Countable and non-countable microembolic signals by TCD in first-ever stroke or TIA patients with PFO

BACKGROUND: There are data in the literature indicating that the number of microembolic signals (MES) in patients with patent foramen ovale (PFO) is directly related to stroke incidence and recurrence. We thus hypothesized that the amount of artificially induced microembolic signals monitored by contrast transcranial Doppler (cTCD) would be greater in younger patients with PFO and stroke (when cryptogenic strokes related to the PFO are frequent). PATIENTS AND METHODS: The final analysis included 109 patients with first-ever ischemic stroke or TIA with PFO, as detected by Transesophageal Echocardiography (TEE), and MES, as measured by cTCD. Thirty-seven patients (aged 19-45 years) were defined as the "younger" group, and the other 72 patients (aged 46-77 years) were defined as the "older" group. Eighty-six patients (78.9%) suffered from stroke, including 28 in the younger group and 58 in the older group. The pattern of microembolization was defined as "countable" when the observers were able to calculate the number of MES. In the case of a "shower" of MES on TCD examination, the pattern of monitoring was defined as "non-countable." RESULTS: Ischemic heart disease, and hyperlipidemia were found to be significantly more frequent in the group of older patients. Twenty-three patients (62.2%) in the younger group had cryptogenic stroke or TIA (no risk factors found), as compared to 26 patients (36.1%) in the older group (p=0.009). There were 23 patients with a non-countable pattern of MES in the older group, as compared with 5 such patients in the younger group (p=0.04). There was no difference found in the number of MES between the groups in those patients with a countable pattern of MES (13.3+/-11.8 in the younger group vs. 13.7+/-11.7 in the older group). CONCLUSIONS: In stroke and TIA patients above 45 years of age, PFOs producing a large amount of MES on TCD examination are frequent. Thus, there is no correlation between a large amount of MES and stroke or TIA in young patients.     

Almost Perfect Concordance Between Simultaneous Transcranial Doppler and Transesophageal Echocardiography in the Quantification of Right-to-Left Shunts

BACKGROUND AND PURPOSE: Transesophageal echocardiography (TEE) and transcranial Doppler (TCD) are the methods of choice to study patent foramen ovale (PFO), but there are discrepancies between the 2 concerning PFO detection. No study has analyzed right-to-left shunt (RLS) quantification concordance. The 2 methods are carried out in different hemodynamic states, and the Valsalva maneuver (VM) required in each also differs. The authors compared PFO detection and concordance of RLS quantification classifications performing the 2 studies simultaneously. METHODS: The authors prospectively included consecutive stroke patients undergoing TEE and applied the TCD protocol of the Consensus Conference. Echocardiographic PFO was diagnosed when at least 3 microbubbles (MBs) were detected in the left atrium within 3 heartbeats after opacification of the right atrium. RLS quantification was (1) TCD: minimum (1-10 MBs), moderate (11-25 MBs), and massive (>25 MBs) and (2) TEE: small (3-10 MBs), moderate (11-30 MBs), and large (>30 MBs). Statistics: contingency tables (chi(2) and K test). Results. The authors studied 110 patients whose mean age was 56.7 +/- 12.1 years, and 60.9% were men. PFO was detected at the first VM in 30% of patients with TCD and in 31.8% with TEE. At the second VM, both methods detected the same patients (32.7%). RLS was minimum (14), moderate (5), and massive (17) in TCD and small (13), moderate (3), and large (20) in TEE. There was an almost perfect concordance in RLS quantification (K = 0.928, P = .001), with only 4 discrepancies. CONCLUSIONS: Simultaneous study with TCD and TEE showed an almost perfect concordance in PFO detection and RLS quantification.     

