PubMed Health⌕ Search

Biomedical subjects

M I Chimowitz

Publications and source records attributed to M I Chimowitz.

At least 19 recordsLinked to original sources
PubMed1995

The Warfarin-Aspirin Symptomatic Intracranial Disease Study.

We conducted a retrospective, multicenter study to compare the efficacy of warfarin with aspirin for the prevention of major vascular events (ischemic stroke, myocardial infarction, or sudden death) in patients with symptomatic stenosis of a major intracranial artery. Patients with 50 to 99% stenosis of an intracranial artery (carotid; anterior, middle, or posterior cerebral; vertebral; or basilar) were identified by reviewing the results of consecutive angiograms performed at participating centers between 1985 and 1991. Only patients with TIA or stroke in the territory of the stenotic artery qualified for inclusion in the study. Patients were prescribed warfarin or aspirin according to local physician preference and were followed by chart review and personal or telephone interview. Seven centers enrolled 151 patients; 88 were treated with warfarin and 63 were treated with aspirin. Median follow-up was 14.7 months (warfarin group) and 19.3 months (aspirin group). Vascular risk factors and mean percent stenosis of the symptomatic artery were similar in the two groups, yet the rates of major vascular events were 18.1 per 100 patient-years of follow-up in the aspirin group (stroke rate, 10.4/100 patient-years; myocardial infarction or sudden death rate, 7.7/100 patient-years) compared with 8.4 per 100 patient-years of follow-up in the warfarin group (stroke rate, 3.6/100 patient-years; myocardial infarction or sudden death rate, 4.8/100 patient-years). Kaplan-Meier analysis showed a significantly higher percentage of patients free of major vascular events among patients treated with warfarin (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Right atrial spontaneous contrast: echocardiographic and clinical features.

We describe the clinical and echocardiographic findings in eight patients with right atrial spontaneous echo contrast who were identified from 648 consecutive patients undergoing transesophageal echocardiography. Common findings in these patients were right atrial enlargement (8 patients), tricuspid regurgitation (7 patients), atrial fibrillation or flutter (6 patients), elevated right ventricular pressure (5 patients), moderate or severe mitral valve disease (5 patients), and right to left interatrial shunts (3 patients). Right heart catheterization in three patients showed markedly elevated right atrial, right ventricular, and pulmonary artery pressures. Two patients had thromboembolic events-one patient had recurrent pulmonary emboli, and another patient with an atrial septal aneurysm had recurrent transient ischemic attacks. Right atrial echo contrast is an uncommon finding at echocardiography that is associated with severe right heart dysfunction. It may also be associated with paradoxical or pulmonary embolism.

Adult↗
PubMed1994

Cardiac prognosis of patients with carotid stenosis and no history of coronary artery disease. Veterans Affairs Cooperative Study Group 167.

BACKGROUND AND PURPOSE: Patients with carotid stenosis have a high frequency of asymptomatic coronary artery disease (CAD). The purpose of this study of patients with asymptomatic carotid stenosis was to test the hypothesis that patients without a history of CAD have the same cardiac prognosis as patients with a history of CAD. METHODS: Men enrolled in the Department of Veterans Affairs study on the efficacy of carotid endarterectomy for asymptomatic carotid stenosis underwent a baseline cardiac evaluation (history, physical examination, and electrocardiogram) to document previous angina or myocardial infarction. Patients were randomized to medical therapy alone or medical therapy and carotid endarterectomy. Medical therapy consisted of aspirin 650 mg twice daily and treatment of risk factors. All episodes of angina, myocardial infarction, or sudden death during follow-up (average of 47.9 months) were recorded. RESULTS: Of 444 men enrolled in the study, 200 (45%) had a history of CAD. During the study 86 (43%) of 200 patients with CAD and 81 (33%) of 244 patients without a history of CAD had cardiac ischemic events (P = .03). In patients without a history of CAD, the first cardiac event was myocardial infarction or sudden death in 45 patients (56%). Factors that were independently associated with cardiac events in patients without a history of CAD were diabetes (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.15 to 3.97), intracranial occlusive disease (OR, 2.13; 95% CI, 1.13 to 4.02), and peripheral vascular disease (OR, 2.04; 95% CI, 1.14 to 3.66). Forty-two percent of patients with two of these factors and 69% of patients with all three factors had cardiac events. CONCLUSIONS: Men with carotid stenosis and no history of CAD have a lower rate of cardiac events than men with carotid stenosis who have a history of CAD. However, a subgroup of patients with carotid stenosis and no history of CAD who have coexistent intracranial occlusive disease, diabetes, or peripheral vascular disease have a risk of cardiac events similar to that of patients with a history of CAD.

