Risk Of Transient Ischemic Attack Research Articles

Severely impaired cerebrovascular reactivity predicts stroke and TIA risk in patients with carotid artery stenosis and occlusion.

Cross-sectional studies suggest that impaired cerebral haemodynamics is associated with symptomatic status in patients with carotid stenosis and occlusion, but there is relatively little prospective data confirming this association. Transcranial Doppler ultrasonography was used to determine the reactivity of the middle cerebral artery to 8% carbon dioxide in air in 107 patients with either carotid occlusion (n = 48) or asymptomatic carotid stenosis (n = 59). Subjects were followed prospectively until stroke, transient ischaemic attack (TIA), death or study end. Mean duration of follow-up was 635 days. No patients dropped out due to operation before an end-point was reached, or were lost to follow-up. There were 11 ipsilateral ischaemic events during follow-up (six strokes, five TIAs). Exhausted ipsilateral middle cerebral artery reactivity (>20% increase in ipsilateral middle cerebral flow velocity in response to 8% carbon dioxide) predicted ipsilateral stroke and TIA risk in the whole group (P: < 0.00001) and in the carotid occlusion (P: = 0.019) and carotid stenosis (P: = 0.015) groups alone. It also predicted the risk of ipsilateral stroke alone in all three groups. Cox regression was performed, controlling for age, gender, hypertension, diabetes, smoking, ipsilateral CT infarct, degree of contralateral stenosis and the presence of ipsilateral stenosis versus occlusion. Exhausted reactivity remained an independent predictor of ipsilateral stroke and TIA (odds ratio 14.4, 95% confidence interval 2.63-78.74, P: = 0.0021). In contrast, the pulsatility index of the middle cerebral artery was a poor predictor of the risk of stroke. Reactivity to 6% carbon dioxide also predicted the risk of stroke and TIA, but slightly less effectively than reactivity to 8% carbon dioxide. Severely reduced cerebrovascular reactivity predicts the risk of ipsilateral stroke and TIA in patients with carotid occlusion, and to a lesser extent in asymptomatic carotid stenosis. Particularly in the former group, a study is required to determine whether revascularization reduces the risk of stroke in patients with exhausted reactivity.

Surgical Patent Foramen Ovale Closure for Prevention of Paradoxical Embolism-Related Cerebrovascular Ischemic Events

The role of surgical closure of patent foramen ovale (PFO) for cerebral infarction (CI) or transient ischemic attack (TIA) resulting from paradoxical embolism is unclear, and its effect on recurrence is unknown. Our objective was to determine the outcome of surgical closure of PFO in patients with a prior ischemic neurological event, define the rate of CI or TIA recurrence after PFO closure, and identify risk factors for these recurrences. We retrospectively analyzed 91 patients (58 men, 33 women) with >/=1 previous cerebrovascular ischemic events who underwent surgical PFO closure between April 1982 and March 1998. The presence of a PFO with a right-to-left shunt was confirmed with transesophageal echocardiography. Mean age was 44.2+/-12.2 years. The index event was a CI in 59 and a TIA in 32; a Valsalva-like episode preceded the event in 15 patients. Deep venous thrombosis was documented in 9 patients, and a hypercoagulable state was identified in 10. Surgical closure was performed with extracorporeal circulation by either direct suture (n=82) or patch closure (n=9). Limited incisions were used in 18.7% of patients. There was no operative mortality. Morbidity included transient atrial fibrillation (n=11), pericardial drainage for effusion (n=4), exploration for bleeding (n=3), and superficial wound infection (n=1). Follow-up totaled 176.3 patient-years, and mean follow-up was 2.0 years. No one had a CI, and 8 had a TIA during follow-up, with 1 caused by temporal arteritis. Transesophageal echocardiography demonstrated all closures to be intact in these patients. The overall freedom from TIA recurrence during follow-up was 92.5+/-3.2% at 1 year and 83.4+/-6.0% at 4 years. Having multiple neurological events before PFO closure was the only significant risk factor for TIA or CI recurrence after closure by univariate analysis (P=0.05); the small number of post-PFO closure cerebral ischemic events precluded multivariate analysis. Surgical closure of PFO can be performed with minimal morbidity and mortality. PFO closure may decrease the risk of recurrent stroke or TIA and may avoid lifelong anticoagulation in the young adult if there is no other indication. Recurrent cerebrovascular ischemic events after surgery should prompt further evaluation to identify causes other than paradoxical embolism.

