Transesophageal echocardiographic findings in stroke subtypes

Advances in the management of cardioembolic stroke associated with patent foramen ovale

Patent foramen ovale (PFO) describes a valve in the interatrial septum that permits shunting of blood or thrombotic material between the atria. PFOs are present in approximately 25% of the healthy population and are not associated with any pathology in the vast majority of cases. However, comparisons between patients with stroke and healthy controls suggest that PFOs may be causative of stroke in certain patients whose stroke is otherwise cryptogenic. Options for the diagnosis of PFO include transthoracic echocardiography, transesophageal echocardiography, and transcranial Doppler ultrasonography. PFOs associated with an interatrial septal aneurysm seem to be more strongly linked to risk of recurrent stroke. Therapeutic options for secondary stroke prevention in the setting of a PFO include antiplatelet therapy, anticoagulation, and percutaneous device closure. Recent randomized clinical trials suggest that percutaneous closure reduces the subsequent risk of stroke in appropriately selected patients, with a large relative benefit but small absolute benefit. Referral for percutaneous PFO closure should therefore be considered in certain patients after a multidisciplinary, patient centered discussion. Areas for future study include structural biomarkers to aid in determining the role of PFO closure in older people with possible PFO associated stroke, the role of direct oral anticoagulants, and very long term outcomes after device closure.

A meta-analysis of the association of atrial septal abnormalities and atrial vulnerability

BACKGROUND

The mechanism of cryptogenic stroke (CS) in patients with atrial septal abnormalities remains unclear, and the increased incidence of atrial vulnerability may be one of the reasons. We performed this meta-analysis to clarify the association between atrial septal abnormalities and atrial vulnerability, and to provide evidence-based basis for the prevention and mechanism of CS.

METHODS

We systematically searched for studies on the association between atrial septal abnormalities and atrial vulnerability, and pooled available data on types of atrial septal abnormalities, types of atrial vulnerability, and methods of atrial vulnerability detection. The primary endpoints were the occurrence of atrial arrhythmias or P wave abnormalities. Random-effects models were used to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Twelve case-control studies were eligible. Compared with the control group, patients with atrial septal abnormalities had a higher risk of atrial vulnerability (OR: 1.93; 95% CI: 1.13-3.30, P = .02). Data based on stroke patients showed that the group with atrial septal abnormalities had a higher risk of atrial vulnerability than the control group (OR: 2.00; 95% CI: 1.13-3.53, P = .02). However, there was no significant difference in the incidence of atrial vulnerability between the 2 groups of nonstroke patients. Subgroup analysis showed that although atrial septal abnormality increased the risk of atrial vulnerability in the subgroup of atrial septal aneurysm (OR: 1.68; 95% CI: 0.47-5.95, P = .42), the subgroup of atrial fibrillation (AF)/atrial fluster (OR: 1.81; 95% CI: 0.94-3.46, P = .07) and the subgroup of subcutaneous recording system (OR: 1.33; 95% CI: 0.68-2.61, P = .41), the difference was not statistically significant.

CONCLUSIONS

Atrial septal abnormalities can increase the risk of atrial vulnerability, and atrial arrhythmia caused by atrial septal abnormalities may be one of the mechanisms of CS.

Examining the evidence for PFO closure and novel oral anticoagulants for treatment of cryptogenic stroke

Introduction: There has been considerable study assessing the treatment of cryptogenic stroke (CS) recently. This review examines the role of patent foramen ovale (PFO) closure in CS, while also discussing the evidence for alternative medical therapies in disease treatment.Areas covered: PFO closure for treatment of CS has been assessed in 6 randomized controlled trials (RCTs). This review summarizes the background, results and limitations of these trials. Methodological and treatment-related differences in RCTs provide potential explanations for the discordance in outcomes observed between older (CLOSURE, PC, RESPECT-Early) and newer PFO closure trials (RESPECT-Late, CLOSE, REDUCE, DEFENSE-PFO). With regards to medical therapy for CS, two RCTs (NAVIGATE ESUS and RE-SPECT ESUS) did not show any benefit in recurrent stroke prevention with the use of novel oral anticoagulants (NOAC) compared with aspirin. Marked differences in baseline characteristics and rates of recurrent stroke between PFO closure and NOAC trials underlie the heterogeneous nature of CS.Expert commentary: In young patients with CS, PFO closure reduces the risk of recurrent stroke, with newer RCTs emphasizing the importance of identifying those with 'high-risk' PFO and the need for continued antiplatelet therapy. Additionally, treatment for CS should not be uniform but directed at disease-specific pathologies.

Early Echocardiography Has a Low Yield in Patients with Transient Ischemic Attack

STUDY OBJECTIVE

Current guidelines recommend patients presenting with transient ischemic attack (TIA) undergo echocardiography to evaluate for a cardiac source. However, echocardiography is not available daily at many centers. We assessed the yield from early transthoracic echocardiography (TTE) in consecutive patients with TIA evaluated in an emergency department observation unit (EDOU) protocol.

METHODS

This observational cohort study took place in an academic medical center from January 1, 2011 to July 31, 2013. Patients seen in the emergency department, assigned to the EDOU for a TIA accelerated diagnostic protocol and discharged with a diagnosis of TIA were included. We retrospectively collected baseline patient characteristics, ABCD2 score, neuroimaging, telemetry, TTE, and 3-month clinical outcomes.

