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

Association between patent foramen ovale and chronic obstructive pulmonary disease: A systematic review and meta-analysis

BACKGROUND

Patent foramen ovale (PFO) is a defect in the intra-atrial septum that occurs when the foramen ovale does not close postnatally. Chronic obstructive pulmonary disease (COPD) is a respiratory condition that causes airflow obstruction.

OBJECTIVE

This systematic review aimed to consolidate current evidence on the association between PFO and COPD outcomes.

METHODS

We searched Medline, Embase, and Cochrane databases from inception to November 2023 for studies conducted among adults who have been diagnosed with COPD and underwent testing for PFO. A structured data extraction sheet was created to collect data from selected studies. A meta-analysis with a random effects model was considered when feasible.

RESULTS

The initial search identified 765 records. After screening for eligibility, we included six cross-sectional and three case report studies. In cross-sectional studies, patients with COPD had almost three times higher odds of having PFO than controls (OR = 2.72, 95 % CI: 1.57 to 4.70, I2 =0 %). When comparing COPD patients with and without PFO, the pooled mean difference was -2.99 mmHg; 95 % CI:5.55 to -0.44, I2 =77 %) in oxygen saturation (SaO2), -6.85 mmHg (95 %CI:11.71 to -2.39, I2 =35 %) in arterial oxygen partial pressure (PaO2) and 9.65 mmHg (95 %CI: 3.38 to 12.92, I2 =0 %) in pulmonary arterial pressure.

CONCLUSIONS

Evidence, based on a few and small size studies, indicates that PFO presence may be associated with worse outcomes in COPD patients. The long-term impact of these findings on COPD outcomes and the need for identifying high-risk patients for PFO screening should be evaluated.

Enhancing the diagnostic efficacy of right-to-left shunt using robot-assisted transcranial Doppler: a quality improvement project

Background

Stroke is the leading cause of adult disability worldwide, with approximately 30% of strokes remaining cryptogenic. One potential important etiology is a patent foramen ovale (PFO), which may contribute to stroke through paradoxical thromboembolism or in situ thromboembolus formation. Recent advancements in robot-assisted transcranial Doppler (raTCD) have shown increased sensitivity in detecting right-to-left shunt (RLS) compared to transthoracic echocardiography (TTE), particularly in detecting the large shunts which are associated with higher stroke risk.

Methods

We conducted a retrospective quality improvement project at our regional stroke center to compare the performance of TTE and raTCD in identifying RLS in ischemic stroke patients. The study involved 148 patients admitted between February 2021 and February 2023. All patients underwent TTE and raTCD with agitated saline bubble contrast, with additional transesophageal echocardiography (TEE) at the treatment team's discretion. The primary metrics analyzed included differences in overall RLS detection and large RLS detection rates for raTCD, TTE and TEE.

Results

raTCD detected RLS in 60.1% of patients compared to 37.2% with TTE (p < 0.001), with a 42.6% detection rate for large shunts on raTCD versus 23.0% on TTE (p < 0.001). The sensitivity and specificity of raTCD were 92 and 87.5%, respectively, compared to 78.57 and 71.43% for TTE, using TEE as the gold standard. Nine patients underwent PFO closure, all correctly identified with large shunts by raTCD, while TTE missed or underestimated the PFO size in 44% of the cases.

Conclusion

raTCD significantly outperforms TTE in detecting RLS and large shunts, suggesting its integration into standard PFO workup protocols may enhance secondary stroke prevention. These findings support the adoption of raTCD as a complementary diagnostic tool alongside TTE and TEE for more accurate PFO detection and risk stratification.

Incorporation of robotic automated transcranial Doppler to screen for patent foramen ovale (PFO) and quantify right-to-left shunt severity in the evaluation of ischemic stroke patients for etiology and PFO management

Background

Right-to-left shunt (RLS) associated with patent foramen ovale (PFO) is common among cryptogenic strokes. Current diagnostic tools have limitations. Transthoratic echocardiography (TTE) is not as sensitive as Transesophageal echocardiography (TEE), TEE is invasive, and manual transcranial Doppler (TCD) requires trained staff to operate. Robotic automated TCD (raTCD) may be feasible and comparable to manual TCD. The study's purpose was to determine the rate of RLS detection using raTCD and combine the Spencer Logarithmic Scale (SLS) with the Risk of Paradoxical Embolism (RoPE) to identify patients at risk of PFO associated stroke or TIA.

Methods

This single-center retrospective cohort study included adult patients (≥18 y/o) admitted from December 2021 to December 2022 with a stroke or transient ischemic attack. Those with no bone window or stroke mimics were excluded. Patients with an RLS on raTCD received a second scan at the physician's discretion. The SLS combined with the RoPE score was used to generate a modified screening PFO-Associated Stroke Causal Likelihood (msPASCAL) classification.

Results

Of 212 patients who received raTCD, the mean age was 56, 14% were >65 years old, most were white (72%), predominantly male (59%), 52% had cryptogenic strokes, and 59% had an RLS. Most patients were able to perform Valsalva (89%) during raTCD. Of those with an RLS, 56% had an SLS of 1-2, while 44% had an SLS of 3-5. There were no significant differences in characteristics by SLS. Most patients with SLS grades 1-2 were classified using msPASCAL as unlikely to have PFO as stroke etiology (n = 55, 44%). A small number of large SLS grades 3-5 were considered probable for having a PFO-associated stroke while the rest were classified as possible (n = 38, 30.4%). Eight patients with positive RLS on raTCD had a negative TTE with bubbles; most of those had small RLS on raTCD (n = 5, 63%) or could not Valsalva due to sedation ((n = 6, 75%).

Discussion

This study supports the feasibility of utilizing raTCD for RLS detection. The modified screening PASCAL classification can be generated for RLS patients and may be used to guide subsequent evaluation and management.

Genetic variation in patent foramen ovale: a case-control genome-wide association study

Background

Patent foramen ovale (PFO) is a congenital defect between the atria, resulting in abnormal hemodynamics. We conducted a genome-wide association study (GWAS) to identify common genetic variants associated with PFO.

Methods

We performed a whole genome sequencing in a discovery cohort of 3,227 unrelated Chinese participants screened for PFO via contrast transthoracic echocardiography (cTTE). Single-nucleotide polymorphisms (SNPs) associated with PFO were further validated by Sanger sequencing and subsequently were evaluated in a validation cohort. Expression quantitative trait loci (eQTL) analysis was conducted using the GTEx database. Single-cell sequencing analyses with pseudotime trajectory modeling were employed to evaluate their expression in human fetal hearts.

Results

The case-control GWAS of discovery cohort ultimately included 517 cases and 517 demographically matched controls. Of the 7,040,407 variants assessed, we identified rs1227675732 (OR = 2.903; 95% CI, 1.961 to 4.297; p = 3.05 × 10-8), rs62206790 (OR = 2.780; 95% CI, 1.864 to 4.146; p = 2.02 × 10-7), rs879176184 (OR = 2.724; 95% CI, 1.822 to 4.073; p = 4.30 × 10-7) and rs13115019 (OR = 2.437; 95% CI, 1.702 to 3.488; p = 5.80 × 10-7) as high-risk variants for PFO, while rs57922961 (OR = 0.5081; 95% CI, 0.388 to 0.666; p = 6.82 × 10-7) was identified as protective variant. These variations were replicated in the validation cohort (111 cases and 152 controls). Single-cell sequencing showed that CNOT2, KCNMB4, MLLT10, IGBP1, and FRG1 were highly expressed with significant changes during heart development.

Conclusion

The identification of susceptible loci for PFO might provide insights into the pathogenesis of PFO and contribute to understanding heart development.

Clinical Trial Registration

https://www.chictr.org.cn/showproj.html?proj=40590, identifier ChiCTR1900024623.

