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Biomedical subjects

T Brott

Publications and source records attributed to T Brott.

At least 55 records · Page 3Linked to original sources
PubMed1995

Guidelines for carotid endarterectomy. A multidisciplinary consensus statement from the ad hoc Committee, American Heart Association.

BACKGROUND AND PURPOSE: Indications for carotid endarterectomy have engendered considerable debate among experts and have resulted in publication of retrospective reviews, natural history studies, audits of community practice, position papers, expert opinion statements, and finally prospective randomized trials. The American Heart Association assembled a group of experts in a multidisciplinary consensus conference to develop this statement. METHODS: A conference was held July 16-18, 1993, in Park City, Utah, that included recognized experts in neurology, neurosurgery, vascular surgery, and healthcare planning. A program of critical topics was developed, and each expert presented a talk and provided the chairman with a summary statement. From these summary statements a document was developed and edited onsite to achieve consensus before final revision. RESULTS: The first section of this document reviews the natural history, methods of patient evaluation, options for medical management, results of surgical management, data from position statements, and results to date of prospective randomized trials for symptomatic and asymptomatic patients with carotid artery disease. The second section divides 96 potential indications for carotid endarterectomy, based on surgical risk, into four categories: (1) Proven: This is the strongest indication for carotid endarterectomy; data are supported by results of prospective contemporary randomized trials. (2) Acceptable but not proven: a good indication for operation; supported by promising but not scientifically certain data. (3) Uncertain: Data are insufficient to define the risk/benefit ratio. (4) Proven inappropriate: Current data are adequate to show that the risk of surgery outweighs any benefit. CONCLUSIONS: Indications for carotid endarterectomy in symptomatic good-risk patients with a surgeon whose surgical morbidity and mortality rate is less than 6% are as follows. (1) Proven: one or more TIAs in the past 6 months and carotid stenosis > or = 70% or mild stroke within 6 months and a carotid stenosis > or = 70%; (2) acceptable but not proven: TIAs within the past 6 months and a stenosis 50% to 69%, progressive stroke and a stenosis > or = 70%, mild or moderate stroke in the past 6 months and a stenosis 50% to 69%, or carotid endarterectomy ipsilateral to TIAs and a stenosis > or = 70% combined with required coronary artery bypass grafting; (3) uncertain: TIAs with a stenosis < 50%, mild stroke and stenosis < 50%, TIAs with a stenosis < 70% combined with coronary artery bypass grafting, or symptomatic, acute carotid thrombosis; (4) proven inappropriate: moderate stroke with stenosis < 50%, not on aspirin; single TIA, < 50% stenosis, not on aspirin; high-risk patient with multiple TIAs, not on aspirin, stenosis < 50%; high-risk patient, mild or moderate stroke, stenosis < 50%, not on aspirin; global ischemic symptoms with stenosis < 50%; acute dissection, asymptomatic on heparin. Indications for carotid endarterectomy in asymptomatic good-risk patients performed by a surgeon whose surgical morbidity and mortality rate is less than 3% are as follows. (1) Proven: none. (As this statement went to press, the National Institute of Neurological Disorders and Stroke issued a clinical advisory stating that the Institute has halted the Asymptomatic Carotid Atherosclerosis Study (ACAS) because of a clear benefit in favor of surgery for patients with carotid stenosis > or = 60% as measured by diameter reduction. When the ACAS report is published, this indication will be recategorized as proven. (2) acceptable but not proven: stenosis > 75% by linear diameter; (3) uncertain; stenosis > 75% in a high-risk patient/surgeon (surgical morbidity and mortality rate > 3%), combined carotid/coronary operations, or ulcerative lesions without hemodynamically significant stenosis; (4) proven inappropriate: operations with a combined stroke morbidity and mortality > 5%.

Aspirin↗
PubMed1995

Emergency physicians. Accuracy in the diagnosis of stroke.

