Pathogenesis of anterior circulation stroke in patients with nonvalvular atrial fibrillation: the Lausanne Stroke Registry

We studied coexisting potential arterial and cardiac causes of stroke in 159 patients with nonvalvular atrial fibrillation (AF), who were admitted to a population-based primary care center for an anterior circulation infarct. Systematic investigations included brain CT, carotid Doppler ultrasounds with frequency analysis and echotomography, and mono- and bidimensional echocardiography. Lacunar infarction due to small-artery disease was at least as likely as an AF-related stroke in 13% of the patients who had hypertension and a small deep infarct. In 67% of the patients, internal carotid artery disease ipsilateral to infarct was present, but it was severe (greater than or equal to 50% stenosis or occlusion) in only 11%. There was a potential cardiac source of embolism other than AF in 14%. Overall, although only 18% of the patients had AF as the only potential cause of stroke, embolism from the heart remained the most likely etiology of infarct in 76%. Our findings emphasize the role of AF-related hemodynamic disturbances, which were often associated with embolic phenomena, and a rather low early risk of recurring embolism (4%) within the 1st month after stroke.     

Significance of aortic atheroma in elderly patients with ischemic stroke. A hospital-based study and literature review

OBJECTIVES: Cardioembolism accounts for 15-30% of ischemic strokes. Transesophageal echocardiography (TEE) is useful in detecting potential sources of cardiac embolism. Aortic atheromas have recently been recognized as important causes of stroke. The aim of this study was to evaluate TEE findings in elderly patients with ischemic stroke. A review of literature was done to highlight the significance of aortic atherosclerotic disease in patients with ischemic stroke. METHODS: One hundred consecutive patients with ischemic stroke aged > or =55 years underwent TEE for evaluation of cardiac sources of embolism. Patients with significant carotid artery stenosis (stenosis of >50% in common or internal carotid arteries) were excluded. RESULTS: The most noteworthy finding was the high prevalence of complex atheromatous plaques in the ascending aorta and/or aortic arch (25%). CONCLUSION: The present study demonstrates that TEE is helpful to detect cardiovascular sources of embolism in elderly patients with ischemic stroke. Aortic atheroma is present in 25% of elderly patients with ischemic stroke and without significant carotid artery stenosis. Aortic atherosclerosis may be an important cause of ischemic stroke in this population.     

New England Medical Center Posterior Circulation Stroke Registry: I. Methods, Data Base, Distribution of Brain Lesions, Stroke Mechanisms, and Outcomes

Among 407 New England Medical Center Posterior Circulation Registry (NEMC-PCR) patients, 59% had strokes without transient ischemic attacks (TIAs), 24% had TIAs before strokes, and 16% had only posterior circulation TIAs. Embolism was the commonest stroke mechanism accounting for 40% of cases (24% cardiac origin, 14% arterial origin, 2% had potential cardiac and arterial sources). In 32%, large artery occlusive lesions caused hemodynamic brain infarction. Stroke mechanisms in the posterior and anterior circulation are very similar. Infarcts most often included the distal posterior circulation territory (rostral brainstem, superior cerebellum and occipital and temporal lobes), while the proximal (medulla and posterior inferior cerebellum) and middle (pons and anterior inferior cerebellum) territories were equally involved. Infarcts that included the distal territory were twice as common as those that included the proximal or middle territories. Most distal territory infarcts were attributable to embolism. Thirty day mortality was low (3.6%). Embolic stroke mechanism, distal territory location, and basilar artery occlusive disease conveyed the worst prognosis.     