Aged↗
PubMed1994

Ischemic stroke and TIA: clinical clues to common causes.

Establishing the cause of a transient ischemic attack (TIA) or minor stroke enables you to institute effective therapy to prevent major stroke. Clinical and radiologic features that help to clarify the cause of cerebrovascular ischemia include characteristics of prior TIAs, temporal progression and nature of the neurologic deficit, and appearance of infarction on CT and MRI of the brain. Carotid and transcranial Doppler ultrasound, magnetic resonance angiography, arterial angiography, and echocardiography are used to confirm the cause of cerebral ischemia. We provide three case studies to illustrate our approach to stroke diagnosis.

Causality↗
PubMed1993

Left atrial spontaneous echo contrast is highly associated with previous stroke in patients with atrial fibrillation or mitral stenosis.

BACKGROUND AND PURPOSE: Spontaneous echo contrast is a dynamic smokelike signal that is detected by transesophageal echocardiography in patients with stasis of blood in the left atrium. We designed this study to determine if spontaneous echo contrast is associated with an increased risk of previous stroke or peripheral embolism. METHODS: Forty-two patients with spontaneous echo contrast were identified (34 had atrial fibrillation or mitral stenosis; 8 had neither). Control subjects comprised 40 patients randomly selected from patients with atrial fibrillation or mitral stenosis who did not have spontaneous echo contrast at transesophageal echocardiography. The frequency of vascular risk factors, echocardiographic features, and stroke or peripheral embolism within 1 year of echocardiography were compared in the two groups. RESULTS: The frequency of traditional risk factors for stroke were the same in both groups, yet 9 of 42 patients with spontaneous contrast had stroke or peripheral embolism compared with only 1 of 40 control subjects (P < .02; relative risk, 10.6; 95% confidence interval, 1.3 to 88.4). In patients with nonvalvular atrial fibrillation, 6 of 12 patients with spontaneous contrast had a stroke or peripheral embolism compared with 1 of 28 patients without spontaneous contrast (P < .001; relative risk, 27.0; 95% confidence interval, 2.7 to 267.8). CONCLUSIONS: Spontaneous echo contrast is highly associated with previous stroke or peripheral embolism in patients with atrial fibrillation or mitral stenosis. Transesophageal echocardiography may enable stratification of cardioembolic risk in patients with nonvalvular atrial fibrillation.

Aged↗
PubMed1992

Further observations on the pathology of subcortical lesions identified on magnetic resonance imaging.

We performed postmortem magnetic resonance imaging and pathologic examinations on the brains of seven consecutive patients older than 50 years of age who died of non-neurologic causes. Multiple hyperintense subcortical lesions were identified in each patient, and a total of 29 lesions were examined histologically (eight rims, six caps, six punctate lesions, and nine patches). Rims were characterized by subependymal gliosis and loss of the ependymal lining; caps were associated with myelin pallor, gliosis, and arteriosclerosis; punctate lesions were characterized by dilated perivascular spaces and perivascular gliosis; and patches were associated with myelin pallor and dilated perivascular spaces. The pattern of myelin pallor defined the size and shape of caps and patches. Arteriosclerosis was identified in six of six caps, three of six punctate lesions, and in three of nine patches. These data indicate that (1) each type of hyperintense subcortical lesion has a distinct pathologic correlate; (2) arteriosclerosis is not invariably associated with all types of hyperintense subcortical lesions on magnetic resonance imaging; and (3) myelin pallor appears to contribute to the magnetic resonance imaging signal at 1.5 tesla.

Aged↗
PubMed1992

Asymptomatic coronary artery disease in patients with stroke. Prevalence, prognosis, diagnosis, and treatment.