BACKGROUND AND PURPOSE: The role of emergency physicians in trials of acute stroke therapy is expanding. We investigated the ability of emergency physicians to accurately identify patients with stroke. METHODS: We reviewed all 446 patients who were evaluated in the emergency department and had an inpatient admitting or discharge diagnosis of ischemic or hemorrhagic stroke from May 1, 1992, to June 30, 1993. The final admitting diagnosis made by the emergency physician was compared with the final hospital discharge diagnosis, 95% of which were made by neurologists or neurosurgeons. RESULTS: All 76 patients with a final discharge diagnosis of intracerebral or subarachnoid hemorrhage were correctly diagnosed by the emergency physicians (sensitivity, 100%; positive predictive value, 100%). Of the 351 patients with a final discharge diagnosis of ischemic stroke or transient ischemic attack, 346 were correctly identified by the emergency physicians (sensitivity, 98.6%; positive predictive value, 94.8%). Nineteen patients were diagnosed with stroke or transient ischemic attack by the emergency physician but had a final discharge diagnosis other than stroke. Discharge diagnoses included paresthesia or numbness of unknown causes (3), seizure (2), complicated migraine (2), peripheral neuropathy (2), cranial nerve neuropathy (2), psychogenic paralysis (1), and other (7). CONCLUSIONS: Emergency physicians at a large urban teaching hospital with a comprehensive stroke intervention program can accurately identify patients with stroke, particularly hemorrhagic stroke. If similar accuracy can be documented in other types of hospitals, emergency physicians may become key providers of urgent stroke intervention.

Adult↗
PubMed1995

Hyperglycemia and hemorrhagic transformation of cerebral infarcts.

BACKGROUND: Identification of factors that predispose to bleeding into ischemic brain could lead to safer use of thrombolytic agents in the setting of ischemic stroke. Recently de Courten-Meyers and colleagues reported that occluding the middle cerebral artery of markedly hyperglycemic cats was associated with 5-fold more frequent and 25-fold more extensive hemorrhage into infarcts than in normoglycemic animals. Hemorrhage associated with hyperglycemia in cats was much more pronounced with reperfusion than with permanent middle cerebral artery occlusion. CASE DESCRIPTION: We describe two patients with a unique presentation of diffuse hemorrhagic infarction of the caudate and lentiform nuclei associated with initially marked hyperglycemia and the subsequent development of hemichorea. CONCLUSIONS: We hypothesize that the marked hyperglycemia due to poor control of diabetes contributed to the hemorrhagic change of the caudate and lenticular nuclei. Because the hemorrhage in hyperglycemic cats was more pronounced in the setting of reperfusion, hemorrhagic risk associated with hyperglycemia should be investigated, particularly in ongoing thrombolytic treatment trials for acute ischemic stroke. We encourage other acute stroke investigators to prospectively look at the risk of brain hemorrhage in stroke patients with marked hyperglycemia.

Aged↗
PubMed1995

Frequency and accuracy of prehospital diagnosis of acute stroke.

BACKGROUND AND PURPOSE: This pilot study evaluated the frequency and accuracy of diagnosis of stroke made by prehospital care system dispatchers, emergency medical technicians (EMTs), and paramedics in one emergency medical services (EMS) system. In addition, the study determined patient prehospital triage and time intervals in the transport and examination of patients given a diagnosis of stroke by this EMS system. METHODS: We reviewed records of 4413 consecutive prehospital records of a two-tiered EMS system for patients with potential stroke. Hospital records were obtained for patients given a diagnosis of stroke or transient ischemic attack (TIA) by an EMS dispatcher, EMT, or paramedic. The EMS system studied serves a community of 13,000 within the greater Cincinnati area. RESULTS: Of 4413 EMS on-scene evaluations, the diagnosis of stroke or TIA was made by an EMT or paramedic for 96 patients (2%). Of the study population (n = 86), a final hospital discharge diagnosis of stroke or TIA was made for 62 patients (72%). EMS dispatchers correctly identified 52% and paramedics 72% of these 86 patients as having sustained a stroke or TIA. Twenty-two of the 86 patients required paramedic-level interventions, which included three intubations. Of the 24 patients whose symptoms were misdiagnosed as stroke or TIA by the paramedics, 16 (19%) had acute conditions for which effective therapies are available. Prehospital personnel arrived at the scene to examine potential stroke patients in a mean of 3 minutes after the emergency 911 call was received by the dispatcher. Patients transported by basic life support units (EMTs) arrived earlier at the hospital than did those transported by advanced life support units (paramedics) (40 +/- 1 versus 45 +/- 1 minutes, P = .004). However, patients transported by advanced life support units were seen by a physician sooner after arrival at the emergency department (10 +/- 2 versus 20 +/- 4 minutes, P = .02) and underwent computed tomography of the brain sooner (47 +/- 5 versus 69 +/- 10 minutes, P = .04). CONCLUSIONS: Prehospital evaluation of potential stroke patients can be accomplished promptly after the EMS system is activated. Urgent evaluation and transport of potential stroke patients is justified because paramedic-level interventions are frequently required and because almost 20% of patients with potential stroke have acute medical conditions for which effective specific therapies are available.