Cryptogenic stroke and patent foramen ovale: clinical clues to paradoxical embolism

BACKGROUND: Patent foramen ovale (PFO) is an independent risk factor for cerebral infarction. Since ~25% of the population have a PFO, the simple association of PFO with stroke is not enough to establish the diagnosis of paradoxical embolism. We evaluated possible clinical clues to the diagnosis of paradoxical embolism. METHODS: Among patients with cryptogenic ischemic stroke (CS) who were investigated for a right-to-left shunt (RLS), we compared clinical, coagulation and biochemical parameters in patients with PFO versus without PFO. RESULTS: Among 1689 new patients referred for TIA/non-disabling stroke between 2001 and 2007, 175 with cryptogenic stroke (CS) were investigated for RLS by transcranial Doppler (TCD) bubble studies; 89 (5.5%) with positive TCD had a PFO confirmed by TEE. In multivariate logistic regression, a history of DVT or pulmonary embolism (OR, 4.39; 95% CI, 1.23-15.69; p=0.023), prolonged travel (OR, 8.77; 95% CI, 1.775-43.3; p=0.008) , migraine (OR, 2.30: 95% CI, 1.07-4.92; p=0.031), a Valsalva maneuver preceding the onset of focal neurological symptoms (OR, 3.33; 95% CI, 1.15-9.64; p=0.026) and waking up with stroke/TIA (OR, 4.53, 95% CI, 1.26-16.2; p=0.018) were independently associated with PFO-associated cerebrovascular events. Patients with PFO had higher plasma total homocysteine levels than patients without PFO (8.9+/-3 versus 7.9+/-2.6 micromol/L respectively; p=0.021). CONCLUSIONS: A history of DVT or pulmonary embolism, migraine, recent prolonged travel, sleep apnea, waking up with TIA or stroke or a Valsalva maneuver preceding the event are clinical clues to the diagnosis of paradoxical embolism among patients with CS.     

Microembolic signals and clinical outcome in patients with acute stroke – a prospective study

The occurrence of microembolic signals (MES) in patients with transient ischemic attack (TIA) or stroke has already been described; the influence of the time interval between onset of symptoms and transcranial Doppler monitoring (TCD) on the MES rate or MES prevalence and the possible prognostic value of the early detected MES rate on the outcome of TIA or stroke symptoms in a 3 month interval are discussed. In a prospective study we evaluated 61 patients consecutively admitted to our stroke unit after their first ischemic neurological deficit involving the vascular territory of MCA and/or ACA. All of the patients underwent a 30-minute bilateral transcranial Doppler monitoring of their MCAs for the identification of MES. Monitoring was performed within 12.3 + -9.3 (average mean + -SD) hours of stroke onset for the first time, the second time 48 hours after first TCD monitoring. Prognosis for the recovery of neurological deficits was evaluated by using the Barthel index (BI) and Scandinavian Stroke Scale (SSS) at the time of admission of the patient to the stroke unit, and with Barthel indices after one month and after 3 months. As a result, 56% of all patients showed MES in at least one of the two registrations. MES were recorded not only on the symptomatic side. The MES prevalence between both TCD monitorings was significantly different (total MES prevalence: 1st TCD: 26 patients: 2nd TCD: 13 patients; p < 0.04; ipsilateral MES prevalence: 1st TCD: 19 patients; 2nd TCD: 9 patients; p < 0.01). The regression analysis showed a significant influence of the total MES rate on both neurological scores at admission (SSS: 0.03; Barthel index: 0.04), but not for the Barthel scores after one and three months. In conclusion, we found an influence of the time interval between onset of neurological symptoms of TIA or stroke on the MES rate and the prevalence of MES. The prevalence of MES or the MES rate, found after a short time interval to the onset of symptoms, did not have a prognostic value on the outcome of neurological deficits up to a three month follow-up.     

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.     

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

Abstract

Objectives: Patent foramen ovale (PFO) is considered as an important risk factor for cerebrovascular diseases. Nevertheless, the relationship between the distribution of highintensity 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.     

