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J F Toole

Publications and source records attributed to J F Toole.

At least 55 records · Page 3Linked to original sources
PubMed1994

Accurate measurement of carotid stenosis. Chaos in methodology.

The methods used for measurement of carotid artery stenosis are not uniform. Witness the chaos that developed when the North American Symptomatic Carotid Endarterectomy Trial (NASCET) group changed its classification system from area to linear measurements only to discover that the European Carotid Stenosis Trial (ECST) used still another angiographic definition of degree of stenosis so that the data from the two studies were not comparable. Fortunately, this has been reconciled by recalculation of the data. In still other studies, using unvalidated ultrasound instruments has made it difficult or impossible to compare results. In part, these problems have been the result of misdirected attempts to amalgamate concepts from Doppler and duplex ultrasound with those of arteriography. The former is more precise and accurate than the latter, yet its methodology is harder to apply and has not been generally distributed. Even such anatomical terms as "carotid bulb" are not standard. Ultrasonographers consider it to be the distal common carotid artery, to vascular surgeons it is the carotid sinus, while still others consider it to be both or neither. The present authors advocate a uniform methodology utilizing duplex ultrasound and predict that it plus magnetic resonance angiography will become the standard by which extracranial carotid artery disease is evaluated in the future.

Carotid Arteries↗
PubMed1994

A prospective reevaluation of transient ischemic attacks as a risk factor for death and fatal or nonfatal cardiovascular events.

BACKGROUND AND PURPOSE: Transient ischemic attack (TIA) is generally considered a risk factor for death and cardiovascular events. This assumption is based on comparisons of the survival of the TIA population with that of the general population. Such comparisons may provide biased estimates of the risk associated with TIA because the general population is usually more healthy than TIA patients. METHODS: Using a prospective case-control study design, we report the comparison of a TIA population (n = 280) and a control group (n = 399) with a comparable cardiovascular risk factor burden. Proportional hazards analysis was used to compare survival time and time to fatal or nonfatal stroke and/or myocardial infarction for the two study groups. Comparisons were made without adjustment for risk factors and after adjustment for age, race, sex, and major cardiovascular risk factors. RESULTS: Before adjustment for age-race-sex or risk factors, TIA proved to be a risk factor for early mortality, stroke, and myocardial infarction (P < .05). Adjustment for age-race-sex disparities between the case and control groups explained much of the differences in mortality, as the hazard ratio was reduced from 2.2 to 1.4. However, adjustment for age-race-sex or age-race-sex and risk factors did not markedly reduce the role of TIA as a risk factor for stroke or myocardial infarction. CONCLUSIONS: Although TIA proved to be a risk factor for stroke or myocardial infarction, it apparently plays a smaller role in the risk of death.

Age Factors↗
PubMed1994

Transient ischemic attack: awareness and prevalence in the community.

Transient ischemic attack (TIA) is the most powerful predictor of stroke. Estimates of its prevalence in various regions of the world differ depending upon the instruments and exclusion criteria used and the population surveyed. For example, if the questioner uses technical language, or if he or she excludes events lasting but a few seconds and symptoms such as dizziness (without accompanying phenomena), numbness and tingling, and transitory amnesia (euphemistically called forgetfulness), an entirely different prevalence results than if these events and symptoms are included. In a survey of people aged 45 to 64, cross-sectional data were ascertained by means of a standardized TIA/stroke questionnaire and an algorithm. For women the prevalence of TIA-like events was 5% and fr men, 3%, increasing with age for both sexes. These events were more prevalent in African-Americans than Caucasians. The most frequent symptoms were change in speech, followed by dizziness and loss of balance.

Black People↗
PubMed1993

Prevalence of stroke and transient ischemic attacks in the Atherosclerosis Risk in Communities (ARIC) study.

The Atherosclerosis Risk in Communities (ARIC) study is a population-based observational study of randomly sampled, census-based populations in four locations within the United States. The study was designed to determine whether there are regional differences in incidence, prevalence, and mortality rates from cardiovascular and cerebrovascular disease in populations aged 45 to 64 years. Both cohort examinations and community surveillance are included. In addition to a standardized transient ischemic attack (TIA) and stroke questionnaire and algorithm for determination of incidence and prevalence, B-scan ultrasonography is used to quantify the degree of atherosclerotic changes in the carotid artery. Initiated in late 1986, the first cohort evaluation was completed in early 1990. The third, which includes magnetic resonance imaging of the brain, is in progress and will be completed in 1996. Positive responses to the TIA/stroke questionnaire increase by decile of age, are greater in women than men, and are more frequent in African Americans than Caucasians. The baseline study using an algorithm for categorization of patient responses into vascular and other causes of TIA and stroke estimated prevalence of 5.5% in African Americans and 6.3% in Caucasians.