The frequency of angiographically defined asymptomatic CAD in patients with carotid disease is 40%. Although the prognosis of patients with asymptomatic 1-vessel or 2-vessel CAD is good (annual cardiac mortality rate less than 2%), the prognosis of asymptomatic 3-vessel disease or left main CAD is substantially less favorable (annual cardiac mortality 5-8%). Preliminary data from nonrandomized studies suggest that coronary artery bypass surgery significantly lowers cardiac mortality in patients with asymptomatic 3-vessel or left main CAD. Further studies are needed to determine 1) vascular risk factor profiles that are predictive of asymptomatic CAD in patients with cerebrovascular disease and 2) the prevalence of asymptomatic CAD, especially 3-vessel and left main CAD, in patients with a variety of subtypes of cerebrovascular disease (e.g., carotid disease, atherosclerotic vertebrobasilar disease, cardioembolism, penetrating artery disease, stroke of undetermined cause). If the prevalence of asymptomatic 3-vessel or left main CAD is high in a subset of patients with cerebrovascular disease, a randomized study comparing coronary artery bypass surgery with best medical therapy (anti-ischemic agents, lipid-lowering therapy, and aspirin) may be warranted.

Cerebrovascular Disorders↗
PubMed1992

Neurologic complications related to cardiac surgery.

Neurologic complications are a major cause of morbidity, complicating open heart surgery, cardiac catheterization, and interventional techniques. Global or focal brain ischemia related to embolism or hypoperfusion predominates. Breakthrough cerebral hemorrhage and infection can complicate cardiac transplantation. Identifying individuals at risk for cerebrovascular complications may lead to more effective preventative and treatment measures.

Brain Damage, Chronic↗
PubMed1991

Comparison of transcranial Doppler ultrasound and transesophageal contrast echocardiography in the detection of interatrial right-to-left shunts.

Transesophageal contrast echocardiography is an effective but semiinvasive technique for the detection of interatrial right-to-left shunts. Transcranial Doppler ultrasound is an alternative noninvasive method, but may be limited by false-positive diagnoses due to intrapulmonary shunting. This study examined the accuracy of transcranial Doppler for the detection of shunt lesions. Transcranial Doppler of the right middle cerebral artery was performed simultaneously with transesophageal and transthoracic contrast echocardiography in 32 patients using agitated saline contrast during normal respiration and Valsalva. Transesophageal contrast echocardiography diagnosed an interatrial right-to-left shunt in 13 patients and intrapulmonary shunting in 6 patients. Transcranial Doppler identified all 13 interatrial right-to-left shunts and an intrapulmonary shunt in 3 of 6 patients. Absence of a shunt was confirmed by transcranial Doppler in 12 of 12 patients. Transcranial Doppler had a sensitivity of 100% (13 of 13), specificity of 100% (18 of 18) and accuracy of 100% (31 of 31) for prediction of an interatrial right-to-left shunt by transesophageal contrast echocardiography. In comparison, transthoracic contrast echocardiography had a sensitivity of 54% (7 of 13), specificity of 94% (17 of 18) and accuracy of 77% (24 of 31). Thus, transcranial Doppler is highly accurate for detection of an interatrial right-to-left shunt and not compromised by physiologic intrapulmonary shunts, whereas transthoracic contrast echocardiography lacks sensitivity. Transcranial Doppler may be useful as an alternative to transesophageal study, where the primary indication for transesophageal echocardiography is exclusion of an interatrial right-to-left shunt.

Adult↗
PubMed1991

Sclerosing vasculopathy of the central nervous system in nonelderly demented patients.

Three nonelderly patients without hypertension whose clinical and radiologic features otherwise resembled Binswanger's subcortical arteriosclerotic encephalopathy underwent biopsy of the hyperintense periventricular lesions seen on magnetic resonance imaging. The pathologic findings of the periventricular lesions consisted of gliosis with mild rarefaction and edema of the white matter. All patients had a sclerosing vasculopathy of unknown cause, which involved numerous small vessels within the periventricular lesions. The vessels stained negatively for amyloid, amyloid precursors, desmin, vimentin, keratin, immunoglobulin, and complement. On electron microscopy, small arteries, arterioles, venules, and capillaries were characterized by swollen astrocytic foot processes surrounding the vessels; dense, perivascular collagen packing; crystalline arrays of filaments within basement membrane; giant lipid-laden lysosomes within perivascular cells; and narrowing of the vascular lumina. Similar changes were not seen in a control group of 19 patients. The pathologic features of the vessels in these cases are distinct from the vasculopathy associated with Binswanger's subcortical arteriosclerotic encephalopathy. We suggest that a spectrum of vasculopathies may be associated with dementia and periventricular hyperintense lesions on magnetic resonance imaging.