Microembolic signal monitoring in hemispheric acute ischaemic stroke: a prospective study

BACKGROUND AND PURPOSE: There are few data on the occurrence of microembolic signals (MES) in the acute phase of ischaemic stroke. The objective of our work was to systematically study the frequency of MES in non-selected patients with a first-ever hemispheric transient ischemic attack (TIA) or acute cerebral infarction, and to evaluate the clinical usefulness of MES detection. METHODS: 182 consecutive patients with hemispheric TIA or acute cerebral infarction, and 54-age-matched healthy controls were studied. Bilateral transcranial Doppler ultrasound (TCD) monitoring was performed for at least 30 min with a mean time from stroke onset to TCD of 69 h. Stroke severity on admission, early recurrent stroke and dependency on discharge were investigated. RESULTS: MES were detected in 20.5% of patients with arterial sources of embolism, 17. 1% of patients with potential sources of cardioembolism and 5% of patients with cryptogenic stroke. They were not registered, however, in lacunar infarctions (p < 0.001). Stroke severity on admission of patients with MES was greater than that of patients without MES (47. 1 vs. 19.4% with the Canadian Stroke Scale < or =6.5; p = 0.009). Early recurrent stroke was more frequent in patients with MES (11.8%) than in those without MES (4.2%) although the difference was not statistically significant. Multiple logistic regression analysis showed that MES increased the risk of dependency on discharge (odds ratio, 4.2; 95% CI, 1.2-14.9; p = 0.01) independently of age, stroke severity on admission and presence of an arterial or cardiac embolic source. CONCLUSIONS: There is a strong association of MES in the acute phase of stroke with known potential arterial and cardiac embolic sources. MES have an independent predictive value of poor outcome.     

Prevalence of atrial septal abnormalities in older patients with cryptogenic ischemic stroke or transient ischemic attack

OBJECTIVE: To evaluate the association of atrial septal abnormalities - patent foramen ovale (PFO), atrial septal aneurysm (ASA), or the combination of both (PFO+ASA) - with cryptogenic stroke or transient ischemic attack (TIA) in older patients. METHODS: We examined the prevalences of PFO, ASA, and PFO+ASA in 132 consecutive patients aged 55 years or more who underwent transesophageal echocardiography (TEE) for evaluation of ischemic stroke or TIA. We compared patients with cryptogenic stroke/TIA and those with stroke/TIA of known cause. RESULTS: PFO+ASA was more common in patients with cryptogenic stroke/TIA than in patients with stroke/TIA of known cause (12/62 or 19% vs. 2/70 or 3%; adjusted odds ratio, 7.4; 95% CI, 1.4-38.2). Differences between groups for isolated PFO, and isolated ASA were not significant. The association of PFO+ASA with cryptogenic stroke/TIA was confirmed in the subgroup of patients aged 75 years or more (odds ratio, 15.0; 95% CI, 1.5-146.7). CONCLUSION: This study indicates a significant association of PFO+ASA with cryptogenic stroke or TIA in older patients.     

Diffusion weighted MRI imaging and MES detection in the assessment of stroke origin

OBJECTIVES: This study compares the additional benefit of diffusion-weighted MRI (DWI) and microembolus detection by transcranial Doppler ultrasonography (TCD) in the assessment of stroke etiology. METHODS: Fifty-five acute anterior circulation stroke or TIA patients were investigated by both cranial DWI and bilateral TCD of the middle cerebral arteries (1 hour). RESULTS: In one of the 13 patients without acute ischemic lesions visualized on DWI, microembolic signal (MES) detection was positive. However, in 33 out of 44 patients without MES, DWI revealed at least one lesion. In two patients with unilateral territorial infarction and otherwise normal cardiovascular work-up, bilateral MES were found thus localizing the embolic source into the aortic arch or the heart. In a further patient with a dissection, the occurrence of contralateral MES raised doubts on a dissection to be the cause of the infarct. DISCUSSION: There is a contribution of both techniques to the understanding of stroke etiology. The impact of DWI is, however, superior to that of MES detection. Longer TCD recording times may diminish this discrepancy.     