Aged↗
PubMed1994

Thrombolytic therapy for stroke.

The physiology of thrombi and the pharmacology of thrombolytic drugs are under active study and improved regimens for the dosing of thrombolytic agents have been developed. In the setting of myocardial infarction, recently reported differences among thrombolytic agents have been slight, including the frequency of thrombolysis-associated hemorrhagic stroke following tissue plasminogen activator or streptokinase. In the setting of ischemic stroke, recanalization rates following intravenous tissue plasminogen activator have been modest and at least partly dependent on clot size. Conclusions regarding clinical benefit will depend on the results of multicenter randomized trials that should available in 1995. Studies of locally administered intra-arterial thrombolytic therapy demonstrate high rates of clot lysis, but clinical benefits have yet to be established. The results of randomized trials will be important in clarifying any cause-effect relationships between thrombolytic therapy and symptomatic and asymptomatic intracranial hemorrhage. Thrombolytic therapy in the study of subarachnoid hemorrhage is under active investigation.

Animals↗
PubMed1994

Improved reliability of the NIH Stroke Scale using video training. NINDS TPA Stroke Study Group.

BACKGROUND AND PURPOSE: Despite the frequent use of clinical rating scales in multicenter therapeutic stroke trials, no generally acceptable method exists to train and certify investigators to use the instrument consistently. We desired to train investigators to use the National Institutes of Health Stroke Scale in a study of acute stroke therapy so that all examiners rated patients comparably. METHODS: We devised a two-camera videotape method that optimizes the visual presentation of examination findings. We then measured the effectiveness of the training by asking each investigator to evaluate a set of 11 patients, also on videotape. We tabulated the evaluations, devised a scoring system, and calculated measures of interobserver agreement among the participants in this study. RESULTS: We trained and certified 162 investigators. We found moderate to excellent agreement on most Stroke Scale items (unweighted kappa > 0.60). Two items, facial paresis and ataxia, exhibited poor agreement (unweighted kappa < 0.40) and should be revised in future editions of the scale. Performance improved with video training compared with previous studies. Inclusion of the motor rating of the unaffected limbs in the total score did not affect reliability. CONCLUSIONS: Video training and certification is a practical and effective method to standardize the use of examination scales. Two cameras must be used during the taping of patients to accurately present the clinical findings. This method is easily adapted to any study in which a large number of investigators will be enrolling patients at multiple clinical centers.

Cerebrovascular Disorders↗
PubMed1994

Baseline silent cerebral infarction in the Asymptomatic Carotid Atherosclerosis Study.

