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PubMed1998

Cerebral embolism and epileptic seizures--the role of the embolic source.

OBJECTIVES: To study the clinical outcome of patients with epileptic seizures due to ischemic stroke (IS) of cardiac or artery-to-artery embolism. METHODS: Seizures due to IS of cardiac or artery-to-artery embolism are differentiated by clinical, neuroimaging and cardiovascular test data. RESULTS: From 174 cases with supratentorial IS, 13 patients suffered from epileptic seizures due to cardiac embolism, 11 patients due to artery-to-artery embolism. The patients with cardiac IS showed an equal sex distribution and EEG abnormalities in 6 patients, the initial seizure occurred on average after 222 days (SD, +/-69 days). Among the 11 patients with artery-to-artery embolic IS, there were 9 males and 2 females and EEG abnormalities in 10 patients. The initial seizure occurred on average after 447 days (SD, +/-177 days). CONCLUSION: In seizures due to artery-to-artery embolism, there is a male preponderance and a higher incidence of EEG abnormalities, symptomatic seizures appear later compared to IS due to cardiac embolism.

Adult↗
PubMed2004

Time period required for transcranial Doppler monitoring of embolic signals to predict recurrent risk of embolic transient ischemic attack and stroke from arterial stenosis.

BACKGROUND AND PURPOSE: We aimed to investigate whether the time period of transcranial Doppler monitoring for embolic signals can be reduced without loss of clinical yield compared with routinely performed 1-hour monitoring. METHODS: Investigations on the basis of a post hoc analysis of a previously published cohort of 86 patients (55 men, 31 women; mean age 60.6 years) with a nondisabling arterioembolic ischemic event in the anterior circulation within the last 30 days (mean 7.3) and an ipsilateral medium-grade or high-grade stenosis of the carotid or middle cerebral artery. Patients underwent 1-hour monitoring for embolic signals and were followed up prospectively for 6 weeks to evaluate the relationship between embolic signals and risk of an early ischemic recurrence. Risk was also calculated after fictitious reduction of the monitoring period from 60 minutes to 50, 40, 30, 20, and 10 minutes, respectively, and compared with the results obtained from the 1-hour period. RESULTS: The number of patients positive for embolic signals decreased with the decreasing monitoring period. By this, the odds ratio of embolic signals for an early ischemic recurrence "decreased" from 40 (derived from the 1-hour monitoring) to 10 when the monitoring lasted < or =30 minutes. The relationship between the rate of embolic signals per hour and risk of a recurrent stroke is described by an S-shaped curve. As a consequence, risk estimated from reduced monitoring periods can differ considerably from that derived from the 1-hour monitoring if the signal frequency lies within a medium range (eg, between 3 and 15 signals in 30 minutes). CONCLUSIONS: The time period of monitoring for embolic signals may be reduced without loss of clinical relevant information when signal frequency is low or already high during the reduced monitoring period, but it should be prolonged to maximally an hour at signal numbers within a medium range. However, our results need to be externally validated on an independent cohort of patients or confirmed by a prospective study before this modification can be recommended in general.

Aged↗
PubMed2006

Embolic lesion pattern in stroke patients with patent foramen ovale compared with patients lacking an embolic source.

BACKGROUND AND PURPOSE: Multiple acute ischemic lesions on diffusion-weighted magnetic resonance imaging (DWI-MRI) are thought to be of embolic origin. However, in several patients with multiple ischemic lesions on DWI-MRI, no embolic source was detected, despite a thorough clinical work-up. Stroke etiology in such cases is then classified as cryptogenic. In other patients, a potential embolic source is limited to a patent foramen ovale (PFO) that may act as an embolic source of unsure relevance. We therefore examined the prevalence of the multiple-lesion pattern in patients with cryptogenic stroke compared with patients with PFO. METHODS: We screened 650 stroke patients by DWI-MRI. For the subsequent evaluation, we excluded patients with a cardiac embolic source other than PFO, symptomatic carotid artery disease, and other apparent stroke causes, such as dissection or vasculitis, and patients whose diagnostic work-up was incomplete. For the remaining 106 patients, we found DWI lesions in 73, who were subjected to further evaluation. RESULTS: There were no differences in the occurrence of the multiple-lesion pattern in patients with cryptogenic stroke compared with patients with PFO, either for the entire group or for the subgroup of young stroke patients who were <50 years old. Patients with PFO showed a significantly higher incidence of multiple lesions in the posterior circulation. CONCLUSIONS: The multiple-lesion pattern on DWI-MRI is not uncommon, even when extensive testing does not reveal any embolic source. Therefore, it is not possible to discriminate between cryptogenic stroke and stroke from an assumed paradoxical embolism.