Silent brain embolism during transcatheter closure of patent foramen ovale: a transcranial Doppler study

Abstract The aim of this report is to quantify the amount of spontaneous microembolism detected in brain vessels by transcranial Doppler (TCD) during transcatheter closure of right-to-left shunt (RLS). We examined 29 patients who had had a stroke or a transient ischaemic attack (17 females and 12 males; mean age 45±15 years). They all underwent TCD monitoring during the procedure and microembolic signals (MES) were recorded. Detection of MES was distributed as follows: during femoral catheterisation in 8 patients (25%), during atrial catheterisation in 5 patients (17%), during transeptal crossing in 14 patients (48%), during left disc opening in 28 patients (96%) and during right disc opening in 7 patients (24%). The highest rates of MES were observed during left disc opening and less during transeptal crossing with an average count of 31 (range 3–135) and 3 (range 1–18) respectively. Brain embolism occurs throughout the procedure after femoral catheterisation for PFO closure. Our results indicate that the majority of MES reached the brain during the opening of the left disc in the left atrium: 28/29 patients exhibited MES with an average of 31 (3–135), thus supporting the notion that gas embolism accounted for the findings.     

反常性栓塞风险量表在合并卵圆孔未闭的隐源性卒中或短暂性脑缺血发作患者中的应用

目的 描述卵圆孔未闭（patent foramen ovale,PFO）造成反常性栓塞（paradoxical embolism,PE）的临
床表现、影像学特点。验证反常性栓塞风险量表（Risk of Paradoxical Embolism,RoPE）评分。
方法 本研究为单中心观察性研究,连续性入选2013年1月～2014年6月首都医科大学附属北京天
坛医院神经科收治的隐源性卒中或短暂性脑缺血发作（transient ischemic attack,TIA）患者79例,其
中经经颅多普勒超声发泡试验（contrast-enhanced transcranial Doppler,cTCD）和经食管超声心动图
（transesophageal echocardiography,TEE）确诊合并PFO的患者44例,其中37例为PFO所致PE,7例仅合并
PFO无栓塞症状。由另一名神经科医师盲法评价颅脑磁共振成像,确定其影像学的特点,收集两组
患者的人口学信息,临床资料,相关辅助检查（如cTCD、TEE、颈部血管超声及双下肢静脉超声结果）,
计算并比较两组RoPE评分情况。PFO所致PE患者根据PFO大小分为3组,依据右向左分流量（rightto-
left shunt,RLS）大小分为3组。比较不同PFO大小和不同RLS患者之间的临床和影像学特点,并评
估不同PFO大小和不同RLS之间的关联性及RoPE评分与PFO的大小和RLS的严重程度之间的关系。
结果 两组的RoPE评分分别为5（4.5,7.0）和6（4.0,8.0）,差异无显著性（P＞0.05）。合并颈内
动脉重度狭窄或闭塞,高度提示非PFO相关缺血性卒中（P＜0.01）。小PFO组（＜2 mm）和中/大PFO组
（≥2 mm）相比较,两组的RoPE评分分别为（5.5±1.9 vs 6.3±2.0,P＞0.05）,后者更容易累及后循
环。不同RLS患者之间相比较,3组的RoPE评分分别为（5.4±1.7,6.5±2.7,5.8±2.0,P＞0.05）。PFO
大小和RLS之间无显著性相关（r =0.031,P＞0.05）。
结论 PFO和脑梗死的关系可以分为：无相关性（即PFO合并存在）或有相关性（即PE）,PE的影像学
特点和PFO大小有一定的相关性。RoPE可能有助于进一步区分PFO的大小和RLS的严重程度。     

Transcranial Doppler and risk of recurrence in patients with stroke and patent foramen ovale