Grading Right-to-Left Shunt With Transforaminal Doppler: A Valid Approach in Patients With Cryptogenic Stroke

BACKGROUND AND PURPOSE

Right-to-left shunt (RLS), usually related to a patent foramen ovale (PFO), is an important cause of cryptogenic stroke (CS) in young patients. Transcranial Doppler (TCD) with an agitated saline bubble study is a highly sensitive modality for RLS diagnosis using a transtemporal approach (TTD). However, a minority of patients have insufficient temporal bone windows. We aimed to evaluate the accuracy of transforaminal TCD (TFD) for RLS diagnosis.

METHODS

We included patients with CS or transient ischemic attack who were tested in the standard protocol for RLS between March 2022 and February 2023. We evaluated the concordance of RLS grades between TFD and transesophageal echocardiogram (TEE) using the weighted kappa index. We also compared TTD and TFD approaches.

RESULTS

Forty patients were included (66.7% men; median age 49 years). Medium or large RLS were found in 28 patients (70%) with TTD and in 27 patients with TFD (67.5%). Through TEE, 19 (82.6%) medium or large PFO were confirmed, and a high agreement rate of 0.684 (p = 0.0003) was observed for grading RLS. Moreover, the agreement rate of RLS grade between TTD and TFD was 0.73 (p < 0.0001).

CONCLUSION

TFD is a valid approach for RLS diagnosis, with substantial concordance with TEE in grading RLS. Our study found a good grade of agreement between TFD and TEE. Therefore, the value of TCD goes beyond quantifying RLS and could assist in identifying the patients with the largest RLS, who would gain the greatest benefit from PFO closure.

Transcranial Doppler With Microbubbles: Screening Test to Detect and Grade Right-to-Left Shunt After an Ischemic Stroke: A Literature Review

Right-to-left shunt, mainly due to patent foramen ovale (PFO), is likely responsible for ≈5% of all ischemic strokes and 10% of those occurring in young and middle-aged adults. Randomized clinical trials demonstrated that, in selected young and middle-aged patients with otherwise cryptogenic acute ischemic stroke and high-risk PFO, percutaneous PFO closure is more effective than antiplatelet therapy alone in preventing recurrence. However, PFO is generally a benign finding and is present in about one-quarter of the population. Therefore, in clinical practice, identifying PFOs that are likely to be pathogenetic is crucial for selecting suitable patients for PFO closure to prevent recurrent stroke and to avoid potentially harmful and costly overtreatment. Contrast transthoracic echocardiography has a relatively low sensitivity in detecting PFO, whereas transesophageal echocardiography is currently considered the gold standard for PFO detection. However, it is a relatively invasive procedure and may not always be easily feasible in the subacute setting. Contrast transcranial Doppler is a noninvasive, inexpensive, accurate tool for the detection of right-to-left shunt. We conducted a literature review on the use of contrast transcranial Doppler to detect and grade right-to-left shunt after an acute ischemic stroke and present a clinical workflow proposal for young and middle-aged patients.

European Stroke Organisation (ESO) Guidelines on the diagnosis and management of patent foramen ovale (PFO) after stroke

Patent foramen ovale (PFO) is frequently identified in young patients with cryptogenic ischaemic stroke. Potential stroke mechanisms include paradoxical embolism from a venous clot which traverses the PFO, in situ clot formation within the PFO, and atrial arrhythmias due to electrical signalling disruption. The purpose of this guideline is to provide recommendations for diagnosing, treating, and long-term managing patients with ischaemic stroke and PFO. Conversely, Transient Ischaemic Attack (TIA) was not considered an index event in this context because only one RCT involved TIA patients. However, this subgroup analysis showed no significant differences between TIA and stroke outcomes. The working group identified questions and outcomes, graded evidence, and developed recommendations following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach and the European Stroke Organisation (ESO) standard operating procedure for guideline development. This document underwent peer-review by independent experts and members of the ESO Guideline Board and Executive Committee. The working group acknowledges the current evidentiary gap in delineating an unequivocal diagnostic algorithm for the detection of PFO. Although transoesophageal echocardiography is conventionally held as the most accurate diagnostic tool for PFO identification, its status as the 'gold standard' remains unsubstantiated by rigorously validated evidence. We found high-quality evidence to recommend PFO closure plus antiplatelet therapy in selected patients aged 18-60 years in whom no other evident cause of stroke is found but a PFO (i.e. PFO-associated stroke). The PASCAL classification system can be used to select such candidates for PFO closure. Patients with both a large right-to-left shunt and an atrial septal aneurysm benefit most from PFO closure. There is insufficient evidence to make an evidence-based recommendation on PFO closure in patients older than 60 and younger than 18 years. We found low quality evidence to suggest against PFO closure in patients with unlikely PFO-related stroke according to the PASCAL classification, except in specific scenarios (Expert Consensus). We suggest against long-term anticoagulation in patients with PFO-associated stroke unless anticoagulation is indicated for other medical reasons. Regarding the long-term AF monitoring after PFO closure, the working group concluded that there remains significant uncertainty regarding the risks and benefits associated with the use of long-term cardiac monitoring, such as implantable loop recorders. This document provides additional guidance, in the form of evidence-based recommendations or expert consensus statements, on diagnostic methods for PFO detection, and medical management after PFO closure.

Techniques for Identifying a Patent Foramen Ovale: Transthoracic Echocardiography, Transesophageal Echocardiography, Transcranial Doppler, Right Heart Catheterization

Noninvasive and invasive imaging modalities play important roles for the detection of patent foramen ovale (PFO). Transthoracic echocardiography or transcranial Doppler bubble study can be used for initial noninvasive PFO screening. For diagnostic confirmation, transesophageal echocardiography bubble study can be utilized, a semiinvasive confirmatory test that can directly visualize a PFO. In selective cases when the diagnosis is in doubt, PFO can be accurately diagnosed invasively with right heart catheterization. Understanding the advantages and limitations of each diagnostic option will help clinicians choose the appropriate test for patients presenting with a PFO-associated condition who may benefit from percutaneous device closure.

Patent Foramen Ovale and Decompression Illness: The Present and Future

Presence of patent foramen ovale (PFO), particularly if high-grade, increases the risk of decompression illness (DCI) and its severe forms. In unprovoked or recurrent DCI, neurologic, cutaneous, or cardiopulmonary DCI, testing for PFO is indicated with bubble contrast echocardiography or transcranial Doppler using provocative maneuvers. In patients with PFO and history of DCI, evaluation by a cardiologist with expertise in diving medicine is recommended. Consideration should be given to PFO closure if cessation of diving or conservative diving cannot be achieved. Prospective studies evaluating long-term outcomes in patients who continue to dive after PFO closure are required.

Percutaneous suture-based patent foramen ovale closure: A state-of-the-art review

Percutaneous closure of a patent foramen ovale (PFO), a common variation of interatrial septum anatomy, is a commonly performed procedure in the catheterization laboratory to reduce the risk of recurrent stroke in selected patients and to treat other PFO-related syndromes. In the last twenty years, disc-based devices have represented the armamentarium of the interventional cardiologist; recently, suture-based devices have become an attractive alternative, despite limited data regarding their long-term performance. The present review gives an overview of the current evidence regarding suture-based PFO closure, the device's characteristics, the echocardiographic evaluation of the PFO anatomy, and recommendations for patient selection. A detailed procedural guide is then provided, and potential complications and future developments in the field are discussed.

Cardioembolic Stroke

Cardioembolism accounts globally for around 25% of ischemic strokes and is more often associated with higher rates of morbidity and mortality. Potential sources of cardioembolism into the intracranial circulation include paradoxic embolism, dysrhythmias, structural heart disease, and valvular heart disease. To identify the etiology of a patient's ischemic stroke, thorough investigation of the intracardiac structures, assessment of dysrhythmias, and consideration of high-risk events such as cardiac surgery are crucial. Treatment after cardioembolic stroke can be personalized based on the underlying cardioembolic source to minimize the risk of recurrent cerebral ischemic events.

