Atrial Septal Pouch Research Articles

Formation of the interatrial septum: Insights obtained from cardiac computed tomographic angiography.

We previously described a septal variant termed left atrial septal pouch (LASP). Present in a third of hearts, it results from incomplete fusion of the septum primum (SP) and septum secundum (SS). We assessed the prevalence of LASP using 64-section multidetector computed tomography and further characterized the different variants. Among 864 scans, 770 were of sufficient quality for assessment (428 male, aged 59.2 ± 11.7 years). They were classified on the basis of the degrees of fusion of the SP and SS into a completely fused septum (CFS), patent foramen ovale (PFO), or LASP. The lengths of the SS, SP, and overlapping SP, the maximal length of the foramen ovale (FO) floor, and the atrial dimensions were compared. A PFO was seen in 181 patients (23.5%), a LASP in 242 (31.4%), and a CFS in 339 (44.0%). There were significant differences in the length of the SS (PFO-13.6 ± 4.3 mm, LASP-17.6 ± 4.8 mm, CFS-14.3 ± 7.7 mm, p < 0.001). Hearts with LASPs had a longer overlapping SP than those with PFOs (PFO-6.3 ± 4.5 mm, LASP-13.1 ± 5.2 mm, p < 0.001). The maximal lengths of the FO floor showed differences in short axis (SAX) view (PFO-21.7 ± 4.5 mm, LASP-15.3 ± 4.3 mm, CFS-16.3 ± 4.3 mm, p < 0.001). Hearts with PFO and LASP showed similar SP lengths (27.3 ± 6.6 mm vs. 26.4 ± 6.6 mm, p = 0.10). There was a positive linear correlation between the length of the SS and the overlapping SP (R2 = 0.28, p < 0.001) with a weaker negative correlation between the SS length and maximal length of the FO floor (R2 = 0.02, p < 0.001). The groups showed similar atrial dimensions and volumes. Present in a third of patients, hearts with LASP have longer SS and overlapping SP.

Atrial septal pouch in cats: first report on interatrial septum anatomical variations.

The atrial septal pouch was first recognised in humans in 2006 and, since 2010, has been described in more detail. The first reports on the left-sided atrial septal pouch linked its occurrence with a higher risk of thromboembolic stroke resulting from left atrial thrombus formation. However, subsequent studies have challenged this theory; therefore, the consequences of septal pouch occurrence remain disputed. Currently, in veterinary species, septal pouch occurrence and morphology have been described in sheep and pigs, showing species-related differences. No studies have been conducted on cats. As cats show a species-related risk of aortic thromboembolic disease resulting from left atrial thrombus formation, we aimed to describe the interatrial septum anatomical variations as the first step in the investigation of the relationship between the septal pouch presence and left atrial thrombus formation. The study was conducted on hearts collected post mortem from 80 cats. After formalin fixation and dissection, a detailed anatomical description of the interatrial septum for all cases was followed by a histopathological analysis of the heart in 25 cases. After dissection, the specimens were embedded in paraffin blocks and stained with haematoxylin and eosin, Masson-Goldner trichrome, Picrosirius Red and Movat pentachrome in a routine manner and evaluated via light microscopy. Our study showed a very high prevalence (95%) of the left-sided septal pouch in cats with a lower incidence (29%) of the right-sided septal pouch. We noted a high morphological variety of the left-sided septal pouch and described anatomical variants not previously reported in the literature. The septal pouch is a common anatomical variation of the interatrial septum in cats. Although, based on the current study, we cannot draw further conclusions on the relationship between the left-sided septal pouch and thromboembolic events in cats, the high prevalence of this anatomical entity points to a need of further studies on the topic.

Left Atrial Septal Pouch (LASP) and Cryptogenic Stroke: A Narrative Review.

Over 20% of ischemic strokes are cardioembolic strokes, necessitating research into thrombus formation locations, particularly the left atrial appendage (LAA). The left atrial septal pouch (LASP), which is linked to thrombus development and stasis, has drawn attention recently as a possible thromboembolic location, especially in atrial fibrillation (AF). The primary aim of this review is to explore LASP's role in cryptogenic strokes and to discuss the methods used to assess LAA anatomy. Imaging modalities such as cardiac computed tomography (CT) and transesophageal echocardiography (TEE) are crucial for diagnosing and characterizing LASP. LASP, found in about one-third of individuals, provides an additional site for thrombus development in the left atrium. The potential clinical implications of LASP-related thromboembolic events include the need for targeted therapeutic strategies, such as anticoagulant medication and, in some cases, consideration of LASP closure to prevent recurrent strokes. Further investigation is required to elucidate LASP's involvement in thromboembolic events and to guide stroke prevention in at-risk patients.

