Patent Foramen Ovale and Atrial Septal Defect

Patent foramen ovale (PFO) and atrial septal defects (ASDs) are two types of interatrial communications with unique clinical presentations and management strategies. The PFO is a normal part of fetal development that typically closes shortly after birth but may persist in as many as 25% to 30% of adults. The communication between atria may result in paradoxic embolism and embolic stroke. On the other hand, ASDs (anatomically defined as secundum, primum, sinus venosus, and coronary sinus in order of prevalence) typically result in right heart volume overload and are often associated with other congenital defects. The diagnostic methods, treatment options including surgical and percutaneous approaches, and potential complications are described. Both conditions underline the significance of precise diagnosis and appropriate management to mitigate risks and ensure optimal patient outcomes.

Diagnostic Accuracy of Transthoracic Echocardiography With Contrast for Detection of Right-to-Left Shunt: A Systematic Review and Meta-analysis

BACKGROUND

The clinical utility of transthoracic echocardiography with contrast (TTE-C) for detection of right-to-left shunt (RLS) remains unknown. In this meta-analysis we evaluated the accuracy of TTE-C for RLS diagnosis compared with transesophageal echocardiography (TEE) as the reference standard.

METHODS

A systematic review and meta-analysis was performed using a search of MEDLINE, EMBASE, PubMed, and Cochrane library databases. Studies that were included provided data to assess sensitivity and specificity of TTE-C compared with TEE for RLS detection.

RESULTS

A total of 35 studies, involving 4209 patients, were analyzed. The average patient age was 49.1 ± 11.2 years and 53.9% were male. For RLS detection in the entire cohort, TTE-C sensitivity was 73% (95% confidence interval [CI], 66%-80%) and specificity was 94% (95% CI, 92%-96%). The sensitivity of TTE-C was 80% (95% CI, 74%-86%) in studies published in 2000 or later compared with 51% (95% CI, 36%-65%) in those published before 2000. In studies that used harmonic imaging, TTE-C sensitivity was 82% (95% CI, 77%-87%) and specificity was 95% (95% CI, 93%-97%). Among those with patent foramen ovale closure indications, TTE-C sensitivity was 74% (95% CI, 59%-89%) and specificity was 98% (95% CI, 95%-100%). In patients in whom RLS was diagnosed using a guideline-suggested 3 cardiac cycle cutoff, TTE-C sensitivity was 75% (95% CI, 66%-83%) and specificity was 94% (95% CI, 92%-97%). Provocative manoeuvres increased sensitivity by approximately 40%.

CONCLUSIONS

TTE-C offers excellent specificity and moderate sensitivity for RLS diagnosis compared with TEE, and it might therefore serve as an initial screening modality for selected patients with a high likelihood of having RLS and for indications for treatment.

Comparison of Different Contrast Agents in Detecting Cardiac Right-to-Left Shunt in Patients with a Patent Foramen Ovale during Contrast-Transthoracic Echocardiography

The aim of this study is to evaluate the ability of two different contrast agents to detect cardiac right-to-left shunting in patients with a patent foramen ovale during contrast transthoracic echocardiography and transesophageal echocardiography. Eighty-four patients who had migraines or experienced cryptogenic stroke were prospectively enrolled. Contrast echocardiography of the right portion of the heart was performed using an injection of either (i) 8 ml of agitated saline, 1 ml of blood, and 1 ml of air (ASB) or (ii) 4 ml of vitamin B₆ and 6 ml of sodium bicarbonate solution (VSBS). All patients underwent contrast echocardiography with different contrast agents successively before undergoing transesophageal echocardiography. The diagnostic sensitivity of VSBS and ASB for cardiac shunting diagnosis was 94.23% and 78.85%, respectively. The diagnostic sensitivity in the VSBS group was significantly higher than that in the ASB group (χ² = 5.283, P = 0.022). The observed semiquantitative shunt grading suggests that the positive rate in the VSBS group was higher than that in the ASB group (Z = −1.998, P = 0.046). The use of vitamin B₆ and sodium bicarbonate solution as a TTE contrast agent yielded a high sensitivity compared with ASB. However, further trials with large sample size are required to confirm this finding.

