Microembolic signals in patients with acute nonembolic stroke.

BACKGROUND: The 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. METHODS: We 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). RESULTS: The 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. CONCLUSIONS: There 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.

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.

Aortic atheromas in acute ischemic stroke patients in northern Israel.

AIM: There are currently no data on ethnic differences in aortic atherosclerosis in Arab and Jewish patients from northern Israel with acute ischemic stroke. METHODS: Data on demographic and risk factors alongside transesophageal echocardiography (TEE) data and treatment details for 509 patients with acute ischemic stroke were included in the study. RESULTS: The patients with aortic atheromas were older and had significantly more frequent vascular risk factors (hypertension, hyperlipidemia, and smoking), as well as vascular disease (ischemic heart disease, peripheral vascular disease, and carotid plaques). They were also treated with statins more often than those without aortic atheroma. Logistic regression analysis showed that age, smoking, ethnicity, and the presence of carotid plaques were independent predictors for aortic atheromas. Aortic plaques were found more frequently in Jewish patients than Arab patients (160 (41.9%) vs. 35 (27.3%); p= 0.003). This finding did not change after adjustment for age, sex, all vascular risk factors, and type of antithrombotic treatment. We did not find any difference between Arab and Jewish patients in the distribution of plaques by location or complexity before and after adjustment for age, sex, all vascular risk factors, or type of antithrombotic or lipid-lowering treatment. CONCLUSIONS: Our findings emphasize the influence of ethnicity on the prevalence of aortic atheromas in acute ischemic stroke patients in northern Israel. The search for genetic, cultural, socioeconomic, and other factors explaining these ethnic differences should be the topic of future studies.

Ethnic differences in ischemic stroke of working age in northern Israel.

BACKGROUND: There are currently no comparative data about ethnic differences in ischemic stroke in Arab and Jewish populations. METHODS: Data on 727 consecutive Arab and Jewish patients of working age (

Ethnic disparities in first primary intracerebral hemorrhage in northern Israel.

BACKGROUND: Ethnic differences among first primary intracerebral hemorrhage (PICH) patients in an Israeli biethnic population have not yet been studied. PATIENTS AND METHODS: We included in the study 546 patients (counting warfarin-related hemorrhages) hospitalized during the period from December 1999 through June 2008. RESULTS: The mean age was 71.1 +/- 14 years for the Jewish patients and 63.3 +/- 13.9 years for the Arab patients (p < 0.0001). Diabetes and smoking were significantly more frequent among the Arab patients. No difference was found between groups by location, extent, or ventricular involvement of PICH. Although the in-hospital mortality rate was significantly higher among the Jewish patients, adjustment of the model combining multiple risk factors for PICH eliminated this difference. CONCLUSIONS: There are differences in the demographic and vascular risk factor profiles between Arab and Jewish PICH patients, with the Arabs found to be younger and to suffer more from diabetes. The location and extent of intracerebral hemorrhage as well as functional outcome were similar between the two groups. The apparent higher in-hospital mortality in the group of Jewish patients was eliminated when the influence of multiple covariates other than ethnicity, main vascular risk factors and international normalized ratio level were taken into consideration.

Microemboli monitoring by trans-cranial doppler in patient with acute cardioemboliogenic stroke due to atrial myxoma.

This is the first reported attempt to examine the emboliogenic potential of cardiac myxoma in patients with acute stroke through the monitoring of microembolic signals (MES) by transcranial doppler. A 43-year old woman was brought to the emergency department because of acute onset of generalized tonic-clonic seizures and left hemiplegia. A CT scan of the brain demonstrated a large acute infraction in the territory of the right middle cerebral artery (MCA) and another smaller one in the territory of the posterior cerebral artery on the same side. Trans-cranial doppler (TCD) microemboli monitoring did not reveal MES. Transesophagial echocardiography (TEE) identified a 5 cm left atrial mass, which was highly suspected to be an atrial myxoma attached to the interatrial septum and prolapsed through the mitral valve. After the TEE results were obtained, another TCD monitoring was performed. Again, there were no MES found in either of the MCAs.Our findings showed the absence of MES on two consecutive TCD examinations, suggesting a spontaneous occurrence, rather than the permanent presence, of embolization, even in the most acute phase of stroke. Thus, the tendency of myxomas to spontaneously produce multiple emboli emphasizes the need for the surgical excision of myxomas.

High plasma high-density lipoprotein levels, very low cardiovascular risk profile, and subclinical carotid atherosclerosis in postmenopausal women.

