Atrial septal aneurysm and stroke: a transesophageal echocardiographic study

Analysis of fossa ovalis membrane velocities by transesophageal Doppler tissue echocardiography: A novel approach to functional assessment of patent foramen ovale

BACKGROUND

Recent studies have suggested that a higher mobility of the fossa ovalis membrane (FOM) may be associated with an increased risk for stroke in patients with patent foramen ovale (PFO). The current study analyzed whether Doppler tissue echocardiography is useful for quantitation of FOM motion velocities.

METHODS

FOM dynamics were prospectively studied in 107 consecutive patients (average age 50.7 +/- 15.3 years, 48 men) with in sinus rhythm who underwent transesophageal echocardiography for various indications. With pulsed wave Doppler tissue echocardiography interrogation, a characteristic quadrophasic signal was recorded in all patients, consisting of a positive wave toward the left atrium (A-wave) at late diastole, followed by a negative wave (B-wave) toward the right atrium, a pronounced, again positive wave during midsystole (C-wave), and a final negative wave (D-wave).

RESULTS

Peak velocities of A-wave, B-wave, C-wave, and D-wave were 0.08 +/- 0.02 m/s, 0.11 +/- 0.05 m/s, 0.17 +/- 0.07 m/s, and 0.14 +/- 0.06 m/s, respectively. In 21 of 107 (19.6%) patients, PFO was detected. Patients with PFO had significantly higher C-wave and D-wave peak velocities compared with the 86 patients without PFO (0.23 +/- 0.10 m/s vs 0.15 +/- 0.05 m/s, P < .001 and 0.16 +/- 0.07 m/s vs 0.12 +/- 0.06 m/s, P = .04, respectively).

CONCLUSIONS

Assessment of FOM dynamics using Doppler tissue echocardiography is feasible. It allows definition of a characteristic quadrophasic FOM motion pattern, thereby providing new insights into the physiology of FOM mobility. Patients with PFO were found to have increased FOM mobility compared with patients without PFO.

Atrial anatomy in non-cardioembolic stroke patients: effect of medical therapy

OBJECTIVES

The purpose of the study was to assess the mechanism responsible for increased stroke risk in patients with atrial septal aneurysm (SA) and patent foramen ovale (PFO), and to determine the efficacy of medical therapy for preventing stroke recurrence or death.

BACKGROUND

Atrial septal aneurysm and PFO are associated with stroke. However, the mechanism for this association is undefined, and the efficacy of medical therapy has not been investigated in a randomized fashion.

METHODS

The Patent foramen ovale In Cryptogenic Stroke Study (PICSS) evaluated transesophageal echocardiography findings in patients enrolled in the Warfarin-Aspirin Recurrent Stroke Study, a randomized double-blind trial to evaluate the efficacy of warfarin compared with aspirin.

RESULTS

Large PFO and prominent eustachian valve (EV) or right atrial (RA) filamentous strands were found more frequently in patients with SA compared with those without SA (37.7% vs. 10.9%, p < 0.001 and 59.4% vs. 43.1%, p = 0.02). Patients with SA and PFO had no significant difference in time to recurrent stroke or death compared with those having neither (hazard ratio [HR] 1.08, 95% confidence interval [CI] 0.49 to 2.38, p = 0.84; two-year event rates 15.9% vs. 14.5%). Patients with SA, PFO, and RA anatomy predisposing to paradoxical embolization also had no difference compared with those without these findings (HR 1.22, 95% CI 0.43 to 3.47, p = 0.71; two-year event rates 18.2% vs. 14.2%). There was no significant difference in time to recurrent stroke or death between the patients treated with warfarin or aspirin (HR 1.00, 95% CI 0.22 to 4.47, p = 1.0; two-year event rates 16.0% vs. 15.8%).

CONCLUSIONS

Atrial septal aneurysm is associated with the presence of large PFO and prominent EV or RA filamentous strands. On medical therapy, patients with SA and PFO did not experience increased risk of adverse events, and there was no difference between treatment results for warfarin and for aspirin.

Race-ethnic differences in patent foramen ovale, atrial septal aneurysm, and right atrial anatomy among ischemic stroke patients

BACKGROUND AND PURPOSE

Stroke remains a substantial cause of mortality and morbidity in the United States. Racial differences in stroke incidence and mortality persist with well-known excesses among blacks. Information on stroke among Hispanics is limited. In particular, little is known about whether patent foramen ovale (PFO), atrial septal aneurysm (ASA), and other atrial anomalies associated with cryptogenic stroke differ among minority populations.

METHODS

As a part of the PFO in Cryptogenic Stroke Study, transesophageal echocardiography was performed in a cohort of 630 ischemic stroke patients (mean age, 59+/-12 years; 44% women; 45% whites, 35% blacks, 17% Hispanics, 3% other). The prevalences of PFO, ASA, and right atrial (RA) anatomy favoring paradoxical embolization were compared among race-ethnic groups. Statistical analyses used analysis of variance for continuous variables and logistic regression for dichotomous variables with adjustments for age and sex.

RESULTS

Age- and sex-adjusted prevalences of PFO and ASA were similar across race-ethnic subgroups. However, large PFO was significantly less prevalent among blacks than among whites (odds ratio, 0.47; 95% confidence interval, 0.24 to 0.91; P=0.02). RA anatomy favoring paradoxical embolization was also significantly less prevalent among blacks compared with whites (odds ratio, 0.62; 95% confidence interval, 0.43 to 0.91; P=0.01). There were no significant differences in prevalence between whites and Hispanics.

CONCLUSIONS

Although the frequency of PFO did not vary among race-ethnic groups, a large PFO and RA anatomy favoring paradoxical embolization were significantly more prevalent among whites and Hispanics compared with blacks. These may be relatively more important risk factors for stroke among whites and Hispanics than among blacks.

Overview of transesophageal echocardiography for the chest physician

Transesophageal echocardiography (TEE) is a growing technology that is frequently utilized in the critical care setting by intensivists, surgeons, anesthesiologists as well as specialists in cardiovascular diseases. The clinical application of TEE continues to emerge, and the indications and diagnostic utility of this technology as currently available are summarized in this review.

Prevalence of atrial septal aneurysm in patients with migraine: an echocardiographic study

OBJECTIVE

To evaluate the prevalence of atrial septal aneurysm in patients with migraine.

BACKGROUND

Migraine has long been considered a risk factor for stroke. Atrial septal aneurysm is often observed in young patients with ischemic stroke and is frequently associated with other conditions potentially leading to embolism.