RESULTS

Of 236 subjects (mean age 62 ± 15 years, 68% female, 57% African American, 17% with history of stroke, 27% with history of cardiac disease, mean ABCD2 score 3.8 ± 1.5, mean EDOU length of stay 18.6 ± 6.2 hours), abnormal bedside cardiac examination was identified in 19 (8%) patients, abnormal electrocardiogram (ECG)/telemetry in 41 (17%), and abnormal TTE in 64 (27%), 41 of which suggested a patent foramen ovale. Among 136 (58%) patients with no previous cardiac disease or stroke, a normal bedside cardiac examination, and normal ECG/telemetry, TTE identified no high-risk cardiac causes.

CONCLUSION

In patients with TIA presenting to an EDOU with no previous cardiac disease or stroke, normal cardiac examination, and normal ECG/telemetry, early TTE had a low yield for identifying high-risk cardiac causes. In EDOUs where TTE is not available daily, outpatient TTE for this patient subgroup may be considered to limit prolonged lengths of stay.

Cost-Effectiveness of Echocardiography to Identify Intracardiac Thrombus among Patients with First Stroke or Transient Ischemic Attack

Background and Purpose . Echocardiography to select stroke patients for targeted treatments, such as anticoagulation (AC), to reduce recurrent stroke risk is controversial. The authors' objective was to evaluate the cost-effectiveness of imaging strategies that use transthoracic (TTE) and transesophageal (TEE) echocardiography for identifying intracardiac thrombus in new stroke patients. Methods . Model-based cost-effectiveness analysis of 7 echocardiographic imaging strategies and 2 nontesting strategies with model parameters based on systematic evidence review related to effectiveness of echocardiography in newly diagnosed ischemic stroke patients (white males aged 65 years in base case). Primary outcome was cost per quality-adjusted life year (QALY). Results . All strategies containing TTE were dominated by others and were eliminated from the analysis. Assuming that AC reduces recurrent stroke risk from intracardiac thrombus by 43% over 1 year, TEE generated a cost per QALY of $137,000 (relative to standard treatment) among patients with 5% thrombus prevalence. Cost per QALY dropped to $50,000 in patients with at least 15% intracardiac thrombus prevalence, or, if an 86% relative risk reduction with AC is assumed, in patients with thrombus prevalence of at least 6%. Probabilistic analyses indicate considerable uncertainty around the cost-effectiveness of echocardiography across a wide range of intracardiac thrombus prevalence (pretest probability). Conclusions . Current evidence on cost-effectiveness is insufficient to justify widespread use of echocardiography in stroke patients. Additional research on recurrent stroke risk in patients with intracardiac thrombus and on the efficacy of AC in reducing that risk may contribute to a better understanding of the circumstances under which echocardiography will be cost-effective. Key words: cost-effectiveness; decision analysis; stroke; transesophageal echocardiography; transthoracic echocardiography; diagnostic imaging. (Med Decis Making 2007;27:161—177)

Impact of transesophageal echocardiography on management in patients with suspected cardioembolic stroke

Transesophageal echocardiography (TEE) is frequently performed in patients with acute ischemic cerebrovascular events to exclude a cardioembolic source. We aimed to determine the clinical impact of TEE on management. This is a retrospective single-center study of 1,458 consecutive patients hospitalized with acute ischemic stroke or transient ischemic attack who underwent TEE for evaluation of a suspected cardioembolic cause. Significant TEE findings were determined for each patient as recorded on the TEE report. The medical record was reviewed for baseline, clinical, and demographic variables and to determine whether significant management changes occurred as a result of the TEE findings. Potential significant changes in management included initiation of anticoagulation, placement of a patent foramen ovale (PFO) closure device, initiation of antibiotic therapy for endocarditis, surgical PFO closure, other cardiac surgery, and coil embolization of a pulmonary arteriovenous malformation. A significant change in management occurred in 243 patients (16.7%); 173 (71%) underwent treatment for PFO with a percutaneous PFO closure device (n = 100), initiation of chronic systemic anticoagulation (n = 68), or surgical PFO closure (n = 5). Additional findings leading to a change in management included endocarditis (n = 20), aortic arch atheroma (n = 14), intracardiac thrombus (n = 13), pulmonary arteriovenous malformation (n = 2), aortic valve fibroelastoma (n = 2), other valve masses (n = 4), and miscellaneous causes (n = 15). In conclusion, in patients with suspected cardioembolic stroke, TEE findings led to a change in management in 16.7% of patients. Of these, most (71%) were directed at prevention of subsequent paradoxical emboli in patients with PFO.

Transcranial Doppler ultrasonography should it be the first choice for persistent foramen ovale screening?

Background

Persistent foramen ovale (PFO) is considered a cause of cryptogenic stroke and a risk factor for neurological events in young patients. The reference standard for identifying a PFO is contrast-enhanced transesophageal echocardiography (TEE).

The goal of this study was to evaluate the feasibility of transcranial color Doppler (TCD) and its diagnostic sensitivity compared with TEE.