Adult↗
PubMed1991

Etiology of motor or sensory stroke: a prospective study of the predictive value of clinical and radiological features.

The diagnostic utility of clinical and radiological features for distinguishing penetrating artery disease from other causes of stroke has been questioned. To address this issue, we prospectively evaluated more than 40 features in 85 patients with pure motor, sensorimotor, or pure sensory syndromes. Nonischemic causes were present in 4 patients. The causes of ischemic stroke in the other 81 patients were penetrating artery disease (32 patients), large artery occlusive disease (17), cardioembolism (12), other causes (8), and undetermined (12). Of the features evaluated, frequent transient ischemic attacks (greater than or equal to 1/day), transient ischemic attacks occurring only within 1 week of stroke, pure motor hemiparesis (similar involvement of face, arm, and leg), pure sensory stroke, and round or oval infarction were associated (p less than 0.05) with penetrating artery disease. However, only pure sensory stroke involving two or more regions of the body and pure motor hemiparesis associated with subcortical infarction of less than 1.5 cm had positive predictive values exceeding 90% for penetrating artery disease. Carotid bruit ipsilateral to an anterior circulation infarction, monoparesis, and striatocapsular infarction had positive predictive values exceeding 90% for causes other than penetrating artery disease; however, half of the striatocapsular infarctions were of undetermined cause. These data suggest that certain clinical and radiological features are useful for distinguishing penetrating artery disease from other causes of stroke.

Aged↗
PubMed1991

Transcranial Doppler ultrasound identifies patients with right-to-left cardiac or pulmonary shunts.

We performed transcranial Doppler ultrasound (TCD) and transesophageal contrast echocardiography simultaneously in four patients. In one patient with a patent foramen ovale and another patient with pulmonary A-V fistulae, we detected micro air bubbles in the right middle cerebral artery three to five cardiac cycles after their appearance in the left atrium following intravenous injection of contrast. In two patients without right-to-left shunts, we did not detect air bubbles in the left atrium or middle cerebral artery following injection of contrast. These results show that TCD can identify patients with right-to-left cardiac or pulmonary shunts.

Adult↗
PubMed1991

Treatment of intractable arterial hemorrhage during stereotactic brain biopsy with thrombin. Report of three patients.

Of 165 consecutive patients undergoing computerized tomography- or magnetic resonance imaging-guided stereotactic brain biopsies at the Cleveland Clinic between June, 1987, and November, 1989, four patients (2.4%) developed arterial hemorrhage refractory to conventional efforts to secure hemostasis. Craniotomy was performed in one of these patients to control the hemorrhage; in the other three, 0.5 to 2 cc of thrombin (5000 U/cc) was slowly injected via the biopsy cannula, resulting in immediate control of bleeding in all three cases. Postoperatively, the first two patients treated with 1 to 2 cc of thrombin were slow to awaken; one had evidence of vasospasm by transcranial Doppler ultrasound studies and multiple infarcts on cranial computerized tomography, while the other had a moderate-sized frontal hematoma with intracranial hypertension. After prolonged recovery periods, only mild neurological deficits persisted in both patients. The third patient, treated with 0.5 cc of thrombin, had an uneventful postoperative course. Thrombin is highly effective for stopping intractable arterial hemorrhage during stereotactic brain biopsy; however, it is a vasospastic agent and may have been responsible for the cerebral infarctions in one patient. Therefore, thrombin should be used only as a last resort, short of craniotomy, to control intractable arterial hemorrhage during stereotactic brain biopsy.

Adolescent↗
PubMed1990

Intracranial hypertension associated with unruptured cerebral arteriovenous malformations.