The importance of patent foramen ovale (PFO) in stroke of unknown cause remains disputed, as PFO may be present in up to 20% of normal people and in a high proportion of patients with non-vascular disorders. Recent evidence suggests that the amount of right-to-left shunt (RLS) may be the crucial factor for stroke occurrence and relapse. The aim of the study was to assess predictors of recurrence in PFO-related stroke patients with particular emphasis on amount of shunting. Patients less than 61 years old who had been admitted for a PFO-related stroke within the previous 5 years, were re-evaluated on a follow-up visit. The clinical syndrome, residual disability, vascular risk factors and number of relapses as the index event were assessed. RLS sizing was semi-quantitatively performed with saline-enhanced transcranial Doppler (TCD), by assuming a cut-off of more or less 10 bubbles recorded in the cerebral vessels as a criterion to discriminate large versus small shunt, respectively. Thereafter patients were prospectively followed-up for a median time of 23 months. Total follow-up was 61 months. Fifty-nine patients (M/F = 23/36, mean age 43 +/- 13) were studied. Overall there were 23 relapses in 13 patients. The amount of shunting was the only significant independent variable associated with relapse: at the end of the follow-up period the recurrence rate was 0.66 and 8.2% per patient per year in patients with small and large shunt, respectively. This difference was statistically significant (chi2 = 10.39, P = 0.0012; OR 17.05, 95% CI 2.10-755.22). In patients with PFO-related stroke, the amount of RLS as assessed with TCD is the only independent predictor of relapse. PFO sizing is mandatory in patients with PFO.     

Lesion patterns in patients with cryptogenic stroke with and without right-to-left-shunt

Background and purpose:  Despite numerous studies, the role of patent foramen ovale (PFO) as a risk factor for stroke due to paradoxical embolism is still controversial. On the assumption that specific lesion patterns, in particular multiple acute ischaemic lesions on diffusion-weighted magnetic resonance imaging, indicate a cardioembolic origin, we compared the MRI findings in stroke patients with right-to-left shunt (RLS) and those without.
Methods:  The records of 486 patients with diagnosis of cerebral ischaemia were reviewed. For detection of RLS, contrast-enhanced transcranial Doppler (c-TCD) was carried out in all patients. An MRI scan of the brain was performed in all patients. Affected vascular territories were divided into anterior cerebral artery, middle cerebral artery, vertebrobasilar artery system including posterior cerebral artery, brain stem and cerebellar stroke, and strokes occurring in more than one territory.
Results:  We did not find a specific difference in neuroradiological lesion patterns in patients with RLS compared with patients without RLS. In particular, 23 of 165 patients (13.9%) with RLS showed multiple ischaemic lesions on MRI in comparison with 45 of 321 patients (14.0%) without RLS ( P  = 0.98). These findings also applied for the subgroup of cryptogenic strokes with and without RLS.
Conclusion:  We found no association between an ischaemic lesion pattern that is considered as being typical for stroke due to cardiac embolism and the existence of PFO. Therefore, our findings do not provide any support for the common theory of paradoxical embolism as a major cause of stroke in PFO carriers.     

Microembolic signals after 7 days but not within 24 hours of stroke onset should be predictor of stroke recurrence

BACKGROUND AND PURPOSE: Microembolic signals (MES) on transcranial Doppler ultrasonography (TCD) are occasionally detected in acute ischemic stroke patients and gradually decrease over time. If MES is detectable at 7 days after stroke onset, embolic source lesions may still be active. We hypothesized that presence of MES at 7 days after stroke onset is strongly associated with stroke recurrence. METHODS: Subjects comprised 143 patients with acute ischemic stroke who were prospectively examined for the presence of MES using TCD both within 24 h and at 7 days after stroke onset. Stroke recurrence was assessed within 3 months of stroke onset. The association between presence of MES and stroke recurrence was investigated. RESULTS: MES was detected in 70 of 143 patients (49%) within 24 h of stroke onset and in 34 patients (24%) at 7 days. Stroke recurrence was observed in 6 patients after 7 days and in 10 patients between 7 days and 3 months after stroke onset. Presence of MES within 24 h of stroke was not associated with stroke recurrence (10% for MES-positive vs. 12% for MES-negative, p=0.792). At 7 days after onset, stroke recurrence was more frequent in the MES-positive group at 7 days than in the MES-negative group (24% vs. 7%, p<0.0001). Cox's proportional hazard analysis demonstrated presence of MES as an independent factor of stroke recurrence (hazard ratio, 6.4; 95% confidence interval, 1.4-28; p=0.015). CONCLUSION: Presence of MES detected on TCD at 7 days of stroke onset should be a predictor of stroke recurrence.     