BACKGROUND: Low plasma concentrations of high-density lipoprotein (HDL) are associated with increased risk of cardiovascular disease. However, recently several studies have questioned the protective role of high plasma HDL levels. OBJECTIVE: This study was designed to evaluate HDL functions in women with high plasma HDL cholesterol and very low risk profile with relation to subclinical carotid atherosclerosis (ATS). METHODS: Included were 158 middle-aged women with plasma HDL >60 mg/dL and Framingham risk score <7% who had B-mode ultrasound of the carotid arteries. Subclinical ATS was determined by the presence of plaques and/or intima-media thickness (IMT) >1.0 mm. RESULTS: ATS was observed in 51 women, with the majority (n=41) having carotid plaques, some with advanced morphology. In a multivariable model analysis, each, HDL or age, were independently associated with increased prevalence of ATS. Odds ratios for ATS were 3.1 and 2.5 greater for age>60 years and HDL >70 mg/dL, respectively. None of HDL functions determined by its antioxidative properties, reverse-cholesterol transport, or activities of HDL-associated enzyme were different between -ATS and +ATS. C-reactive protein was similar in both groups. CONCLUSION: Subclinical carotid ATS is present in one-third of middle-aged women independently of conventional risk factors. A greater ATS prevalence was associated with very high HDL values. We could not find association between ATS and HDL dysfunction.

Ischemic middle cerebral artery stroke missing the tissue plasminogen activator time window: transcranial Doppler evaluation.

We investigated the interconnection between natural history of middle cerebral artery (MCA) recanalization by transcranial Doppler (TCD) and stroke severity in patients not treated by fibrinolysis. A total of 54 patients with an acute MCA stroke were examined within the first 24 hours and again within 120 hours after stroke onset. The first TCD examination detected 16 patients (29.6%) with complete occlusion, 27 patients (50%) with partial occlusion, and 11 patients (20.4%) with patent MCA. There were no significant differences among groups according to mean National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale values. The second examination revealed 7 patients (13.2%) with complete occlusion, 31 patients (58.5%) with partial occlusion, and 15 patients (28.3%) with patent MCA. The mean NIHSS score in patients with total occlusion was significantly higher than in patients without occlusion or with partial occlusion. There was no significant difference in mean NIHSS value between patients with and without improvement on the second TCD examination. We conclude that MCA occlusion by TCD is associated with more severe stroke than that of patients without occlusion or with only a partial occlusion. A later MCA recanalization is not accompanied by significant improvement of neurologic or functional status.

Microemboli in MCA ipsilateral to occluded common carotid artery: an observation and short review of the literature.

Sixty-five years old patient suffering from acute stroke was treated by rTPA intravenously. TCD monitoring of both middle cerebral arteries (MCA) was carried out simultaneously with administration of rTPA. Seven microemboli were found in right and four in left MCA. Duplex ultrasound, CT angiography and digital subtractional angiography revealed occlusion of left common carotid artery (CCA) and moderate to severe stenosis of right internal carotid artery (ICA). The case presented here is, to the best of our knowledge, the first description of MCA microemboli signals in patient with occlusion of ipsilateral CCA. This location of occlusion eliminates the possibility of microemboli passage from carotid bulb proximally to the site of occlusion through the ipsilateral external carotid artery or from the distal stump of occluded ICA. The possibility of emboli from contralateral stenosed ICA through the patent anterior communicating artery (ACoA) or from the distal stump of occluded CCA seems to be the most probable explanation.

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.

Preoperative cerebral hemodynamics and shunting during carotid endarterectomy in patients with severe unilateral carotid stenosis.

PURPOSE: To estimate the possible predictors for the need for shunting during carotid endarterectomy in patients with severe unilateral carotid stenosis based on preoperative transcranial Doppler sonographic examination. MATERIALS AND METHODS: One hundred twenty-six patients were included in the study. Pulsatility index, flow acceleration, peak systolic velocity, and mean velocity were measured in the middle cerebral artery (MCA) and anterior cerebral artery on both sides. Cerebrovascular reactivity (CVR) was evaluated in 21 patients with shunts and in 55 patients without shunts. RESULTS: The shunted and nonshunted groups did not differ with regard to demographic and clinical characteristics. The side-to-side difference in peak systolic velocity and mean velocity of the MCA was significantly higher in patients with shunts. CVR were significantly higher in the patients without shunts (36.0 +/- 17.2%) than in patients with shunts (16.6 +/- 11.4%; p = 0.0003). The peak systolic velocity and mean velocity asymmetry of the MCA had relatively low receiver operating characteristics, whereas CVR exhibited a relatively high accuracy in predicting the need for shunting. CONCLUSION: Low CVR and increased asymmetry of MCA velocities were found in patients who subsequently required shunting during carotid endarterectomy. The relatively low accuracy of the MCA asymmetry should prevent the use of this criterion as a reliable preoperative predictor for shunting during carotid surgery, whereas CVR was more accurate and may prove useful in this setting.