Transesophageal echocardiography discloses unexpected cardiac sources of embolus in stroke patients aged more than 45 years

Cerebral embolism from cardiac source is an important cause of stroke, specially in patients younger than 45 years old. OBJECTIVE: To describe the transesophageal echocardiography (TEE) findings in young and non-young stroke patients without any prior evidence of cardiac source for cerebral embolism. METHOD: Transversal study: 523 patients (267 men and 256 women) with ischemic stroke, without any evidence of cardiac abnormality, underwent to TEE. RESULTS: Ten percent were aged 45 years; or less. Left ventricle hypertrophy, left atrial enlargement, spontaneous contrast in aorta, interatrial septum aneurysm, mitral and aortic valve calcification, aortic valve regurgitation, and atherosclerotic plaques in aorta were significantly more frequent in patients aged more than 45 years; 2.8% of non-young patients had thrombus in left heart. CONCLUSION: TEE is widely used to diagnose cardiac source of cerebral embolism in young patients, but it seems to be as useful for older ones, in whom cerebral embolism risk is underestimated; atherogenic and cardioembolic causes may actually coexist, and both should be treated.     

Clinical features and mechanism of occipital infarction

To clarify the clinical features and mechanism of infarction in the posterior cerebral artery territory, we investigated 35 consecutive patients who presented with homonymous visual field defects and occipital infarction documented by computed tomography. Cerebral angiographic findings in 23 patients, and the clinical features of rare transient ischemic attacks and maximal deficit occurring at stroke onset, were consistent with embolism of the posterior cerebral artery. Visual field defects were the only neurological abnormality in 17 patients; the remainder had additional findings. Three patients had a major brainstem stroke. Stroke in the posterior cerebral artery territory was found in a heterogeneous group of patients, although embolism was the most common stroke mechanism. Several distinct patient groups were identified: cardiac source embolism (10 patients), vertebrobasilar atheroma with local embolism (6), migraine (5), systemic illness with presumed coagulopathy (3), and "unknown source embolism" after negative cardiac investigation (11 patients). During follow-up, 26 patients had no further neurological events (the majority on anticoagulation or antiplatelet treatment), 3 suffered new strokes, and 6 died.     

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.     

Mechanisms involved in large subcortical infarcts]

Large subcortical infarcts(maximum diameter of infarct > or = 20 mm) result from various stroke patterns, including striatocapsular infarcts (SCI), corona radiata infarcts, centrum semiovale infarcts, and internal borderzone infarcts. A systematic investigation of stroke pathogenesis involved in large subcortical infarcts, however, has not been performed. This study attempted to clarify the stroke mechanisms involved in large subcortical infarcts, by examining 50 patients with large subcortical infarcts out of 430 ischemic stroke patients consecutively registered in our department. The subjects were divided into two groups according to the vascular territories involved on the MRI: 1) the lenticulostriate arteries group for 39 patients whose infarcts were restricted to within the vicinity of the lenticulostriate arteries; 2) the internal borderzone group for 11 patients whose infarcts mainly involved the internal borderzone (the upper part of the corona radiata and the centrum semiovale) between the territories of the deep perforating branches from the basal cerebral arteries and the medullary branches from the superficial pial arteries. Stroke pathogenesis were classified into the following 6 categories: A) cardiogenic embolism, 9 patients; B) artery-to-artery embolism, 6 patients; C) cryptogenic embolism, 2 patients; D) thrombotic MCA (M1) occlusion, 9 patients; E) thrombotic ICA occlusion, 10 patients; F) undetermined cause, 14 patients. The lenticulostriate arteries group consisted of 9 patients with cardiogenic embolism, 6 with artery-to-artery embolism, 2 with cryptogenic embolism, 8 with thrombotic M1 occlusion, and 14 with undetermined cause. The internal borderzone group consisted of 10 patients with thrombotic ICA occlusion and 1 patient with thrombotic M1 occlusion. The stroke pathogenesis of the undetermined cause is considered to be thrombotic occlusion at the orifice of the lateral lenticulostriate artery, a so-called "branch atheromatous disease (BAD)". The patients in this group experienced a gradual onset, and did not have a cardiac source of the embolism or proximal large artery disease. Among the patients reported as having SCI, BAD may play a role in some cases, especially in those whose the cause was classified as "undetermined". In conclusion, the lenticulostriate arteries group exhibited a higher frequency of cerebral embolisms (cardiogenic embolism, artery-to-artery embolism, and cryptogenic embolism) and thrombotic M1 occlusion, whereas the internal borderzone group had a higher frequency of thrombotic ICA occlusion.     