Surgical Patent Foramen Ovale Closure for Prevention of Paradoxical Embolism–Related Cerebrovascular Ischemic Events

Background —The role of surgical closure of patent foramen ovale (PFO) for cerebral infarction (CI) or transient ischemic attack (TIA) resulting from paradoxical embolism is unclear, and its effect on recurrence is unknown. Our objective was to determine the outcome of surgical closure of PFO in patients with a prior ischemic neurological event, define the rate of CI or TIA recurrence after PFO closure, and identify risk factors for these recurrences. Methods and Results —We retrospectively analyzed 91 patients (58 men, 33 women) with ≥1 previous cerebrovascular ischemic events who underwent surgical PFO closure between April 1982 and March 1998. The presence of a PFO with a right-to-left shunt was confirmed with transesophageal echocardiography. Mean age was 44.2±12.2 years. The index event was a CI in 59 and a TIA in 32; a Valsalva-like episode preceded the event in 15 patients. Deep venous thrombosis was documented in 9 patients, and a hypercoagulable state was identified in 10. Surgical closure was performed with extracorporeal circulation by either direct suture (n=82) or patch closure (n=9). Limited incisions were used in 18.7% of patients. There was no operative mortality. Morbidity included transient atrial fibrillation (n=11), pericardial drainage for effusion (n=4), exploration for bleeding (n=3), and superficial wound infection (n=1). Follow-up totaled 176.3 patient-years, and mean follow-up was 2.0 years. No one had a CI, and 8 had a TIA during follow-up, with 1 caused by temporal arteritis. Transesophageal echocardiography demonstrated all closures to be intact in these patients. The overall freedom from TIA recurrence during follow-up was 92.5±3.2% at 1 year and 83.4±6.0% at 4 years. Having multiple neurological events before PFO closure was the only significant risk factor for TIA or CI recurrence after closure by univariate analysis ( P =0.05); the small number of post-PFO closure cerebral ischemic events precluded multivariate analysis. Conclusions —Surgical closure of PFO can be performed with minimal morbidity and mortality. PFO closure may decrease the risk of recurrent stroke or TIA and may avoid lifelong anticoagulation in the young adult if there is no other indication. Recurrent cerebrovascular ischemic events after surgery should prompt further evaluation to identify causes other than paradoxical embolism.

Management of transient ischaemic attacks and stroke

The management of stroke and transient ischaemic attacks (TIAs) has changed greatly in the last two decades. The importance of good blood pressure control is the hallmark of stroke prevention. Large multicentre trials have proven beyond doubt the value of aspirin in TIAs, warfarin in patients with atrial fibrillation and embolic cerebrovascular symptoms, and carotid endarterectomy in patients with carotid TIAs. There seems little doubt that patients managed in acute stroke units are more likely to be independent at six months than those managed in a general medical ward. This article emphasizes the importance of basing clinical management on simple history taking and examination and appropriate investigation. This, combined with knowledge of the natural history risk of TIA and stroke and the results of randomised trials, allows individuals to be managed in the most appropriate manner. This review is designed to be a practical guide, useful in the day to day management of patients with cerebrovascular disease.

Implications of Small Reductions in Diastolic Blood Pressure for Primary Prevention

To estimate the impact of small reductions in the population distribution of diastolic blood pressure (DBP), such as those potentially achievable by population-wide lifestyle modification, on incidence of coronary heart disease (CHD) and stroke. Published data from the Framingham Heart Study, a longitudinal cohort study, and from the National Health and Nutrition Examination Survey II, a national population survey, were used to examine the impact of a population-wide strategy aimed at reducing DBP by an average of 2 mm Hg in a population including normotensive subjects. White men and women aged 35 to 64 years in the United States. Incidence of CHD and stroke, including transient ischemic attacks (TIAs). Data from overviews of observational studies and randomized trials suggest that a 2-mm Hg reduction in DBP would result in a 17% decrease in the prevalence of hypertension as well as a 6% reduction in the risk of CHD and a 15% reduction in risk of stroke and TIAs. From an application of these results to US white men and women aged 35 to 64 years, it is estimated that a successful population intervention alone could reduce CHD incidence more than could medical treatment for all those with a DBP of 95 mm Hg or higher. It could prevent 84% of the number prevented by medical treatment for all those with a DBP of 90 mm Hg or higher. For stroke (including TIAs), a population-wide 2-mm Hg reduction could prevent 93% of events prevented by medical treatment for those with a DBP of 95 mm Hg or higher and 69% of events for treatment for those with a DBP of 90 mm Hg or higher. A combination strategy of both a population reduction in DBP and targeted medical intervention is most effective and could double or triple the impact of medical treatment alone. Adding a population-based intervention to existing levels of hypertension treatment could prevent an estimated additional 67,000 CHD events (6%) and 34,000 stroke and TIA events (13%) annually among all those aged 35 to 64 years in the United States. A small reduction of 2 mm Hg in DBP in the mean of the population distribution, in addition to medical treatment, could have a great public health impact on the number of CHD and stroke events prevented. Whether such DBP reductions can be achieved in the population through lifestyle interventions, in particular through sodium reduction, depends on the results of ongoing primary prevention trials as well as the cooperation of the food industry, government agencies, and health education professionals.