METHODS

We performed a transthoracic echocardiogram in 90 consecutive patients (65 women and 25 men; mean age, 35.3 years [standard deviation, 9]) with migraine but free from cerebral and cardiovascular disease and in 53 control subjects (37 women and 16 men; mean age, 34 years [standard deviation, 10]). The diagnosis of atrial septal aneurysm was performed according to Olivares-Reyes criteria. A transesophageal echocardiogram also was performed in 75 patients with migraine (83.3%).

RESULTS

The prevalence of isolated atrial septal aneurysm was higher in patients with migraine with aura (28.5%) than in patients with migraine without aura (3.6%) (P <.005) or in control subjects (1.9%) (P <.005).

CONCLUSIONS

Our data suggest a role of atrial septal aneurysm in the genesis of aura in patients with migraine.

[Prevalence of patent foramen ovale in young patients with cerebral ischemic accident of unknown origin]

INTRODUCTION AND OBJECTIVE

Patent foramen ovale has been associated with stroke in young patients with cryptogenic stroke. The purpose of this study is to examine the prevalence of patent foramen ovale in this group of patients, as well as their anatomical and functional characteristics by contrast echocardiography, trying to determine ictus risk markers in young patients with acute ischemic stroke.

PATIENTS AND METHOD

Prospective study of 90 patients under the age of 50 who were hospitalised consecutively due to a clinical presentation suggestive of stroke. No cause was found in 55 out of 90 (group I) and the rest, in which an stroke was finally disregarded, were used as the control group (group II). A transthoracic and transesophageal echocardiography examination with 2 types of contrast agents was performed in all patients to determine the presence of a patent foramen ovale and its anatomical and functional characteristics.

RESULTS

Patent foramen ovale was observed more frequently in group I than in group II (43 versus 21%; p < 0.05). Among patients with a patent foramen ovale those with an ischemic stroke showed greater mobility of the oval membrane, more frequent large shunts of contrast in a single frame in the left heart, and more frequent shunts at rest. Transesophageal echocardiography without contrast showed a high sensitivity (90%) and specificity (93%) for detecting anatomically permeable foramen ovale whereas contrast transthoracic echocardiography showed a low sensitivity (13%). There were no differences between the two contrasts used.

CONCLUSIONS

Near half of young patients with ischemic stroke of an unknown origin have a patent foramen ovale. A bigger mobility of the membrane of the oval cavity and a large degree of shunt contrast as well as shunt at rest detected by contrast transesophageal echocardiography, seem to identify patent foramen ovale patients with ischemic stroke. In these patients, transthoracic echocardiography has low sensibility for detecting permeability of the foramen ovale.

Aneurysm of fossa ovalis in adults: a pathologic study

BACKGROUND

Aneurysm of the fossa ovalis is an out pouching, space-occupying, interatrial septal structure. The anatomic morphology and characteristics of this aneurysm are of interest for pathologists and cardiologists alike.

METHODS

We identified 33 specimens of adult hearts with a large size aneurysm of the fossa ovalis (length equal to or more than 10 mm from the plane of the atrial septum) in a registry of cardiovascular disease. Anatomic-morphologic features of these aneurysms were examined by macroscopic and histopathologic studies.

RESULTS

Nineteen aneurysms were from females (57%) and 14 were from males (43%). Most aneurysms had a dome shape with maximal length of the aneurysmal excursion into an atrium varying from 10 to 35 mm (mean 16+/-5 mm) and width varying from 16 to 40 mm (mean 24+/-6 mm). Twenty-four aneurysms (73%) protruded into the right atrium while only nine (27%) penetrated into the left atrium. In 24 patients the interatrial ostium II was patent, and in 22 (91%) of them, abnormal increased intracardiac pressure was deemed responsible for the formation of the aneurysm. Among nine patients in whom the foramen ovale was closed, eight (89%) had an aneurysm protruding into the right atrium, and only one aneurysm penetrated into the left atrium. In six patients, the aneurysm further stretched an already patent foramen ovale resulting in creation of an atrial septal defect so that bidirectional shunting could occur, and in three cases, the aneurysm narrowed the inferior vena caval orifice. In three hearts, the aneurysm wall had endocardial fibrosis, and in three other specimens, a focal mural thrombus was present on the aneurysmal surface. Most common associated cardiac conditions in this series included atherosclerotic coronary artery disease (51%), aortic valvular disease (21%) and mitral valve disease (24%).

CONCLUSIONS

Aneurysm of the fossa ovalis is a space-occupying, redundant structure, most commonly with a dome shape. In a majority of cases, the formation of this aneurysm relates to the effect of extrinsic mechanisms, which create abnormally elevated intracardiac pressures. The aneurysm protruded into the right atrium in 73% of cases. Endocardial fibrosis and a focal mural thrombus were present in several cases on the aneurysmal wall. Bidirectional shunt via stretched patent foramen ovale and distal embolization can contribute to complications related to the aneurysm.

Patent foramen ovale: anatomy versus pathophysiology--which determines stroke risk?

This study investigated anatomic and pathophysiologic variables that may determine which patent foramen ovale (PFO) are associated with cerebrovascular accidents (CVAs). Anatomic features of a PFO have been identified as risk factors that predispose certain people to cryptogenic strokes (strokes of unknown cause). However, potential pathophysiologic variables that can determine the pressure gradient between left and right atria, which could influence the right-to-left shunt through a PFO, have not been examined. A retrospective study included 78 consecutive patients in whom PFOs were detected during routine transesophageal echocardiography examination. Group I included 36 patients with CVAs of unknown cause (cryptogenic stroke). Group II included 42 patients without CVAs whose PFOs were incidental findings. Anatomic features measured included separation and overlap between septum primum and septum secundum, interatrial septal motion, and the relative size of the right-to-left shunt with peripheral saline solution contrast injections. Pathophysiologic variables considered were those that could cause elevated left atrial pressure, thereby minimizing the right-to-left shunt.Patients with a clinical neurologic event (group I) had a larger right-to-left shunt volume of contrast bubbles than did patients with asymptomatic PFO (group II; P =.004). The size of the overlap between septum primum and septum secundum was less in patients from group I as compared with patients from group II (7.5 +/- 3.4 mm versus 9.9 +/- 6.0 mm; P =.026). However, other anatomic features of PFO that are determinants of the "opening" were not significantly different between the 2 groups. No statistically significant difference was found in the distance of the separation between septum primum and septum secundum (2.5 +/- 2.0 mm versus 1.9 +/- 1.6 mm; P = not significant). The prevalence of interatrial septal aneurysm was also similar between the 2 groups (28% versus 21%; P = not significant). However, the prevalence of variables that could potentially raise left atrial pressure was greater in patients without CVA as compared with those with a CVA (48% versus 14%; P =.01). In our study, anatomic features alone did not determine interatrial shunt size and pathophysiologic variables that could raise left atrial pressures did differentiate between patients with a PFO with a CVA/transient ischemic attack and those without it. Thus, both anatomic and pathophysiologic mechanisms should be considered in determination of the potential clinical significance of a PFO.

