Efim Kouperberg

Size of PFO and amount of microembolic signals in patients with ischaemic stroke or TIA.

Background and purpose:u2002 The inter‐relation between the size of patent foramen ovale (PFO) by transesophageal echocardiography (TEE) and the amount of microembolic signals (MES) on transcranial doppler (TCD) is still not determined.

Potential relevance of low-intensity microembolic signals by TCD monitoring

The significance of low-intensity microembolic signals (MES), as well as their relationship with high-intensity MES, has not yet been studied. We monitored MES by TCD in 256 arteries of 229 patients with carotid stenosis. All microemboli were detected automatically without a preliminary set threshold. For those 110 patients who evidenced any emboli, the correlation between the number of high- and low-intensity MES was rxa0=xa00.50, pxa0<xa00.0001. A statistically significant relationship between both types of MES was found, with a degree of association of 0.42, as assessed by Cohen’s kappa. Later occurrence of high-intensity MES based on early low-intensity MES was statistically significant, with a chi-square pxa0=xa00.0006 and a degree of association of 0.24, as assessed by Cohen’s kappa. There is a significant relationship between low- and high-intensity MES, thereby indicating that many MES routinely rejected because of their low intensity are real.

TCD evaluation before and after stenting in patients with severe primary carotid artery stenosis versus restenosis.

Purpose: To evaluate cerebral hemodynamics before and after carotid angioplasty and stenting (CAS) using transcranial Doppler (TCD). Methods: Sixty-eight patients (52 men; mean age 69±9.5 years) with severe carotid stenosis (83.4%±10.2%) were examined by TCD before and 2 months after CAS. Thirty-two (47%) patients had primary carotid stenosis and 36 (53%) had restenosis after carotid endarterectomy (CEA). A broad TCD protocol was employed to estimate cerebral hemodynamics, including assessment of velocities (V) and asymmetry of cerebral blood flow velocity (CBFV) in the middle cerebral artery, (MCA) anterior cerebral artery (ACA), and basilar artery (BA); the pulsatility indexes; and flow acceleration. Results: Ipsilateral MCA mean velocities before stenting were 46.3±12.6 cm/s in the primary stenosis group and 47.1±12.3 cm/s in restenosis group; after stenting, the velocities were 53.8±12.1 and 52.7±9.6 cm/s, respectively (p<0.005 for both groups). MCA asymmetry by Vmean before CAS was higher in the primary stenosis group (27.6%±2.4% versus 19.8%±2.3%, p<0.05). After stenting, this index was significantly lower in both groups: 16.4%±2.4% and 12.3%±2.3%, respectively (p<0.0001 for each group). All other TCD parameters improved significantly in both groups after CAS as well (p<0.05), showing the strong hemodynamic effect of this procedure. Conclusion: CAS effectively improves cerebral hemodynamics in patients with severe primary and restenosis of the internal carotid artery.

Embolic potential and ultrasonic characteristics of plaques in patients with severe unilateral carotid restenosis more than one year after surgery

PURPOSEnThe purpose of the study is to investigate the embolic potential as well as ultrasonic characteristics of plaques in patients presenting with severe unilateral restenosis at least 1 year after carotid endarterectomy (CEA), compared with patients with severe unilateral primary carotid stenosis.nnnMETHODSnWe used transcranial Doppler (TCD) to monitor microembolic signals (MES) and Doppler ultrasound to classify types and density of plaques in 27 patients with restenosis after CEA and in 97 patients with primary stenosis.nnnRESULTSnMean period between surgery and examination in patients with restenosis was 36.7+/-30.5 months (range 12-96). The groups were similar in distribution of main vascular risk factors. There were 36 (37.1%) patients with MES on TCD in primary stenosis versus 11 (40.7%) in restenosis group (NS). An average number of MES in primary stenosis group was 2.9+/-3.5/30 min and in restenosis group -3.4+/-2.9 (NS). There was no difference in distribution of plaques by echogenicity as well as by density. After adjustment by age, sex, and main risk factors, no influence was found for the effect of stenosis or restenosis on either the presence or the amount of emboli, as well as on the ultrasonic character of plaques.nnnCONCLUSIONnCarotid plaques in patients with severe unilateral carotid restenosis at least 1 year after surgery and in patients with primary lesions are similar in their embolic potential and ultrasonic characteristics.

Young patient with acute ischemic stroke due to papillary carcinoma of the thyroid

Hypercoagulability is a condition predisposing to arterial or venous thrombosis and is associated frequently with malignancy. We present a rare acute ischemic stroke in a young patient that was the presenting feature for a newly diagnosed papillary carcinoma of the thyroid. Extensive vascular and hematological work-up was normal except for a large patent foramen ovale (PFO). This finding, along with the association of most vascular events with hypercoagulability being of venous origin, makes the mechanism of paradoxical embolism through the large PFO the probable cause of stroke in our patient.