Double infarction in one cerebral hemisphere

Thirty-two patients whose first stroke was due to double infarct in one cerebral hemisphere were identified among 1,911 consecutive patients from the Lausanne Stroke Registry. The double infarct involved territories of the superficial middle cerebral artery, superficial posterior cerebral artery, lenticulostriate, anterior choroidal artery, or borderzone. The most common combination involved territories of the anterior middle cerebral artery plus the posterior middle cerebral artery. In the patients with the double infarct, the prevalence of potential cardiac sources of embolism (19%) was similar to that found in the registry in general, but the double infarct was closely associated with tight (greater than or equal to 90% of the lumen diameter) stenosis or occlusion (75%) of the internal carotid artery. The most common neurological picture mimicked large infarction in the middle cerebral artery territory, but nearly half of the patients with double infarct in one cerebral hemisphere had a specific clinical syndrome, which was not found in the 1,879 remaining patients from the registry, including hemianopia-hemiplegia (in 6), acute conduction aphasia-hemiparesis (in 2), and acute transcortical mixed aphasia (in 6), in relation to characteristic combinations of infarcts. These unique clinical and etiological correlates warrant the recognition of double infarct in one cerebral hemisphere from other acute ischemic strokes.     

Diffusion-weighted magnetic resonance imaging in internal carotid artery dissection

BACKGROUND: Acute multiple brain infarction pattern on diffusion-weighted imaging is associated with arterial or cardiac sources of embolism. OBJECTIVES: To review the diffusion-weighted imaging characteristics of patients with strokes secondary to internal carotid artery (ICA) dissection and to gain further insights into the mechanisms of cerebral ischemia. DESIGN: Patients with ICA dissection and ischemic stroke were identified by review of an angiographic database and hospital discharge codes. Patients were included if the diagnosis of ICA dissection was confirmed and diffusion-weighted imaging was obtained within 10 days of symptom onset. Infarct patterns were analyzed according to established templates of vascular territories. RESULTS: Inclusion criteria were met by 14 patients. Internal carotid artery occlusion was present in 10. Acute multiple brain infarction was found in 10 (71%) of the 14 patients. Cortical involvement was found in 8 patients, while the infarct was restricted to the subcortical region in 6. In 9 (64%) of the 14 patients, ischemic lesions were located in 1 of the 3 border zones. CONCLUSIONS: Acute multiple brain infarction pattern with border zone involvement is frequently found in ICA dissection-related strokes. This finding may further support an interaction of hemodynamic and embolic mechanisms as a cause of cerebral ischemia in this condition.     

Cerebral microembolism in patients with stroke or transient ischaemic attack as a risk factor for early recurrence

The incidence of early recurrence in 32 patients who had had atransient ischaemic attack or stroke in the anterior circulation wasstudied. Patients with a potential cardiac source of embolism wereexcluded from the study. All patients had transcranial Doppler (TCD)monitoring of the symptomatic middle cerebral artery for microembolicsignal detection within seven days from the onset of symptoms. Fourpatients had early recurrence during a mean follow up of 15 (SD11)days. All early recurrences occurred in the same arterial territory asthe initial ischaemic event. Three of the four patients with earlyrecurrence had prior microembolic signals. The incidence of earlyrecurrence was 50% (3/6) in patients with microembolic signals and3.8% (1/26) in patients without microembolic signals (P=0.02). Thefindings suggest that TCD monitoring of patients with recent cerebralischaemia of presumed arterial origin allows recognition of a subset ofpatients at high risk for early recurrence.

     

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.     