Impact of patent foramen ovale with left-to-right shunt on atrial fibrillation ablation in young patients

OBJECTIVE

The CABANA study shows that atrial fibrillation (AF) paitents younger than 65 years benefit more from the AF radiofrequency catheter ablation (RFCA) procedure. The aim of this study is to investigate the impact of inherent patent foramen ovale (PFO) with a Left-to-Right Shunt on the RFCA procedure in young AF patients.

METHODS

Based on the presence or absence of inherent PFO, the AF patients were divided into the PFO groups and the non-PFO group. Clinical follow-up was also investigated.

RESULTS

A total of 285 AF patients were enrolled. PFO was detected by TEE in 42 patients. The age of patients at initial AF onset was younger in the PFO group than in the non-PFO group (58.3 ± 8.9 vs. 62.3 ± 9.6 years, P = 0.012). There were more AF patients aged <55 years in the PFO group than in the non-PFO group. For the 9 AF patients with PFO who experienced AF recurrence and the left-to-right shunts decreased in size in 5 of the patients aged <65 years. The LAD decreased in those patients. In the PeAF patients, 53/64 patients aged <65 years and 23/40 patients aged older than 65 years were free of AF (82.8 % vs. 57.5 %, respectively; P = 0.005).

CONCLUSION

Success is not affected when AF is combined PFO compared with AF without PFO. Young patients have better PeAF RFCA outcomes. AF in young patients with left atria enlargement and a serious AF burden, may lead to reduced EF and render PFO easy to detect.

Congenital heart disease: types, pathophysiology, diagnosis, and treatment options

Congenital heart disease (CHD) is a structural abnormality of the heart and/or great vessels and patients with CHD are at an increased risks of various morbidities throughout their lives and reduced long-term survival. Eventually, CHD may result in various complications including heart failure, arrhythmias, stroke, pneumonia, and sudden death. Unfortunately, the exact etiology and pathophysiology of some CHD remain unclear. Although the quality of life and prognosis of patients with CHD have significantly improved following technological advancement, the influence of CHD is lifelong, especially in patients with complicated CHD. Thus, the management of CHD remains a challenge due to its high prevalence. Finally, there are some disagreements on CHD among international guidelines. In this review, we provide an update of the pathophysiology, diagnosis, and treatment in most common type of CHD, including patent foramen ovale, atrial septal defect, ventricular septal defect, atrioventricular septal defect, patent ductus arteriosus, coarctation of the aorta, transposition of the great arteries, congenitally corrected transposition of the great arteries, coronary anomalies, left and right ventricular outflow tract obstruction, tetralogy of Fallot and Ebstein anomaly. In particular, we focus on what is known and what is unknown in these areas, aiming to improve the current understanding of various types of CHD.

Contrast-enhanced transcranial Doppler for the detection of right-to-left shunt: A new provocation method with a syringe-modified Valsalva maneuver

BACKGROUND

Contrast-enhanced transcranial Doppler (cTCD) study has been established as one of the most common investigations for detecting right-to-left shunt (RLS). Although the conventional Valsalva maneuver (c-VM) has been used to increase the sensitivity of cTCD for RLS, efforts are still needed to improve the detection rate further. We proposed a new provocation method with a syringe-modified Valsalva maneuver (sm-VM) during cTCD and compared the efficacy of this strategy with cTCD measured at resting and with the provocation of c-VM.

METHODS

Consecutive patients with suspicion of RLS who underwent cTCD in our institution between September 27, 2021, and April 1, 2022, were included in this study. Examination of cTCD was performed separately at the resting state and provoked with c-VM and sm-VM. The overall proportion of patients with RLS and their distribution with different RLS grades were compared.

RESULTS

A total of 389 patients (mean age: 49.37 years, male: 52.2%) were included in this study. The positive rate for RLS was significantly higher for cTCD detected with sm-VM than those detected at resting state and with c-VM (46.8% vs. 21.6% and 34.2%, all p < .05). Besides, cTCD detected with sm-VM was also associated with a higher proportion of patients with grade III RLS than those detected at resting state and with c-VM (11.3% vs. 1.8% and 0%, all p < .05).

CONCLUSIONS

Compared to cTCD detected at resting state and with c-VM, cTCD with sm-VM could further increase the positive detection rate of RLS.

Transorbital sonography in idiopathic intracranial hypertension: Single-center study, systematic review and meta-analysis

BACKGROUND AND PURPOSE

Transorbital sonography (TOS) provides a noninvasive tool to detect intracranial pressure by assessing optic nerve sheath diameter (ONSD) and optic disc elevation (ODE). The utility of TOS in the diagnosis of idiopathic intracranial hypertension (IIH) has been increasingly recognized.

METHODS

A single-center case-control study sought to compare TOS-acquired ONSD and ODE among IIH-cases versus patients with other neurological diseases (controls). Furthermore, a systematic review and meta-analysis was conducted to present pooled mean differences and diagnostic measures of ONSD and ODE between IIH-cases and controls.

RESULTS

In the single-center study, consisting of 31 IIH-cases and 34 sex- and age-matched controls, ONSD values were higher among IIH-cases than controls (p<.001), while ODE was more prevalent in cases (65% vs. 15%; p<.001). The receiver-operating characteristic (ROC)-curve analysis revealed that the optimal cutoff value of ONSD for predicting IIH was 5.15 mm, with an area under the curve (AUC) of 0.914 (95% confidence interval [CI]: 0.861-0.967) and sensitivity and specificity values of 85% and 90%, respectively. In a meta-analysis of 14 included studies with 415 IIH-cases, ONSD and ODE values were higher in IIH-cases than controls (mean difference in ONSD 1.20 mm; 95% CI: 0.96-1.44 mm and in ODE 0.3 mm; 95% CI: 0.33-0.67 mm). With regard to ONSD, pooled sensitivity, specificity, and diagnostic odds ratio were calculated at 85.5% (95% CI: 77.9-90.8%), 90.7% (95% CI: 84.6-94.5%), and 57.394 (95% CI: 24.597-133.924), respectively. The AUC in summary ROC-curve analysis was 0.878 (95% CI: 0.858-0.899) with an optimal cutoff point of 5.0 mm.

CONCLUSIONS

TOS has a high diagnostic utility for the noninvasive diagnosis of IIH and may deserve wider implementation in everyday clinical practice.

Multimodal Cardiac Imaging in the Assessment of Patients Who Have Suffered a Cardioembolic Stroke: A Review

Cardioembolic strokes account for 20-25% of all ischaemic strokes, with their incidence increasing with age. Cardiac imaging plays a crucial role in identifying cardioembolic causes of stroke, with early and accurate identification affecting treatment, preventing recurrence, and reducing stroke incidence. Echocardiography serves as the mainstay of cardiac evaluation. Transthoracic echocardiography (TTE) is the first line in the basic evaluation of structural heart disorders, valvular disease, vegetations, and intraventricular thrombus. It can be used to measure chamber size and systolic/diastolic function. Trans-oesophageal echocardiography (TOE) yields better results in identifying potential cardioembolic sources of stroke and should be strongly considered, especially if TTE does not yield adequate results. Cardiac computed tomography and cardiac magnetic resonance imaging provide better soft tissue characterisation, high-grade anatomical information, spatial and temporal visualisation, and image reconstruction in multiple planes, especially with contrast. These techniques are useful in cases of inconclusive echocardiograms and can be used to detect and characterise valvular lesions, thrombi, fibrosis, cardiomyopathies, and aortic plaques. Nuclear imaging is not routinely used, but it can be used to assess left-ventricular perfusion, function, and dimensions and may be useful in cases of infective endocarditis. Its use should be considered on a case-by-case basis. The accuracy of each imaging modality depends on the likely source of cardioembolism, and the choice of imaging approach should be tailored to individual patients.