Cardiovascular involvement in Behçet's disease

The incidence and nature of cardiac involvement in Behçet's disease are not yet clearly documented. We first used transesophageal echocardiography in combination with resting and signal averaged electrocardiography to define cardiac involvement in Behçet's patients. Transthoracic and multiplane transesophageal echocardiography, and resting and signal averaged electrocardiography were performed in 35 Behçet's disease patients (9 women and 26 men, mean age: 38 +/- 12 years) and 30 normal subjects. Higher incidences of interatrial septum aneurysm (31% to 6%), mitral valve prolapse (25% to 3%), mitral regurgitation (40% to 6%) and aneurysmal dilatations of sinus valsalva and ascendan aorta were observed in the Behçet's disease patients than in the normal subjects. Mean QT dispersion and mean corrected QT dispersion values were significantly greater in the patients with Behçet's disease. Patients with interatrial septum aneurysm (and/or PFO), valvular dysfunction or proximal aorta dilatation had greater QT dispersion values than thase without these pathologies in the Behçet's group (63 +/- 11 vs 44 +/- 19 ms, 58 +/- 23 vs 41 +/- 24 and 60 +/- 27 vs 42 +/- 23 ms respectively, P<0.05). Positive signal averaged electrocardiography parameters were detected in 18 (51%) Behçet's disease patients compared with one (3%) in controls (P<0.001). Dilatation of the proximal aorta, interatrial septal aneurysm, mitral valve prolapse, and mitral regurgitation are the common findings of cardiac involvement in Behçet's disease. Increased dispersion of ventricular repolarisation and positive late potentials are also detected. QT dispersion is significantly higher in patients with these cardiac abnormalities. These findings suggest that cardiac involvement in this disorder is a diffuse process which involves both cardiac structure and vascular elements.

Interobserver and intraobserver variability in detection of patent foramen ovale and atrial septal aneurysm with transesophageal echocardiography

BACKGROUND

An accurate diagnosis of patent foramen ovale (PFO) and atrial septal aneurysm (ASA) may be of decisional importance in the management of patients with ischemic stroke. Very few studies have been devoted to observer agreement in the diagnosis of these atrial septum abnormalities using contrast transesophageal echocardiography, which is considered as the method of choice for the diagnosis. The aim of this study was to assess interobserver and intraobserver variability in the diagnosis of PFO and ASA with contrast echocardiography.

METHODS

Three sonographers independently reviewed 100 contrast studies stored on videotape on 2 occasions each. The interobserver and intraobserver variability was assessed by calculating kappa statistics.

RESULTS

The overall interobserver and intraobserver kappa values for the assessment of degree of shunting through a PFO were 0.77 (first and second reading) and 0.82, respectively. The best kappa statistics were obtained when no and small shunts (less than 10 microbubbles) were pooled and compared with larger shunts. For the diagnosis of ASA, the overall interobserver kappa value was 0.45 for the first reading and 0.71 for the second reading, whereas the overall intraobserver kappa value was 0.74.

CONCLUSION

Interobserver and intraobserver agreements for the diagnosis of PFO and ASA by transesophageal echocardiography are not perfect and need to be improved, particularly for ASA. This variability has to be taken into account when deciding on a potential risky treatment to prevent recurrent strokes.

Large atrial septal aneurysm and delayed improvement of renal failure due to nephrotoxic drugs (and hemodialysis) in a diabetic patient

Atrial septal aneurysm (ASA) is a well known morphologic abnormality and has been largely investigated with both transthoracic (TTE) and/or transesophageal echocardiography (TEE). Its association with other congenital and acquired heart diseases and midsystolic clicks has been reported. ASA also may be associated with an increased risk of embolic events. In many cases, it is an incidental finding. We describe a patient with acute renal failure associated with nephrotoxic drugs and ASA suggesting endocarditis.

Outcome of patients with cryptogenic stroke and patent foramen ovale

OBJECTIVES

The aim was to estimate the recurrence rate and to define subgroups at increased risk for recurrent cerebral ischaemia in patients with patent foramen ovale (PFO) and so called cryptogenic stroke due to paradoxical embolism.

METHODS

Patent foramen ovale was diagnosed in 318 patients with otherwise unexplained ischaemic stroke or transient ischaemic attack (TIA). One hundred and fifty nine were treated medically (oral anticoagulation 79, platelet inhibitors 80) and represent the study population. The remaining 159 patients underwent endovascular or surgical closure of the PFO and are not part of this study.

RESULTS

Mean age was 50.7 (SD 13.5) years. The event leading to the diagnosis of PFO was a TIA in 38 patients (23.9%), an ischaemic stroke in 119 (74.8%), and an amaurosis fugax in two patients (1.3%). Forty four patients (27.7%) had experienced multiple cerebrovascular ischaemic events before the diagnosis of the PFO. During mean follow up of 29 (SD 23) months 21 patients (13.4%) had a recurrent cerebrovascular event (seven strokes and 14 TIAs). The average annual rate of recurrent strokes was 1.8% and that of recurrent strokes or TIAs was 5.5%. When patients with PFO with multiple cerebrovascular events before the diagnosis of the PFO were analyzed separately, the average annual rates of recurrent cerebral ischaemia were 3.6% for recurrent strokes and 9.9% for recurrent strokes or TIAs. These rates were significantly higher than in patients with first ever stroke or TIA (p=0.02).

CONCLUSIONS

The study confirms a risk of stroke recurrence that is similar to the rates of previously published series of patients with PFO and cryptogenic strokes. Patients with more than one previous event were at increased risk of recurrent cerebral ischaemia.

Clinical and imaging findings in cryptogenic stroke patients with and without patent foramen ovale: the PFO-ASA Study. Atrial Septal Aneurysm

BACKGROUND AND PURPOSE

Patent foramen ovale (PFO) has been identified as a potential risk factor for stroke, but the mechanisms of PFO-associated stroke remain unsettled. The aim of our study was to evaluate possible differences in stroke risk factors and stroke patterns between patients with and without PFO that may give clues to the mechanism of PFO-associated stroke.