LEFT ATRIAL SEPTAL POUCH THROMBUS: AN UNUSUAL CAUSE OF EMBOLIC STROKE

LEFT ATRIAL SEPTAL POUCH THROMBUS: AN UNUSUAL CAUSE OF EMBOLIC STROKE

The 2022 FASEB Virtual Catalyst Conference on the Cardiac Interatrial Septum and Stroke Risk, December 7, 2022.

There is emerging evidence that the cardiac interatrial septum has an important role as a thromboembolic source for ischemic strokes. There is little consensus on treatment of patients with different cardiac interatrial morphologies or pathologies who have had stroke. In this paper, we summarize the important background, diagnostic, and treatment considerations for this patient population as presented during the Federation of American Societies for Experimental Biology (FASEB) Virtual Catalytic Conference on the Cardiac Interatrial Septum and Stroke Risk, held on December 7, 2022. During this conference, many aspects of the cardiac interatrial septum were discussed. Among these were the embryogenesis of the interatrial septum and development of anatomic variants such as patent foramen ovale and left atrial septal pouch. Also addressed were various mechanisms of injury such as shunting physiologies and the consequences that can result from anatomic variants, as well as imaging considerations in echocardiography, computed tomography, and magnetic resonance imaging. Treatment options including anticoagulation and closure were addressed, as well as an in-depth discussion on whether the left atrial septal pouch is a stroke risk factor. These issues were discussed and debated by multiple experts from neurology, cardiology, and radiology.

241 LEFT ATRIAL SEPTAL POUCH THROMBOSIS AFTER COVID19 INFECTION: IS IMMUNOTHROMBOSIS THE CULPRIT MECHANISM?

Abstract Aims The atrial septal pouch (ASP) is an incomplete fusion between septum primum (SP) and septum secundum (SS), resulting in a kangaroo pouch, that has a high prevalence in general populations (47%) and it is a potential site of blood stasis and thrombosis. After the novel coronavirus disease (COVID19) -related thrombotic complications, immunothrombosis has been widely investigated and proposed as key pathogenic mechanism linking coagulation and inflammation, leading sometimes to intracardiac thrombosis. In this paper we describe a case of thrombus in the ASP interestingly developed after COVID19 and made a literature review. Methods and Results A 85 years old woman with a history of hypertension and chronic atrial fibrillation (AF) in therapy with dabigatran, was admitted to our hospital for dyspnea, atypical chest pain and fever. Laboratory exams showed only mild leukocytosis and elevated levels of d-dimer; EKG confirmed AF with a normal ventricular rate and CT scan excluded pulmonary embolism. Transthoracic and transesophageal echocardiogram (TEE) (Figure 1) showed a mobile ovoid mass (13×26 mm) attached to a left-sided ASP mimicking a myxoma, no mass was seen in the left atrial appendage (LAA). Four months earlier she had been hospitalized for idiopathic thrombocytopenia and concurrent COVID19 infection with mild symptoms, therefore dabigatran was discontinued for a month. The patient underwent surgery and histopathology confirmed it was a thrombus. In the PubMed search we conducted for reports demonstrating ASP masses, or alleged thromboembolism (TE) from this site, we found 25 reports, whose characteristics are briefly summarized in Table 1. Interestingly mild thrombocytopenia was described just in one case. Conclusions In addition to the LAA, the atrial septal pouch is a newly described, common anatomic entity of the interatrial septum, that potentially serves as a site of stasis and thrombus formation. Despite its high prevalence, the finding of a thrombus in this site is very rare. According to Virchow triad, we assume that in this case an endothelial injury and hypercoagulability could have played a pivotal role, since the concomitant thrombocytopenia and high levels of d-dimer. This could be the first case of a thrombus in the ASP associated with COVID19-immunothrombosis.