Patent Foramen Ovale and the Risk of Cerebral Infarcts in Acute Pulmonary Embolism-A Prospective Observational Study

BACKGROUND

Pulmonary embolism (PE) is associated with a risk of consecutive paradoxical embolism with brain infarction through a patent foramen ovale (PFO). The aims of this study were to assess the rate of new ischemic brain lesions (IBLs) using magnetic resonance imaging (MRI) during a 12-month follow-up period with anticoagulation and to evaluate the potential relationship with the presence of PFO on transesophageal echocardiography (TEE).

SUBJECTS AND METHODS

Seventy-eight patients with acute PE underwent baseline contrast TEE with brain MRI. After the 12-month follow-up, 58 underwent brain MRI. The rates of MRI documenting new IBLs were measured based on the presence of PFO.

RESULTS

PFO was detected in 31 patients (39.7%). At baseline MRI, IBL was present in 39 of 78 patients (50%). The presence of IBL was not significantly higher in patients with PFO than in patients without PFO (20 [64.5% patients with PFO] versus 19 [40.4% without PFO] of 39 patients with baseline IBL, P = .063). At the follow-up MRI, in the group with new IBL (9 of 58 patients, 15.5%), the number of patients with PFO was significantly higher than that without PFO (7 [33.3%] versus 2 [5.4%], P = .008). PFO was identified as an independent predictor of new IBL (odds ratio 4.6 [1.6-47.4], P = .008).

CONCLUSIONS

The presence of PFO was associated with new IBL in patients with PE. These patients are at a higher risk of ischemic stroke despite effective anticoagulation therapy.

Transcranial Doppler versus transthoracic echocardiography for the detection of patent foramen ovale in patients with cryptogenic cerebral ischemia: A systematic review and diagnostic test accuracy meta-analysis

OBJECTIVE

Patent foramen ovale (PFO) can be detected in up to 43% of patients with cryptogenic cerebral ischemia undergoing investigation with transesophageal echocardiography (TEE). The diagnostic value of transthoracic echocardiography (TTE) in the detection of PFO in patients with cryptogenic ischemic stroke or transient ischemic attack has not been compared with that of transcranial Doppler (TCD) using a comprehensive meta-analytical approach.

METHODS

We performed a systematic literature review to identify all prospective observational studies of patients with cryptogenic cerebral ischemia that provided both sensitivity and specificity measures of TTE, TCD, or both compared to the gold standard of TEE.

RESULTS

Our literature search identified 35 eligible studies including 3,067 patients. The pooled sensitivity and specificity for TCD was 96.1% (95% confidence interval [CI] = 93.0-97.8%) and 92.4% (95% CI = 85.5-96.1%), whereas the respective measures for TTE were 45.1% (95% CI = 30.8-60.3%) and 99.6% (95% CI = 96.5-99.9%). TTE was superior in terms of higher positive likelihood ratio values (LR+ = 106.61, 95% CI = 15.09-753.30 for TTE vs LR+ = 12.62, 95% CI = 6.52-24.43 for TCD; p = 0.043), whereas TCD demonstrated lower negative likelihood values (LR- = 0.04, 95% CI = 0.02-0.08) compared to TTE (LR- = 0.55, 95% CI = 0.42-0.72; p < 0.001). Finally, the area under the summary receiver operating curve (AUC) was significantly greater (p < 0.001) in TCD (AUC = 0.98, 95% CI = 0.97-0.99) compared to TTE studies (AUC = 0.86, 95% CI = 0.82-0.89).

INTERPRETATION

TCD is more sensitive but less specific compared to TTE for the detection of PFO in patients with cryptogenic cerebral ischemia. The overall diagnostic yield of TCD appears to outweigh that of TTE.

Transesophageal Contrast Echocardiography is Not Always the Gold Standard Method in the Identification of a Patent Foramen Ovale: A Clinical Case

In the embryo, Eustachian valve is a crescent-shaped membrane extending from the lower margin of the inferior vena cava and the ostium of the coronary sinus into the right atrium toward fossa ovalis and tricuspid valve. At birth, after the functional closure of the foramen ovale, the Eustachian valve loses its function, reducing to an embryo remnant. According to growing evidence, a persistent Eustachian valve is a frequent finding in patients with a patent foramen ovale (PFO). By directing the blood from the inferior cava to the interatrial septum, it may prevent the spontaneous closure of PFO after birth and indirectly predispose to paradoxical embolism. Transesophageal contrast enhanced echocardiography (cTEE) is considered the gold standard to diagnose a PFO in postnatal life, but its accuracy maybe is not so high in the presence of a persistent Eustachian valve. In these cases, color Doppler TEE is more sensitive and simplifies the diagnostic process, reducing the duration of TEE and improving the patient compliance.