[Percutaneous carotid artery stenting in high-risk patients].

UNLABELLED: Recent studies have shown that percutaneous carotid artery angioplasty and stenting can be safely performed in patients with carotid artery stenosis, especially those considered to be at high-risk for surgery. AIM: We evaluated the safety and feasibility of carotid artery angioplasty and stenting, with and without distal protection devices in patients at high-risk for surgical endarterectomy. METHODS: A total of 169 consecutive patients underwent 185 procedures and 189 stents were deployed successfully in 195 lesions. The majority of patients (51%) had restenosis after a prior carotid endarterectomy, 40% were considered to be ineligible for carotid endarterectomy by both the vascular surgeons and the interventional cardiologist and 7% were considered ineligible for surgery due to hostile neck anatomy. RESULTS: Distal embolic protection devices were used in 52% of all cases. Procedural success was achieved in 181 of 185 procedures (98%). The overall rate of in-hospital major adverse cerebrovascular events (death, major stroke, and myocardial infarction) was 2.4%. In-hospital event rates in patients with prior carotid endarterectomy were comparable to patients with de novo lesions with 3.3% vs. 1.1% death/ stroke at 30 days, and 3.3% and 3.3% stroke/death rates at 30 days, respectively. When distal protection devices were used death/stroke rates were 0% as compared to 4.7% when distal protection was not used (p = NS). However, minor embolic phenomena were observed in both primary and secondary lesions independent of the use of distal protection. CONCLUSIONS: These results support the use of carotid artery angioplasty and stenting in high-risk patients with significant primary or secondary carotid artery stenosis. In both types of lesions, acceptable results justify its use as a valid revascularization method. While clinical embolic events occur in a minority of patients in both lesion types, they are not entirely prevented by distal protection devices.

Duplex ultrasound verified by angiography in patients with severe primary and restenosis of internal carotid artery.

There are very limited data in the literature about the reliability of duplex ultrasound (DU) verified by angiography in patients with restenosis of the internal carotid artery (ICA) after carotid surgery compared with primary carotid artery stenosis patients. Our objective was to compare the reliability of DU verified by conventional angiography in the diagnosis of severe primary stenosis versus restenosis of ICA. One hundred thirty-four patients (238 arteries) were examined by both DU and angiography. Severe stenosis (>70%) was found in 47 primary stenotic arteries and in 70 restenotic arteries. Accuracy, specificity, sensitivity, positive predictive value (PPV), and negative predictive value were obtained for basic DU criteria after verification of ultrasound data by angiography. The best accuracy for detection of >70% stenosis by end diastolic velocity was found for the velocity of 70 cm/sec or more in both groups, but accuracy for the restenosis group was significantly higher (96.9% vs. 89.8%, p = 0.025). Additionally, specificity (p = 0.01) and PPV (p = 0.01) were significantly higher in the restenosis group. The best accuracy for detection of >70% stenosis by peak systolic velocity was found for the velocity of 220 cm/sec or more for restenoses and 200 cm/sec or more for primary stenoses. The accuracy of the ultrasound was significantly higher in the restenosis group (94.6% vs. 87%, p = 0.04), as were specificity (p = 0.01) and PPV (p = 0.02). The diagnosis of severe restenosis by DU is reliable and can be used for decision making regarding surgery or stenting without angiography. In patients with Doppler parameters pointing to borderline moderate/severe primary carotid stenosis and technically complicated cases, angiography in addition to sonography before surgery is recommended.

Carotid artery stenting in surgical high-risk patients.

Recent studies have shown that carotid artery angioplasty and stenting may offer a viable alternative for symptomatic and asymptomatic patients with carotid artery stenosis, especially in high-risk patients. We report the results of a prospective single-center registry designed to evaluate the feasibility and safety of carotid artery angioplasty and stenting with and without distal protection devices in high-risk patients. A total of 116 consecutive patients underwent 126 procedures and 127 stents were deployed successfully in 130 lesions. The majority of patients (63%) had restenosis after a prior carotid endarterectomy; 31% were considered to be ineligible for carotid endarterectomy by both the vascular surgeons and the interventional cardiologist and 9% were considered ineligible for surgery due to hostile neck anatomy. Periprocedural and follow-up evaluation included a thorough independent clinical and neurological assessment. Distal embolic protection devices were used in 44% of all cases. Procedural success was achieved in 122 procedures (97%). The overall rate of in-hospital major adverse cerebrovascular events (death, stroke, and myocardial infarction) was 2.6%. Event rates in patients with prior carotid endarterectomy were comparable to patients with de novo lesions with 5.2% vs. 2.4% death/stroke at 30 days and 8.3% and 6.6% stroke/death rates at 1 year, respectively. When distal protection devices were used, death/stroke rates were 0% as compared to 4.5% when distal protection was not used (P = NS). However, minor embolic phenomena were observed in both primary and secondary lesions independent of the use of distal protection. These results support the use of carotid artery angioplasty and stenting in high-risk patients with significant primary or secondary carotid artery stenosis. In both types of lesions, acceptable results justify its use as a valid revascularization method. While clinical embolic events occur in a minority of patients in both lesion types, they are not entirely prevented by distal protection.