Methods

We investigated 420 patients admitted to our department with cryptogenic stroke, transient ischemic attacks or other neurological symptoms. All patients underwent TCD and TEE evaluation. TCD and TEE examinations were performed according to a standardized procedure: air-mixed saline was injected into the right antecubital vein three times, while the Doppler signal was recorded during the Valsalva maneuver. During TCD the passage of contrast into the right-middle cerebral artery was recorded 25 seconds following the Valsalva maneuver.

Results

We detected a right-to-left shunt in 220 patients (52.3%) and no-shunts in 159 patients (37.9%) with both TCD and TEE. In 20 (4.8%) patients TEE did not reveal contrast passage which was then detected by TCD. In 21 (5.0%) patients only TEE revealed a PFO. The feasibility of both methods was 100%. TCD had a sensitivity of 95% and a specificity of 92% in the diagnosis of PFO.

Conclusions

TCD has a relatively good sensitivity and specificity. TCD and TEE are complementary diagnostic tests for PFO, but TCD should be recommended as the first choice for screening because of its simplicity, non-invasive character, low cost and high feasibility.

Embolic strokes of undetermined source: the case for a new clinical construct

Cryptogenic (of unknown cause) ischaemic strokes are now thought to comprise about 25% of all ischaemic strokes. Advances in imaging techniques and improved understanding of stroke pathophysiology have prompted a reassessment of cryptogenic stroke. There is persuasive evidence that most cryptogenic strokes are thromboembolic. The thrombus is thought to originate from any of several well established potential embolic sources, including minor-risk or covert cardiac sources, veins via paradoxical embolism, and non-occlusive atherosclerotic plaques in the aortic arch, cervical, or cerebral arteries. Accordingly, we propose that embolic strokes of undetermined source are a therapeutically relevant entity, which are defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources, with a clear indication for anticoagulation. Because emboli consist mainly of thrombus, anticoagulants are likely to reduce recurrent brain ischaemia more effectively than are antiplatelet drugs. Randomised trials testing direct-acting oral anticoagulants for secondary prevention of embolic strokes of undetermined source are warranted.

Interactions between cardiovascular and cerebrovascular disease

OPININION STATEMENT: All patients with ischemic stroke should undergo a comprehensive assessment of cardiovascular risk. Patients with carotid artery disease, symptoms of cerebral ischemia and high cardiovascular risk profiles should be considered for noninvasive testing for coronary artery disease (CAD). Routine testing for CAD before carotid endarterctomy is not recommended. Patients with coexisting coronary and carotid artery disease should be more aggressively treated for reducing their "very high" risk of cardiovascular events. In patients candidates to carotid revascularization, a preoperative coronary angiography and coronary revascularization are not recommended. Warfarin is recommended in all patients with moderate to high risk of stroke. Novel oral anticoagulants represent an attractive alternative to warfarin. However, their place in therapy in clinical practice is not yet established. Percutaneous closure of the left atrial appendage for stroke prophylaxis may be considered in selected patients with atrial fibrillation and contraindications for oral anticoagulant therapy. Warfarin is not indicated in patients with heart failure who are in sinus rhythm. Percutaneous closure of patent foramen does not seem to be superior to medical therapy for the prevention of recurrences in patients with cryptogenic stroke.

Paroxysmal atrial fibrillation in cryptogenic stroke

INTRODUCTION

Paroxysmal atrial fibrillation (PAF) is perhaps the most underdiagnosed mechanism of apparent cryptogenic stroke (CS). Various studies have shown that increasing the duration of monitoring can increase the diagnosis of PAF in CS.

METHODS

We compared demographic and risk factors for ischemic stroke across different TOAST (Trial of ORG 10172 in Acute Stroke Treatment) stroke subtypes to look for clinical differences between other subtypes and CS and subsequently performed periodic Holter monitoring and imaging studies in apparent CS patients.

RESULTS

Of the 298 patients with ischemic stroke, 17% had CS. Periodic holter monitoring enabled diagnosis of PAF in 29% of patients. Five of 51 patients with CS had recurrent ischemic stroke and all 5 were demonstrated as PAF on repeated Holter monitoring.

CONCLUSIONS

Long-term periodic rhythm monitoring in patients with apparent CS showed PAF in a significant percentage of CS patients, which altered subsequent treatment.

Transesophageal echocardiography screening in subjects with a first cerebrovascular ischemic event

Our goal was to develop decision guides to predict the presence of a high-risk source of embolus and to predict a change in management following transesophageal echocardiography (TEE) in subjects who present with a first cerebral ischemic event. We conducted a retrospective review of subjects age ≥18 years who underwent TEE after a first ischemic event and were admitted to our stroke service between 2004 and 2007 (n = 287). A high-risk source of embolus and a change in clinical management (including medication changes or subsequent testing) were analyzed as separate endpoints, using multivariate techniques and receiver operating characteristic curves. We found that 14.3% of the subjects had a high-risk source, and an additional 61.3% had a potential (or low-risk) source of embolus. Increasing age and no history of diabetes mellitus were independently associated with a high-risk source of embolus. TEE would be recommended for nondiabetic individuals age ≥66 years (sensitivity, 68%; specificity, 76%). The area under the curve (AUC) for detecting a high-risk source was 0.773. TEE results changed medications or clinical management in 30.3% of the subjects. Current smokers were less likely to undergo a change in management. The AUC was uninformative (0.56) for predicting changes in management. Subjects presenting with a first ischemic event age ≥66 years may benefit from TEE. Although changes in management occurred in at least 30% of our cohort, no factors that predicted a change in management better than chance alone could be identified.