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.

Diagnostic value of transthoracic echocardiography for patent foramen ovale: a meta-analysis

As a non-invasive and convenient modality, transthoracic echocardiography (TTE) has been widely recommended for the diagnosis of patent foramen ovale (PFO). In this study our aim was to systematically review the diagnostic accuracy of TTE in detection of PFO. We conducted comprehensive searches in PubMed, Embase and the Cochrane Library to the end of September 1, 2012. Sixteen studies comprising 1831 patients were included in the meta-analysis. The quality of reported studies was modest. The summary sensitivity and specificity of TTE in diagnosis of PFO were 88% (95% confidence interval [CI], 79-94) and 97% (95% CI, 92-99), respectively. The positive likelihood ratio was 27.1 (95% CI, 11.2-65.1), and the negative likelihood ratio was 0.12 (95% CI, 0.07-0.22). The summary diagnostic odds ratio was 221 (95% CI, 95-518). Subgroup analyses suggested that age and initial disease may affect the accuracy of TTE in detection of PFO. The meta-analysis suggested that TTE is a test with high sensitivity and specificity in detection of PFO, but it may not be appropriate for screening for PFO in all patients, especially patients with a small right-left shunt.

Determination of the optimum number of cardiac cycles to differentiate intra-pulmonary shunt and patent foramen ovale by saline contrast two- and three-dimensional echocardiography

INTRODUCTION

Patent foramen ovale (PFO) and intra-pulmonary shunt (IPS) are potential causes of stroke. The most optimum cardiac cycle cutoff for bubbles to appear in the left heart on saline contrast transthoracic echocardiography (TTE) as criteria to differentiate the 2 entities is unknown.

METHODS

Ninety-five adult patients had saline contrast transesophageal echocardiography (TEE), two-dimensional (2D) and 3DTTE. Sensitivity and specificity of each cardiac cycle as cutoff to differentiate a PFO and IPS were obtained.

RESULTS

Transesophageal echocardiography showed IPS in 28 and PFO in 15 patients. If bubbles appeared in the left heart within the first 4 cardiac cycles (the 4th cardiac cycle rule) as compared to alternate cutoffs, a PFO was most accurately diagnosed by both 2D and 3DTTE. Bubbles appearing at or after the 5th cardiac cycle most accurately determined an IPS. 3D versus 2DTTE had a trend for a higher sensitivity (61% vs. 36%, P = 0.06), but similar specificity (94% vs. 91%) for IPS. Accuracy of 3DTTE was 84% and 2DTTE was 75% (P = 0.08) for IPS. For PFO, 2DTTE sensitivity (87%) and specificity (98%) did not differ (P = NS) from that of 3DTTE sensitivity (73%) and specificity (100%).

CONCLUSIONS

This study demonstrates for the first time that the 4th cardiac cycle rule differentiates PFO and IPS most optimally by 2D and 3DTTE. 3DTTE appears to have higher sensitivity for diagnosing IPS. These data suggest that 3DTTE is preferable when IPS is to be diagnosed. Both methods are similar for diagnosing PFO.

The brain's heart - therapeutic opportunities for patent foramen ovale (PFO) and neurovascular disease

Patent foramen ovale (PFO), a common congenital cardiac abnormality, is a connection between the right and left atria in the heart. As a "back door to the brain", PFO can serve as a conduit for paradoxical embolism, allowing venous thrombi to enter the arterial circulation, avoiding filtration by the lungs, and causing ischemic stroke. PFO-related strokes affect more than 150,000 people per year in the US, and PFO is present in up to 60% of migraine patients with aura, and in one out of four normal individuals. So, in such a highly prevalent condition, what are the best treatment and prevention strategies? Emerging studies show PFO-related neurovascular disease to be a multi-organ condition with varying individual risk factors that may require individualized therapeutic approaches - opening the field for new pharmacologic and therapeutic targets. The anatomy of PFO suggests that, in addition to thrombi, it can also allow harmful circulatory factors to travel directly from the venous to the arterial circulation, a concept important in finding novel therapeutic targets for PFO-related neurovascular injury. Here, we: 1) review emerging data on PFO-related injuries and clinical trials; 2) discuss potential mechanisms of PFO-related neurovascular disease in the context of multi-organ interaction and heart-brain signaling; and 3) discuss novel therapeutic targets and research frontiers. Clinical studies and molecular mapping of the circulatory landscape of this multi-organ disease will both be necessary in order to better individualize clinical treatment for a condition affecting more than a quarter of the world's population.