Neurovascular territory involved in different etiological subtypes of ischemic stroke in the Perugia Stroke Registry

We studied the correlation between the potential causes of stroke (TOAST etiological groups) and the involvement of different vascular territories seen on computed tomography (CT) scans in patients with ischemic stroke. Information from consecutive patients with a first-ever stroke have been prospectively coded and entered into a computerized data bank (Perugia Stroke Registry). A population of 1,719 patients were evaluated: 1,284 patients (74.7%) had ischemic stroke. Large artery disease was the main cause of entire middle cerebral artery (MCA) territory infarcts (40.9%), superficial MCA territory infarcts (35.7%), and watershed infarcts (68.2%). The highest presence of emboligenic heart disease was found in the entire MCA territory infarcts (28.8%) or superficial (29.4%) supratentorial infarcts and in cerebellar infarcts (36.8%). Small artery disease was the most common presumed cause of deep MCA infarcts (75.0%) and posterior cerebral artery (PCA) territory infarcts (52.1%). In conclusion: stroke location could depend on its etiology. Lacunar infarcts are the most prevalent (36.7%), being mostly localized in the deep MCA territory; large artery disease includes more than two-thirds of watershed infarcts; the most prevalent territories involved in cardioembolic stroke are the entire MCA and posterior fossa.     

Lesion patterns and mechanism of ischemia in internal carotid artery disease: a diffusion-weighted imaging study

CONTEXT: Although embolism and low-flow phenomenon are the 2 main mechanisms of stroke in internal carotid artery (ICA) occlusive disease, the mechanism of border-zone infarction remains controversial. Diffusion-weighted imaging (DWI) can more easily detect small or multiple ischemic lesions than conventional imaging. OBJECTIVES: To investigate the ischemic lesion patterns on DWI and to discuss the mechanisms of stroke in ICA disease. DESIGN: Case series. SETTING: A tertiary referral center. PATIENTS: We enrolled 35 consecutive patients who had an acute ischemic stroke and (> or = 70%) stenosis or an occlusion of the extracranial ICA confirmed by cerebral angiography and an acute relevant stroke lesion on DWI within 1 week of onset, but without cardiac sources of embolism and tandem intracranial arterial disease. MAIN OUTCOME MEASURES: The lesion pattern on DWI was categorized as territorial or border zone. Multiple ischemic lesions were defined as noncontiguous lesions on DWI in more than 1 vascular territory. RESULTS: There were 3 distinctive stroke lesion patterns. (1) A territorial lesion without a border-zone lesion was found in 21 patients: superficial and superficial territorial in 9, superficial and deep territorial in 7, and single in 5. (2) A border-zone lesion with or without a territorial lesion was found in 10 patients: border zone and territorial in 9 and border zone alone in 1. (3) Bilateral hemispheric lesions were found in 4 patients. Multiple ischemic lesions were found in 29 (82.9%) of the 35 patients. No patient had episodes of hemodynamic compromise. CONCLUSIONS: An acute ischemic lesion in ICA occlusive disease is mainly multiple. Border-zone infarction was mostly associated with territorial infarction. These results support the fact that embolism is the predominant stroke mechanism in ICA occlusive disease.     

New England Medical Center Posterior Circulation registry

Among 407 New England Medical Center Posterior Circulation registry patients, 59% had strokes without transient ischemic attacks (TIAs), 24% had TIAs then strokes, and 16% had only TIAs. Embolism was the commonest stroke mechanism (40% of patients including 24% cardiac origin, 14% intraarterial, 2% cardiac and arterial sources). In 32% large artery occlusive lesions caused hemodynamic brain ischemia. Infarcts most often included the distal posterior circulation territory (rostral brainstem, superior cerebellum and occipital and temporal lobes); the proximal (medulla and posterior inferior cerebellum) and middle (pons and anterior inferior cerebellum) territories were equally involved. Severe occlusive lesions (>50% stenosis) involved more than one large artery in 148 patients; 134 had one artery site involved unilaterally or bilaterally. The commonest occlusive sites were: extracranial vertebral artery (52 patients, 15 bilateral) intracranial vertebral artery (40 patients, 12 bilateral), basilar artery (46 patients). Intraarterial embolism was the commonest mechanism of brain infarction in patients with vertebral artery occlusive disease. Thirty-day mortality was 3.6%. Embolic mechanism, distal territory location, and basilar artery occlusive disease carried the poorest prognosis. The best outcome was in patients who had multiple arterial occlusive sites; they had position-sensitive TIAs during months to years.     