Distribution of artificial cerebral microemboli in stroke patients with patent foramen ovale.

OBJECTIVES: Patent foramen ovale (PFO) is considered as an important risk factor for cerebrovascular diseases. Nevertheless, the relationship between the distribution of high-intensity transient signals (HITS), resulting from injection of air mixed with saline and detected by transcranial Doppler (TCD), and clinical cerebrovascular syndromes in these patients has not been investigated. METHODS: Using TCD, we screened 40 patients with stroke or transient ischemic attack (TIA), in whom PFO was proven by transesophageal echocariography (TEE). Of these, 30 patients (75%) with artificially produced HITS either in the middle cerebral artery (MCA) or the basilar artery (BA) were included in the analysis. RESULTS: Nineteen patients had a stroke or TIA in the carotid territory and 11 patients in the vertebro-basilar territory. HITS were found in the MCA in all 30 patients and in 21 of the 30 patients in the BA. Of the latter, ten patients were in the carotid group and 11 patients were in the veretebro-basilar group, p = 0.011. CONCLUSION: There is a significant association between the distribution of artificial HITS and the clinical cerebrovascular syndromes.

Vertebral artery stenting using distal emboli protection and transcranial Doppler.

Recent studies have shown the feasibility and safety of the percutaneous approach for the treatment of vertebrobasilar disease using either balloon angioplasty alone, coronary stents, or combined angioplasty followed by stenting. The major concern in performing percutaneous procedures for the treatment of obstructive disease of the vertebrobasilar circulation involves the risk of embolic phenomena. We describe the successful treatment of a symptomatic patient with bilateral vertebrobasilar disease utilizing a distal protection filter during stenting with simultaneous use of transcranial Doppler to measure microembolization and vertebral artery blood flow during the procedure.

The positions of the patients in the diagnosis of patent foramen ovale by transcranial Doppler.

BACKGROUND AND PURPOSE: There is no information about the optimal position of a patient for the performance of a transcranial Doppler (TCD) examination to detect patent foramen ovale (PFO). Such information is important to improving the sensitivity of the test in comparison to the gold standard of transesophageal echocardiography (TEE). METHODS: Thirty-four patients with TEE-proved PFO were examined by contrast TCD. Examinations were done in both the sitting and supine positions in random order. RESULTS: Eight hundred ninety-two microemboli were recorded. Patients' positions and the sequence of testing did not affect the number of microemboli detected. Yet for each individual, 1 of the 2 positions was more sensitive. CONCLUSIONS: To improve the sensitivity of TCD in the detection of PFO, it is recommended, in the case of a first negative test, to change the patient's position for a repeated TCD examination.

Velocity of microemboli and transit time from the heart to the brain in patients with patent foramen ovale and artificial heart valves.

There is no information about the physical behavior of microemboli en route from their source to the cerebral vessels. Microemboli could abide to a certain laminae, and have a consistent velocity, or wander between different laminae, and keep changing their velocity. Two hundred and seventy four microemboli were recorded by transcranial Doppler (TCD) in six patients with artificial valves, and 119 microemboli were recorded in response to i.v. injection of saline agitated with air in eight patent foramen ovale (PFO) patients. Transit time of microemboli, calculated based on their arrival time at the cerebral vessel (site of monitoring) was explored as a possible function of their measured velocity at the detection point. In the PFO group, the relation between embolus velocity and transit time was: embolus velocityPFO = -41.8 * transit time + 100.6, whereas for the artificial heart valve group it was: embolus velocityValve = -22.6 * transit time + 67.1. Transit time, in both clinical groups, was inversely related to velocity (p < 0.001), thus, early appearing emboli had higher velocity and vice versa. The inverse relation between transit time and measured terminal velocity implies a consistent velocity per microemboli en route, in both groups. Thus, a flow abided to a certain laminae seems to characterize microemboli.