METHODS

This prospective, multicentric study involved 581 young cryptogenic stroke patients. The presence of PFO and atrial septal aneurysm was assessed by transesophageal echocardiography and reviewed independently by 2 experienced sonographers. Clinical, brain, and vascular imaging findings were reviewed by 2 neurologists and 2 neuroradiologists.

RESULTS

Of the 581 stroke patients, 267 (45.9%) had PFO. Patients with PFO were younger (OR, 0.95; 95% CI, 0.93 to 0.97) and less likely to have traditional risk factors such as hypertension (OR, 0.49; 95% CI, 0.28 to 0.85), hypercholesterolemia (OR, 0.56; 95% CI, 0.34 to 0.93), or current smoking (OR, 0.67; 95% CI, 0.47 to 0.97). Features suggestive of paradoxical embolism, such as Valsalva-provoking activities or deep vein thrombosis, were not more frequent in patients with PFO. Migraine was more common in patients with PFO (27.3%) than in those without PFO (14.0%). PFO (OR, 1.75; 95% CI, 1.08 to 2.82), particularly when associated with atrial septal aneurysm (OR, 2.71; 95% CI, 1.36 to 5.41), was significantly associated with migraine after adjustment for age and sex.

CONCLUSIONS

Differences in stroke risk factors and stroke patterns suggest that different stroke mechanisms occur in patients with and without PFO. PFO is significantly and independently associated with migraine, and this association is even stronger in patients with PFO and atrial septal aneurysm.

Recurrent cerebrovascular events associated with patent foramen ovale, atrial septal aneurysm, or both

BACKGROUND

Patent foramen ovale and atrial septal aneurysm have been identified as potential risk factors for stroke, but information about their effect on the risk of recurrent stroke is limited. We studied the risks of recurrent cerebrovascular events associated with these cardiac abnormalities.

METHODS

A total of 581 patients (age, 18 to 55 years) who had had an ischemic stroke of unknown origin within the preceding three months were consecutively enrolled at 30 neurology departments. All patients received aspirin (300 mg per day) for secondary prevention.

RESULTS

After four years, the risk of recurrent stroke was 2.3 percent (95 percent confidence interval, 0.3 to 4.3 percent) among the patients with patent foramen ovale alone, 15.2 percent (95 percent confidence interval, 1.8 to 28.6 percent) among the patients with both patent foramen ovale and atrial septal aneurysm, and 4.2 percent (95 percent confidence interval, 1.8 to 6.6 percent) among the patients with neither of these cardiac abnormalities. There were no recurrences among the patients with an atrial septal aneurysm alone. The presence of both cardiac abnormalities was a significant predictor of an increased risk of recurrent stroke (hazard ratio for the comparison with the absence of these abnormalities, 4.17; 95 percent confidence interval, 1.47 to 11.84), whereas isolated patent foramen ovale, whether small or large, was not.

CONCLUSIONS

Patients with both patent foramen ovale and atrial septal aneurysm who have had a stroke constitute a subgroup at substantial risk for recurrent stroke, and preventive strategies other than aspirin should be considered.

Patent foramen ovale: a review of associated conditions and the impact of physiological size

Patent foramen ovale (PFO) is implicated in platypnea-orthodeoxia, stroke and decompression sickness (DCS) in divers and astronauts. However, PFO size in relation to clinical illness is largely unknown since few studies evaluate PFO, either functionally or anatomically. The autopsy incidence of PFO is approximately 27% and 6% for a large defect (0.6 cm to 1.0 cm). A PFO is often associated with atrial septal aneurysm and Chiari network, although these anatomic variations are uncommon. Methodologies for diagnosis and anatomic and functional sizing of a PFO include transthoracic echocardiography (TTE), transesophageal echocardiography (TEE) and transcranial Doppler (TCD), with saline contrast. Saline injection via the right femoral vein appears to have a higher diagnostic yield for PFO than via the right antecubital vein. Saline contrast with TTE using native tissue harmonics or transmitral pulsed wave Doppler have quantitated PFO functional size, while TEE is presently the reference standard. The platypnea-orthodeoxia syndrome is associated with a large resting PFO shunt. Transthoracic echocardiography, TEE and TCD have been used in an attempt to quantitate PFO in patients with cryptogenic stroke. The larger PFOs (approximately > or =4 mm size) or those with significant resting shunts appear to be clinically significant. Approximately two-thirds of divers with unexplained DCS have a PFO that may be responsible and may be related to PFO size. Limited data are available on the incidence of PFO in high altitude aviators with DCS, but there appears to be a relationship. A large decompression stress is associated with extra vehicular activity (EVA) from spacecraft. After four cases of serious DCS in EVA simulations, a resting PFO was detected by contrast TTE in three cases. Patent foramen ovales vary in both anatomical and functional size, and the clinical impact of a particular PFO in various situations (platypnea-orthodeoxia, thromboembolism, DCS in underwater divers, DCS in high-altitude aviators and astronauts) may be different.

Effect of low-intensity warfarin therapy on left atrial thrombus resolution in patients with nonvalvular atrial fibrillation: a transesophageal echocardiographic study

The presence of left atrial thrombus (LAT) is associated with an increased risk of embolic stroke. However, it has yet to be established definitively whether low-intensity warfarin therapy (INR: 1.5-2.0) can prevent LAT formation in patients with nonvalvular atrial fibrillation (NVAF). The present study analyzed the clinical and transesophageal echocardiography (TEE) features of 123 such patients to identify risk factors for LAT formation and the efficacy of prophylactic low-intensity warfarin therapy. Left atrial thrombi were found in 35 patients (28%) in whom systemic hypertension (49% vs 23%; p<0.01) and ischemic heart disease (17% vs 3%; p<0.01) were more frequent. Left ventricular ejection fraction (54+/-14% vs 60+/-11%; p<0.05), left ventricular end-diastolic dimension (51+/-7 mm vs 48+/-5 mm; p<0.05), spontaneous echo contrast (2.2+/-0.7 vs 1.4+/-0.9; p<0.01), left atrial diameter (50+/-6 mm vs 43+/-7 mm; p<0.01), left atrial appendage blood velocity (22.3+/-8.7 cm/s vs 37.2+/-21.5 cm/s; p<0.01) and the incidence of left ventricular hypertrophy (37% vs 15%; p<0.01) were also significantly different between the groups. Fourteen patients received continuous warfarin therapy (target INR: 1.5-2.0) and on the follow-up TEE study the left atrial thrombus resolved in 10 (71%). There were no thromboembolic events or major hemorrhagic complications in these patients, so it was concluded that low-intensity warfarin therapy is efficacious in treating LAT formation in patients with NVAF.