Thalamic infarcts: clinical syndromes, etiology, and prognosis

We studied forty patients with CT-proven thalamic infarcts without involvement of the superficial territory of the posterior cerebral artery. The delineation into four arterial thalamic territories (inferolateral, tuberothalamic, posterior choroidal, paramedian) corresponded clinically to four different syndromes. The most common etiologies were lacunar infarction, large artery atherosclerosis with presumed artery-to-artery embolism, cardioembolism, and migrainous stroke. We found no risk factor other than age or oral contraceptive use in six patients. One patient died in the acute phase. During follow-up (45.6 months), the stroke or death rate was 7.4% per year. Delayed pain developed in three patients and abnormal movements in three. Late disability was mainly secondary to persisting neuropsychological dysfunction (thalamic dementia).     

Prediction of in-hospital mortality after first-ever stroke: the Lausanne Stroke Registry.

We aimed to study in-hospital mortality after a first-ever stroke (brain infarction or parenchymatous hemorrhage) and to determine its predictors using easily obtainable variables. The main outcome measure was vital status at hospital discharge. Clinical features and type of stroke, with a particular emphasis on age, stroke topography and presumed causes of stroke, were studied in 3362 consecutive patients from the Lausanne Stroke Registry. Overall mortality was 4.8%. Brain hemorrhage mortality was 14.4% (48/333) and brain infarction mortality was 3.70% (112/3029). Localizations with high mortality included infratentorial (17.5%) and deep hemispheric (15.9%) territories for brain hemorrhage and, for brain infarction, multiple localizations in the posterior circulation (18.4%) and large middle cerebral artery territory (15.5%). Presumed causes of stroke associated with high mortality included saccular aneurysm (58.3%) and hypertensive arteriopathy (13.0%) for brain hemorrhage and, for brain infarction, dissection (10.4%), arteritis (8.3%), hematologic conditions (6.7%) and coexisting arterial and cardiac sources of embolism (5.2%). Multivariate logistic analysis showed that impaired consciousness on admission and limb weakness were good predictors of mortality for brain hemorrhage, while impaired consciousness and the cumulative effect of progressive worsening, limb weakness, left ventricular hypertrophy, past history of cardiac arrhythmia and previous transient ischemic attack were predictors of mortality for brain infarction. Age was not an independent predictor of stroke mortality, but for brain infarction the number of cumulative factors considered in the model increased with age. Our study shows that several factors associated with death risk are available during the first few hours after onset of stroke. Age alone is not critical, although its interaction with other factors should be considered.     

Transesophageal echocardiography in the detection of potential cardiac source of embolism in stroke patients

To compare the diagnostic yields of transesophageal and transthoracic echocardiography in the detection of potential cardiac sources of embolism, 63 patients (mean +/- SD age 63 +/- 15 [range 18-87] years) with transient ischemic attacks or stroke underwent both procedures. Transthoracic echocardiography revealed a potential cardiac source of embolism in 14% (nine) of the patients, all of whom had clinical evidence of heart disease. Transesophageal echocardiography revealed a potential cardiac source of embolism in 41% (26) of the patients; 27% (seven) of these patients had no clinical cardiovascular abnormalities. Abnormalities detected only by transesophageal echocardiography in the patients with unsuspected cardiac disease included atrial septal aneurysm in two, patent foramen ovale in two, left atrial appendage thrombus in one, and myxomatous mitral valve in two. The 26 patients with an identified cardiac source of embolism were older (67.5 versus 59.4 years, p = 0.04), more frequently in atrial fibrillation (62% [16] versus 8% [3], p less than 0.0001), had a larger left atrium (43 versus 37 mm, p = 0.01) and more commonly had left ventricular hypertrophy (62% [16] versus 32% [12], p less than 0.02) than the 37 patients in whom no cardiac source of embolism was identified. Thus, transesophageal echocardiography is more sensitive than transthoracic echocardiography in the detection of potential cardiac sources of embolism in patients with cerebral ischemic events.     