Adult↗
PubMedDate not supplied

Immediate anticoagulation of embolic stroke: a randomized trial. Cerebral Embolism Study Group.

A randomized trial of immediate versus delayed anticoagulation of patients with cardiogenic embolic brain infarction was carried out in a multi-centered study. Patients who were within 48 hours of onset of deficit and who had no evidence of hemorrhage on computed tomography (CT) were randomized to receive either immediate heparinization or no anticoagulants for the initial 14 days following stroke. There were 63 patients with embolic stroke identified during the study period. Eighteen patients were not randomized because of specific exclusion criteria or delayed identification more than 48 hours after stroke. Of 45 patients who were randomized, 44 patients (98%) completed the initial week of the protocol: 24 were immediately heparinized at an average of 32 hours after stroke, 21 received no immediate anticoagulation. Two patients developed delayed hemorrhagic infarction and two patients experienced early recurrent embolism, all among the nonanticoagulated group. Of all patients with embolic stroke who were not receiving coumadin at onset of stroke, only two of 56 (4%) had hemorrhagic infarction on initial CT. Follow-up CT in 40 of these patients showed late developing hemorrhagic infarction in two additional patients (5%). All four hemorrhagic infarctions occurred in 18 non-anticoagulated patients with large infarcts. There were no major complications associated with immediate heparinization of 24 unselected patients with all sizes of embolic infarction. A trend toward reduction of early recurrent embolism was apparent. These data support immediate anticoagulation of nonhypertensive patients with embolic brain infarction who have no evidence of hemorrhage on CT performed 24-48 hours after stroke.

Adult↗
PubMed2006

Clinical and economic outcomes of embolic complications and strategies for distal embolic protection during percutaneous coronary intervention in saphenous vein grafts.

BACKGROUND: Although distal embolic protection (DEP) is increasingly utilized in saphenous vein graft percutaneous coronary intervention (SVG PCI), the clinical and economic outcomes of different DEP strategies are unknown. METHODS: We compared 3 DEP strategies (no DEP, routine DEP, selective DEP in high-risk cases) in 126 consecutive cases of SVG PCI performed without DEP in a single catheterization laboratory over a 4-year period. No SVG PCI was excluded. High risk was defined using 2 multivariate predictors of embolic complication previously validated by NCDR (graft age greater than or equal to 8 years and or friable appearance with thrombus). Costs were determined by a ratio of cost-to-charges methodology and average cost of the two FDA-approved DEP devices ($1,350) with similar efficacy. RESULTS: Without DEP, the incidence of embolic complications was 17% (22/126), resulting in major adverse coronary events (MACE) in 3.2% (4/126) of all cases: 2 deaths, 1 myocardial infarction, and 1 emergency coronary artery bypass. Embolic complications significantly increased both procedure costs by $2,725 (p < .001) and total hospital costs approximately $2,800 (p < 0.05). Risk adjustment for selective DEP use correctly predicted 86% (19/22) of embolic complications, including all MACE, at an incremental cost of $684 per patient for selective DEP versus $1,150 per patient for routine DEP. Selective DEP would cost $43,127 per death prevented versus $72,461 using routine DEP during the index hospitalization. CONCLUSIONS: Embolic complications increase cost in excess of the cost of a DEP device. This risk adjustment model correctly predicted the majority of cases of embolic complication and all MACE, suggesting that selective DEP use may help reduce utilization of DEP by an almost 50% cost reduction compared to routine use.

Aged↗
PubMed1990

[Experimental studies of segmental hepatic artery embolization with a super absorbent embolic agent].