Adult↗
PubMed1992

Comparison of multicenter study designs for investigation of carotid endarterectomy efficacy.

BACKGROUND: Our report summarizes and compares the characteristics of six prospective, multicenter, randomized clinical trials of carotid endarterectomy underway in North America and Europe. SUMMARY OF REVIEW: Three trials are designed to evaluate the safety and efficacy of endarterectomy in patients with asymptomatic carotid artery stenosis. The other three trials enroll patients who have had transient ischemic attacks or a minor cerebral infarction in the distribution of the randomized artery. Considered together, these six clinical trials span the range of candidates for carotid endarterectomy. The inclusion and exclusion criteria, methodology, and statistical considerations of each study are detailed in tables. CONCLUSIONS: The results from these trials will be helpful in resolving some of the questions surrounding endarterectomy, provided the similarities and differences in the study designs are considered when interpreting the results.

Carotid Arteries↗
PubMed1991

The community hospital-based stroke programs in North Carolina, Oregon and New York--V. Stroke diagnosis: factors influencing the diagnostic evaluation of patients following acute stroke.

Among the 4129 patients of the Community Hospital-based Stroke Program, 30% had an unspecified stroke diagnosis. Since specific diagnosis and, perhaps, eventual treatment, derives in part from diagnostic testing, we examined the effect of clinical condition, geographic and demographic factors on the incidence of certain diagnostic tests after acute stroke. In this multivariable analysis, race, sex, history of hypertension and history of diabetes did not influence the chance of having any test, but older age strongly reduced the chances of receiving extensive evaluation. When CT scanning was available, the utilization of a CT as well as other diagnostic studies including cerebral angiography, radionuclide brain scan, EEG and EKG was increased. The odds of receiving a CT scan increased if the patient was married, and decreased with a history of previous stroke. A history of previous TIA increased the chance of having a cerebral angiogram while a history of cardiac disease decreased the chance. There were striking regional geographic differences in the use of CT, radionuclide brain scanning and cerebral angiography which may, in part, reflect differences between the availability of these technologies in urban and rural hospitals. These results indicate that evaluation of stroke patients remains heterogenous.

Aged↗
PubMed1991

The Willis lecture: transient ischemic attacks, scientific method, and new realities.

First described by Thomas Willis in 1679 and defined in the 1950s, transient ischemic attack is universally agreed to be an episode of focal neurologic deficit in a vascular distribution, sudden in onset and resolving without residual deficit in less than or equal to 24 hours. Transient ischemic attack is diagnosed by characteristic history and absence of residua on neurologic examination. After these criteria had been accepted, regional cerebral blood flow and computed cranial tomography in the 1970s, later positron emission tomography, and even more recently, magnetic resonance imaging reveal prolonged pathophysiologic and metabolic disturbances even in persons with all the definitional characteristics of transient ischemic attack. These persistent abnormalities necessitate reexamination of the validity of the concept of transient ischemic attack. Furthermore, our group suspects that transient ischemic attack is probably only a marker, and not itself the risk factor, for the cerebral infarction which frequently follows transient ischemic attack. Additionally, the surprising frequency with which cerebral infarction, unrecognized by patient or physician, is revealed using neuroimaging techniques has created a need to redefine the categories heretofore used for diagnosis and assessment of therapy and prognosis for transient ischemic attack and cerebral infarction.

Algorithms↗
PubMed1991

Selection process for surgeons in the Asymptomatic Carotid Atherosclerosis Study.

BACKGROUND AND PURPOSE: The Asymptomatic Carotid Atherosclerosis Study is a prospective, multicenter, randomized clinical trial of carotid endarterectomy for the treatment of asymptomatic hemodynamically significant stenosis. This report describes the selection process for participating surgeons in the trial. METHODS: The Surgical Management Committee established guidelines for minimal annual experience and maximum neurological morbidity and mortality for surgeons to qualify to participate in the study. For approval, a surgeon must perform at least 12 carotid endarterectomies per year. Based on a review of the surgeon's last 50 consecutive endarterectomies, the combined neurological morbidity and mortality rate must be no greater than 5% for all indications and no greater than 3% for endarterectomies performed on asymptomatic patients. RESULTS: One hundred sixty-four surgeons from 48 centers applied for approval: 117 were approved, 17 were rejected, and 30 were not reviewed. The 117 approved surgeons submitted a total of 5,641 endarterectomies with a combined mortality and neurological morbidity rate of 2.3% for the variety of indications for operation. CONCLUSIONS: This overall experience with carotid endarterectomy is one of the largest series reported to date. The data from approved surgeons are well within the range of acceptable neurological morbidity and mortality rates recommended by the Stroke Council of the American Heart Association, which attests to the overall quality of the surgeons participating in the study.

Carotid Artery Diseases↗
PubMed1991

Cerebral infarction verified by cranial computed tomography and prognosis for survival following transient ischemic attack.