Abstract 9436: Treatment Options for Left Atrial Septal Pouch: A Case Report

Introduction: Left Atrial Septal pouch (LASP) is defined as an incomplete closure between the septum primum and septum secundum with an elongated septum secundum. This produces a crevice in the left atrium that functions as a source for static blood and atrial dissociation. This in turn could progress to the formation of thrombi within the left atrium that has the potential to embolize causing ischemic infarcts. Case Description: Here we present a 63 year old Hispanic female with a past medical history of paroxysmal atrial fibrillation on apixaban, recurrent strokes, dyslipidemia, and hypertension who presented with expressive aphasia, and prosopagnosia. Previously, the patient was reported of having two cardioembolic cerebral vascular accidents (CVA). Computed tomography of the brain demonstrated an old infarct of the left posterior parietal lobe. Patient was treated with intra-arterial tissue plasminogen activator of the left posterior cerebral artery and right middle cerebral artery. MRI demonstrated four acute punctate infarcts in the left frontal lobe consistent with embolic infarcts. TEE demonstrated a large patent foramen ovale (PFO), a prominent eustachian valve, and LASP. It was determined that her PFO and LASP were the culprit for her recurrent CVA despite appropriate AC. The PFO/LASP were successfully closed with an Amplatzer PFO occluder device. Patient was discharged home. Discussion: The LASP can function as a source of thrombus formation and atrial disassociation, which can cause embolic CVA. No guidelines exist on how to properly address a LASP. One option would be to use a PFO closure device to close LASP. Other options may include AC despite the absence of atrial fibrillation. Conclusions: In conclusion, further studies are necessary in order to establish the most appropriate management in patients with LASP.

LEFT ATRIAL SEPTAL POUCH IN A PATIENT WITH RECURRENT STROKE

LEFT ATRIAL SEPTAL POUCH IN A PATIENT WITH RECURRENT STROKE

P113 HIDDEN POCKET. LEFT ATRIAL SEPTAL POUCH: VARIANT OF NORMALITY OR CARDIOEMBOLIC SOURCE?

Abstract During embryological period the blood flows from right to left atrium trought patent interatial septum. Embryon’s interatrial semptum consists on the apposition of Septum Secundum (SS) over Septum Primum (SP) that go to seal each other just afther birth. Sometimes this fusion doesn’t happen or partially happens, leading respectively to patent foramen ovale (PFO) or the less known eventuality of Atrial Septal Pouch (ASP). 48–year–old woman, history of chronic anemia treated with blood transfusions, underwent a routine transthoracic echocardiogram (TTE) as recommended by her transfusion center. The patients is asymptomatic, denies cardiovascular risk factors, denies any signs or symptoms suggestive of recent infectious or inflammatory disease. The TTE documented preserved left ventricular sistolic function, normal sized cardiac chembers, no valvular abnormalities, evidence of linear formation (10 x 5 mm), near foramen ovale, on the left side of interatrial septum, increased in echogenicity. It was performed a transesophageal echocardiogram (TEE) which confirmed the finding at SIA level. It was therefore recommended in depth study with cardiac magnetic resonance (CMR) which described the same mobile formation, characterized by the same signal strength as the atrial walls, both before and afther contrat administration, compatible in the first hypotesis with an embryonic residue (Left Atrial Septal Pouch, LASP). There is still much uncertainty regarding the clinical significance of LASP, however, its large prevalence among general population suggests that its potential embolism requires other predisposing conditions in order to be of real clinical relevance. CMR represents a usefull test for cardiac structures analysis owing its better tissue characterization cormpared to other diagnostic tests. In the event of an occasional finding and in absence of any other indication for anticoagulant therapy, no therapeutic measures are currently indicated. These patients could be followed up in order to promptly identify the onset of prothrombotic conditions likely to expose them to higher risk compared with patients who do not have LASP.

Prevalence of Left Atrial Septal Pouch Among Patients with Embolic Stroke of Undetermined Source Or Stroke of Known Etiology: a Retrospective Study.