Transient Ischemic Attacks

A transient ischemic attack (TIA) is a symptom of underlying vascular disease that requires prompt, accurate diagnosis to prevent its possible complications of stroke, myocardial infarction or death. This article presents the clinical features, pathophysiology, clinical course and management of TIAs. Study of the pathophysiology includes a review of normal physiology of the cerebral vascular system, as well as age-related physiologic changes that put the elderly at increased risk for TIAs. The management plan presented includes reduction of risk factors, patient education, physician referral, and medical and/or surgical treatment. Controversies over medical and surgical treatment are briefly examined.

Life history of patients with transient ischemic attacks and essentially normal angiograms

Eighty-three patients, 43 women and 40 men, with hemispheric transient ischemic attacks (TIAs) and normal angiograms were studied. Fifty-two of the patients had a single episode of transient ischemia, whereas 31 had multiple episodes prompitng initial evaluation. Follow-up ranging from 3 to 132 months was obtained for all patients. In this period, six patients suffered a cerebrovascular accident and five had further hemispheric TIAs. These results are in contrast to our earlier data, which suggested a benign prognosis in this group of patients. Results of this updated study show that the prognosis of patients with hemispheric TIAs and normal angiograms is not so benign as originally reported. Those patients with multiple events before initial evaluation are at increased risk of subsequent cerebrovascular accident or TIA. Close observation of this group of patients is recommended.

The natural history of isolated carotid siphon stenosis

Between August 1978 and July 1983, 93 patients (71 with unilateral and 22 with bilateral isolated carotid siphon stenosis) were identified from a review of 885 consecutive cerebral arteriograms. This yielded 115 cerebral hemispheres at risk. At the time of arteriography, 93 hemispheres were asymptomatic regarding the hemisphere with siphon stenosis (group I), whereas 22 hemispheres in 22 patients had had neurologic events referable to the hemisphere with siphon stenosis (group II). During follow-up (range 1 to 62 months, mean 22.5 months), 64.5% of initially asymptomatic hemispheres remained asymptomatic, 6.5% experienced transient ischemic attacks (TIAs), and 4.3% developed strokes. During the same follow-up period, 63.6% of initially symptomatic hemispheres became asymptomatic, 9.1% had recurrence of TIAs, and 9.1% developed strokes. Sixteen of 71 group I patients (22.5%) and 5 of 22 group II patients (22.7%) died during follow-up. The overall incidence of nonfatal stroke and TIAs was 6.5% and 8.6%, respectively. Myocardial infarction (MI) and stroke accounted for deaths in 6.5% and 4.3% of patients, respectively. There was no significant difference in the incidence of TIA, stroke, or death between group I and group II. The percentage of siphon stenosis in all patients experiencing stroke or TIA (35.4 ± 14.4%) was not significantly different from that in patients who remained asymptomatic (32.3 ± 10.6%). Patients with carotid siphon stenosis are at an increased risk of death, stroke, and TIAs compared with the population at large. However, the risk of stroke is less than the risk of stroke in patients with TIAs assumed to be caused by carotid bifurcation disease. The risk of fatal MI is similar to the annual incidence of MI in patients with other manifestations of atherosclerosis.

The natural history of isolated carotid siphon stenosis.