Abnormalities of interatrial septum and ischemic stroke in young people

OBJECTIVE: To verify the frequency of patent foramen ovale (PFO) among patients with ischemic stroke (cryptogenic or with a known cause) investigated by transcranial doppler (TCD) and transesophageal echocardiography. Secondarily, to determine the diagnostic validity of the former, compared with the later method. METHOD: Retrospectively, 124 patients (<51 years old) with ischemic stroke were submitted to TCD and or transesophageal echocardiography. The patients were classified as cryptogenic stroke or not. RESULTS: We could found an important association between cryptogenic ischemic stroke and PFO (odds ratio 4.3--CI 95% 1.7-10.7). Only five cases of interatrial septal aneurysm were diagnosed among patients with PFO. Sensitivity, specificity and positive and negative predictive values exhibited values upper of 85%, equivalents, at least based on confidence intervals. CONCLUSION: We could determine, for the first time in our country, a strong association between cryptogenic ischemic stroke and PFO. The TCD is a valuable diagnostic resource in this context since its validity was considered excellent. A detailed investigation in these cases should always be done due to the possibility of FOP closure.     

TIA患者脑动脉微栓子的监测及其与颈动脉斑块的相关性

目的 监测短暂性脑缺血发作(TIA)患者脑动脉微栓子(MES)的出现率,探讨其与颈动脉斑块的相关性.方法 112例TIA患者均进行MES的监测和颈动脉彩色多普勒超声检测,分别观察MES阳性与有颈动脉斑块的病例数.结果 (1)MES阳性者31例,阳性率27.68%.有颈动脉斑块者67例,斑块出现率59.82%,其中不稳定斑块28例,占有斑块病例的41.79%.(2)67例有斑块者MES阳性率35.82%,较45例无斑块者15.56%高(P<0.05);28例不稳定斑块者MES阳性率57.14%,较39例稳定斑块者20.51%高(P<0.01).(3)MES与斑块的大小、部位和个数无相关性.结论 颈动脉不稳定斑块的脱落是TIA患者脑动脉MES的主要来源之一,稳定颈动脉斑块的处理是减少TIA复发及其后出现脑梗死的重要举措.

Abstract：

Objective To study the prevalence of cerebral microembolism(MES)in patients with TIA and its relation to carotid plaque.Methods Total 112 patients with TIA were studied.The cerebral artery MES were monitored by TCD.and carotid plaques were detected by color transcranial Doppler.The cases with cerebral artery MES and with carotid plaques were respectively recorded.Results There were 31 patients with MES and the prevalence WaS 27.68%.There were 67 patients with carotid plaques and the presence was 59.82%;among them,28 patients with unstable carotid plaques constituted 41.79%.The prevalence of MES in 67 patients with carotid plaques(35.82%)Was significantly hisher than 45 patients without carotid plaques(15.56%)(P<0.05),while the prevalence of MES in 28 patients with unstable carotid plaques(57.14%)was greatly higher than 39 patients with stable carotid plaques(20.51%)(P<0.01).The prevalence of MES had nothing to do with the size,position and quantity of the carotid plaque.Conclusions The desquamation of unstable carotid plaque is one of the main sources of cerebral artery MES.The stabilization of carotid plaque is an important measure to reduce relapse of TIA and prevent the patient from cerebral infarction after TIA.     