Catheter closure of atrial septal defects and patent foramen ovale in patients with an atrial septal aneurysm using different devices

BACKGROUND

Atrial septal aneurysm is frequently associated with patent foramen ovale (PFO) and atrial septal defects (ASD). Moreover, a relationship between atrial septal aneurysm and embolic cerebrovascular events has been suggested. The aims of this study were to analyze morphological and functional characteristics of atrial septal aneurysm in PFO and ASD patients and to assess the feasibility and efficacy of different devices for transcatheter closure and the influence of atrial septal aneurysm.

METHODS

Between March 1997 and May 2000 transcatheter ASD or PFO closure was attempted in 63 patients (mean age 47 +/- 13 years) with an atrial septal aneurysm using one of the following devices: Angelwings (n = 3), Cardioseal (n = 5), Cardioseal-Starflex (n = 7), Amplatzer (n = 11), Amplatzer-PFO (n = 5), PFO-Star (n = 25), or Helex (n = 7).

RESULTS

Implantation was primarily successful (after the first or second attempt) in all patients. One PFO-Star device embolized 12 hours after the procedure. During follow-up (0.6-37 months, mean 10.4 +/- 9.2) a residual shunt could be detected by transesophageal echocardiography after 2 weeks in four patients and after 6 months in one patient. Three PFO patients had cerebrovascular events after implantation. Two patients had a transient ischemic attack (TIA) and one patient a stroke. A thrombus formation on the device detected in three patients disappeared after antithrombotic therapy.

CONCLUSION

We conclude that ASDs and PFOs with an associated atrial septal aneurysm can be closed with different available devices. There seem to be no additional risks compared with patients without atrial septal aneurysm.

The association between the diameter of a patent foramen ovale and the risk of embolic cerebrovascular events

PURPOSE

We sought to determine whether the size of a patent foramen ovale affected the risk of embolic cerebrovascular events of unknown origin.

PATIENTS AND METHODS

We ascertained the presence and measured the size of patent foramen ovale using multiplane transesophageal echocardiography in 121 consecutive patients younger than 60 years who had transient ischemic attacks or ischemic strokes and in 123 control subjects. None of the patients had left heart, aortic, or carotid sources of embolism, or echocardiographic signs of elevated left or right atrial pressure. We used multivariate logistic regression to determine whether the size of the patent foramen ovale was an independent risk factor for cerebrovascular events.

RESULTS

The mean (+/- SD) diameter of a patent foramen ovale was significantly larger in patients (4 +/- 2 mm) than in control subjects (2 +/- 1 mm, P <0.0001). A patent foramen ovale greater than 4 mm was associated with an increased risk of transient ischemic attacks [odds ratio (OR) = 3.4; 95% confidence interval (CI), 1.0 to 11, P = 0.04], ischemic strokes (OR = 12; 95% CI, 3.3 to 44, P = 0.0001), and, especially, having evidence of two or more strokes (OR = 27; 95% CI, 4.7 to 160, P = 0.0002).

CONCLUSION

The diameter of a patent foramen ovale is an independent risk factor for ischemic events, especially recurrent strokes.

Morphological and functional characteristics of patent foramen ovale and their embolic implications

BACKGROUND AND PURPOSE

Transesophageal echocardiography (TEE) has detected a high prevalence of patent foramen ovale (PFO) in stroke patients, but the clinical implications of the distinctive characteristics of this patency are still a matter of debate.

METHODS

We studied 350 patients with acute ischemic stroke or transient ischemic attack (TIA) within 1 week of admission. Of these, 101 (29%) were identified by contrast TEE to have a PFO; 86 patients (25%) were cryptogenic stroke patients, and 163 were excluded because of the presence of a definite or possible arterial or clinical evidence of a source of emboli or small-vessel disease. Thirteen PFO subjects without a history of embolism were designated as the control group. All PFO and cryptogenic stroke patients were followed up by neurological visits.

RESULTS

Compared with controls, PFO patients with acute stroke or TIA more frequently presented with a right-to-left shunt at rest and a higher membrane mobility (P:<0. 05). Patients with these characteristics were considered to be at high risk. During a median follow-up period of 31 months (range, 4 to 58 months), 8 PFO and 18 cryptogenic stroke patients experienced recurrent cerebrovascular events. The cumulative estimate of risk of cerebrovascular event recurrence at 3 years was 4.3% (95% confidence interval [CI], 0% to 10.2%) for "low-risk" PFO patients, 12.5% (95% CI, 0% to 26.1%) for "high-risk" PFO patients, and 16.3% (95% CI, 7. 2% to 25.4%) for cryptogenic stroke patients (high-risk PFO versus low-risk PFO, P:=0.05).

CONCLUSIONS

The association of right-to-left shunting at rest and high membrane mobility, as detected by contrast TEE, seems to identify PFO patients with cerebrovascular ischemic events who are at higher risk for recurrent brain embolism.

Transesophageal echocardiography risk factors for stroke in nonvalvular atrial fibrillation

Atrial fibrillation is a common arrhythmia, particularly in the older age groups. It confers an increased risk of thromboembolism to these patients, and multiple clinical risk factors have been identified to be useful in predicting the risks of thromboembolic events. Recent studies have evaluated the role of transesophageal echocardiography (TEE) in the evaluation of patients with atrial fibrillation. The purpose of this review is to evaluate the significance of transesophageal echocardiographic findings in the prediction of thromboembolic events, particularly stroke, in patients with nonvalvular atrial fibrillation, with an emphasis on recently reported prospective studies. Aortic plaque and left atrial appendage abnormalities are identified as independent predictors of thromboembolic events. Although they are associated with clinical events, they also have independent incremental prognostic values. Other transesophageal echocardiographic findings, such as patent foramen ovale and atrial septal aneurysm, have not been found to be predictors of thromboembolic events in this patient group. Thus, TEE is a useful tool in stratifying patients with nonvalvular atrial fibrillation into different risk groups in terms of thromboembolic events, and it will likely play an important role in future studies to assess new treatment strategies in high-risk patients with atrial fibrillation.