Correlation between right-to-left shunt and sudden sensorineural hearing loss: protocol for a case-control study

BACKGROUND AND PURPOSE

Sudden sensorineural hearing loss (SSNHL) is a neurological and otolaryngological emergency during which rapid diagnosis and early treatment are of great importance. Clinical experience indicates that a considerable number of patients with SSNHL have concurrent right-to-left shunt (RLS). With limited reports, the association between SSNHL and RLS is yet unclear and there is a need for large observational studies to explore their latent relationship.

METHODS AND ANALYSIS

This proposed study is a prospective, observational case-control study. A total of 194 eligible participants matched in age and sex will be divided equally into two groups: 97 patients with SSNHL included in the case group and 97 individuals without SSNHL in the control group. Medical evaluations, including clinical characteristics, laboratory examination, audiological examination and ultrasonography examination, will be performed in all subjects. The primary outcome of the study is the difference in RLS rates between the groups. Differences in patent foramen ovale rates and other measured variables will be further assessed. A conditional logistic regression as a correlation analysis will be used to evaluate the relationship between RLS and SSNHL.

DISCUSSION

This study may provide evidence on the correlation between RLS and SSNHL in order to enrich the aetiology of SSNHL.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Ethics Committee of Peking University Shenzhen Hospital. A written informed consent form will be signed and dated by the participants and the researchers before the study begins. The results will be disseminated in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ChiCTR2200064067.

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.

Intrapulmonary and Intracardiac Shunts in Adult COVID-19 Versus Non-COVID Acute Respiratory Distress Syndrome ICU Patients Using Echocardiography and Contrast Bubble Studies (COVID-Shunt Study): A Prospective, Observational Cohort Study

OBJECTIVES

Studies have suggested intrapulmonary shunts may contribute to hypoxemia in COVID-19 acute respiratory distress syndrome (ARDS) with worse associated outcomes. We evaluated the presence of right-to-left (R-L) shunts in COVID-19 and non-COVID ARDS patients using a comprehensive hypoxemia workup for shunt etiology and associations with mortality.

DESIGN

Prospective, observational cohort study.

SETTING

Four tertiary hospitals in Edmonton, Alberta, Canada.

PATIENTS

Adult critically ill, mechanically ventilated, ICU patients admitted with COVID-19 or non-COVID (November 16, 2020, to September 1, 2021).

INTERVENTIONS

Agitated-saline bubble studies with transthoracic echocardiography/transcranial Doppler ± transesophageal echocardiography assessed for R-L shunts presence.

MEASUREMENTS AND MAIN RESULTS

Primary outcomes were shunt frequency and association with hospital mortality. Logistic regression analysis was used for adjustment. The study enrolled 226 patients (182 COVID-19 vs 42 non-COVID). Median age was 58 years (interquartile range [IQR], 47-67 yr) and Acute Physiology and Chronic Health Evaluation II scores of 30 (IQR, 21-36). In COVID-19 patients, the frequency of R-L shunt was 31 of 182 COVID patients (17.0%) versus 10 of 44 non-COVID patients (22.7%), with no difference detected in shunt rates (risk difference [RD], -5.7%; 95% CI, -18.4 to 7.0; p = 0.38). In the COVID-19 group, hospital mortality was higher for those with R-L shunt compared with those without (54.8% vs 35.8%; RD, 19.0%; 95% CI, 0.1-37.9; p = 0.05). This did not persist at 90-day mortality nor after adjustment with regression.

CONCLUSIONS

There was no evidence of increased R-L shunt rates in COVID-19 compared with non-COVID controls. R-L shunt was associated with increased in-hospital mortality for COVID-19 patients, but this did not persist at 90-day mortality or after adjusting using logistic regression.

Synchronous multimode ultrasound for assessing right-to-left shunt: a prospective clinical study

Background

Right-to-left shunt (RLS) is associated with several conditions and causes morbidity. In this study, we aimed to evaluate the effectiveness of synchronous multimode ultrasonography in detecting RLS.

Methods

We prospectively enrolled 423 patients with high clinical suspicion of RLS and divided them into the contrast transcranial Doppler (cTCD) group and synchronous multimode ultrasound group, in which both cTCD and contrast transthoracic echocardiography (cTTE) were performed during the same process of contrast-enhanced ultrasound imaging. The simultaneous test results were compared with those of cTCD alone.

Results

The positive rates of grade II (22.0%:10.0%) and III (12.7%:10.8%) shunts and the total positive rate (82.1748%) in the synchronous multimode ultrasound group were higher than those in the cTCD alone group. Among patients with RLS grade I in the synchronous multimode ultrasound group, 23 had RLS grade I in cTCD but grade 0 in synchronous cTTE, whereas four had grade I in cTCD but grade 0 in synchronous cTTE. Among patients with RLS grade II in the synchronous multimode ultrasound group, 28 had RLS grade I in cTCD but grade II in synchronous cTTE. Among patients with RLS grade III in the synchronous multimode ultrasound group, four had RLS grade I in cTCD but grade III in synchronous cTTE. Synchronous multimode ultrasound had a sensitivity of 87.5% and specificity of 60.6% in the patent foramen ovale (PFO) diagnosis. Binary logistic regression analyses showed that age (odds ratio [OR] = 1.041) and risk of paradoxical embolism score ≥ 7 (OR = 7.798) were risk factors for stroke recurrence, whereas antiplatelets (OR = 0.590) and PFO closure with antiplatelets (OR = 0.109) were protective factors.

Conclusion

Synchronous multimodal ultrasound significantly improves the detection rate and test efficiency, quantifies RLS more accurately, and reduces testing risks and medical costs. We conclude that synchronous multimodal ultrasound has significant potential for clinical applications.

Detection rate and shunt grading with synchronous testing of contrast transcranial Doppler and contrast transthoracic echocardiography: Preliminary findings

Patent foramen ovale, a common congenital atrial septal defect, may lead to cardiac right-to-left shunting (RLS), which has been associated with various diseases. Reliable techniques for detecting RLS are essential for diagnosis and assist with treatment decision-making. Contrast transcranial Doppler (c-TCD), contrast transthoracic echocardiography (c-TTE), and contrast transesophageal echocardiography can be used to detect RLS. However, it is still unclear which ultrasound modalities are the most practical and cost-effective. To evaluate the efficacy of synchronous c-TCD and c-TTE in detecting cardiac RLS. We prospectively designed and continuously recruited 100 patients with cryptogenic stroke, migraines, transient ischemic attack, unexplained syncope, or dizziness admitted at the First Affiliated Hospital of Shenzhen University between February 2020 and August 2020. Ninety-five patients underwent synchronous c-TCD and c-TTE (during a single contrast-enhanced ultrasound session). We compared synchronous test results with the results of c-TCD alone and c-TTE alone. Ninety-five patients successfully underwent synchronous c-TCD and c-TTE, with the data analyzed for each individual. The positive detection rates of Grade I, II, and III shunts with synchronous c-TCD and c-TTE were higher than those with c-TTE or c-TCD alone (P = .047, P = .002, and P = .024, respectively). Overall, the positive detection rates of synchronous tests, c-TCD alone, and c-TTE were 69.5%, 51.6%, and 31.6%, respectively (P = .000, and P = .012). Among the 66 patients who were double-RLS-positive (both c-TTE and c-TCD showed positive results), as detected by the synchronous test, 26 (39.3%) patients who underwent c-TTE alone had higher shunt grades detected than those who underwent c-TCD alone. Conversely, 5 (7.6%) patients who underwent c-TCD alone had higher shunt grades detected than those who underwent c-TTE alone (P = .000). Synchronous c-TCD and c-TTE testing can significantly improve the detection rate, accuracy, and test process efficacy for quantifying RLS, and reduce the testing risk, workload, and medical costs.