急性缺血性卒中患者大脑中动脉狭窄微栓子信号预测再发脑缺血事件

本文是采用经颅多普勒超声(TCD)检测大脑中动脉狭窄(MCA)微栓子信号(MES)的研究,选择了114例MCA狭窄的急性缺血性卒中患者,结果发现22%的患者有MES,平均18个(1～102),重度狭窄(48%)患者较轻中度狭窄者(15%)更易出现MES。平均随访13．6个月(1～32个月),其中12例(12．2%)患者再次出现MCA供血区域的缺血事件(10例卒中,2例TIA)。Cox回归分析显示调整其他卒中高危因素后,MES是再发缺血性卒中/TIA的独立预测因子(P=0．01)。检测MES能够预测MCA狭窄的急性卒中患者脑缺血的复发,因此提出应将MES检测作为常规检查的一部分,这或许能识别那些最可能从抗栓治疗中获益的患者。     

Transcranial Doppler ultrasonography in the detection of venous to arterial shunting in acute stroke and transient ischaemic attacks.

OBJECTIVES: To prospectively evaluate the prevalence of venous to arterial shunting in patients with acute stroke and transient ischaemic attacks (TIAs) using transcranial Doppler ultrasonography (TCD) with saline contrast. METHODS: A consecutive series of patients with stroke or TIA underwent contrast TCD. Patients were subsequently divided into groups according to causative factors for stroke or TIA. The prevalence of right to left shunt was assessed within these groups. RESULTS: A total of 210 patients underwent contrast TCD. A right to left shunt was detected in 28.6% of patients (60 of 210). Among the patients with cryptogenic stroke or TIA, 37.1% (43 of 116) had a positive contrast TCD whereas only 18% (17 of 94) with another identifiable cause had a positive test (P = 0.0024). When age was used to further classify those patients with cryptogenic stroke, TCD was positive in 59.3% patients (16 of 27) of < or = 50 years of age versus 30.3% of patients (27 of 89) > 50 years of age (P = 0.0058). CONCLUSIONS: There was a significantly higher prevalence of venous to arterial shunting in patients with stroke or TIA of undetermined cause than in stroke patients with identifiable aetiologies, as detected by contrast TCD. The prevalence of a venous to arterial shunt was significantly higher in the younger group with cryptogenic stroke. Saline contrast TCD is a relatively non-invasive bedside procedure useful in the detection of venous to arterial shunting.     

经颅多普勒超声在不明原因缺血性脑卒中的应用研究

目的探讨经颅多普勒超声(transcranial Doppler,TCD)技术结合生理盐水发泡试验在不明原因缺血性脑卒中患者卵圆孔未闭(PFO)筛查中的应用价值。方法收集51例55岁以下不明原因缺血性脑卒中患者,行TCD结合生理盐水发泡试验和经胸超声心动图(TTE)检查。结果 51例患者中,23例患者TCD检查栓子信号阳性,其中18例患者TTE检查发现PFO,而在28例TCD检查栓子信号阴性的患者中未发现PFO;TCD检查阳性患者中偏头痛发病率、合并下肢深静脉血栓比例以及房间隔瘤比例较阴性者高(P<0.05)。结论 TCD结合生理盐水发泡试验是筛查PFO的有效手段,可以作为不明原因缺血性脑卒中病因筛查的手段。     

Right-to-left-shunts detected by transesophageal echocardiography and transcranial Doppler sonography

BACKGROUND: Transesophageal echocardiography (TEE) and transcranial Doppler sonography (TCD) can identify right-to-left-shunts that predispose to paradoxical embolism. In a large cohort we compared the results of both techniques. METHODS: 222 patients were investigated by both techniques using the contrast agent Echovist-300 and performing each test once without and once with the Valsalva maneuver (VM). RESULTS: TEE-proven right-to-left-shunts were detected by TCD with a high sensitivity of 94%. In addition, TCD revealed shunts not noted during TEE in about 20% of all patients studied. These shunts are in general smaller than those concordantly identified; however, 9% of the patients without a TEE-proven shunt presented with a shunt that allows a considerable amount of contrast medium to pass. There were 12% more microbubbles detected in the right middle cerebral artery than in the left middle cerebral artery during the TCD test performed with VM, but not during the TCD test performed without VM. CONCLUSIONS: Contrast-enhanced TEE and TCD are complementary methods in the assessment of stroke and stroke-prone patients. The side difference of microbubbles may indicate a selective streaming of cardiac emboli during VM.