Prevention of Stroke in Patients with Patent Foramen Ovale

Patent foramen ovale is found in 24% of healthy adults and 38% of patients with cryptogenic stroke. This ratio and case reports indicate that patent foramen ovale and stroke are associated, probably because of paradoxical embolism. In healthy people with patent foramen ovale, embolic events are not more frequent than in controls, and therefore no primary prevention is needed. However, once ischaemic events occur, the risk of recurrence is substantial and prevention becomes an issue. Acetylsalicylic acid and warfarin reduce this risk to the same level as in patients without patent foramen ovale. Patent foramen ovale with a coinciding atrial septal aneurysm, spontaneous or large right-to-left shunt, or multiple ischaemic events potentiates the risk of recurrence. Transcatheter device closure has therefore become an intriguing addition to medical treatment, but its therapeutic value still needs to be confirmed by randomised-controlled trials.

Patent foramen ovale in cryptogenic stroke: incidental or pathogenic?

BACKGROUND AND PURPOSE

Patent foramen ovale (PFO) is significantly associated with cryptogenic stroke (CS). However, even in patients with CS, a PFO can be an incidental finding. We sought to estimate the probability that a PFO in a patient with CS is incidental.

METHODS

A systematic search identified 23 case-control studies examining the prevalence of PFO in patients with CS versus control subjects with stroke of known cause. Using simple assumptions and Bayes' theorem, we calculated the probability a PFO is incidental in patients with CS. Random effects meta-analyses estimated the odds ratio (OR) of a PFO in CS versus control subjects in different age populations, with or without atrial septal aneurysms, and were used to summarize across studies the probability that a PFO in CS is incidental.

RESULTS

The summary OR (95% CIs) for PFO in CS versus control subjects was 2.9 (CI, 2.1 to 4.0). The corresponding ORs for young and old patients (< or >or=55 years) were 5.1 (3.3 to 7.8) and 2.0 (>1.0 to 3.7), respectively. The corresponding probabilities that a PFO in patients with CS is incidental were 33% (28% to 39%) in age-inclusive studies, 20% (16% to 25%) in younger patients, and 48% (34% to 66%) in older patients. These probabilities were much lower when an atrial septal aneurysm was present.

CONCLUSIONS

In patients with otherwise CS, approximately one third of discovered PFOs are likely to be incidental and hence not benefit from closure. This probability is sensitive to patient characteristics such as age and the presence of an atrial septal aneurysm, suggesting the importance of patient selection in therapeutic decision-making.

Transoesophageal echocardiographic findings in patients with ischemic lacunar and nonlacunar stroke

The aim of this study was to compare risk factors and concomitant potential cardioembolic sources detected by transthoracic (TTE) and transoesophageal echocardiography (TEE) in patients with lacunar and nonlacunar infarcts. Clinical data of 139 patients with a first episode of ischemic stroke who underwent both TTE and TEE were analysed. Patients were divided into two groups, lacunar (LACI=36), and nonlacunar infarcts (NLACI=103); then the latter group was divided into two subgroups, anterior (ACI=76) and posterior circulation infarct (POCI=27). Presence of hypertension and diabetes mellitus were not significantly different between LACI and NLACI groups. The rate of potential cardioembolic risk factors detected by echocardiography was similar in the NLACI groups. At least one potential cardiac source of embolism was identified in 44% (n=16) of LACI, 52.6% (n=40) of ACI and 55.5% (n=15) of POCI patients. Atrial fibrillation was significantly frequent in the ACI group. No significant differences were found between all groups regarding age, sex, hyperlipidemia, and smoking. Our findings demonstrate that hypertension and diabetes mellitus are equally important in the pathogenesis of both LACI and NLACI groups and there is a need for careful cardiac evaluation in cases even with lacunar infarct.

Significance of aortic atheroma in elderly patients with ischemic stroke

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.

Patent foramen ovale: a new disease?

Patent foramen ovale is a frequent remnant of the fetal circulation. Affecting approximately 25% of the adult population. Its recognition, evaluation and treatment has attracted increasing interest as the importance and frequency of its implication in several pathologic processes, including ischemic stroke secondary to paradoxic embolism, the platypnea-orthodeoxia syndrome, decompression sickness (DCS) (an occupational hazard for underwater divers and high altitude aviators and astronauts) and migraine headache, has become better understood. Echocardiographic techniques have emerged as the principle means for diagnosis and assessment of PFO, in particular contrast echocardiography and transcranial Doppler. Its treatment remains controversial with a general tendency to propose a percutaneous closure among the symptomatic patients.

Patent foramen ovale and the risk of ischemic stroke in a multiethnic population

OBJECTIVES

We sought to assess the risk of ischemic stroke from a patent foramen ovale (PFO) in the multiethnic prospective cohort of northern Manhattan.

BACKGROUND

Patent foramen ovale has been associated with increased risk of ischemic stroke, mainly in case-control studies. The actual PFO-related stroke risk in the general population is unclear.