Of 564 consecutive patients with transient ischemic attack, 350 (62%) had cranial computed tomography performed. Except for date of admission and smoking history, there were few differences between the patients evaluated with computed tomography and the 214 who were not. Cerebral infarcts were found in 59 (17%) of the 350 tomographic evaluations. Previous clinically diagnosed stroke, older age, and male sex were all significantly associated with the occurrence of tomographically verified infarcts (p less than 0.05). After controlling for stroke history and other important covariates, patients with tomographically verified infarcts had significantly shorter survival times than did patients without evidence of infarction on computed tomography (p = 0.035). Thus, cranial computed tomography findings appear to have important prognostic value for estimating survival following transient ischemic attack.

Cerebral Angiography↗
PubMed1990

Characteristics of stroke victims associated with early cardiovascular mortality in their children.

We assessed the relationship between characteristics of stroke victims and the risk of early death from coronary or cerebrovascular disease (CCVD) among their children. For each of 55 stroke patients selected from a registry which enrolled patients between 1969 and 1973, an index of their progeny's survival was calculated using the age in 1987 of 197 surviving children, and the age at and cause of death for 55 deceased children. Increased risk of CCVD death within families was significantly related to parental age at the time of first stroke, and with the parental history of diabetes mellitus. No significant relationship was found between the children's risk of CCVD death and the stroke patient/parent's sex, race, history of hypertension or cardiac disease, stroke diagnosis (infarction vs hemorrhage), or severity upon admission. These results suggest that family histories of cerebrovascular disease may impart differential risks, depending upon a family history of diabetes, and perhaps, the ages at which ancestral strokes first occurred.

Adolescent↗
PubMed1990

Evaluation of the associations between carotid artery atherosclerosis and coronary artery stenosis. A case-control study.

To evaluate the consistency, strength, and independence of the relation of carotid atherosclerosis to coronary atherosclerosis, we quantified coronary artery disease risk factors and extent of carotid atherosclerosis (B-mode score) in 343 coronary artery disease patients and 167 disease-free control patients. In univariable analyses, there was a strong association between coronary status and extent of carotid artery disease in men and women older than and younger than 50 years (p less than 0.001 for men and women greater than 50 years, p less than 0.001 for women less than or equal to 50 years, p = 0.045 for men less than or equal to 50). The relation remained strong after control for age in men and women older than 50 years and in women younger than 50 (p less than 0.001 for men and women greater than 50 years, p = 0.003 for women less than or equal to 50) but did not persist after control for age in men younger than 50. Logistic models that included coronary disease risk factors, with or without B-mode score, as independent variables and presence or absence of coronary disease as the outcome variable indicated that the extent of carotid atherosclerosis was a strong, statistically significant independent variable in models for men and women older than 50 years of age. Next, we examined the usefulness of B-mode score as an aid in screening for coronary artery disease in men and women older than 50 years. Classification rules, both including and excluding B-mode score, were developed based on logistic regression and, for comparison, recursive partitioning (decision trees). The performance of these rules and the bias of their performance statistics were estimated. The improved classification of the study sample when B-mode score was incorporated in the rule was statistically significant only for men (p = 0.015). However, the addition of B-mode score was found to 1) increase the median discrimination score for both sex groups based on the logistic model, and 2) yield better sensitivities and specificities for rules based on recursive partitioning. Thus B-mode score is strongly, consistently, and independently associated with coronary artery disease in patients older than 50 and is at least as useful as well-known risk factors for identifying patients with coronary artery disease.

Aging↗
PubMed1990

Community hospital-based stroke programs in North Carolina, Oregon, and New York. IV. Stroke diagnosis and its relation to demographics, risk factors, and clinical status after stroke.

The use of diagnostic tests, the accuracy of stroke type diagnosis, and their relationship to outcome are important from the standpoint of patient management and health care costs. To address this issue, we examined the differences between stroke types in terms of demographics, risk factors, diagnostic tests, and clinical outcome in the 4,129 patients who comprise the Community Hospital-Based Stroke Program. Previous transient ischemic attacks were equally frequent among patients with embolic and those with thrombotic stroke. For all stroke types, previous stroke was as frequent as previous transient ischemic attacks. Hypertension and cardiac disease were the most common risk factors, but 10% of all stroke patients had no recognized risk factors. Intracerebral hemorrhage was most often associated with death (45%). There was a strong direct relation between in-hospital mortality and a decreased level of consciousness at admission. Overall, 30% of patients did not receive a specific stroke type diagnosis; these patients were elderly, usually nonwhite, and often had an altered level of consciousness at admission but had a risk factor profile similar to that of patients who received a specific stroke type diagnosis. In summary, our findings suggest the continued need for physician education about and refinement of stroke type diagnosis.

Aged↗