Only 6 patients with intracranial hypertension associated with unruptured cerebral arteriovenous malformations have been reported. We report 6 additional patients seen at the Cleveland Clinic during the past 10 years. The average age was 28 years (range, 19-44 years); 4 were women. Symptoms and signs included papilledema (6 patients), headache (6), transient nonepileptic focal symptoms (4), visual obscurations (3), ipsilateral carotid or ocular bruits (3), abnormal visual fields (3), focal seizures (2), and progressive visual loss (1). Enhanced computed tomography (CT) or magnetic resonance imaging (MRI) demonstrated the malformations in all 6 patients. The malformations were large, supplied by the branches of the middle and anterior cerebral arteries, with the posterior cerebral artery contributing in 3 patients, and all drained into the superior sagittal sinus. Associated venous obstruction was seen in 2 patients. Four patients underwent excision of the arteriovenous malformation, with resolution of papilledema in all 4. Measurements of cortical arterial and venous pressures during surgery in 3 patients showed decreased feeding artery pressures and elevated draining vein pressures, which normalized after removal of the malformation. Treatment in the 2 remaining patients consisted of medical therapy (acetazolamide, furosemide, steroids) alone in 1 patient, and in conjunction with proton beam radiation in the other. Papilledema resolved in the former patient, but the patient receiving proton beam radiation still had papilledema 2 years later. Intracranial hypertension associated with unruptured cerebral arteriovenous malformations occurs in young patients with high flow malformations that drain into the superior sagittal sinus, and is likely the result of increased cortical venous and superior sagittal sinus pressure. Excision of the malformation effectively reduces the intracranial pressure.

Adult↗
PubMed1990

The accuracy of bedside neurological diagnoses.

The accuracy of bedside diagnoses was prospectively studied in 100 consecutive patients admitted to the neurology service at New England Medical Center, Boston. Each patient was evaluated independently by a junior resident, a senior resident, and a staff neurologist, who were required to make an anatomical and etiological diagnosis based solely on the history and physical examination. Fourteen patients were excluded because their diagnoses were known before admission. Of the remaining 86 patients, it was possible to confirm anatomical and etiological diagnoses in 40 by matching the clinical syndromes with highly specific laboratory findings. In the other 46 patients, the diagnoses could not be confirmed because the laboratory studies (including magnetic resonance imaging) were negative or nondiagnostic. In the 40 patients with laboratory confirmed final diagnoses, the clinical diagnoses of the junior residents, senior residents, and staff neurologists were correct in 26 (65%), 30 (75%), and 31 (77%), respectively. There was a trend for error rates to be higher among junior residents than staff (p = 0.06). The errors by the junior residents, [senior residents], (staff) were attributed to incomplete history and examination in 4 [1] (0), inadequate fund of knowledge in 4 [3] (3), and poor diagnostic reasoning in 6 [6] (6). These results indicate that technology is not a panacea for our diagnostic difficulties and that there is room for improvement in our clinical skills, especially diagnostic reasoning.

Adult↗
PubMed1990

Ipsilateral leg weakness associated with carotid stenosis.

Ipsilateral motor or sensory symptoms associated with carotid occlusive diseases are rare. We report a 52-year-old man who presented with aphasia, right hemiparesis, mild left leg weakness, and bilateral Babinski's signs. During the previous 10 days, he had experienced three episodes of left leg numbness and incoordination that occurred either alone or in association with right arm and leg weakness. Computed tomography showed infarcts in the right frontoparietal (parasagittal), left frontal, and left parietal lobes. Cerebral angiography revealed 60% stenosis of the right internal carotid artery, 80% stenosis of the left internal carotid artery, absence of the A1 segment of the right anterior cerebral artery, filling of the right anterior cerebral artery from the left carotid circulation only, and a normal vertebrobasilar system. This report illustrates that leg weakness may occur ipsilateral to carotid disease if the contralateral anterior cerebral artery is supplied by the ipsilateral carotid artery.

Carotid Arteries↗
PubMed1990

Mechanism of stroke in patients taking aspirin.

During a 1-year period, we prospectively studied the mechanism and severity of stroke in 47 patients sustaining a cerebral infarction while taking aspirin. The mechanism of stroke was undetermined in 12 patients (26%). In the remaining 35 patients, we identified 39 potential mechanisms: large-artery atherosclerosis (19 patients, 40%), cardioembolism (15 patients, 32%), and small-vessel occlusive disease (5 patients, 11%). Of 11 patients with carotid atherosclerosis and stroke, 9 (82%) had greater than 90% carotid stenosis or occlusion; of 12 patients with stroke of undetermined mechanism, 10 (83%) had previous stroke, of which 8 were also of undetermined mechanisms. Disability after stroke was moderate or severe in 27 patients (57%). These data suggest that (1) stroke in patients taking aspirin has a variety of etiologies and frequently causes moderate or severe disability; (2) patients with carotid disease failing aspirin often have high-grade carotid stenosis or occlusion; (3) stroke of undetermined mechanism may recur more frequently than other stroke subtypes in patients taking aspirin.

Adult↗