METHODS

The presence of PFO was assessed at baseline by using transthoracic 2-dimensional echocardiography with contrast injection in 1,100 stroke-free subjects older than 39 years of age (mean age 68.7 +/- 10.0 years) from the Northern Manhattan Study (NOMAS). The presence of atrial septal aneurysm (ASA) also was recorded. Subjects were followed annually for outcomes. We assessed PFO/ASA-related stroke risk after adjusting for established stroke risk factors.

RESULTS

We detected PFO in 164 subjects (14.9%); ASA was present in 27 subjects (2.5%) and associated with PFO in 19 subjects. During a mean follow-up of 79.7 +/- 28.0 months, an ischemic stroke occurred in 68 subjects (6.2%). After adjustment for demographics and risk factors, PFO was not found to be significantly associated with stroke (hazard ratio 1.64, 95% confidence interval [CI] 0.87 to 3.09). The same trend was observed in all age, gender, and race-ethnic subgroups. The coexistence of PFO and ASA did not increase the stroke risk (adjusted hazard ratio 1.25, 95% CI 0.17 to 9.24). Isolated ASA was associated with elevated stroke incidence (2 of 8, or 25%; adjusted hazard ratio 3.66, 95% CI 0.88 to 15.30).

CONCLUSIONS

Patent foramen ovale, alone or together with ASA, was not associated with an increased stroke risk in this multiethnic cohort. The independent role of ASA needs further assessment in appositely designed and powered studies.

Prevalence and clinical importance of spontaneous echo contrast within the carotid artery in patients with ischemic cerebrovascular disease

OBJECTIVE

Spontaneous echo contrast (SEC) is composed of numerous microechoes swirling in the cardiovascular lumen, usually appearing during blood stasis. This study aimed to clarify the clinical importance of SEC in the carotid artery (CA) in patients with ischemic cerebrovascular disease (ICVD).

METHODS

In 264 CAs of 132 consecutive patients with ICVD and in 40 CAs of 20 healthy control subjects, SEC was classified as none, faint, or dense, and CA abnormalities, including plaque, plaque ulcer, mural thrombus, and internal CA stenosis, were assessed with 10-MHz sonography.

RESULTS

The overall prevalence of SEC was greater in CAs of patients with ICVD (164/264 [62%]) than in CAs of control subjects (6/40 [15%]; P < .0001). Dense SEC was more specifically detected in CAs of ICVD with the prevalence of 81 (31%) of 264, which was greater than that of controls (1/40 [3%]; P = .0002). Dense SEC was more frequently detected in CAs with plaque (38/98 [39%]) than in those without (43/166 [26%]; P = .0285), in CA plaque with ulcerative lesions (7/10 [70%]) than in those without (31/88 [35%]; P = .0325), in CA plaque with a thrombus (11/12 [92%]) than in those without (27/86 [31%]; P < .0001), and in CAs with severe stenosis (11/13 [85%]) than in those with mild stenosis (25/75 [33%]; P = .0005) and in those without stenosis (45/176 [26%]; P < .0001).

CONCLUSIONS

Dense SEC was frequently observed in CAs of patients with ICVD, especially in those with local atheromatous lesions, although the influence of systemic factors could not be excluded. Dense SEC within a CA may be a marker of ICVD.

Lacunar syndrome associated with paradoxical brain embolism

We report a patient who developed lacunar syndrome due to left upper pons infarction after performing leg exercises associated with paradoxical brain embolism. A 32-year-old man developed right arm weakness and moderate dysarthria following leg exercise. Brain MRI showed a paramedian pontine infarction of the left upper pons, and contrast transesophageal echocardiographic examination indicated that the patent foramen ovale was the embolic source. Simultaneous RI venography examination of the lower limbs identified deep venous thrombosis in the right leg as a paradoxical emboligenic source. We concluded that the presence of lacunar syndrome suggests that this mechanism was responsible for the paradoxical brain embolism.

Stroke Patients With Cardiac Atrial Septal Abnormalities: Differential Infarct Patterns on DWI

BACKGROUND

Stroke mechanism in patent foramen ovale (PFO) and/or atrioseptal aneurysm (ASA) remains unclear. We aimed to study the stroke pattern on diffusion weighted imaging (DWI), in cryptogenetic stroke according to septal abnormalities.

METHODS

We prospectively evaluated 314 cryptogenetic strokes. Patients were categorized according to transesophageal echocardiography (TEE) findings: PFO with ASA, PFO alone, and no abnormalities. The study group consisted of 126 patients with acute DWI lesions within the first 7 days after the stroke onset. We considered the presence of scattered lesions or a cortico-subcortical territorial lesion as highly suggestive of an embolic pattern.

RESULTS

PFO was identified in 77 patients (61%) and no alterations in 49 patients (39%). TEE revealed ASA in 42 patients (54.5% of PFO patients). An "embolic" pattern was depicted in 84 (66.7%) and subcortical in 42 (33.3%). An "embolic" pattern was significantly (P= .01) more frequently seen in PFO with ASA patients (n= 37;44%) as compared to PFO without ASA (n= 22; 26.2%) or no abnormalities (n= 25; 29.8%) on TEE. Univariate analysis revealed that age (P= .06), hyperlipidemia (P= .04), degree of shunt on TEE (P= .002), and the presence of an ASA (P= .008) were associated with an embolic pattern. After adjusting for sex, age, and vascular risk factors, only the presence of PFO, with ASA (OR 7.27; 95% CI 1.5-35.22 P= .014) was independently associated with an embolic pattern.

