Pearls and Pitfalls in the Transesophageal Echocardiographic Diagnosis of Patent Foramen Ovale

Diagnostic value of transesophageal echocardiography on morphology and function of left atrial appendage in patients with unclosed foramen ovale complicated with atrial fibrillation

BACKGROUND

This study investigates the diagnostic value of transesophageal echocardiography (TEE) for assessing the left atrial appendage (LAA) in patients with patent foramen ovale (PFO) and atrial fibrillation (AF). TEE provides detailed images that help evaluate the morphology and function of the LAA, which are crucial in diagnosing and managing these conditions.

METHODS

The study included 104 PFO patients admitted between December 2021 and January 2024, divided into AF (n = 53) and non-AF groups (n = 51). Additionally, 30 healthy individuals served as controls. All participants underwent TEE to compare ultrasound indices, LAA morphology, and function. The diagnostic values of these measurements were analyzed and compared across the three groups.

RESULTS

The AF group had a larger left atrial diameter (LAD) compared to the non-AF and control groups (P < 0.001). Both PFO groups had lower left ventricular ejection fractions (LVEF) than controls (P < 0.001), with the AF group showing lower LVEF than the non-AF group (P < 0.001). The AF group's LAA long diameter was greater (P < 0.05). LAA ejection fraction (LAAEF) and maximal emptying velocity (LAAPEV) were lower in PFO groups compared to controls, with the AF group also lower than the non-AF group (P < 0.01). Combined diagnostic measurements of LAA parameters showed higher accuracy (AUC = 0.979) than single measurements.

CONCLUSIONS

TEE evaluates LAA morphology and function effectively, providing significant diagnostic value for PFO with AF. Combined diagnostic parameters yield high specificity and sensitivity, enhancing diagnostic accuracy.

The diagnostic value of contrast-enhanced transcranial Doppler and contrast-enhanced transthoracic echocardiography for right to left shunt in patent foramen ovale: a systematic review and meta-analysis

Purpose

To evaluate and compare the diagnostic value of contrast-enhanced transcranial Doppler (c-TCD) and contrast-enhanced transthoracic echocardiography (c-TTE) for right to left shunt (RLS) in patent foramen ovale (PFO) by meta-analysis.

Methods

The literature included in the Cochrane Library, PubMed, and Embase were searched by using "contrast-enhanced transcranial Doppler (c-TCD), contrast-enhanced transthoracic echocardiography (c-TTE), patent foramen ovale (PFO), and right to left shunt (RLS)" as the keywords from inception through April 30, 2024. The diagnostic accuracy research quality assessment tool (QUADAS-2) was used to evaluate the quality of the included literature. The combined sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and Diagnostic odds ratio (DOR) were pooled, and a comprehensive ROC curve analysis was performed. Statistical software StataSE 12.0 and Meta-Disc 1.4 were used for data analysis.

Results

A total of 8,536 articles were retrieved, and 9 articles that met all inclusion criteria were included in this meta-analysis. The meta-analysis results show that the combined sensitivity, specificity, PLR, NLR, DOR, and area under the SROC curve of c-TCD for the diagnose of PFO-RLS were 0.91 (95% CI, 0.88-0.93), 0.87 (95% CI: 0.84-0.91), 6.0 (95% CI, 2.78-12.96), 0.10 (95% CI, 0.06-0.18), 91.61 (95% CI, 26.55-316.10), and 0.9681, respectively; the corresponding values of c-TTE were 0.86 (95% CI, 0.84-0.89), 0.88 (95% CI, 0.84-0.91), 5.21 (95% CI, 2.55-10.63), 0.16 (95% CI, 0.09-0.31), 71.43 (95% CI, 22.85-223.23), and 0.9532. The ROC curve shows that c-TCD has slightly higher diagnostic value for PFO than c-TTE, but there is no significant statistical difference (Z = 0.622, p > 0.05). Deek funnel pattern showed no significant publication bias.

Conclusion

Both c-TCD and c-TTE have high diagnostic values for PFO-RLS. However, c-TCD has slightly higher sensitivity and lower specificity in diagnosing PFO-RLS compared to c-TTE.Systematic review registration: identifier [CRD42024544169].

Comparative diagnostic accuracy of transcranial Doppler and contrast-enhanced transthoracic echocardiography for the diagnosis of patent foramen ovale and atrial septal defect

BACKGROUND

Recognition of right-to-left shunt is crucial in the work-up of patients with suspected patent foramen ovale (PFO) or atrial septal defect (ASD). While transesophageal echocardiography (TEE) remains the gold standard diagnostic tool for the anatomic assessment of PFO/ASD, transcranial Doppler (TCD) and contrast-enhanced transthoracic echocardiogram (CE-TTE) hold the promise of providing minimally invasive yet accurate clinical details. Their comparative accuracy remains however debated.

METHODS

We conducted a retrospective observational study leveraging our extensive institutional experience with systematic TCD and CE-TTE in patients with suspected PFO/ASD. Several measures of diagnostic test accuracy were computed, with point estimates and 95% confidence intervals, when applicable.