Lesion patterns and etiology of ischemia in superior cerebellar artery territory infarcts

BACKGROUND AND PURPOSE: Infarcts in the territory of superior cerebellar artery (SCA) are uncommon. The clinical, and etiological mechanisms of different infarct patterns of SCA are not well known. Diffusion-weighted imaging (DWI) is superior to conventional magnetic resonance imaging for detecting acute small and multiple ischemic lesions. METHODS: We studied 60 patients with lesions involving SCA territory proved by DWI, which have been selected from 3,800 patients with first ischemic stroke consecutively admitted to our stroke unit over a period of 5 years. RESULTS: There are 7 distinctive SCA lesion patterns: (1) a lesion was found in the medial (m) branch territory of SCA (mSCA) in 14 patients; (2) a lesion in the lateral (l) branch territory of SCA (lSCA) was seen in 9 patients; (3) a coexisting lesion involving mSCA and lSCA was found in 9 patients; (4) a lesion in cortical borderzones between SCA and m/l branches of the posterior inferior cerebellar artery (PICA) was observed in 6 patients; (5) a lesion in deep borderzones between lSCA and mSCA, and lPICA and mPICA was present in 8 patients; (6) a lesion involving the medial rostral cerebellum between the right and left SCA was found in 4 patients; (7) multiple lesions involving SCA and other vertebrobasilar artery territories were present in 10 patients. The main cause was possible artery-to-artery embolism from atherosclerotic vertebrobasilar arteries to distal branches of SCA in 20 patients (33%). Fourteen patients had a source of cardioembolism (23%), and 6 patients (8%) had concomitant atherosclerotic vertebrobasilar artery disease and a source of cardioembolism. CONCLUSIONS: An acute ischemic lesion in the SCA territory is mainly multiple. The lSCA territory was the most involved area. Small territorial infarcts were frequently associated with large territorial SCA infarcts. Borderzone SCA infarcts occurred in one third of the patients with transient benign symptoms. Mass effects are unusual despite the large amount of SCA involvement. Our results supported the fact that embolism is the predominant stroke mechanism in the SCA territory infarction.     

Paradoxical embolism: an unusual cause of cerebral ischemia

Paradoxical embolism (PE) is an uncommonly diagnosed cause of unexplained ischemic cerebral event. Its diagnosis is based on established criteria and the failure to identify an arterial or cardiac embolic source. The association between patent foramen ovale (PFO) and cryptogenic stroke has repeatedly been demonstrated in clinical studies. Transesophageal contrast echocardiography is the best diagnostic test. Surgical or endovascular PFO closure is recommended for the long-term prevention of PE.     

Recurrent embolic stroke originating from an internal carotid aneurysm in a young adult

An unruptured intracranial aneurysm is an uncommon but possible embolic source to the brain. We report a young patient who developed recurrent ischemic strokes occurring mainly in the left internal carotid arterial territory within a short interval; the first stroke occurred midway through a long-distance race, and the second stroke occurred immediately following a bowel movement. The angiographical contrast deficit indicated a thrombus in the left anterior cerebral artery as a result of the embolism. A saccular aneurysm of the left distal internal carotid artery was the only detectable potential embolic source. Initially anticoagulant therapy was given, and then surgical clipping of the aneurysm was performed. The patient has been free from stroke recurrence. As a cause of ischemic stroke in young adults, a carotid saccular aneurysm should be considered. Hard exercise and a Valsalva maneuver may be important triggers of thrombus detachment from the aneurysm.