CONCLUSION

In patients with cryptogenetic stroke, the presence of PFO with ASA, but not isolated PFO, is associated with an embolic pattern on DWI. These findings provide insights into the patho-mechanism of stroke in patients with PFO.

Population-based study of the relationship between patent foramen ovale and cerebrovascular ischemic events

OBJECTIVE

To determine whether patent foramen ovale (PFO) is a risk factor for a cryptogenic cerebrovascular ischemic event (CIE).

METHODS

This case-control study of 1072 residents of Olmsted County, Minnesota, who underwent contrast transesophageal echocardiography between 1993 and 1997 included 519 controls without CIE randomly selected from the population, 262 controls without CIE referred for transesophageal echocardiography because of cardiac disease, 158 cases with incident CIE of obvious cause (noncryptogenic), and 133 cases with incident CIE of uncertain cause (cryptogenic).

RESULTS

Large PFOs were detected in 108 randomly selected controls (20.8%), 22 referred controls (8.4%), 17 noncryptogenic CIE cases (10.8%), and 22 cryptogenic CIE cases (16.5%). After adjustment for age, sex, hypertension, smoking, atrial fibrillation, ischemic heart disease, and number of contrast injections, the presence of a large PFO was not significantly associated with group status (P=.07). Using the odds of the presence of large PFO in the randomly selected controls as the reference, the odds ratio (95% confidence interval) of the presence of large PFO was 0.47 (0.26-0.87) for referred controls, 0.69 (0.37-1.29) for noncryptogenic CIE cases, and 1.10 (0.63-1.90) for cryptogenic CIE cases.

CONCLUSIONS

Patent foramen ovale is not a risk factor for cryptogenic ischemic stroke or transient ischemic attack in the general population. The PFO's importance in the genesis of cryptogenic CIE may have been overestimated in previous studies because of selective referral of cases and underascertainment of PFO among comparison groups of patients referred for echocardiography for clinical indications other than cryptogenic CIE.

Is TEE useful in patients with small subcortical strokes?

Although the role of transesophageal echocardiography (TEE) in the investigation of stroke mechanism is well established, the value of this test in patients with lacunar presentation is unclear. Review of 214 patients with acute cerebral ischemia referred for TEE to exclude cardioaortic sources of embolism after non-diagnostic basic work-up including carotid ultrasound and transthoracic echocardiography. TEE was considered positive when it showed large or complex aortic arch plaques, left atrial thrombus, mitral or aortic valve vegetations, or patent foramen ovale with atrial septal aneurysm. Multivariate regression analysis was performed to assess the value of lacunar syndrome and radiological small subcortical infarctions in predicting TEE result. Predictive values and likelihood ratios for these variables were calculated. Fifty-two patients (24%) had positive TEE. The most common embolic source was large or complex aortic plaques in 19% of patients. Neither clinical presentation with lacunar syndrome nor the presence of small subcortical infarction on CT scan predicted a negative TEE result on univariate or multivariate analysis. However, the combination of lacunar syndrome with radiological small subcortical infarction was uniformly associated with negative TEE (P=0.01; negative predictive value 100%). The combination of lacunar syndrome with small subcortical radiological infarct predicts the absence of cardioaortic sources of embolism on TEE in patients with acute cerebral ischemia.

Transesophageal Echocardiography Impacts Management and Evaluation of Patients with Stroke, Transient Ischemic Attack, or Peripheral Embolism

The relative impact of transesophageal echocardiography (TEE) on the management of patients with specific embolic events, namely nonhemorrhagic cerebrovascular accident (CVA), transient ischemic attack (TIA), or peripheral embolism is controversial. The impact of TEE in 234 adult subjects with CVA (n = 141), TIA (n = 59), or peripheral embolism (n = 34) was determined. TEE was diagnostic of a potential embolic source in 61%, 51%, and 62% of patients with CVA, TIA, and peripheral embolism, respectively (P = NS). TEE results changed medication or surgical treatment in 32%, 22%, and 32% of patients with CVA, TIA, and peripheral embolism, respectively (P = NS). Anticoagulation was started on the basis of TEE findings in 11%, 12%, and 18% of patients with CVA, TIA, and peripheral embolism, respectively (P = NS). In 77% of all patients, TEE findings confirmed as appropriate the empiric decision made prior to TEE, to anticoagulate (60%; 12/20) or not to anticoagulate (79%; 168/214). These data demonstrate that TEE findings have a significant and similar impact on the clinical management of patients with various types of potential embolism. Future studies addressing the effectiveness of treatment, guided by TEE findings, in the prevention of recurrent embolic events are needed.

Patent foramen ovale: innocent or guilty? Evidence from a prospective population-based study

OBJECTIVES

We sought to determine the association between patent foramen ovale (PFO), atrial septal aneurysm (ASA), and stroke prospectively in a unselected population sample.

BACKGROUND

The disputed relationship between PFO and stroke reflects methodologic weaknesses in studies using invalid controls, unblinded transesophageal echocardiography examinations, and data that are unadjusted for age or comorbidity.