Between August 1978 and July 1983, 93 patients (71 with unilateral and 22 with bilateral isolated carotid siphon stenosis) were identified from a review of 885 consecutive cerebral arteriograms. This yielded 115 cerebral hemispheres at risk. At the time of arteriography, 93 hemispheres were asymptomatic regarding the hemisphere with siphon stenosis (group I), whereas 22 hemispheres in 22 patients had had neurologic events referable to the hemisphere with siphon stenosis (group II). During follow-up (range 1 to 62 months, mean 22.5 months), 64.5% of initially asymptomatic hemispheres remained asymptomatic, 6.5% experienced transient ischemic attacks (TIAs), and 4.3% developed strokes. During the same follow-up period, 63.6% of initially symptomatic hemispheres became asymptomatic, 9.1% had recurrence of TIAs, and 9.1% developed strokes. Sixteen of 71 group I patients (22.5%) and 5 of 22 group II patients (22.7%) died during follow-up. The overall incidence of nonfatal stroke and TIAs was 6.5% and 8.6%, respectively. Myocardial infarction (MI) and stroke accounted for deaths in 6.5% and 4.3% of patients, respectively. There was no significant difference in the incidence of TIA, stroke, or death between group I and group II. The percentage of siphon stenosis in all patients experiencing stroke or TIA (35.4 +/- 14.4%) was not significantly different from that in patients who remained asymptomatic (32.3 +/- 10.6%). Patients with carotid siphon stenosis are at an increased risk of death, stroke, and TIAs compared with the population at large. However, the risk of stroke is less than the risk of stroke in patients with TIAs assumed to be caused by carotid bifurcation disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasound shows carotid stenosis in just half of cervical bruit cases

Acervical bruit indicates the presence of substantial carotid stenosis only about half the time, according to researchers at the University of Toronto. They suggest that only in the minority of persons with a bruit and carotid stenosis—those in whom the stenosis is severe—is there a substantially increased risk of cerebrovascular events. Even then, the incidence of stroke and transient ischemic attack (TIA) is "surprisingly low," according to one of the Canadian clinicians. But cardiac events are more frequent and more often fatal. Those were the main conclusions that Brian Chambers, MD, a research fellow of the Ontario Heart and Stroke Foundation at Sunnybrook Medical Centre of the University of Toronto, reported to the Ninth International Joint Conference on Stroke and Cerebral Circulation. He and James W. Norris, MD, professor of neurology, are interested in clarifying the risk of stroke and TIAs in persons with cervical bruits. "Our data would suggest

Carotid Artery Stenosis—Hemodynamic Significance and Clinical Course

Two hundred fifteen patients with a history of either stroke, transient ischemic attack (TIA), or asymptomatic carotid bruit underwent noninvasive carotid artery testing using oculopneumoplethysmography. Of patients with hemodynamically significant stenosis, 51 (40.8%) underwent endarterectomy, and 74 (59.2%) were treated nonoperatively. The incidence of stroke in the nonoperated group was 12/74 (16.2%) compared with only 1/51 (1.9%) in the operated group. Similarly, recurrent TIA occurred in 29/74 (39.2%) of the nonoperated group vs 9/51 (17.6%) of the operated. In nonhemodynamically significant carotid stenosis, the risk of cerebrovascular death and stroke was exceedingly low: 2/90 (2.2%). Patients with hemodynamically significant stenosis treated nonoperatively have a greater risk of cerebrovascular death, stroke, and TIA than patients treated with carotid endarterectomy. (<i>JAMA</i>1981;245:1438-1441)

Carotid artery stenosis - hemodynamic significance and clinical course.

Two hundred fifteen patients with a history of either stroke, transient ischemic attack (TIA), or asymptomatic carotid bruit underwent noninvasive carotid artery testing using oculopneumoplethysmography. Of patients with hemodynamically significant stenosis, 51 (40.8%) underwent endarterectomy, and 74 (59.2%) were treated nonoperatively. The incidence of stroke in the nonoperated group was 12/74 (16.2%) compared with only 1/51 (1.9%) in the operated group. Similarly, recurrent TIA occurred in 29/74 (39.2%) of the nonoperated group vs 9/51 (17.6%) of the operated. In nonhemodynamically significant carotid stenosis, the risk of cerebrovascular death and stroke was exceedingly low: 2/90 (2.2%). Patients with hemodynamically significant stenosis treated nonoperatively have a greater risk of cerebrovascular death, stroke, and TIA than patients treated with carotid endarterectomy.

Cooperative Study of Hospital Frequency and Character of Transient Ischemic Attacks

A total of 969 (73%) of 1,328 patients with cases of suspected transient ischemic attacks (TIAs) who came to six institutions during a 21-month period were followed up. Factors were identified and prospectively analyzed for risk for further TIAs, stroke, and deatn. A history of multiple carotid artery TIAs was significantly related to further TIAs. A single TIA placed the patient at greater risk for early infarction. Older age, male sex, and unreliability to take dangerous medication were risk factors for cerebral infarction. Anticoagulant therapy, older age, male sex, diabetes mellitus, heart disease, abnormal ECG, and poor surgical risk were factors for death. The increased mortality associated with anticoagulants was confined to the older age group. While white patients treated with antiplatelet-aggregating agents had a lower mortality than those treated otherwise, this was not true amont black patients.