Diagnosis and Management of Cardioembolic Stroke

OBJECTIVE

Cardioembolic stroke accounts for nearly 30% of ischemic strokes. Prompt diagnosis of the underlying mechanism may improve secondary prevention strategies. This article reviews recent randomized trials, observational studies, case reports, and guidelines on the diagnosis and treatment of cardioembolic stroke.

LATEST DEVELOPMENTS

Several pathologies can lead to cardioembolic stroke, including atrial fibrillation, aortic arch atheroma, patent foramen ovale, left ventricular dysfunction, and many others. Secondary stroke prevention strategies differ across these heterogeneous mechanisms. In addition to medical treatment advances such as the use of direct oral anticoagulants in patients with atrial fibrillation, surgical treatments such as closure of patent foramen ovale have been shown to reduce the risk of recurrent stroke in select patients. Furthermore, left atrial appendage occlusion is a promising strategy for patients with atrial fibrillation who are candidates for short-term oral anticoagulation therapy but not long-term oral anticoagulation therapy.

ESSENTIAL POINTS

A thorough diagnostic evaluation is essential to determine cardioembolic causes of stroke. In addition to risk factor management and lifestyle modifications, identification and targeting of the underlying cardioembolic stroke mechanisms will lead to improved stroke prevention strategies in patients with cardioembolic stroke.

Recent progress in patent foramen ovale and related neurological diseases: A narrative review

Patent foramen ovale (PFO) is a common congenital cardiac abnormality when the opening of the interatrial septum is not closed in adulthood. This abnormality affects 25% of the general population. With the development of precision medicine, an increasing number of clinical studies have reported that PFO is closely related to various neurological diseases such as stroke, migraine, obstructive sleep apnea, and decompression syndrome. It has also been suggested that PFO closure could be effective for preventing and treating these neurological diseases. Therefore, increasing attention has been given to the prevention, diagnosis, and treatment of PFO-related neurological diseases. By reviewing existing literature, this article focuses on the pathogenesis, epidemiology, and clinical characteristics of PFO-related neurological diseases, as well as the prevention and treatment of different neurological diseases to discuss, and aims to provide current progress for this field and decision-making evidence for clinical practice.

The Role of Transcranial Doppler in Detecting Patent Foramen Ovale

Air embolic signals detected in the intracranial arteries using transcranial Doppler after intravenous injection of agitated saline bubbles indicate right-to-left cardiac shunting. They prove that emboli from venous sites can bypass the lungs and flow to the intracranial arteries. The Valsalva maneuver immediately after an intravenous injection of agitated saline bubbles helps the air bubbles pass through the shunt. If the air embolic signal appears in the intracranial arteries without the Valsalva maneuver, the shunting is highly significant to the etiology of embolism. Transcranial Doppler to detect air embolic signals after intravenous injection of agitated saline bubbles may not be mandatory to diagnose and treat patent foramen ovale; however, as with echocardiography, transcranial Doppler is considered a noninvasive, convenient, and low-cost investigation. The test should be helpful to confirm the significance of the corresponding patent foramen ovale.

Diagnostic Ultrasonography in Neurology

OBJECTIVE

Ultrasonography allows neurologists to complement clinical information with additional useful, easily acquired, real-time data. This article highlights its clinical applications in neurology.

LATEST DEVELOPMENTS

Diagnostic ultrasonography is expanding its applications with smaller and better devices. Most indications in neurology relate to cerebrovascular evaluations. Ultrasonography contributes to the etiologic evaluation and is helpful for hemodynamic diagnosis of brain or eye ischemia. It can accurately characterize cervical vascular atherosclerosis, dissection, vasculitis, or other rarer disorders. Ultrasonography can aid in the diagnosis of intracranial large vessel stenosis or occlusion and evaluation of collateral pathways and indirect hemodynamic signs of more proximal and distal pathology. Transcranial Doppler (TCD) is the most sensitive method for detecting paradoxical emboli from a systemic right-left shunt such as a patent foramen ovale. TCD is mandatory for sickle cell disease surveillance, guiding the timing for preventive transfusion. In subarachnoid hemorrhage, TCD is useful in monitoring vasospasm and adapting treatment. Some arteriovenous shunts can be detected by ultrasonography. Cerebral vasoregulation studies are another developing field of interest. TCD enables monitoring of hemodynamic changes related to intracranial hypertension and can diagnose cerebral circulatory arrest. Optic nerve sheath measurement and brain midline deviation are ultrasonography-detectable signs of intracranial hypertension. Most importantly, ultrasonography allows for easily repeated monitoring of evolving clinical conditions or during and after interventions.

ESSENTIAL POINTS

Diagnostic ultrasonography is an invaluable tool in neurology, used as an extension of the clinical examination. It helps diagnose and monitor many conditions, allowing for more data-driven and rapid treatment interventions.

Residual Right-to-Left-Shunt Following Transcatheter Patent Foramen Ovale Closure: The Role of Antithrombotic Treatment

BACKGROUND

Transcatheter closure of patent foramen ovale (PFO) is a highly effective therapy for patients with left circulation thromboembolism, not attributable to other conditions.

OBJECTIVES

This retrospective cohort study investigates the impact of baseline foramen ovale anatomy on the severity of the postclosure shunt.

METHODS

Patients with PFO, who underwent percutaneous closure, were followed up for at least 5 years postimplantation. Patients were classified into two groups based on the presence of high-risk features of the baseline PFO anatomy. At the follow-up follow-up, residual right-to-left shunt was assessed for the high and non-highrisk anatomy groups, via transcranial Doppler at rest and after performing the Valsalva maneuver, with the injection of agitated saline.

RESULTS

38 patients were examined after a mean follow-up period of 9 ± 3 years after implantation. After retrospective evaluation of the baseline transthoracic and transesophageal echo studies, 14 patients with high-risk PFO anatomy were identified. The degree of the residual right-to-left shunt, as assessed by the number of microbubbles was higher in the high-risk PFO anatomy group compared to the non-high-risk group, both at rest [1.50 (IQR: 0.00-3.25) vs. 0.00 (IQR: 0.00-0.00), p < 0.001] and post-Valsalva maneuver [7.50 (IQR: 1.50- 10.25) vs. 0.00 (IQR: 0.00-3.75), p = 0.003]. Furthermore, in the high-risk group, more microbubbles were detected at rest (p = 0.008) and post-Valsalva (p = 0.002) in subjects without antiplatelet treatment compared to subjects on prolonged antiplatelet therapy.

CONCLUSION

Baseline PFO anatomy affects the severity of the residual right-to-left shunt. Prolonged antiplatelet therapy may benefit patients with high-risk anatomical features.

Transcranial Doppler ultrasound: Clinical applications from neurological to cardiological setting

Transcranial Doppler (TCD) ultrasonography is a rapid, noninvasive, real-time, and low-cost imaging technique. It is performed with a low-frequency (2 MHz) probe in order to evaluate the cerebral blood flow (CBF) and its pathological alterations, through specific acoustic windows. In the recent years, TCD use has been expanded across many clinical settings. Actually, the most widespread indication for TCD exam is represented by the diagnosis of paradoxical embolism, due to patent foramen ovale, in young patients with cryptogenic stroke. In addition, TCD has also found useful applications in neurological care setting, including the following: cerebral vasospasm following acute subarachnoid hemorrhage, brain trauma, cerebrovascular atherosclerosis, and evaluation of CBF and cerebral autoregulation after an ischemic stroke event. The present review aimed to describe the most recent evidences of TCD utilization from neurological to cardiological setting.

Patent foramen ovale: diagnostic evaluation and the role of device closure

Although seemingly benign, the presence of a patent foramen ovale (PFO) may play an important role in the pathophysiology of disease, specifically a paradoxical embolism leading to cryptogenic stroke. The European Society of Cardiology recently published guidelines detailing how PFOs are associated with paradoxical embolism and how they are diagnosed and managed. This review guides physicians in the diagnostic and referral process to a multidisciplinary team involved in PFO closure. It reviews the clinical trials comparing device closure with medical therapy and highlights the current NHS England commissioning process on PFO management. Finally, we give an overview of other conditions where PFO device closure may need to be considered.