Super absorbent (Sumikagel) is a unique polymer mainly composed of polysodium acrylate (PSA). When PSA contacts water, it absorbs water and swells in a few seconds. This new embolic material suspended in Lipiodol (Lp-PSA), was used for hepatic artery embolization in five dogs. The purpose of this study is to examine the necrotizing effect of the new embolic material on segmental hepatic artery embolization. Gross liver examination demonstrated congestion and segmental infarction within the embolized area, and microscopically focal necrosis of liver parenchyma was observed. Segmental hepatic artery embolization with Lp-PSA should be an effective method of hepatic tumor embolization.

Absorption↗
PubMedDate not supplied

Volume changes of experimental carotid sidewall aneurysms due to embolization with liquid embolic agents: a multidetector CT angiography study.

Iodine-containing polyvinyl alcohol polymer (I-PVAL) is a novel precipitating liquid embolic that allows for artifact-free evaluation of CT angiography (CTA). As accurate aneurysm volumetry can be performed with multidetector CTA, we determined volumes of experimental aneurysms before, immediately after, and 4 weeks after embolization of 14 porcine experimental carotid sidewall aneurysms with this liquid embolic. An automated three-dimensional software measurement tool was used for volumetric analysis of volume-rendering CTA data. Furthermore, intra-aneurysmal pressure changes during liquid embolization were measured in four silicone aneurysms and potential polymer volume changes within 4 weeks were assessed in vitro. Liquid embolic injection was performed during temporary balloon occlusion of the aneurysm neck, resulting in a mean occlusion rate of 98.3%. Aneurysms enlarged significantly during embolization by 61.1 +/- 28.9%, whereas a significant shrinkage of 5.6 +/- 2.7% was observed within the follow-up period. Histologic analysis revealed an inflammatory foreign body reaction with partial polymer degradation. In silicone aneurysm models, intra-aneurysmal pressure remained unchanged during liquid embolic injection, whereas balloon inflation resulted in a mean pressure increase of 31.2 +/- 0.7%. No polymer shrinkage was observed in vitro. The aneurysm enlargement noted was presumably due to pressure elevation after balloon inflation, which resulted in dilatation of the weak venous wall of the newly constructed aneurysm--another shortcoming of this experimental aneurysm model. The volume decrease after 4 weeks expressed partial polymer degradation.

Angiography, Digital Subtraction↗
PubMed1978

Transcatheter embolization: prevention of embolic reflux using balloon catheters.

Reflux of embolic material during therapeutic transcatheter embolization is a potential complication which can result in occlusion of distal vascular beds. The conditions under which reflux was demonstrated in laboratory animals include (1) low flow states, (2) overvigorous flushing, (3) selective contrast injections, and (4) placement of embolic material too proximally. Balloon occlusion of the orifice of the vessel undergoing embolization protects against reflux and allows more homogenous embolization. Because of experience gained in the laboratory, therapeutic transcatheter embolization is now performed in patients with balloon catheter protection. Preliminary clinical experience is described.

Catheterization↗
PubMed2004

[Cyanoacrylate pulmonary embolism after embolization of a cerebral arteriovenous malformation. Report of one case].

Arterial embolization with cyanoacrylate is commonly used for the treatment of arteriovenous malformations. We report the case of a 40 years old man who four days after an embolization with cyanoacrylate, begins with cough, bloody sputum, and right hemithorax pleuritic pain. Pulmonary embolism was confirmed with chest X ray, CT scan and scyntigraphy. The patient received anticoagulation, with adequate response. The most common complications of cerebral embolization are related to central nervous system and pulmonary embolism is exceptional. Considering the high number of embolization procedures done nowadays, this complication must be borne in mind.

Adult↗
PubMed1989

Cardiogenic brain embolism. The second report of the Cerebral Embolism Task Force.