Modern management of a patent foramen ovale

A patent foramen ovale (PFO) has been associated with medical conditions such as cryptogenic stroke, migraine with aura, and decompression illness. Whether closure of the PFO has clinical benefit has been suggested from registry studies, but not yet confirmed in multiple randomized trials. Methods of diagnosis of a PFO and a summary of the current evidence for treatment is presented and discussed as a guide to patient-centred decision-making.

The role of echocardiography in the management of the sources of embolism

The echocardiographic diagnosis of cardiac thrombi, vegetations and tumors as well as the identification of predisposing conditions such as patent foramen ovale, aortic atherosclerosis and other minor causes (e.g., mitral valve prolapse, mitral and aortic valve calcification) have crucial clinical relevance, affecting the choice of surgery and/or of pharmaceutical therapy in the setting of patients presenting embolism. The echocardiographic assessment helps not only for the retrospective diagnosis of sources of embolism but also for the prevention of events in asymptomatic patients. Echocardiography can also distinguish normal variants and artifacts from cardiac masses and tumors. Echocardiographic characterization/typology of cardiac sources of embolism is currently below par when compared with cardiac MRI, the current gold standard. Nevertheless, echocardiography remains the 'first-line' imaging tool, because of its low cost and the possibility to add easily available, functional and structural information at the patient's bedside.

Current clinical applications of transthoracic three-dimensional echocardiography

The advent of three-dimensional echocardiography (3DE) has significantly improved the impact of non-invasive imaging on our understanding and management of cardiac diseases in clinical practice. Transthoracic 3DE enables an easier, more accurate and reproducible interpretation of the complex cardiac anatomy, overcoming the intrinsic limitations of conventional echocardiography. The availability of unprecedented views of cardiac structures from any perspective in the beating heart provides valuable clinical information and new levels of confidence in diagnosing heart disease. One major advantage of the third dimension is the improvement in the accuracy and reproducibility of chamber volume measurement by eliminating geometric assumptions and errors caused by foreshortened views. Another benefit of 3DE is the realistic en face views of heart valves, enabling a better appreciation of the severity and mechanisms of valve diseases in a unique, noninvasive manner. The purpose of this review is to provide readers with an update on the current clinical applications of transthoracic 3DE, emphasizing the incremental benefits of 3DE over conventional two-dimensional echocardiography.

Visualization of patent ductus arteriosus using real-time three-dimensional echocardiogram: Comparative study with 2D echocardiogram and angiography

PURPOSE

To determine the feasibility and accuracy of real time 3D echocardiography (RT3DE) in determining the dimensions and anatomical type of the patent ductus arteriosus (PDA).

METHODS

The study included 42 pediatric patients with a mean age of 3.6 years (ranging from 2 months to 14 years) who were referred for elective percutaneous PDA closure. All patients underwent full 2D echocardiogram as well as RT3DE with off line analysis using Q lab software within 6 h from their angiograms. The PDA was studied as regard the anatomical type, length of the duct as well as the ampulla and the pulmonary end of the PDA. Data obtained by RT3DE was compared against 2D echocardiogram and the gold standard angiography.

RESULTS

Offline analysis of the PDA was feasible in 97.6% of the cases while determination of the anatomical type using gated color flow 3D acquisitions was achieved in 78.5% of the cases. The pulmonary end of the duct was rather elliptical using 3D echocardiogram. There was significant difference between the pulmonary end measured by 3D echocardiogram and angiography (P < 0.001). There was no significant difference between either the length or the ampulla of the PDA measured by 3D echocardiogram and that measured by angiography (P value = 0.325 and 0.611, respectively). There was a good agreement between both 2D or 3D echocardiogram and angiography in determining the anatomical type of the PDA (K = 0.744 and 0.773, respectively). However 3D echocardiogram could more accurately determine type A and type E ductus compared to 2D echocardiogram.