Ethnic Differences in Ischemic Stroke of Working Age in Northern Israel

BACKGROUNDnThere are currently no comparative data about ethnic differences in ischemic stroke in Arab and Jewish populations.nnnMETHODSnData on 727 consecutive Arab and Jewish patients of working age (<or=65 years) with stroke were compared for risk profile, etiology, subtyping, and immediate functional outcome.nnnRESULTSnThe mean age was 59.4 +/- 8.2 years for the Jewish and 53.7 +/- 8.6 years for the Arab patients (P = .03). Higher prevalence of diabetes was found in the Arab patients after adjustment by age, sex, and main vascular risk factors (P < .0001). After adjustment, a higher prevalence of normal transesophageal echocardiography results in the Arab population was found. Small vessel disease-related strokes were significantly more frequent in the Arab patients, whereas large vessel disease-related strokes and strokes resulting from multiple causes were significantly more frequent in the Jewish patients. No correlations were found between the high prevalence of diabetes (or any other examined factor) and the predominance of small vessel disease-related strokes in the Arab patients and large vessel disease-related strokes in the Jewish patients. There was no difference found in treatment or outcome between the Arab and the Jewish patients.nnnCONCLUSIONSnThere are substantial differences in the risk profiles and subtyping of strokes between Arab and Jewish patients of working age.

Comparison of risk factors and work-up in young and middle-aged patients with TIA and ischaemic stroke

Background:u2002 The transient ischaemic attack (TIA) is accepted as a subtype of resolved ischaemic stroke. In that case, the risk factor profiles as well as the work‐up results of TIA and stroke patients should be similar in both groups. Given that such data are limited, we compared the risk factor profiles and work‐up results in young and middle‐aged patients with TIA and ischaemic stroke.

Pretreatment with aspirin and etiology of first-ever ischemic stroke in young and middle-aged patients

BACKGROUNDnThere are very limited data on the influence of pretreatment with aspirin (ASA) on the etiology of subsequent first-ever ischemic stroke.nnnMATERIALS AND METHODSnFive hundred ninety eight patients 65 years old or younger with first-ever ischemic stroke either pretreated (N=167) or not treated with aspirin (N=431) participated.nnnRESULTSnThe mean age was 56.5+/-6.0 years for patients treated with ASA and 53.1+/-8.9 years for those not treated (p<.0001). All major vascular risk factors except smoking were significantly more frequent among the patients pretreated with aspirin. Logistic regression analysis adjustments for age, gender, and major vascular risk factors revealed an overall significant effect (p<0.0001) of aspirin treatment on the distribution of stroke etiologies. Subsequent separate analyses on stroke etiology subtypes indicated that the incidence of small vessel disease (SVD) related strokes was significantly reduced by pretreatment with aspirin (OR=0.63). Logistic regression analysis showed no influence of aspirin on the likelihood of a favorable or unfavorable outcome, as expressed by Rankin scale.nnnCONCLUSIONnPretreatment with ASA has significant influence on the distribution of etiologies of first-ever ischemic stroke in young and middle-aged patients, when the immediate functional stroke outcome is not influenced by ASA pretreatment.

Middle Cerebral Artery Stenosis in Patients with Acute Ischemic Stroke and TIA in Israel

BACKGROUND AND PURPOSE: Middle cerebral artery stenosis is not frequent but a well-established cause of first and recurrent ischemic stroke. Our aim was to investigate middle cerebral artery stenosis in the biethnic (Jewish and Arab) population of patients with acute ischemic stroke and transient ischemic attack in northern Israel. MATERIALS AND METHODS: The study population included 1344 patients from the stroke data registry who had been hospitalized in the neurologic department because of acute ischemic stroke (1041) or TIA (303) and had undergone transcranial Doppler sonographic examination during the hospitalization. RESULTS: Of the 1344 patients, 120 (8.9%) were found to have MCA stenosis. The patients with intracranial stenosis were older and had more vascular risk factors (hypertension, diabetes, and hyperlipidemia) and vascular diseases (ischemic heart and peripheral vascular disease) than those without intracranial stenosis. Logistic regression analysis revealed that diabetes (P = .002) and peripheral vascular disease (P = .01), but not ethnicity, were independent and significant predictors for the presence of MCA stenosis. CONCLUSIONS: An independent and significant correlation was found between MCA stenosis and vascular risk factors (diabetes mellitus) and vascular diseases, thus emphasizing the similarity of intracranial MCA stenosis and other vascular diseases originating from atherosclerosis. There was no influence of ethnicity on intracranial stenosis in our population.

Microembolic signals in patients with acute nonembolic stroke.

BACKGROUNDnThe nature of microembolic signals (MES) in patients without apparent sources of embolism remains elusive. We hypothesize that MES in acute stroke patients without an embolic source may represent a transient phenomenon related to blood rheology or clot dissolving, in which case the characteristics of such MES would differ from those with definitive sources of emboli.nnnMETHODSnWe compared the intensity and duration of 250 MES in 62 acute nonembolic stroke patients (stroke group) and 217 MES in 57 patients with asymptomatic carotid stenosis (≥50%; carotid group).nnnRESULTSnThe duration of MES was significantly different between the 2 groups (24.86 ± 0.89 ms in the carotid group v 18.8 ± 0.83 in the stroke group; P < .001). When comparing the groups for MES with an intensity higher than 6 dB, a highly significant difference in the duration of MES was found (27.87 ± 1.26 ms in the carotid group v 18.57 ± 1.29 ms in the stroke group; P < .0001). A strong linear relationship between the duration and intensity of MES was found for the carotid group, but not for the stroke group.nnnCONCLUSIONSnThere are significant differences between the characteristics of MES in acute stroke patients as compared with MES in patients with carotid plaques. There is a strong correlation between the intensity and duration of MES from a definitive embolic source, which is absent from MES in patients with nonembolic stroke. These findings may point to the different mechanisms of MES origin in the examined groups.