METHODS

The use of transesophageal echocardiography to identify PFO was performed by a single echocardiographer using standardized definitions in 585 randomly sampled, Olmsted County (Minnesota) subjects age 45 years or older participating in the Stroke Prevention: Assessment of Risk in a Community (SPARC) study.

RESULTS

A PFO was identified in 140 (24.3%) subjects and ASA in 11 (1.9%) subjects. Of the 140 subjects with PFO, 6 (4.3%) had an ASA; of the 437 subjects without PFO, 5 had an ASA (1.1%, two-sided Fisher exact test, p = 0.028). During a median follow-up of 5.1 years, cerebrovascular events (cerebrovascular disease-related death, ischemic stroke, transient ischemic attack) occurred in 41 subjects. After adjustment for age and comorbidity, PFO was not a significant independent predictor of stroke (hazard ratio 1.46, 95% confidence interval 0.74 to 2.88, p = 0.28). The risk of a cerebrovascular event among subjects with ASA was nearly four times higher than that in those without ASA (hazard ratio 3.72, 95% confidence interval 0.88 to 15.71, p = 0.074).

CONCLUSIONS

These prospective population-based data suggest that, after correction for age and comorbidity, PFO is not an independent risk factor for future cerebrovascular events in the general population. A larger study is required to test the putative stroke risk associated with ASA.

The management of patients with patent foramen ovale and stroke

The management of patients with patent foramen ovale (PFO) and stroke remains uncertain. What is known is that PFO is a very common finding in the general population. The risk of initial and recurrent stroke in individuals with PFO is relatively low. With the advent of transesophageal echocardiography, PFO is more commonly being diagnosed. There are insufficient data to support a benefit of warfarin over aspirin in preventing recurrent stroke in most patients with PFO. In those with PFO and a history of a procoagulant state or deep venous thrombosis, anticoagulation may be indicated after weighing the risks of anticoagulation against potential benefits in preventing recurrent stroke. PFO closure does not guarantee the prevention of future stroke and should be addressed case by case, with consideration of patients for entry into ongoing clinical trials of safety, efficacy, and durability.

Treatable Potential Cardiac Sources of Embolism in Patients with Cerebral Ischemic Events: A Selective Transesophageal Echocardiographic Study

OBJECTIVES

To characterize cardiac sources of emboli detected by transesophageal echocardiography (TEE) in patients without recognizable cause of transient ischemic attack (TIA) and/or ischemic stroke and TIA.

METHODS

We examined a prospective registry that included all patients with TIA and/or stroke evaluated by TEE between July 2000 and August 2001 at our medical center. Ischemic events were classified according to clinical and neuroimaging findings as cortical, lacunar, or vertebrobasilar circulation. Demographic, clinical, neuroimaging, and echocardiographic characteristics were studied.

RESULTS

TEE was performed in 237 patients without recognized cause of TIA and/or stroke, of which 105 (44%) events were cortical, 35 (15%) were lacunar, 32 (14%) were vertebrobasilar, and 65 (27%) were in multiple distributions. Mean age of patients was 59 +/- 14 years (range, 21 to 93 years); 119 (51%) were men. Potential treatable cardioembolic sources were detected in 146 (61%) patients: patent foramen ovale with right-to-left shunt (n = 59), left atrial clot (n = 6), left atrial appendage clot (n = 8), and severe thoracic aortic atherosclerotic plaque disease (plaque thickness >4 mm) (n = 79 patients [33%], 56 had an ulcerated plaque and 4 had mobile plaque). Patient age and topography of the ischemic event did not correlate with TEE-defined cardioembolic sources.

CONCLUSIONS

TEE identified high frequencies of potential treatable cardioembolic sources in patients with ischemic events. TEE should be considered in all patients who do not have identified cause of TIA and/or stroke for early treatment and prevention of recurrent events.

Risk factors for intracardiac thrombus in patients with recent ischaemic cerebrovascular events

BACKGROUND

Intracardiac thrombus is a common cause of cardiogenic cerebral ischaemia. Stroke recurrence is high, but thrombus detection with therapeutic intervention can reduce the risk. Accurate detection requires transoesophageal echocardiography (TOE), which is semi-invasive and costly.

OBJECTIVE

To identify risk factors for cardiac thrombus, enabling selection of patients for TOE and initiation of measures to prevent the formation of cardiac thrombus.

METHODS

151 consecutive patients with ischaemic stroke or transient ischaemic attacks (mean age 62 years) underwent TOE for intracardiac thrombus detection within one week of a qualifying event.

RESULTS

Intracardiac thrombus was found in 26% of the patients (70% in the left atrial appendage). Multivariate analysis indicated the following clinical correlates: large stroke, odds ratio (OR) = 2.8 (95% confidence interval, 1.2 to 6.4); symptomatic coronary artery disease, OR = 3.0 (1.2 to 7.4); and ECG evidence of ischaemia, OR = 2.8 (1.1 to 7.7). Neither carotid stenosis >70%, nor stroke location correlated with the presence of thrombus.

CONCLUSIONS

Clinical factors correlate with and appear to be risk factors for cardiac thrombus in patients with recent cerebral ischaemia. These may be used to select appropriate patients for invasive and costly TOE investigation, irrespective of the presence of significant carotid stenosis (>/=70%) or stroke location.