BACKGROUND AND PURPOSE: In a group of patients with high-grade asymptomatic carotid artery stenosis, we prospectively determined the prevalence and radiological characteristics of clinically asymptomatic brain infarction evident on computed tomography. Risk factors and extent of carotid disease were also determined. METHODS: Patients randomized into the Asymptomatic Carotid Atherosclerosis Study (ACAS) underwent a neurological history, a detailed stroke/transient ischemic attack questionnaire, and a detailed neurological examination. Computed tomography scans were examined by standardized criteria developed as part of a quality-control program supervised by a neuroradiologist. The presence, location, and size of all cerebral infarctions evident by computed tomography were determined. RESULTS: Among 1132 patients, 848 had no history of stroke or transient ischemic attack. One hundred twenty-six patients (15%) had a silent infarct; 95 (11%) had one, 24 (3%) had two, and 7 (1%) had three or more infarcts. The infarct size was small and deep for 117 patients (72%), less than one-half lobe for 45 (28%), and one-half to less than one lobe for 1 (0.5%). The silent infarcts were evenly distributed ipsilaterally and contralaterally to the study artery but were significantly more frequent in the right hemisphere (P < .05). Factors associated with silent infarction were abnormal gait (P < .001), abnormal deep tendon reflexes or plantar responses (P = .038), but not degree of carotid stenosis. Silent infarction was less frequent among this totally asymptomatic cohort (15%) compared with those with transient ischemic attacks (34/139, 25%; P < .001). CONCLUSIONS: Silent infarction in the setting of asymptomatic carotid stenosis is not uncommon, but silent infarctions are rarely sizable. The clinical significance of silent cerebral infarction in patients with asymptomatic carotid artery stenosis has yet to be established.

Adult↗
PubMed1994

Management of intracerebral hemorrhage in a large metropolitan population.

The management of all patients with spontaneous, nonaneurysmal intracerebral hemorrhages that occurred in the 1.26 million population of Greater Cincinnati during 1988 was reviewed. Of the 188 patients with intracerebral hemorrhage, 26 had operative removal of their intracerebral hemorrhage, and 8 had removal of their intracerebral hemorrhage and an arteriovenous malformation. In 15 of the 34 patients, the operation was performed within 12 hours of onset. The operative removal of parenchymal hemorrhages was performed in 29% of cerebellar, 24% of lobar, 13% of deep, and 10% of pontine hemorrhages. Admission Glasgow Coma Scale scores were similar for operated and nonoperated patients (11 +/- 3 versus 11 +/- 3), but operated patients were significantly younger (58 +/- 17 versus 72 +/- 15 yr), were more likely to have a lobar hemorrhage (64 versus 43%) or a cerebellar hemorrhage (29 versus 7%), and had larger parenchymal hemorrhages (50 +/- 31 versus 37 +/- 38 ml). Operated patients had a borderline lower 30-day mortality (25%) than nonoperated patients (46%), but the overall morbidity and mortality for the two groups did not differ significantly. Patients undergoing an early operation were more critically ill preoperatively and had a greater 30-day mortality (45%) than did those patients undergoing a late operation (12%). Half of the 43% mortality for all hospitalized cases occurred during the first 2 days after onset, and two-thirds occurred during the first 4 days. Only 12% of all patients had a minor handicap or better at 30 days. Neurosurgeons in our community performed operative removal of parenchymal hemorrhage in nearly one fifth of all patients with intracerebral hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Blood pressure during the first minutes of focal cerebral ischemia.

STUDY OBJECTIVE: To determine whether blood pressure declines spontaneously during the first minutes and hours of focal cerebral ischemia. DESIGN: Multiple blood pressure measurements as part of an urgent stroke therapy trial (treatment within 90 minutes of stroke onset). SETTING: Thirteen hospitals in three metropolitan communities. PARTICIPANTS: Sixty-nine patients (mean age, 65 +/- 9 years) with acute ischemic stroke who were participants in a phase I urgent stroke therapy trial of recombinant tissue plasminogen activator. MAIN OUTCOME MEASURE: Blood pressures recorded at the scene of stroke by life-squad personnel, in the emergency department, and in the ICU. RESULTS: The mean time from stroke onset to the time of first blood pressure measurement was 19 +/- 13 minutes. Twenty-four of the 69 patients in the urgent stroke therapy trial had an initial systolic blood pressure of at least 160 mm Hg. Of these, 23 had a significant decline in systolic and diastolic blood pressure during the first 90 minutes after the onset of stroke (mean change in systolic pressure, -29 +/- 22 mm Hg, P < .001; mean change in diastolic pressure, -10 +/- 14 mm Hg, P < .01). No patients received antihypertensive therapy during the time in which the decline in blood pressure was noted. CONCLUSION: Mildly or moderately elevated blood pressure frequently declines spontaneously during the first minutes and hours of focal cerebral ischemia and generally does not require urgent pharmacologic treatment.