Stroke prevention: cardiac and carotid-related stroke

The aim of this article is to discuss cardiac sources of stroke as well as the management of symptomatic and asymptomatic carotid stenosis. The authors detail the risks of cardioembolic stroke in the following conditions: aortic arch atheroma, atrial fibrillation, atrial myxoma, atrial septal aneurysm, dilated cardiomyopathy, infective endocarditis, left ventricular thrombus, mitral annular calcification, mitral valve prolapse, patent foramen ovale, prosthetic heart valves, valvular strands, and the optimal medical management for these conditions. The indications for carotid endarterectomy, angioplasty, and stenting are also outlined.

Significant association of atrial vulnerability with atrial septal abnormalities in young patients with ischemic stroke of unknown cause

BACKGROUND AND PURPOSE

Atrial septal abnormalities have been associated with cryptogenic ischemic stroke in young patients, but the causal link has not yet been established. Paradoxical embolism is considered the most likely mechanism but is rarely proven. It can be hypothesized that, in those patients, paroxysmal atrial arrhythmias, potentially favored by the anatomic abnormalities, can be another cause of thrombus formation and subsequent embolism to the brain. In this study we assessed the relationship between atrial vulnerability, reflecting arrhythmogenic properties of the atria, and atrial septal abnormalities in young patients with cryptogenic ischemic stroke.

METHODS

We enrolled 62 consecutive patients aged <55 years who had ischemic stroke of unknown cause and transesophageal echocardiography to assess atrial septal aneurysm (ASA) or patent foramen ovale (PFO) (ie, atrial septal abnormalities). These patients underwent electrophysiological study to measure atrial refractoriness and conduction time defining a vulnerability index (ie, latent atrial vulnerability) and to assess the inducibility of sustained (lasting >60 seconds) atrial fibrillation with the use of programmed atrial stimulation. Actual atrial vulnerability was defined by the presence of both latent vulnerability and inducibility of sustained atrial fibrillation lasting >60 seconds.

RESULTS

We found atrial vulnerability in 58% of patients with atrial septal abnormalities and in 25% of patients without (odds ratio=4.1 [95% CI, 1.3 to 12.7; P<0.02]). The difference between patients with and without PFO or between patients with both PFO and ASA and those without were also significant. Patients with inducible sustained atrial fibrillation had more frequent past history of palpitations and syncope than patients without (P<0.02).

CONCLUSIONS

Atrial vulnerability is associated with atrial septal abnormalities in patients with cryptogenic stroke. This result raises the question of the potential role of transient atrial arrhythmias in thrombus formation in the presence of PFO or ASA.

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.

Frequency of atrial septal aneurysms in patients with cerebral ischemic events

BACKGROUND

Atrial septal aneurysm (ASA) is a putative risk factor for cardioembolism. However, the frequency of ASA in the general population has not been adequately determined. Therefore, the frequency in patients with cerebral ischemic events, compared with the frequency in the general population, is poorly defined. We sought to determine the frequency of ASA in the general population and to compare the frequency of ASA in patients with cerebral ischemic events with the frequency in the general population.

METHODS AND RESULTS

The frequency of ASA in the population was determined in 363 subjects, a sample of the participants in the Stroke Prevention: Assessment of Risk in a Community study (control subjects), and was compared with the frequency in 355 age- and sex-matched patients undergoing transesophageal echocardiography in search of a cardiac source of embolism after a focal cerebral ischemic event. The proportion with ASA was 7.9% in patients versus 2.2% in control subjects (P=0.002; odds ratio of ASA, 3.65; 95% CI, 1.64 to 8.13, in patients versus control subjects). Patent foramen ovale (PFO) was detected with contrast injections in 56% of subjects with ASA. The presence of ASA predicted the presence of PFO (odds ratio of PFO, 4.57; 95% CI, 2.18 to 9.57, in subjects with versus those without ASA). In 86% of subjects with ASA and cerebral ischemia, transesophageal echocardiography did not detect an alternative source of cardioembolism other than an associated PFO.

CONCLUSIONS

The prevalence of ASA based on this population-based study is 2.2%. The frequency of ASA is relatively higher in patients evaluated with transesophageal echocardiography after a cerebral ischemic event. ASA is frequently associated with PFO, suggesting paradoxical embolism as a mechanism of cardioembolism. In patients with cerebral ischemia and ASA, ASA (with or without PFO) commonly is the only potential cardioembolic source detected with transesophageal echocardiography.

Increased prevalence of patent foramen ovale in patients with severe chronic obstructive pulmonary disease

This study was designed to assess the prevalence of patent foramen ovale (PFO) in patients with severe chronic obstructive pulmonary disease (COPD) and the magnitude of any effects of right-to-left interatrial PFO shunting on systemic arterial oxygen desaturation after the Valsalva maneuver. The prevalence of PFO was compared between a group of 20 patients with severe chronic obstructive pulmonary disease (FEV1% <50%; FEV1/FVC <50%) and 20 control subjects (FEV1% >70%; FEV1/FVC >70%) by contrast transesophageal echocardiography during the Valsalva maneuver with simultaneous measurement of systemic arterial oxygen saturation (SaO2) by pulse oximetry. Patients with severe COPD (FEV1 = 27.2% +/- 8.4%; FEV1 /FVC = 44.3% +/- 11.0%) had a significantly higher pulmonary artery systolic pressure (38.3 +/- 7.3 vs 21.0 +/- 2.4 mm Hg; P <.005), higher prevalence of PFO (14/20 = 70% vs 7/20 = 35%; P <.05), and greater systemic arterial desaturation after Valsalva (Sao2 change: -2.6% +/- 1.4% vs -1.1% +/- 0.9%; P <.005) than control subjects. In the severe COPD group, the degree of systemic arterial desaturation after Valsalva in patients with PFO was significantly greater than in patients without PFO (Sao2 change: -3.1% +/- 1.4% vs -1.5% +/- 0. 5%; P <.05). Significant systemic arterial oxygen desaturation was observed after Valsalva in 45% of patients with interatrial PFO shunting and severe COPD. This significantly correlated with the degree of pulmonary hypertension (r = 0.6; P <.05). We conclude (1) that patients with severe COPD have an increased prevalence of PFO and (2) that approximately one half of subjects with severe COPD and PFO demonstrate statistically significant systemic arterial oxygen desaturation after the Valsalva maneuver.

Course of valvular strands in patients with stroke: cooperative study with transesophageal echocardiography

BACKGROUND

Native valve strands might be related to the acute stage of thrombosis or might suggest a long-term valvular change. We aimed to estimate changes in the strands in patients with stroke through a serial transesophageal echocardiographic (TEE) study.