Cardioembolic stroke: an update

Cardioembolic stroke accounts for approximately 15% of all strokes and is thought to be one of the more preventable types of strokes. Features that have been reported to support cardioembolism as a mechanism for ischemic stroke have included documented cardiac source of embolism, maximal neurologic deficit at onset, multiple cerebrovascular territories involved, enhanced tendency toward hemorrhagic transformation, enhanced risk of syncope or seizure associated with presentation, and lower likelihood of premonitory transient ischemic attacks. Features that tend to make cardioembolic stroke less likely include significant cerebral atherosclerosis, step-wise progression of the neurologic deficit within a finite period of time, vascular distribution such as entire internal carotid artery territory with combined middle cerebral artery and anterior cerebral artery involvement or watershed distribution, and premonitory transient ischemic attacks. A number of cardiac conditions can promote thromboembolism, and there is risk stratification reflective of the specific condition or coexistent conditions. Anticoagulant therapy generally has been found to be the most effective means of preventing cardiogenic brain embolism, but the intensity of anticoagulation needs to be optimized to reflect the risk-to-benefit ratio for the particular patient.

Effect of batroxobin on spontaneous echo contrast and hemorheology in left atrial appendage in atrial fibrillation assessed by transesophageal echocardiograpy

Controversy exists regarding the effect of defibrination on spontaneous echo contrast and flow dynamics in left atrial appendage (LAA) in atrial fibrillation. We aimed to investigate the effect of batroxobin, which decreases plasma fibrinogen level, on the echo intensity of spontaneous echo contrast in LAA. In 36 patients with atrial fibrillation (duration 7 +/- 4 years), transesophageal echocardiography was performed at baseline and 24 hours after batroxobin administration (0.2 U/kg). At the orifice of the LAA, integrated backscatter of echo contrast and peak velocity of LAA emptying flow were measured. Plasma fibrinogen and whole blood viscosity were also measured. Fibrinogen and viscosity were significantly lower after batroxobin administration (96 +/-38 mg/dl and 4.35 +/- 0.56 cp) than those at baseline (320 +/- 61 mg/dl and 4.71 +/- 0.61 cp, both p <0.001). A significant positive correlation between changes in plasma fibrinogen and whole blood viscosity (r = 0.49, p = 0.002) was shown. The integrated backscatter significantly decreased from 14 +/- 3 to 12 +/- 3 decibels after batroxobin (p <0.001), and the changes in integrated backscatter and plasma fibrinogen was significantly correlated. Therefore, batroxobin administration improved blood rheology and decreased blood cell aggregation, which are effective in preventing left atrial thrombus formation.

Incidence and clinical significance of interatrial shunting in patients with atrial septal aneurysm detected by contrast transesophageal echocardiography

The prevalence of atrial septal aneurysm (ASA) in a general referral population of patients was investigated by use of transthoracic (TTE) and transesophageal echocardiographies (TEE). Contrast TEE was performed to detect interatrial shunting in patients with ASA. In this population, the prevalence of ASA as determined by TTE was 0.47% (24/5,079), and 0.78% (40/5,079) by TEE. Of these 40 patients 16 (40%) were judged to be normal by TTE. Of the forty patients who were positive for ASA, 50% demonstrated interatrial shunting (atrial septal defects, 10; patent foramen ovale, 10). The authors concluded that TEE is of significant value in detecting the presence of ASA and associated cardiac abnormalities. Contrast TEE further enhances the detection of interatrial shunting in patients with ASA.

Transesophageal echocardiography and unexplained cerebral ischemia: a multicenter follow-up study. The STEPS Investigators. Significance of Transesophageal Echocardiography in the Prevention of Recurrent Stroke

BACKGROUND

Transesophageal echocardiography (TEE) continues to play a prominent role in the evaluation of patients with unexplained cerebral ischemia. The STEPS Study Group (Significance of Transesophageal Echocardiography in the Prevention of Recurrent Stroke) was established to further examine the clinical significance of TEE findings in patients with suspected cardiac source of embolus and to assess the impact of these findings with respect to specific therapy and the prevention of recurrent events.

METHODS

A total of 242 patients from 15 institutions within the United States underwent TEE study for evaluation of unexplained cerebral ischemia. Over a 1-year period, detailed follow-up was obtained with respect to recurrent stroke, transient ischemia attacks, or documented embolic events as well as detailed information concerning nonrandomized antithrombotic therapy.

RESULTS

Recurrent stroke occurred in 17 of 132 (13%) of the patients in the aspirin group versus 5 of 110 (5%) of the patients receiving warfarin therapy (P <.02). This decrease in cerebral ischemic events in the warfarin group was noted, despite the higher prevalence of atrial fibrillation and impaired ventricular function in the warfarin group. The selection of antithrombotic therapy appears, at least in part, to have been influenced by the TEE findings. Among patients receiving aspirin, a higher recurrent stroke rate was noted in those with left ventricular enlargement and atherosclerotic aortic plaque.

CONCLUSION

Abnormalities are commonly found by TEE in patients with unexplained cerebral ischemia. Patients with left ventricular enlargement and demonstrable aortic plaque on TEE study are at increased risk for recurrent stroke when receiving aspirin therapy alone. Empiric therapy with systemic anticoagulation may be indicated in patients with stroke unexplained by carotid atherosclerotic disease.