Cardiogenic embolism has accounted for one in six ischemic strokes in recent clinical studies. We review the recent clinical literature about the natural history, diagnosis, and management of cardioembolic stroke. Long-term anticoagulation may be indicated for primary stroke prevention in high-risk patient subgroups with non-rheumatic atrial fibrillation. The prevalence of left ventricular thrombi, and probably also emboli, following an acute anterior myocardial infarction has been reduced by heparin, but the value of subsequent oral anticoagulation for persistent left ventricular thrombi has been disputed. Two clinical subgroups of mitral valve prolapse have been emerging: one benign and the other prone to complications, including embolism. Paradoxical embolism has increasingly been reported as contrast echocardiography has permitted a reliable diagnosis of patent foramen ovale. The embolic risk of infective endocarditis is low (less than 5%) when infection is controlled; early embolism during uncontrolled infection does not strongly predict later stroke. Low-intensity anticoagulation (international normalized ratio, 2.0 to 3.0) may be sufficient prophylaxis for many embolism-prone cardiac disorders.

Atrial Fibrillation↗
PubMed1998

Early complete recanalization in internal carotid artery embolism treated with high-dose t-PA: a sequential angiographic study in a novel model of embolism in rats.

Complete early recanalization rate of human internal carotid artery embolic occlusion treated with thrombolytic drugs is low. To study factors related with this difficulty to recanalize we have developed a novel model of rat ica embolism using a fragment of human embolus. In 50 male Wistar rats the ica was embolized through the external carotid artery with a fragment of an embolus obtained from a human embolectomy passed through a catheter of 0.8 mm diameter. Recanalization was assessed by sequential angiograms from 15 to 120 min after embolization. Reperfusion was classified according to TIMI grades. Emboli of either 1 (group 1) or 2 mm (group 2) in length were cut. In group 1, four groups of nine animals each were treated, 15 min after embolization, with i.v. t-PA at doses of 1 mg/kg, 10 mg/kg and 20 mg/kg or saline. In group 2 there was one control group of seven animals treated with saline and another of seven animals treated with 10 mg/kg t-PA. Complete recanalization (TIMI grade 3) within the first 30 min was present in two animals treated with 10 and 20 mg/kg. Complete recanalization within the first 60 min was present in 0% of controls and animals treated with 1 mg/kg and in 44% of the 10 and 20 mg/kg groups (P<0.05 in chi-square test). Incomplete recanalization (TIMI grades 0, 1 and 2) occurred in 33%. In group 2 total recanalization occurred in 1/7 controls and in 3/7 animals receiving 10 mg/kg of t-PA. Early (60 min) complete i.v. t-PA induced internal carotid artery embolic recanalization is low with standard doses and increases moderately when high doses are used. Further increases in the dose do not improve recanalization rate, which is not clearly influenced by embolus size. Complete recanalization within 30 min, the period after which infarction develops in the rat, is uncommon in our model.

Angiography↗
PubMed1997

An experimental study of embolic effect according to infusion rate and concentration of suspension in transarterial particulate embolization.

RATIONALE AND OBJECTIVES: The authors evaluate the embolic effect according to infusion rate and concentration of particulate suspension, focusing on arterial occlusion level. METHODS: The renal arteries of 14 rabbits were embolized with 150 to 250 microns polyvinyl alcohol (PVA) particles, divided into four groups according to two different infusion rates (1 mg/second and 0.1 mg/second) and two different concentrations of suspension (10 mg/mL and 2.5 mg/mL). Arteriograms obtained immediately and a week after embolization were assessed for occlusion level. For the nephrograms obtained a week after embolization, the opacifying areas were graded from 0 to 4. Median coronal sections of each kidney specimen were investigated for the presence of peripheral infarct grossly and for the presence of PVA particles in the small artery microscopically. RESULTS: Arteriograms showed various occlusion levels. Using a 0 to 4 grading system, the opacifying area of the nephrogram obtained 1 week after embolization was noted to be smaller in the low infusion rate group (P < 0.05). In gross and microscopic pathologic examination, the number of cases with peripheral infarct or PVA particles in the small artery (< 300 microns) was greater in the group with the low infusion rate and low concentration (P < 0.05). CONCLUSIONS: In transarterial particulate embolization, slower infusion of more diluted suspension provides for a more distal arterial occlusion.

Animals↗
PubMed1999

Embolization of superior mesenteric artery branches in dogs. Ischemic bowel changes depend on location of vessel occlusion and embolic materials.