METHODS AND RESULTS

A study was conducted among patients who were referred for TEE for stroke or cardiac pathology. Patients had TEE examinations with a 5-MHz multiplane TEE probe. Echocardiography was repeated 3 months later in patients with stroke. TEE was performed in 180 patients admitted to cardiology units and in 160 patients referred to neurology units. Among 34 patients with valvular strands, 30 were referred to neurology for stroke, whereas 4 patients were admitted to cardiology (18.8% versus 2.2%, difference 16.5%, 95% confidence interval 10% to 22.9%, P =.001). Strands were located on the mitral valve in 16 patients, the aortic valve in 6 patients, and both left heart valves in 8 patients. Among the 38 valves with strands, 17 (44. 7%) were morphologically normal, 4 (10.5%) were thickened, 7 (18.4%) were redundant, and 10 (26.3%) had both abnormalities. TEE showed other abnormalities in 16 (53.3%) patients, whereas 14 patients had only strands. Twenty-six (86.6%) patients had a second TEE study 3 months later. Strands were not found in 4 (15.4%) patients (95% confidence interval 4.3% to 34.9%).

CONCLUSIONS

Valvular thickening or redundancy may predispose valves to strand formation. Native valve strands usually persist and thus reflect a chronic valvular change.

The need to quantify right-to-left shunt in acute ischemic stroke: a case-control study

BACKGROUND AND PURPOSE

Although right-to-left shunt (RLSh) has been reported to be significantly more frequent in young stroke patients with cryptogenic stroke, its relevance in a nonselected population of acute ischemic stroke is not well known. The aim of this study was to determine the importance of the RLSh magnitude as a risk factor for stroke in nonselected patients.

METHODS

Two hundred eight patients hospitalized consecutively with transient ischemic attack or acute cerebral infarction and 100 healthy control subjects were studied. Transcranial Doppler ultrasonography (TCD) was performed in both middle cerebral arteries (MCAs) after intravenous application of agitated saline solution. The magnitude of RLSh was quantified by counting the number of signals in 1 MCA during a Valsalva maneuver. RLSh was classified as "no shunt," "small" (< 10 signals), and "large" (> 10 signals), with the latter including the "shower" (> 25 signals) and "curtain" (uncountable signals) patterns. Extensive investigations, including contrast transesophageal echocardiography, were carried out on patients diagnosed as suffering from stroke of an uncertain etiology. The importance of RLSh for stroke was assessed by logistic regression analysis.

RESULTS

Contrast TCD detected a large RLSh in 40 (19.7%) patients and in 21 (21%) control subjects, all with cardiac RLSh characteristics. A large RLSh was present in 4.7% of atherothrombotic strokes, 10.5% of cardioembolic strokes, 15.4% of lacunar strokes, and 45.3% of cryptogenic strokes (P<0.001). Although the overall frequency of RLSh was not significantly different between patients and control subjects, the detection of curtain or shower patterns by contrast TCD was associated with a higher risk of stroke (odds ratio, 3.5; 95% confidence interval, 1.29 to 9.87), particularly with cryptogenic stroke (odds ratio, 12.4; 95% confidence interval, 4.08 to 38.09) after adjustment for concomitant vascular risk factors.

CONCLUSIONS

It is essential to quantify RLSh by contrast TCD during the Valsalva maneuver given that only those with shower and curtain patterns are associated with a higher risk of ischemic stroke in a nonselected population.

Role of routine transthoracic echocardiography in evaluation and management of stroke

OBJECTIVE

To determine the value of routine transthoracic echocardiography in patients with cerebral ischemia without known cardiac disease.

DESIGN

The literature from 1990 to 1995 was searched and relevant bibliographies from these papers reviewed. Articles reporting the prevalence and/or risk of stroke for myxoma, vegetation, mitral stenosis, left atrial thrombus, left ventricular thrombus or cardiomyopathy, patent foramen ovale, and atrial septal aneurysm were used. Prevalences and recurrent stroke risk were examined for adult patients less than and greater than 45 years.

RESULTS

Both the prevalence of transthoracic echocardiographic findings and recurrent risk of stroke differ by age. The finding of a patent foramen ovale can be expected in nearly half of younger patients with stroke, whilst transthoracic echo can be expected to yield no relevant lesion in three quarters of patients > 45 years. Warfarin anticoagulation appears beneficial in patients with mitral stenosis, left atrial thrombus, left ventricular thrombus, and left ventricular dysfunction, but is of unproven benefit for patent foramen ovale, atrial septal aneurysm, or in the absence of a risk-associated abnormality.

CONCLUSION

For most transthoracic echo findings in stroke, optimal management strategies have not been well defined. Future research is needed to evaluate the appropriate therapeutic approaches.

Cardiac changes in stroke patients and controls evaluated with transoesophageal echocardiography

In stroke patients several cardiac changes associated with embolism can be detected with transoesophageal echocardiography. Potential major cardiac embolic sources (e.g. atrial fibrillation, thrombi of left ventricle/atrium, vegetation, myxoma, dilated cardiomyopathy) have a causal relationship to embolism. Other changes with no certain causal relationship are regarded as potential minor cardiac embolic sources (e.g. atrial septal aneurysm, patent foramen ovale, mitral annular calcification, mitral valve prolapse, protruding atheroma of the aorta). We compared the prevalences of major and minor potential cardiac embolic sources in a stroke population with that in controls. One hundred and twenty-one patients with first-ever stroke were compared with 68 randomly selected controls. All subjects underwent magnetic resonance imaging of the brain, carotid ultrasound and transthoracic/transoesophageal echocardiography. The patients were slightly older (mean age 70.7 +/- 10.3 years) than the controls (65.5 +/- 15.5 years) (p < 0.05). Potential major cardiac embolic sources were found in 27% of the patients and in 4% of the controls (p < 0.001). The most common major potential embolic source was atrial fibrillation, detected in 22/121 patients. Fifteen of these also had spontaneous echocontrast in the left atrium. Eleven left atrial thrombi were found (four of these patients had atrial fibrillation and seven had sinus rhythm). A history of heart disease was more common in patients with a potential major cardiac embolic source or a carotid artery stenosis (77%) than in those patients without (44%) (p < 0.01). After excluding subjects with a major potential cardiac embolic source and/or carotid artery stenosis, no differences in the prevalence of minor potential cardiac embolic sources were found between patients (55%) and control subjects (47%) (p = NS). Even when subjects without a major potential cardiac embolic source or a carotid artery stenosis were categorized into three age groups (35-54, 55-74 and > 74 years) the prevalence of potential minor cardiac embolic sources did not differ between patients and controls. To conclude, major potential cardiac embolic sources are more common in an older population with first-ever stroke than in a comparable control group. However, potential minor cardiac embolic sources did not differ in prevalence in the patients compared with controls. Certain changes (e.g. atrial septal aneurysm) might have a potential embolic role in younger stroke patients but in our study no difference was found between older stroke patients and controls.