Point-of-Care Ultrasound in Neurology - Report of the EAN SPN/ESNCH/ERcNsono Neuro-POCUS Working Group

In the last decade, ultrasound examination in neurology has been undergoing a significant expansion of its modalities. In parallel, there is an increasing demand for rapid and high-quality diagnostics in various acute diseases in the prehospital setting, the emergency room, intensive care unit, and during surgical or interventional procedures. Due to the growing need for rapid answers to clinical questions, there is particular demand for diagnostic ultrasound imaging. The Neuro-POCUS working group, a joint project by the European Academy of Neurology Scientific Panel Neurosonology, the European Society of Neurosonology and Cerebral Hemodynamics, and the European Reference Centers in Neurosonology (EAN SPN/ESNCH/ERcNsono Neuro-POCUS working group), was given the task of creating a concept for point-of-care ultrasound in neurology called "Neuro-POCUS". We introduce here a new ultrasound examination concept called point-of-care ultrasound in neurology (Neuro-POCUS) designed to streamline conclusive imaging outside of the ultrasound center, directly at the bedside. The aim of this study is to encourage neurologists to add quick and disease-oriented Neuro-POCUS to accompany the patient in the critical phase as an adjunct not a substitution for computed tomography, magnetic resonance imaging, or standard comprehensive neurosonology examination. Another goal is to avoid unwanted complications during imaging-free periods, ultimately resulting in advantages for the patient.

Short-term results of percutaneous closure of a patent foramen ovale guided by transoesophageal echocardiography in patients with cryptogenic stroke: a retrospective study

Background

A patent foramen ovale (PFO) is a risk factor for cryptogenic stroke (CS), and interventional therapy for PFO can reduce the recurrence rate of CS. However, interventional therapies are primarily guided by X-ray imaging, and data on regular post-surgical follow-up with the transthoracic ultrasound foaming test (UFT) are rare. Thus, this study aimed to assess the short-term (12 months) results of PFO occlusion guided by transoesophageal echocardiography (TEE) and the results of regular UFTs.

Methods

Clinical records, echocardiographic data, and UFT results of 75 patients who underwent interventional therapy for PFO and CS were retrospectively analysed. The patients were grouped according to their preoperative UFT results: group A (n = 21), small volume of right-to-left shunts; group B (n = 22), moderate volume of right-to-left shunts; and group C (n = 32), large volume of right-to-left shunts. All patients were treated with an Amplatzer occluder under TEE guidance. UFT follow-up was conducted regularly until 12 months after surgery.

Results

No significant differences in preoperative data, length of hospital stay, or operative time were noted between the groups (p > 0.05). The length of the PFO and diameter of the occluder differed between the groups as follows: group A = group B < group C (p < 0.001). Notably, 1 patient in group C developed recurrent stroke 11 months postoperatively, and 2 patients in group C developed atrial arrhythmia, which improved after 3 months of antiarrhythmic treatment. However, 19 patients still had positive UFT results 12 months postoperatively. Furthermore, the positive UFT rate 12 months postoperatively differed between the groups as follows: group A = group B < group C (p < 0.05). A preoperative large-volume shunt was negatively associated with a negative UFT rate 12 months postoperatively (OR = 0.255, 95% CI: 0.104–0.625).

Conclusions

In patients with PFO and CS, interventional therapy guided by TEE could lead to satisfactory short-term (12 months) outcomes. Although the positive UFT rate gradually decreased, some patients still had positive UFT results 12 months postoperatively. Preoperatively, a large volume of right-to-left shunts and a longer PFO were the two risk factors for positive UFT results postoperatively. Further studies are required to clarify the relationship between postoperative positive UFT results and stroke recurrence.

Current Challenges and Future Directions in Handling Stroke Patients With Patent Foramen Ovale—A Brief Review

The role of patent foramen ovale (PFO) in stroke was debated for decades. Randomized clinical trials (RCTs) have shown fewer recurrent events after PFO closure in patients with cryptogenic stroke (CS). However, in clinical practice, treating stroke patients with coexisting PFO raises some questions. This brief review summarizes current knowledge and challenges in handling stroke patients with PFO and identifies issues for future research. The rationale for PFO closure was initially based on the concept of paradoxical embolism from deep vein thrombosis (DVT). However, RCTs did not consider such details, limiting their impact from a pathophysiological perspective. Only a few studies explored the coexistence of PFO and DVT in CS with varying results. Consequently, the PFO itself might play a role as a prothrombotic structure. Transesophageal echocardiography thus appears most appropriate for PFO detection, while a large shunt size or an associated atrial septum aneurysm qualify for a high-risk PFO. For drug-based treatment alone, studies did not find a definite superiority of oral anticoagulation over antiplatelet therapy. Remarkably, drug-based treatment in addition to PFO closure was not standardized in RCTs. The available literature rarely considers patients with transient ischemic attack (TIA), over 60 years of age, and competing etiologies like atrial fibrillation. In summary, RCTs suggest efficacy for closure of high-risk PFO only in a small subgroup of stroke patients. However, research is also needed to reevaluate the pathophysiological concept of PFO-related stroke and establish strategies for older and TIA patients and those with competing risk factors or low-risk PFO.

Bubble Test and Carotid Ultrasound to Guide Indication of Transesophageal Echocardiography in Young Patients With Stroke

Background and Purpose

Indication of transesophageal echocardiography (TEE) in patients ≤60 years with brain ischemia is uncertain.

Methods

This prospective double-blinded study included patients with cryptogenic acute ischemic stroke or transient ischemic attack (TIA) ≥18 and ≤60 years. After routine diagnostics, all patients underwent patent foramen ovale (PFO) screening by transcranial Doppler (TCD) bubble test, carotid ultrasound for atherosclerosis screening (intima-media-thickness >0.90 mm or plaques), and TEE. We calculated sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV) of the combined non-invasive ultrasound to predict therapy-relevant TEE findings.

Results

We included 240 consecutive patients (median 51 years, 39% women) of which 68 (28.3%) had both a negative bubble test and no carotid atherosclerosis. Of these, 66 (97.1%) had unremarkable TEE findings; in one patient a small PFO was found and closed subsequently, in another patient a 4.9 mm thick aortic atheroma was found, and double platelet inhibition initiated. Of the other 172 (71.7%) patients, 93 (54%) had PFO and 9 (5.2%) complex aortic plaques. No other therapy-relevant findings were present in both groups. Non-invasive ultrasound had a sensitivity of 98.0%, specificity of 47.8%, NPV of 97.1%, and PPV of 58.1% for therapy-relevant TEE findings.

Conclusions

Bubble test and carotid ultrasound could be used for the individual decision for/against TEE in patients with cryptogenic stroke ≤60 years. If they are unremarkable, TEE can be omitted with high safety regarding secondary prevention. If bubble test is positive and/or carotid ultrasound shows atherosclerosis, TEE should be carried out if PFO or aortic atheroma are potentially relevant for further patient management.

Evaluation of right-to-left shunt on contrast-enhanced transcranial Doppler in patent foramen ovale-related cryptogenic stroke: Research based on imaging

BACKGROUND

Cardiogenic embolism caused by patent foramen ovale (PFO) is a common etiology of cryptogenic stroke (CS), particularly in young and middle-aged patients. Studies about right-to-left shunt (RLS) detection using contrast-enhanced transcranial Doppler (c-TCD) are numerous. According to the time phase and number of microbubbles detected on c-TCD, RLS can be classified and graded. We hypothesized that the characteristics of an infarction lesion on diffusion-weighted imaging differs when combining the type and grade of RLS on c-TCD in patients with PFO-related CS.