OBJECTIVE: To evaluate the degree of ischemic changes of the small intestine after arterial embolization of proximal or distal arteries with Gelfoam particles and coils in dogs. METHODS: Superselective arterial embolization in 18 dogs was performed using a coaxial catheter system. Gelfoam occlusion of the proximal level of ileal or jejunal arteries was performed in four dogs (group A). Gelfoam occlusion of the distal level was performed in four dogs (group B). Coil occlusion of the proximal level was performed in five dogs (group C). Coil occlusion of the distal level was performed in five dogs (group D). All 18 dogs were killed 1 day after the procedure. Gross and microscopic findings were evaluated. RESULTS: The embolizations were successful in all dogs. In group B, significant mucosal destruction, lymphocyte proliferation of the submucosa and mucosa, and diffuse swelling in all layers of the intestine were found in all four dogs. Three revealed diffuse ischemic changes and one showed focal ischemic changes. In groups A and C, all the layers of the intestine were intact and did not show any ischemic changes. In group D, one dog showed erosion of a small portion of mucosa and lymphocytic infiltration. The other dogs showed nonspecific findings in all layers of the intestine. CONCLUSIONS: Proximal embolization with Gelfoam and coils as well as distal embolization with coils did not cause ischemia. However, ischemic changes in the intestinal wall could be observed after distal embolization with Gelfoam.

Angiography↗
PubMed2004

Embolization itself stimulates thrombus propagation in pulmonary embolism.

The role of active thrombosis in the pathophysiology of pulmonary embolism is unclear. We tested the hypothesis that venous thrombi significantly increase their thrombotic activity once they embolize into the high-flow circulation of the pulmonary arteries. Thrombotic activity was measured using an immunoassay that measures both fibrinopeptide B (FPB) as well as its most abundant metabolite des-arginine FPB. Thrombi were formed in the femoral veins of adult dogs. In one group, the thrombi were embolized without anticoagulation. In the second group, heparin (300 U/kg bolus, then 90 U x kg(-1) x h(-1) infusion) was administered before embolization to prevent subsequent thrombotic activity. Plasma FPB concentrations were significantly suppressed in the heparinized group relative to the nonheparinized group for 1 h postembolization (P = 0.038). We conclude that pulmonary embolization itself causes preexisting venous thrombi to greatly intensify their thrombotic activity and that embolization-associated thrombus propagation can be prevented by heparin.

Ancrod↗
PubMedDate not supplied

Immediate anticoagulation of embolic stroke: brain hemorrhage and management options. Cerebral Embolism Study Group.

The clinical implications of hemorrhagic transformation of embolic brain infarction were explored by studying 30 patients with cardiogenic brain embolism and either hemorrhagic infarct (HI) or intracerebral hematoma (ICH) on CT. At the time of identification of hemorrhage, 19 patients were receiving anticoagulants and 11 were not. Eight anticoagulated patients and three nonanticoagulated patients developed late HI without attendant worsening after an initial CT was nonhemorrhagic. Hemorrhagic transformation without worsening most often occurred after 12 hours but before 48 hours following stroke onset and was associated with large infarcts (82%) but not with age, blood pressure or embolic source. Seven anticoagulated patients, six with large infarcts, and one nonanticoagulated patient with a small infarct abruptly worsened from eight hours to 11 days after stroke, with CT revealing ICH or severe HI. Excessive anticoagulation or acute hypertension potentially contributed to hemorrhagic transformation in four of five patients who were receiving heparin. Brain hemorrhage in embolic strokes most often occurs with large infarcts. Early CT may not allow the identification of large embolic infarcts that are destined to later undergo spontaneous hemorrhagic transformation. For large embolic infarcts, a delay of several days before anticoagulation and special efforts to avoid excessive anticoagulation and hypertension may be prudent. The initial administration of large, bolus doses of heparin should perhaps be avoided.

Adult↗
PubMed2000

Chest radiographs in acute pulmonary embolism. Results from the International Cooperative Pulmonary Embolism Registry.