Transesophageal echocardiographic findings in patients with anterior and posterior circulation infarcts

OBJECTIVES

The aim of this study was to assess the role of transesophageal echocardiography in detecting the source of cerebral embolism in ischemic stroke patients and to evaluate the difference in occurrence of heart abnormalities in anterior and posterior circulation infarcts.

MATERIAL AND METHODS

The study group included 104 patients, 51 males and 53 females with ischemic stroke without significant atherosclerosis in the carotid arteries. Age of the patients ranged from 14 to 82 years (mean 55). The clinical picture of stroke suggested the embolic etiology, 34 of them had atrial fibrillation. Transthoracic and transesophageal echocardiography were performed in all patients. All patients were separated as anterior or posterior circulation infarcts. The control group consisted of 100 patients aged from 14 to 73 years (mean 53) without stroke history.

RESULTS

Transesophageal echocardiography (TEE) examination revealed left atrial thrombus in 12%, left atrial spontaneous contrast in 16%, interatrial communication in 31%, mitral valve prolapse in 20%, atrial septal aneurysm in 14%, ventricular thrombus in 6% and aortic atheromas of 5 mm or more in size in 7% of stroke patients. In the control group left atrial spontaneous contrast was found in 10%, interatrial communication in 17%, mitral valve prolapse in 4%, atrial septal aneurysm in 8%, neither atrial nor ventricular thrombi were found. At least one abnormal TEE finding was present in 70 (67%) of stroke patients. Abnormal TEE findings were more often seen in patients with anterior circulation infarct than in those with posterior circulation infarcts, although the difference was not statistically significant. Left atrial thrombus and mitral valve prolapse occurred statistically significantly more often in stroke patients than in the control group.

CONCLUSIONS

Echocardiographic examination is often abnormal in patients with ischemic stroke. The study did not reveal the statistically significant difference in the prevalence of abnormal transesophageal echocardiography findings between patients with anterior and posterior circulation infarcts.

Mobility of the flap valve of the primary atrial septum in the developing human fetus

It has already been suggested that redundancy of the primary atrial septum could be associated with primary fetal arrhythmias. There are few reports, however, concerning the mobility of the primary septum and its behavior during fetal life. In this study, fifteen fetuses without anatomic heart disease were serially evaluated by fetal echocardiography. The time interval between three separate examinations was at least two weeks. A redundancy index was calculated as the ratio between the maximum excursion of the flap valve of the septum and the maximal left atrium as seen in a four chamber view. The indexes observed in the three examinations were: 0.55 +/- 0.15, 0.48 +/- 0.13 and 0.41 +/- 0.13, respectively. Analysis of variance for normal distribution and Tukey's test were performed. A significant decrease (p < 0.05) in the redundancy index was observed with increasing gestational age. We postulate that this finding may be related to the decrease in frequency of premature atrial beats throughout fetal life.

Prevalence of patent foramen ovale and its contribution to hypoxemia in patients with obstructive sleep apnea

STUDY OBJECTIVES

The objectives of this study were (1) to assess the prevalence of patent foramen ovale (PFO) by means of contrast transesophageal echocardiography (TEE) in patients with obstructive sleep apnea, and (2) to determine the potential contribution of right to left interatrial shunting to systemic oxygen desaturation following the performance of Valsalva maneuver.

DESIGN

Performance of contrast TEE during Valsalva maneuver with simultaneous measurement of systemic arterial oxygen saturation (SaO2) by means of pulse oximetry in patients with obstructive sleep apnea and a control group.

SETTING

Government teaching hospital, university hospital affiliate.

PATIENTS

Study group comprised 48 patients with documented obstructive sleep apnea and 24 control subjects.

INTERVENTIONS

Sleep studies, contrast TEE, Valsalva maneuver, pulse oximetry.

MEASUREMENTS AND RESULTS

Thirty-three of 48 patients with obstructive sleep apnea compared with 4 of 24 control patients had a detectable PFO (69% vs 17%; p < 0.0001). All sleep apnea patients had comparable baseline SaO2 regardless of the presence of a PFO (93.9+/-1.7% vs 95+/-1.2%; p=not significant). After performance of a Valsalva maneuver, however, a significantly greater fall in SaO2 was observed in patients with obstructive sleep apnea and PFO compared with patients with obstructive sleep apnea without PFO (-2.4 +/- 1.5% vs -1.3 +/- 0.6%; p=0.007). A statistically significant fall in SaO2 (defined as > 4 SD of recorded SaO2 values after Valsalva maneuver in patients without PFO) was found in one third of patients with sleep apnea and PFO.

CONCLUSION

We conclude that there is an increased prevalence of PFO in patients with obstructive sleep apnea that could contribute to significant hypoxemia after a Valsalva maneuver in approximately one third of these patients.

Role of transesophageal echocardiography in the management of thromboembolic stroke

Cardiac causes of stroke account for approximately 20% of strokes occurring in the United States. Transthoracic echocardiography (TTE) remains the cornerstone of non-invasive cardiac imaging, but transesophageal echocardiography (TEE) is superior for identifying potential cardiac sources of emboli, including left atrial thrombi, valvular vegetations, thoracic aortic plaque, patent foramen ovale, and spontaneous left atrial echocardiographic contrast. The diagnostic yield of TEE for potential cardiac causes of thromboembolism exceeds 50%. The impact of TEE on the clinical management of this group, however, remains undefined for most TEE-specific diagnoses. Thus, routine use of TEE in these patients has been questioned. The diagnostic yield is highest if the clinical history/physical examination suggests a cardiac source. However, the clinical scenario often dictates patient management, and TEE data are used to "validate" the clinical impression. Data from large, prospective, randomized (aspirin/warfarin) studies, in which TEE data are obtained from patients with suspected cardiac thromboembolism, are needed. If specific TEE diagnoses can be identified in which defined therapies are beneficial, "source of embolism" will continue to be the most common indication for TEE referral. In this paradigm, TEE (without initial TTE) will probably become a more direct diagnostic pathway. However, if these studies demonstrate that all patients with suspected cardiac source benefit from one (or no) therapy, independent of TEE data, referrals for TEE will decline. Results of ongoing randomized trials to evaluate the efficacy of TEE in patients with cryptogenic stroke or transient ischemic attack are awaited.