AIM

To explore the characteristics of infarction lesions on diffusion-weighted imaging when combining the RLS type and grade determined by c-TCD.

METHODS

We retrospectively evaluated CS patients from August 2015 to December 2019 at a tertiary hospital. In total, 111 PFO-related CS patients were divided according to whether RLS was permanent (microbubbles detected both at resting state and after the Valsalva maneuver) or latent (microbubbles detected only after the Valsalva maneuver) on c-TCD. Each group was subdivided into small, mild and large RLS according to the grade of shunt on c-TCD. A normal control group was composed of 33 patients who suffered from simple dizziness. Intragroup and intergroup differences were analyzed in terms of clinical, laboratory and diffusion-weighted imaging lesion characteristics. The correlation between RLS grade evaluated by c-TCD and size of PFO determined by transesophageal echocardiography were also analyzed.

RESULTS

In 111 patients with PFO-related CS, 68 had permanent RLS and 43 had latent RLS. Clinical characteristics and laboratory tests were not significantly different among the permanent RLS, latent RLS and normal control groups. The proportion of patients with multiple territory lesions in the permanent RLS group (50%) was larger than that in the latent RLS group (27.91%; P = 0.021). Posterior circulation was more likely to be affected in the latent RLS group than in the permanent RLS group (30.23% vs 8.82%, P = 0.004). Permanent-large and latent-large RLS were both more likely to be related to multiple (P_trend = 0.017 and 0.009, respectively), small (P_trend = 0.035 and 0.006, respectively) and cortical (P_trend = 0.031 and 0.033, respectively) lesions. The grade of RLS evaluated by c-TCD was correlated to the size of PFO determined by transesophageal echocardiography (r = 0.758, P < 0.001).

CONCLUSION

Distribution of the infarct suggested the possible type of RLS. Multiple, small and cortical infarcts suggest large RLS induced by a large PFO.

The Genetic Landscape of Patent Foramen Ovale: A Systematic Review

Patent Foramen Ovale (PFO) is a common postnatal defect of cardiac atrial septation. A certain degree of familial aggregation has been reported. Animal studies suggest the involvement of the Notch pathway and other cardiac transcription factors (GATA4, TBX20, NKX2-5) in Foramen Ovale closure. This review evaluates the contribution of genetic alterations in PFO development. We systematically reviewed studies that assessed rare and common variants in subjects with PFO. The protocol was registered with PROSPERO and followed MOOSE guidelines. We systematically searched English studies reporting rates of variants in PFO subjects until the 30th of June 2021. Among 1231 studies, we included four studies: two of them assessed the NKX2-5 gene, the remaining reported variants of chromosome 4q25 and the GATA4 S377G variant, respectively. We did not find any variant associated with PFO, except for the rs2200733 variant of chromosome 4q25 in atrial fibrillation patients. Despite the scarceness of evidence so far, animal studies and other studies that did not fulfil the criteria to be included in the review indicate a robust genetic background in PFO. More research is needed on the genetic determinants of PFO.

Recent ultrasound advancements for the manipulation of nanobiomaterials and nanoformulations for drug delivery

Recent advances in ultrasound (US) have shown its great potential in biomedical applications as diagnostic and therapeutic tools. The coupling of US-assisted drug delivery systems with nanobiomaterials possessing tailor-made functions has been shown to remove the limitations of conventional drug delivery systems. The low-frequency US has significantly enhanced the targeted drug delivery effect and efficacy, reducing limitations posed by conventional treatments such as a limited therapeutic window. The acoustic cavitation effect induced by the US-mediated microbubbles (MBs) has been reported to replace drugs in certain acute diseases such as ischemic stroke. This review briefly discusses the US principles, with particular attention to the recent advancements in drug delivery applications. Furthermore, US-assisted drug delivery coupled with nanobiomaterials to treat different diseases (cancer, neurodegenerative disease, diabetes, thrombosis, and COVID-19) are discussed in detail. Finally, this review covers the future perspectives and challenges on the applications of US-mediated nanobiomaterials.

Comparison of right-to-left shunt characteristics in cryptogenic embolic ischemic stroke and non-cardioembolic ischemic stroke

BACKGROUND

Patent foramen ovale (PFO) has been considered a potential mechanism of embolic stroke of undetermined origin.

OBJECTIVE

The aim of the present study was to identify the features of the right-to-left shunt (RLS) in patients with undetermined embolic ischemic stroke and compare them with those of patients with non-cardioembolic ischemic stroke.

METHODS

A retrospective study was conducted with 168 patients with stroke and RLS separated into the following two groups: the undetermined embolic stroke group (UES group) and non-cardioembolic stroke group (NCES group). All patients were assessed by transcranial Doppler to evaluate the presence and quantification of microembolic signals (MES) at rest and under Valsalva maneuver.

RESULTS

Of all patients evaluated in the current study, 96 were included in the UES group and 72 in the NCES group. In the UES group, 65 patients had RLS with ≥10 MES (67.7%), which was higher than that observed in the NCES group (51.4%, p=0.038). According to the moment of the cardiac cycle, 75 patients (78.1%) in the UES group had a positive test at rest compared to 42 (58.3%) in the NCES group (p=0.007).

CONCLUSIONS

The current study demonstrated that almost 70% of patients with undetermined embolic stroke and PFO presented a large RLS and more than 75% had RLS at rest. These findings suggest that the size of the shunt should be taken into account when evaluating whether PFO could be a possible mechanism underlying cryptogenic stroke.

Estimation of patent foramen ovale size using transcranial Doppler ultrasound in patients with ischemic stroke

BACKGROUND AND PURPOSE

Patent foramen ovale (PFO)is associated with cryptogenic stroke, especially in young adults. Transcranial Doppler (TCD) ultrasound is used as a screening tool before transesophageal echocardiography (TEE). However, the use of Valsalva maneuver (VM) to identify a right-to-left-shunt underlies interindividual variability. Here, we aimed to assess whether a pressure-controlled standardization of VM is useful to estimate PFO size.

METHODS

We included patients aged 18-80 years with a PFO according to TEE. Subjects underwent TCD with microembolic signals (MES) counted under four pressure conditions (i.e., at rest, 15 mbar, 40 mbar, and maximum expiratory pressure). Findings were correlated with TEE-based PFO size. The predictive value of TCD at rest and VM-based TCD for PFO size estimation was assessed by stepwise multivariate linear regression models and multiple cross-tab-analyses.

RESULTS

We screened 203 subjects after a cerebrovascular event, of which 78 (48 males [61.5%], median age 55 years [22-80]) with PFO were included. We found an association between MES count and expiratory pressure (p < .001). Predefined MES count categories at TCD pressure conditions correlated significantly with PFO size measured by TEE. We propose a PFO size estimation model based on TCD at rest and under VM, which classified PFO size correctly in 64.1% with the highest accuracy for small PFOs.

CONCLUSION

Our data provide evidence that TCD with step-wise barometric standardization allows an estimation of PFO size with good accuracy. Though TCD will not replace TEE in future, this might be of clinical value in circumstances where TEE cannot be easily performed.

Transcatheter Closure of PFO and ASD: Multimodality Imaging for Patient Selection and Perioperative Guidance

Transcatheter closure of patent foramen ovale (PFO) and secundum type atrial septal defect (ASD) are common transcatheter procedures. Although they share many technical details, these procedures are targeting two different clinical indications. PFO closure is usually considered to prevent recurrent embolic stroke/systemic arterial embolization, ASD closure is indicated in patients with large left-to-right shunt, right ventricular volume overload, and normal pulmonary vascular resistance. Multimodality imaging plays a key role for patient selection, periprocedural monitoring, and follow-up surveillance. In addition to routine cardiovascular examinations, advanced neuroimaging studies, transcranial-Doppler, and interventional transesophageal echocardiography/intracardiac echocardiography are now increasingly used to deliver safely and effectively such procedures. Long-standing collaboration between interventional cardiologist, neuroradiologist, and cardiac imager is essential and it requires a standardized approach to image acquisition and interpretation. Periprocedural monitoring should be performed by experienced operators with deep understanding of technical details of transcatheter intervention. This review summarizes the specific role of different imaging modalities for PFO and ASD transcatheter closure, describing important pre-procedural and intra-procedural details and providing examples of procedural pitfall and complications.