CONCLUSION

3D echocardiogram was more accurate than 2D echocardiogram in determining the length and the ampulla of the PDA. The morphologic assessment of the PDA using gated 3D color flow was achieved in 78.5% of the patients. Nevertheless the use of 3D echocardiogram in assessment of small vascular structures like PDA in children with rapid heart rates is still of limited clinical value.

Toward understanding the atrial septum in cryptogenic stroke

Ischemic stroke in younger people is common, and often remains unexplained. There is a well-documented association between unexplained stroke in younger people, and the presence of a patent foramen ovale. Therefore, in the absence of a clear cause of stroke, the heart is often assessed in detail for such lower risk causes of stroke. This usually involves imaging with a transesophageal echo, and investigation for a right-to-left shunt. An understanding of the anatomy of the atrial septum, and its associated abnormalities, is important for the stroke neurologist charged with decision making regarding appropriate secondary prevention. In this paper, we review the development and anatomy of the right heart with a focus on patent foramen ovale, and other associated abnormalities. We discuss how the heart can be imaged in the case of unexplained stroke, and provide examples. Finally, we suggest a method of investigation, in light of the recent European Association of Echocardiography guidance. Our aim is to provide the neurologist with an understanding on how the heart can be investigated in unexplained stroke, and the significance of abnormalities detected.

Diagnosis and quantification of patent foramen ovale. Which is the reference technique? Simultaneous study with transcranial Doppler, transthoracic and transesophageal echocardiography

INTRODUCTION AND OBJECTIVES

Patent foramen ovale (PFO) is the most common cause of cryptogenic stroke in patients younger than 55. Transesophageal echocardiography (TEE) has been accepted as the reference diagnostic technique. The purpose of this study was to compare the accuracy of transthoracic echocardiography (TTE), TEE and transcranial Doppler (TCD) in the diagnosis and quantification of patent foramen ovale.

METHODS

We studied 134 patients prospectively. Simultaneous TTE with TCD and TEE with TCD were performed, using agitated saline solution to detect right to left shunt.

RESULTS

In 93 patients diagnosed with PFO, the shunt was visualized at baseline by TCD in 69% of cases, by TTE in 74% and by TEE in 58%. The Valsalva maneuver produced a similar improvement in shunt diagnosis with all 3 techniques (26%-28%). TTE and TCD showed higher sensitivity (100% vs 97%; non significant difference) than TEE in the diagnosis of PFO (86%; P<.001). TCD performed during TEE did not diagnose 12 (13%) shunts previously diagnosed during TTE. Similarly, TEE underestimated shunt severity.

CONCLUSIONS

TTE enables adequate diagnosis and quantification of PFO. TEE is less sensitive and tends to underestimate the severity of the shunt.

Usefulness of intravenously administered fluid replenishment for detection of patent foramen ovale by transesophageal echocardiography

Patent foramen ovale (PFO) is associated with cryptogenic stroke, migraine headache, decompression sickness, and platypnea-orthodeoxia syndrome. Patients undergoing transesophageal echocardiography are often hypovolemic from preprocedural fasting and might not demonstrate right to left shunting owing to insufficient right atrial pressure generation, despite provocative maneuvers. We hypothesized that volume replenishment with saline loading could potentially unmask a PFO by favorably modulating the interatrial pressure gradient. Our study sought to examine the role of pre- or intraprocedural intravenous fluid replenishment on PFO detection during transesophageal echocardiography. A total of 103 patients were enrolled. An initial series of bubble injections was performed unprovoked and then with provocative maneuvers such as the Valsalva maneuver and coughing. The patients were then given a rapid 500 ml saline bolus, and the same sequence of bubble injections was repeated. The presence, type, and magnitude of the right to left shunts were noted before and after the saline bolus. The detection rate of PFO increased from 10.6% to 26.2% after saline loading without any provocative maneuvers. When combined with provocative maneuvers (Valsalva or cough), saline loading improved the detection rate from 17.4% to 32.0%. Overall, from amongst the 103 enrolled patients, saline bolusing resulted in a de novo diagnosis of PFO in 15 patients, atrial septal aneurysm in 15, PFO coexisting with an atrial septal aneurysm in 10, and pulmonary arteriovenous fistula in 5 patients. In conclusion, saline infusion in appropriately selected patients during transesophageal echocardiography significantly enhances the detection of PFOs and pulmonary arteriovenous fistulas.