Background and objectivesCryptogenic strokes can be defined by the criteria established for an embolic stroke of undetermined source (ESUS). Some embolic events might be caused by a left atrial septal pouch (LASP), due to the potential of thrombus formation. In this study we aimed to determine if LASP is a risk factor for ESUS when compared to a population of strokes of known origin, the LASP screening rate in our institution and if LASP dimensions influences the risk of ESUS.MethodsWe retrospectively analyzed transesophageal echocardiograms (TEEs) in a large cohort of patients that had experienced ischemic strokes. Two authors performed blinded, independent searches for LASPs by reviewing 1152 TEEs from patients that had experienced a stroke or transient ischemic attack. We excluded 26 TEEs, due to incorrect imaging. Next, we reviewed patient medical files.ResultsAmong the 1126 included patients, 148 had an ESUS (ESUS+ group) and 978 had strokes of known origin (ESUS– group). A LASP was present in 176 patients, including 32 patients (21.6% of LASPs) in the ESUS+ group and 144 patients (14.7% of LASPs) in the ESUS– group. In multivariate analysis, LASP was independently associated with ESUS (P = 0,019). 61.9% of LASPs that we found were not mentioned in reports from the original TEE operators.ConclusionThis study demonstrated that LASPs were more prevalent in patients with ESUS than in patients with strokes of known origin. Our results gave rise to the question of whether anticoagulation would be appropriate for some patients with ESUS. New large-scale, prospective studies should be conducted to address this issue. Additionally, considering the low rate of LASP descriptions, we concluded that the awareness of operators should be raised to improve their success in identifying LASPs.

Prevalence of left atrial septal pouch among patients with embolic stroke of undetermined source or stroke of known etiology: A retrospective study

Abstract Background and objectives Cryptogenic strokes can be defined by the criteria established for an embolic stroke of undetermined source (ESUS). Some embolic events might be caused by a left atrial septal pouch (LASP), due to the potential of thrombus formation. In this study we aimed to determine if LASP is a risk factor for ESUS when compared to a population of strokes of known origin, the LASP screening rate in our institution and if LASP dimensions influences the risk of ESUS. Methods We retrospectively analyzed transesophageal echocardiograms (TEEs) in a large cohort of patients that had experienced ischemic strokes. Two authors performed blinded, independent searches for LASPs by reviewing 1152 TEEs from patients that had experienced a stroke or transient ischemic attack. We excluded 26 TEEs, due to incorrect imaging. Next, we reviewed patient medical files. Results Among the 1126 included patients, 148 had an ESUS (ESUS+ group) and 978 had strokes of known origin (ESUS– group). A LASP was present in 176 patients, including 32 patients (21.6% of LASPs) in the ESUS+ group and 144 patients (14.7% of LASPs) in the ESUS– group. In multivariate analysis, LASP was independently associated with ESUS (P = 0,019). 61.9% of LASPs that we found were not mentioned in reports from the original TEE operators. Conclusion This study demonstrated that LASPs were more prevalent in patients with ESUS than in patients with strokes of known origin. Our results gave rise to the question of whether anticoagulation would be appropriate for some patients with ESUS. New large-scale, prospective studies should be conducted to address this issue. Additionally, considering the low rate of LASP descriptions, we concluded that the awareness of operators should be raised to improve their success in identifying LASPs.

Morphological Study of Fossa Ovalis in Formalin-Fixed Human Hearts and Its Clinical Importance.

Background and Objectives: Our study aimed to investigate the gross anatomy aspects of the fossa ovalis (FO) and the presence of some anatomical variation resulting from the incomplete fusion of septum primum and septum secundum, such as an atrial septal pouch (SP) and left atrial septal ridge. Materials and Methods: Thirty-one adult human hearts removed from formalin-fixed specimens were examined to provide information about the morphology of the FO. The organs were free of any gross anatomically visible pathological conditions. Results: The most common variants were the FO located in the inferior part of the interatrial septum (64.51%), circular (61.3%), with a net-like structure (51.62%), prominent limbus (93.55%), and patent foramen ovale (PFO) (25.8%). The right SP was observed in 9.67% of specimens, the left SP was observed in 29.03% of cases, and in 51.61% of cases, a double SP was observed. One sample presented a right SP and a double left SP, and one case showed a triple left SP, which was not reported previously to our knowledge. Conclusions: Knowledge of the interatrial septal anatomy becomes important for interventional cardiologists and should be documented before transeptal puncture.

Research progress on the diagnosis and management of atrial septal pouch

Research progress on the diagnosis and management of atrial septal pouch

Left Atrial Septal Pouch-Is it Really a New Risk Factor for Ischemic Stroke?: Subanalysis of the ASSAM Study.