Acute Disease↗
PubMed1993

Lobar hemorrhage in the elderly. The undiminishing importance of hypertension.

BACKGROUND AND PURPOSE: We sought to determine whether hypertension is less common in primary lobar hemorrhage than intracerebral hemorrhage in other locations and whether the frequency of hypertension in lobar hemorrhage diminishes with advancing age. METHODS: We identified all cases of intracerebral hemorrhage in Greater Cincinnati during 1988 by review of hospital and autopsy records as well as computed tomographic and magnetic resonance scans. RESULTS: During 1988, 66 primary lobar hemorrhages occurred, constituting 46% of all intracerebral hemorrhages in those under 75 years of age and 34% in those age 75 and older. A history of hypertension was present in 67% of patients with lobar, 73% of those with deep, 73% of those with cerebellar, and 78% of those with pontine hemorrhages. Left ventricular hypertrophy was present in 21% of patients with lobar, 27% of those with deep, and 47% of those with pontine/cerebellar hemorrhages. The frequency of hypertension in patients with lobar hemorrhage did not decrease with advancing age. CONCLUSIONS: The proportion of all intracerebral hemorrhages that are lobar does not increase with advancing age. Hypertension is nearly as common in primary lobar hemorrhage as in deep, cerebellar, and pontine hemorrhages, and its importance as an associated condition for lobar hemorrhage does not diminish with advancing age.

Adult↗
PubMed1993

Stroke in children within a major metropolitan area: the surprising importance of intracerebral hemorrhage.

Our objective was to determine the incidence rate of stroke and stroke subtypes in children. We reviewed the medical records, autopsy records, and brain imaging studies of all children with a possible stroke within the Greater Cincinnati metropolitan area population of nearly 1.3 million during 1988 and 1989. Traumatic brain hemorrhages and germinal matrix hemorrhages were excluded. Of the 295,577 children in Greater Cincinnati, medical records of 178 children were screened. Sixteen cases (13 whites and three blacks) less than age 15 years fit strictly defined criteria for first-ever stroke. The incidence rate for cerebral infarction was 1.2 cases per 100,000 (95% confidence interval, 0.3 to 2.0). The combined incidence rate for intracerebral hemorrhage and subarachnoid hemorrhage was 1.5 cases per 100,000 children (95% confidence interval, 0.4 to 2.3). The incidence rate of all stroke in white children was 2.6 cases per 100,000 (95% confidence interval, 1.2 to 4.1), compared to 3.1 per 100,000 in black children (95% confidence interval, 0 to 6.6). The combined 30-day mortality for intracerebral hemorrhage and subarachnoid hemorrhage was 22% (two of nine) compared to 14% (one of seven) for cerebral infarction. We conclude that in contrast to the picture in adults, hemorrhagic stroke among infants and children is at least as common as ischemic infarction.

Adolescent↗
PubMed1993

Intracerebral hemorrhage more than twice as common as subarachnoid hemorrhage.

The authors report a study of all instances of spontaneous intracerebral hemorrhage (ICH) (188 cases) and subarachnoid hemorrhage (SAH) (80 cases) that occurred in the Greater Cincinnati area during 1988. Adjusted for age, sex, and race, the annual incidence of ICH was 15 per 100,000 population (95% confidence interval 13 to 17) versus six per 100,000 for SAH (95% confidence interval 5 to 8). The incidence of ICH was at least double that of SAH for women, men, and whites and approximately 1 1/2 times that for blacks. The 30-day mortality rate of 44% for ICH was not significantly different from the 46% mortality rate for SAH. Despite the evidence that ICH is more than twice as common and the disorder just as deadly as SAH, clinical and laboratory research continues to focus primarily on SAH.

Adolescent↗
PubMed1992

The risk of subarachnoid and intracerebral hemorrhages in blacks as compared with whites.

