimal dose of aspirin for stroke prevention has not been established. Carotid endarterectomy reduces the risk of stroke in symptomatic patients with at least 70 percent stenosis, as determined by arteriography. Current trials are addressing the question of whether endarterectomy is beneficial for patients with moderate degrees of carotid stenosis. The benefit of endarterectomy for patients with asymptomatic carotid lesions remains unclear.

Physician attitudes toward treatment options for cerebrovascular disease

One-hundred physicians older than 50 and 100 physicians younger than 50 were surveyed concerning treatment preferences for patients with transient ischemic attacks (TIAs) or completed stroke. These attitudes were compared to cardiovascular disease prevention strategies for patients with angina pectoris and myocardial infarction. Physicians younger than 50 were therapeutically aggressive for cerebrovascular and cardiovascular disease; physicians older than 50 were aggressive for cardiovascular disease but therapeutically nihilistic for cerebrovascular disease. Physicians younger than 50 were more likely to be aggressive for TIA than for completed stroke patients, and these physicians were more likely to utilize ticlopidine and oral anticoagulants for both TIA and completed stroke patients.

Delayed neutropenia with ticlopidine

OBJECTIVE

To report a case of ticlopidine-induced neutropenia occurring 18 days after discontinuation of the drug.

CASE SUMMARY

A 68-year-old woman was placed on ticlopidine after a transient ischemic attack. Ten days later the drug was discontinued because the patient developed a rash. Eighteen days later she developed pneumonia and neutropenia, which were believed to be induced by ticlopidine.

DISCUSSION

Drug-induced neutropenia is serious and at times life-threatening. Ticlopidine-induced neutropenia has been described in patients receiving the medication. We report neutropenia occurring 18 days after discontinuation of ticlopidine.

CONCLUSIONS

Indications for prescribing ticlopidine must be closely followed. Complete blood cell count monitoring is imperative while the patient is receiving the medication. This case suggests that the duration of monitoring after the discontinuation of ticlopidine may need to be longer than the 14 days recommended by the manufacturer.

Stroke Management

With as many as 500,000 new strokes per year in the United States, the need for safe and effective therapy of these patients is evident. The area in which the greatest impact has been made is in the development of prophylactic treatments for patients at risk of stroke. Aspirin, long the mainstay of stroke management, has repeatedly been shown to reduce the risk of cerebral ischemia in patients who have had a transient ischemic attack (TIA) or minor stroke and is first-line therapy for these patients. Either 325 mg or 975 mg of aspirin may be used. Ticlopidine (250 mg twice daily) is a new antiplatelet agent that is recommended for the prophylaxis of stroke in patients who cannot tolerate or who are resistant to aspirin therapy. The surgical procedure, carotid endarterectomy, has been shown to reduce the stroke rate in symptomatic patients, with between 70% to 99% stenosis of a carotid artery. The use of warfarin has been shown to be extremely useful in patients with atrial fibrillation for prevention of recurrent embolic events. The use of pharmacological agents in the acute treatment of the ischemic stroke patient has not yet been proven successful. It is hoped that with the trend towards hyperacute (less than 6 hours) intervention, investigators may be successful in finding an agent to decrease the ultimate neurological deficit due to stroke. Some of the more promising agents are thrombolytics, glutamate antagonists, and aminosteroids. Future research in cerebral ischemia will undoubtedly improve the prognosis of stroke patients.