RESULTS

A total of 1358 patients were included, with age 48±14 years and 772 (58%) women. Tests were performed for diagnostic purposes in 797 (58.6%) and during follow-up in 740 (54.5%). A PFO was eventually diagnosed in 1038 (77.9%) patients, and an ASD in 60 (4.5%). Agreement between TCD and CE-TTE occurred in 1309 (85.2%) cases, with TCD yielding worse findings than CE-TTE in 91 (5.9%) patients, and vice versa in 137 (8.9%), yielding a Cohen kappa of 78.6% (95% CI: 76.3-81.1%) and a highly significant P value at McNemar test (P<0.001). After dichotomization, and using TCD as benchmark, CE-TTE yielded sensitivity 96.9%, specificity 95.1%, area under the curve 92.1%, and P=0.249. Similar findings were obtained when focusing only on diagnostic tests or follow-up ones (Cohen kappa respectively 74.0% [70.2-77.1%], P<0.001 and 80.3% [76.4-84.3%], P<0.001). Notably, Valsalva was necessary to disclose the presence of shunt during TCD in 487 (31.7%) patients and during CE-TTE in 482 (31.4%) cases. Finally, performance of TCD and CE-TTE in a subset of patients eventually undergoing TTE was quite similar.

CONCLUSIONS

The diagnostic accuracy of CE-TTE appears favorable, and this imaging test may identify patients who may be missed if only TCD is used to screen patients with suspected PFO/ASD. Accordingly, CE-TTE is recommended as an adjunct diagnostic modality for all patients with a high pre-test probability of PFO/ASD and right-to-left shunt.

A Rare Case of Platypnea-Orthodeoxia Syndrome in a Patient With Undiagnosed Atrial Septal Defect

Platypnea-orthodeoxia syndrome (POS) is a rare condition characterized by dyspnea and oxygen desaturation that worsens in the upright position and improves when lying down. We report the case of a 67-year-old male who presented with a 14-month history of dyspnea in the sitting/standing position. Despite treatment for suspected asthma, his symptoms persisted, and he was referred to our hospital for further evaluation. Physical examination and arterial blood gas analysis confirmed the presence of POS, with a significant decrease in PaO2 and SpO2 when moving from a supine to an upright position. Contrast-enhanced CT showed no obvious embolism nor arteriovenous fistula, and ventilation-perfusion scintigraphy demonstrated ventilation-perfusion mismatch with a right-to-left shunt fraction of 9.4%, without any focal defect. Transthoracic echocardiography with a microbubble test demonstrated a right-to-left shunt that increased in the upright position. Transesophageal echocardiography revealed an atrial septal defect (ASD) with an atrial septal aneurysm and the presence of an inferior vena cava valve, causing a bidirectional shunt. The patient was diagnosed with POS secondary to ASD and was referred for percutaneous closure of the defect. Following the procedure, the shunt resolved, and the patient's orthostatic oxygen desaturation improved. This case highlights the importance of considering POS in patients with positional dyspnea and the value of performing diagnostic tests, such as echocardiography, in different positions to identify the underlying cause. Early recognition and appropriate management of POS can significantly improve patients' quality of life and prevent complications associated with chronic hypoxemia.

Prevalence of Aortic Root Pathologies in Platypnea-Orthodeoxia Syndrome Secondary to Intra-Cardiac Shunts

Background

Atrial septal defects can allow right to left shunting of venous blood which presents clinically as platypnea-orthodeoxia syndrome. It is believed that concomitant presence of aortic root pathologies increases the likelihood of shunting.

Methods

The study included a review of 510 articles listed in PubMed of patients with platypnea-orthodeoxia syndrome. Case reports of patients with extra-cardiac etiologies of platypnea-orthodeoxia were excluded.

Results

We reviewed 191 case reports, and 98 cases (51.3%) had evidence of concomitant aortic root pathology. Furthermore, of the remaining 93 case reports, 69 ones excluded any mention of the nature of the aortic root altogether, further suggesting that this is an underreported number.

Conclusions

There is a high prevalence of aortic root pathologies in patients with platypnea-orthodeoxia syndrome secondary to intra-cardiac shunts. In patients with unexplained hypoxemia and incidental finding of aortic root pathology, it may be worthwhile to obtain postural oxygen saturation measurements to exclude intra-cardiac shunts as the potential cause.

Right-to-Left Shunt Evaluation in Cardiac Patent Foramen Ovale Using Bubble Contrast Transcranial Color-Coded Doppler: A Cryptogenic Stroke Case

Traditional diagnosis of patent foramen ovale (PFO) in the heart has involved the use of transcranial Doppler (TCD). However, TCD is essentially a blind test that cannot directly visualize the location of blood vessels. Since TCD relies on qualitative assessments by examiners, there is room for errors, such as misalignment of the ultrasound's angle of incidence with the actual blood vessels. This limitation affects the reproducibility and consistency of the examination. In this study, we presented an alternative approach for assessing right-to-left shunt (RLS) associated with PFO using contrast transcranial color-coded Doppler (C-TCCD) with bubble contrast. The patient under consideration had been diagnosed with an ischemic stroke through imaging, but the subsequent cardiac work-up failed to determine the cause. Employing C-TCCD for RLS screening revealed a confirmed RLS of Spencer's three grades. Subsequently, transesophageal echocardiography (TEE) was conducted to evaluate PFO risk factors, confirming an 8 mm PFO size, a 21 mm tunnel length, a hypermobile interatrial septum, and persistent RLS. The calculated high-risk PFO score was 4 points, categorizing it as a very high risk PFO. This case underscores the importance of C-TCCD screening in detecting RLS associated with PFO, especially in cryptogenic stroke patients, when identifying the underlying cause of ischemic stroke becomes challenging.