BACKGROUND: Stroke is an important cause of death among blacks, and intracerebral and subarachnoid hemorrhages account for nearly half of all early deaths from stroke. The present study investigates whether blacks and whites differ in their risk of having either intracerebral or subarachnoid hemorrhage. METHODS: We reviewed the medical records, autopsy reports, and CT scans of all patients suspected of having had an intracerebral or subarachnoid hemorrhage during 1988 among the nearly 1.3 million people in the Greater Cincinnati metropolitan area. RESULTS: There were 221 cases of first spontaneous intracranial hemorrhage among 1,086,462 whites (159 intracerebral and 62 subarachnoid hemorrhages), and 45 cases among 171,718 blacks (27 intracerebral and 18 subarachnoid hemorrhages). Blacks had 2.1 times the risk of subarachnoid hemorrhage of whites (95 percent confidence interval, 1.3 to 3.6) and 1.4 times the risk of intracerebral hemorrhage (95 percent confidence interval, 0.9 to 2.1). In those under the age of 75, the risk of intracerebral hemorrhage among blacks was 2.3 times that of whites (95 percent confidence interval, 1.5 to 3.6), whereas the risk among blacks 75 or older was one fourth that of whites (95 percent confidence interval, 0.1 to 0.8). Deaths within 30 days of intracerebral or subarachnoid hemorrhage accounted for 1.9 years of life lost per 1000 blacks under 65 years of age, as compared with 0.5 year per 1000 whites. CONCLUSIONS: Young and middle-aged blacks have a substantially higher risk of subarachnoid or intracerebral hemorrhage than whites of similar age. These types of stroke are important causes of excess mortality among young and middle-aged blacks.

Adult↗
PubMed1992

Thrombolytic therapy.

Following the successful application of thrombolytic therapy for acute myocardial infarction, investigations have proceeded on several different thrombolytic agents as therapy for ischemic stroke. Early clot lysis has been demonstrated following both intra-arterial and intravenous drug administration. Clinical outcomes have been encouraging, but conclusions regarding efficacy must await the completion of randomized clinical trials. Intra-cerebral hemorrhage following thrombolytic therapy for ischemic stroke is not uncommon and may be fatal, and risk factors for this complication have been difficult to identify.

Animals↗
PubMed1991

Thrombolytic therapy for stroke.

Thrombolytic therapy has recently been shown to be beneficial in the setting of acute myocardial infarction, and thrombolysis resulting in vascular recanalization has been achieved in several other human disease states, including stroke. Advances in the understanding of the fibrinolytic system have led to the development of several new and distinctive thrombolytic strategies. Animal studies of stroke have been encouraging with regard to arterial recanalization and safety. Clinically, the availability of brain computed tomography has allowed pilot studies to proceed by providing rapid identification of patients with nonhemorrhagic stroke. Arterial recanalization has been demonstrated in patients with ischemic stroke following the administration of any one of several thrombolytic drugs. Placebo-controlled trials have not been completed, and so clinical benefit has not been established. Even though the development of brain hemorrhage has been an infrequent complication, the very high morbidity and mortality have been worrisome. Ironically, thrombolytic therapy holds promise for treatment of subarachnoid hemorrhage and perhaps also for spontaneous intracerebral hemorrhage. Human studies have been limited, but complications have been modest, and clinical outcomes have been encouraging.

Animals↗
PubMed1991

Prevention and management of medical complications of the hospitalized elderly stroke patient.

Medical complications may account for 30% or more of the deaths resulting from acute ischemic stroke in the elderly. In descending order of frequency, the most deadly complications are bacterial pneumonia, pulmonary embolism, myocardial infarction, and sepsis without pneumonia (often in the setting of a urinary tract infection or a necrotic decubitus). Normal aging is associated with declining pulmonary and cardiovascular functions as well as declining immunocompetence and physical barriers to infection. The neurological effects of acute ischemic brain injury compound these susceptibilities. Accordingly, a high degree of vigilance is emphasized in the diagnostic and therapeutic guidelines provided for care of the lungs, the heart, the urinary tract, and the skin. Guidelines are also provided for management of blood pressure during the first hours and days following stroke onset. Treatment should be withheld unless specific medical indications are identified. When antihypertensive agents are administered, the appropriate dose may be lower than usually recommended (e.g. labetalol) in order to minimize abrupt drops in blood pressure that may result in further injury to potentially viable ischemic brain tissue.

Aged↗