The atrial septal pouch is an anatomic variant of the interatrial septum caused by incomplete fusion of the septum primum and secundum. It is debatable whether coexistence of septal pouch and atrial fibrillation (AF) increases the risk of stroke. Thus, the aim of the study was to evaluate the coexistence of left atrial septal pouch (LASP) and AF in patients with a history of stroke in comparison with those without an earlier history of stroke. We analyzed 145 patients with AF (68 in the study group, 77 in the control group). The study group consisted of patients with previous stroke and AF; control group consisted of patients scheduled for AF ablation. All patients underwent computed tomography with the assessment of atrial septum morphology and presence of LASP. The study was a subanalysis of the ASSAM (AssesSment of the left atrial appendage morphoLogy in patients aAfter ischaeMic Stroke) study. The prevalence of LASP in the entire group was 38.6%. There were no significant differences in the prevalence of LASP between the study and control groups (33.8% vs. 42.9%, P=0.265). Mean longitudinal and transverse dimensions of LASP were 9.34±3.27 and 2.4±0.6 mm, respectively, and there was no significant difference between the study and controls. Patients from the stroke group were older (P<0.0001), had a higher CHA2DS2-VASc score (5.41±1.93 vs. 1.62±1.46, P<0.0001) compared with controls. Presence of LASP is not more prevalent in patients with a history of stroke. Additional information on the presence of LASP do not improve accuracy of risk stratification for stroke in patients with AF.

The Left Atrial Septal Pouch: A New Stroke Risk Factor?

The left atrial septal pouch (LASP) occurs due to incomplete fusion of septa primum and secundum at the inter-atrial septum, creating an open flap that may serve as a thromboembolic source. Prior studies have demonstrated increased prevalence of LASP in cryptogenic strokes. The aim of the current study was to validate the above findings in a separate, larger group of stroke and non-stroke patients. We examined transesophageal echocardiograms (TEEs) performed between July 2011 and December 2018. LASP prevalence was determined in TEEs referred for ischemic stroke or transient ischemic attack (“stroke”) and compared with LASP prevalence in patients undergoing TEEs for other reasons (“non-stroke”). Stroke subtyping was performed using the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. There were 306 TEEs from 144 non-stroke and 162 stroke patients. Mean age and sex distribution were 56 ± 1 (mean ± SE) and 65% male in the non-stroke group and 58 ± 1 and 54% male in the stroke group. The overall prevalence of LASP was 31%. The prevalence of LASP was 28% (41/144) in non-stroke patients, 25% (24/95) in non-cryptogenic stroke patients, and 43% (29/67) in cryptogenic stroke patients. LASP prevalence was significantly higher in the cryptogenic subgroup compared with the non-cryptogenic subgroup (p = 0.02). These findings demonstrate a significant association of LASP with risk of cryptogenic stroke, suggesting that LASP may serve as a thromboembolic nidus. Additional studies are needed to determine the generalizability of these findings, and their therapeutic implications, supporting LASP as a stroke risk factor.

Blue toe syndrome caused by emboli from anomalous left atrial septal pouch thrombus: a case report

BackgroundLeft atrial septal pouches (LASPs) are a relatively newly described but common anatomical cardiac variant thought to be associated with atrial fibrillation (AF) and cardio-embolic stroke. Blue toe syndrome (BTS) describes ischemic changes in the toes due to microembolisation of the digital arteries. Establishing the etiology of BTS is vital so that the underlying cause can be treated. Here we describe the first case of BTS arising due to emboli from LASP thrombus arising on a background of new-onset AF.Case presentationA 65-year-old man presented with a two-day history of progressive painful swelling and bluish-purple discoloration of the second and fourth toes of his left foot and new-onset AF. Tests for hypercoagulability disorders were negative. Duplex ultrasound and CT angiography excluded deep venous thrombosis and an absence of embolus, thrombus, or occlusion in the arterial tree in the lower extremities bilaterally, so BTS was diagnosed. While transthoracic echocardiography and chest CT initially showed no cardiac abnormalities or mural thrombus, subsequent transesophageal echocardiography revealed a LASP with an associated pedunculated thrombus. The affected toes were amputated due to wet gangrene, but the patient recovered well with thrombus resolution after anticoagulation.ConclusionThe presence of a LASP in the absence of any other identifiable cause of BTS should trigger careful investigation of the interatrial septum, preferably using a multimodality imaging approach. The possibility that LASPs may not merely be an innocent bystander but a causative mechanism for peripheral ischemia must be considered.

Abstract WP261: The Left Atrial Septal Pouch: A New Stroke Risk Factor?