OBJECTIVES: To characterize chest radiographic interpretations in a large population of patients who have received a diagnosis of acute pulmonary embolism and to estimate the sensitivity and specificity of chest radiographic abnormalities for right ventricular hypokinesis that has been diagnosed by echocardiography. DESIGN: A prospective observational study at 52 hospitals in seven countries. PATIENTS: A total of 2,454 consecutive patients who had received a diagnosis of acute pulmonary embolism between January 1995 and November 1996. RESULTS: Chest radiographs were available for 2,322 patients (95%). The most common chest radiographic interpretations were cardiac enlargement (27%), normal (24%), pleural effusion (23%), elevated hemidiaphragm (20%), pulmonary artery enlargement (19%), atelectasis (18%), and parenchymal pulmonary infiltrates (17%). The results of chest radiographs were abnormal for 509 of 655 patients (78%) who had undergone a major surgical procedure within 2 months of the diagnosis of pulmonary embolism: normal results for chest radiograph often accompanied pulmonary embolism after genitourinary procedures (37%), orthopedic surgery (29%), or gynecologic surgery (28%), whereas they rarely accompanied pulmonary emboli associated with thoracic procedures (4%). Chest radiographs were interpreted to show cardiac enlargement for 149 of 309 patients with right ventricular hypokinesis that was detected by echocardiography (sensitivity, 0.48) and for 178 of 485 patients without right ventricular hypokinesis (specificity, 0.63). Chest radiographs were interpreted to show pulmonary artery enlargement for 118 of 309 patients with right ventricular hypokinesis (sensitivity, 0.38) and for 117 of 483 patients without right ventricular hypokinesis (specificity, 0.76). CONCLUSIONS: Cardiomegaly is the most common chest radiographic abnormality associated with acute pulmonary embolism. Neither pulmonary artery enlargement nor cardiomegaly appears sensitive or specific for the echocardiographic finding of right ventricular hypokinesis, an important predictor of mortality associated with acute pulmonary embolism.

Acute Disease↗
PubMed1982

Longterm follow-up of patients with suspected pulmonary embolism and a normal lung scan. Perfusion scans in embolic suspects.

There is widespread acceptance of the thesis that in a patient with suspected embolism, a normal perfusion lung scan excludes the diagnosis of acute pulmonary embolism. However, limited published data exist which validate this thesis. We have explored this question by longitudinal follow-up of 68 patients who were referred for lung scanning to rule out embolism and proved to have normal perfusion lung scans. Risk factors for venous thromboembolism among these patients were similar to those reported in prior series of patients with pulmonary embolism. Our data support the widely-held views that: 1) a normal perfusion lung scan excludes the diagnosis of clinically significant pulmonary emboli; 2) the diagnostic work-up for suspected pulmonary embolism need not extend beyond a normal perfusion scan; 3) anticoagulant therapy can be discontinued after a normal perfusion scan, except in the presence of documented venous thrombosis; and 4) a normal lung scan has the same value in ruling out embolism in man as does a normal pulmonary angiogram.

Adult↗
PubMed1998

Differences in clinical features and computed tomographic findings between embolic and non-embolic acute ischemic stroke: a quantitative differential diagnosis.

A diagnosis based on the presumed mechanism of stroke onset is useful for management strategies in acute ischemic stroke. Ninety-two patients with embolic (cardiac or artery-to-artery) and 107 with non-embolic (thrombotic or hemodynamic) stroke were diagnosed on strict cerebral angiographic criteria alone. To clearly discriminate between these two groups, the neurological and computed tomographic (CT) findings were then compared. Rapidity of onset, vomiting, urinary incontinence, level of consciousness, cervical bruit, anisocoria, tongue deviation, sensory disturbance, and CT findings (location of hypodense area, findings of brain edema and hemorrhagic transformation) were discriminatory factors between the two groups (p<0.01). According to these 11 items, we prepared a numerical table for quantitative differential diagnosis. A diagnostic accuracy of 98.9% for embolic and 87.9% for non-embolic stroke in internal verification, and 90.0% and 82.9%, respectively, in external verification was observed. The differences in clinical features and CT findings between embolic and non-embolic stroke may reflect the pathophysiological mechanisms of the occlusive process of cerebral artery as well as the extent and severity of ischemia.

Acute Disease↗