Background: The left atrial septal pouch (LASP) is a common anatomic variant produced by the incomplete fusion of septa primum and secondum at the inter-atrial septum, thus creating a potential embolic source from an open flap or blind pouch in the left atrium. Our prior work demonstrated increased prevalence of LASP in cryptogenic strokes (Frontiers Neurology 3-24-15). The aim of the current study was to examine the prevalence of LASP in a separate, more recent group of stroke patients and control subjects who underwent transesophageal echocardiography (TEE). Methods: We examined consecutive TEE studies performed between July, 2011 and December, 2018 at UC Irvine Medical Center. Prevalence of LASP was determined in TEE studies referred for ischemic stroke or TIA (“stroke subjects”), and compared to LASP prevalence in patients undergoing TEE for other reasons (“control subjects”). Stroke subtyping was performed using TOAST (Trial of Org 10172 in Acute Stroke Treatment) criteria. Results: TEE studies were performed on 221 cerebrovascular cases and 164 control subjects. Age and sex were 57±1 years (mean±SE) and 53% male for stroke subjects, and 56±1 years and 62% male for control subjects. Prevalence of LASP was 24% (40/164) in control subjects, 17% (24/138) in non-cryptogenic stroke subjects, and 36% (30/83) in cryptogenic stroke subjects. LASP prevalence was significantly higher for cryptogenics compared to the other groups (p=0.007). There was no significant difference between LASP prevalence in controls vs non-cryptogenic stroke. Elimination from analysis of subjects with other inter-atrial septal abnormalities (ie, patent foramen ovale or atrial septal defect) did not significantly change results. Conclusions: These findings demonstrate an increased prevalence of LASP in cryptogenic stroke, confirming our prior published findings. Given the plausibility of LASP acting as a thromboembolic nidus, additional studies are needed to determine the generalizability of these findings and their therapeutic implications.

Left-Sided Atrial Septal Pouch as a Risk Factor of Cryptogenic Stroke: A Systematic Review and Meta-Analysis

Background: Despite some evidence of left-sided septal pouch (LSSP) involvement in the pathogenesis of cardioembolic stroke, the question of LSSP clinical significance still remains unsolved. In this study, we aimed to determine the association between the LSSP presence and cryptogenic stroke using meta-analytical approach. Methods: We performed a systematic review of electronic databases for studies that compared the presence of LSSP in subjects with cryptogenic stroke and non-stroke control. Data were extracted and pooled into a meta-analysis. Results: Seven studies (400 cryptogenic stroke patients and 1,456 non-stroke controls) were included in the meta-analysis. A total of 138 LSSPs were identified among the cryptogenic stroke patients, with a pooled prevalence of 29.8% (95% CI 17.5–43.7%), and 268 LSSPs were identified in the non-stroke controls, with a pooled prevalence of 21.0% (95% CI 13.7–29.5%). After meta-analysis, the risk of cryptogenic stroke was higher in patients with an LSSP than in patients without LSSP (OR 1.52; 95% CI 1.15–2.00; p < 0.001). No significant heterogeneity was detected across the included studies (p > 0.05). Conclusion: Our meta-analysis demonstrated association between LSSP and cryptogenic stroke. In our univariate analysis, the risk of cryptogenic stroke is higher among patients with LSSP than in cases without the LSSP.

P6349Left-sided atrial septal pouch as a risk factor of cryptogenic stroke: a meta-analysis

P6349Left-sided atrial septal pouch as a risk factor of cryptogenic stroke: a meta-analysis

Left-Sided Atrial Septal Pouch is a Risk Factor for Cryptogenic Stroke

The atrial septal pouch is an anatomic variant of the interatrial septum. The morphology of the left-sided septal pouch (LSSP) may favor blood stasis and predispose to thromboembolic events. The aim of this study was to determine the association between LSSP presence and cryptogenic stroke. A total of 126 consecutive patients with cryptogenic stroke and 137 age-matched control patients without stroke were analyzed retrospectively. The presence and dimensions of LSSPs were assessed using transesophageal echocardiography. LSSP was present in 55.6% of patients with cryptogenic stroke and in 40.9% of those without stroke (P=.02). In univariate analysis, patients with LSSP were more likely to have cryptogenic stroke (odds ratio, 1.81; 95% CI, 1.11-2.95; P=.02). After adjusting for other risk factors using multiple logistic regression, the presence of an LSSP was found to be associated with an increased risk for cryptogenic stroke (odds ratio, 2.02; 95% CI, 1.19-3.41; P=.01). There were no statistically significant differences in size of the LSSP between patients with and those without stroke (P>.05). There is an association between the presence of an LSSP and an increased risk for cryptogenic stroke. More attention should be paid to clinical evaluations of LSSPs.