Novel robotic TCD ultrasound with bubbles versus standard care to detect right to left shunt: Study methods

BACKGROUND AND PURPOSE

Right to left shunt (RLS), from patent foramen ovale (PFO) or elsewhere, is a recognized risk factor for stroke. Current standard of care for RLS diagnosis includes transthoracic echocardiography (TTE) which is insensitive, transesophageal echocardiography (TEE) which is invasive, and transcranial Doppler (TCD) which has excellent sensitivity and specificity for RLS but is heavily operator dependent and expertise is scarce. The purpose of this study was to evaluate the RLS detection rate of a novel robotic-assisted TCD (ra-TCD) to standard of care diagnostic techniques, including TTE, TEE, and TCD.

METHODS

This is a multicenter, prospective, single-arm, nonsignificant risk device study of ra-TCD versus TTE for RLS diagnosis in adult patients who present with neurological signs and symptoms that include embolic stroke or transient ischemic attack on the differential diagnosis. Up to 150 subjects will be enrolled at up to seven centers considering the prevalence of PFO, suboptimal transtemporal windows, and potential dropouts. Enrolled patients will undergo ra-TCD supine and at 45° in a manner otherwise in line with standard of care TCD bubble technique. The enrolled patients will have undergone TTE, and optionally standard TCD and TEE, per usual care.

RESULTS

The primary efficacy endpoint is percent detection of RLS by ra-TCD compared against TTE. The primary safety endpoint is the incidence of device-related serious adverse events.

CONCLUSIONS

This is the first multicenter, prospective study evaluating the accuracy, feasibility, and safety of novel ra-TCD for the diagnosis of RLS as compared to standard of care diagnostics.

Right-to-left shunt detection using transforaminal insonation of the basilar artery

BACKGROUND AND PURPOSE

Investigation for patent foramen ovale (PFO) is warranted in patients with cryptogenic stroke (CS), as PFO closure is recommended in select CS patients for secondary stroke prevention. Transcranial Doppler (TCD) is noninvasive and has high sensitivity for PFO screening. However, 10% of the population has insufficient temporal bone windows to perform standard TCD monitoring of the middle cerebral arteries (MCAs). Prior reports showed similar diagnostic accuracy between the basilar artery and MCAs insonation. Our objective was to assess the accuracy of transforaminal insonation of the basilar artery (TIBA) in diagnosis of right-to-left shunt (RLS) in patients with inadequate temporal windows.

METHODS

We performed a retrospective, single-center, observational study of TIBA in patients with CS and inadequate temporal windows. We compared the PFO screening accuracy using TIBA versus echocardiogram, either transthoracic (TTE) or transesophageal echocardiogram (TEE).

RESULTS

Sixteen females and four males were included (mean age 63.2). All patients underwent TTE, 10 (50%) underwent gold-standard TEE. Nine patients had positive PFO with both TCD and echocardiogram. Two patients with negative echocardiogram had TCD-positive shunt. Three patients had PFO present on echocardiogram, whereas TCD was negative. Six patients had absent shunt with both TCD and echocardiogram. The sensitivity and specificity of TIBA for RLS detection were 75%, positive predictive value 82%, and negative predictive value 67%.

CONCLUSION

PFO screening accuracy using TIBA was 75%. Prospective evaluation of CS patients with TIBA and comparison to the gold-standard TEE should be performed to further guide clinical practice.

The role of echocardiography in the embolic stroke of undetermined source

: Echocardiography plays an important role both in the diagnosis and the treatment/prevention of embolic stroke of undetermined source and should be performed as soon as possible for preventing ischemic stroke recurrencies, which occur more frequently during the first week after the first ischemic event. Early identification of the cause of a transient ischemic attack or stroke is indeed a primary goal for the neurologist in the Stroke Unit and requires specific diagnostic strategies. Echocardiography, together with other diagnostic tools such as carotid and transcranial ultrasounds, provides this information promptly. In particular, echocardiography might be able to detect the main sources of the embolic stroke, such as atrial fibrillation, ventricular akinesia, aortic atheroma plaques and/or cardiac shunts. The present review discusses the importance and the practical role of echocardiography as a crucial diagnostic tool for detecting the main source of emboli in the setting of the acute stroke.

The evolving role of echocardiography in the assessment of patent foramen ovale in patients with left-side thromboembolism

Patent foramen ovale (PFO) is the most common congenital cardiac abnormality found approximately in 25% of the adult population The pathophysiological role of paradoxical embolization through the PFO in ischemic stroke is well established. "Self-expanding double disk" and, more recently, suture-based "deviceless" systems are used for PFO closure in the setting of secondary prevention after ischemic stroke likely related to paradoxical embolization. Ultrasound plays a significant role in PFO assessment, indication to treatment, intra-procedural guidance, and follow-up for those undergoing PFO closure. Three different techniques are frequently used for these purposes: transesophageal echocardiography, transthoracic echocardiogram, and transcranial Doppler. In this review, advantages and limits of these techniques are discussed in detail to improve our skills in detection and treatment of this important condition by using ultrasound.

Comparing the diagnostic value of Echocardiography In Stroke (CEIS) - results of a prospective observatory cohort study

BACKGROUND

Echocardiography is one of the main diagnostic tools for the diagnostic workup of stroke and is already well integrated into the clinical workup. However, the value of transthoracic vs. transesophageal echocardiography (TTE/TEE) in stroke patients is still a matter of debate. Aim of this study was to characterize relevant findings of TTE and TEE in the management of stroke patients and to correlate them with subsequent clinical decisions and therapies.

METHODS

We evaluated n = 107 patients admitted with an ischemic stroke or transient ischemic attack to our stroke unit of our university medical center. They underwent TTE and TEE examination by different blinded investigators.

RESULTS

Major cardiac risk factors were found in 8 of 98 (8.2%) patients and minor cardiac risk factors for stroke were found in 108 cases. We found a change in therapeutic regime after TTE or TEE in 22 (22.5%) cases, in 5 (5%) cases TEE leads to the change of therapeutic regime, in 4 (4%) TTE and in 13 cases (13.3%) TTE and TEE lead to the same change in therapeutic regime. The major therapy change was the indication to close a patent foramen ovale (PFO) in 9 (9.2%) patients with TTE and in 10 (10.2%) patients with TEE (p = 1.000).

CONCLUSION

Major finding with clinical impact on therapy change is the detection of PFO. But for the detection of PFO, TTE is non inferior to TEE, implicating that TTE serves as a good screening tool for detection of PFO, especially in young age patients.

TRIAL REGISTRATION

The trial was registered and approved prior to inclusion by our local ethics committee (1/3/17).

Pulmonary arteriovenous fistula diagnosed by transthoracic contrast echocardiography: A case report

We report the case of a 38-year-old woman who was admitted due to right limb numbness. A right-to-left shunt (RLS) was detected by transthoracic contrast echocardiography (cTTE), and microbubbles appeared in the left heart seven cardiac cycles after opacification of the right heart, suggesting pulmonary arteriovenous fistula. This was supported by computed tomography angiography. She underwent thoracoscopic partial right lower pneumonectomy and recovered after surgery. At 1 year follow-up, she had no relapse of stroke or cerebral infarction. This case shows the typical signs of pulmonary arteriovenous fistula on contrast-enhanced trans-thoracic echocardiography, which allowed an accurate and rapid diagnosis.

Patent foramen ovale closure for secondary prevention of cryptogenic stroke

Introduction: A patent foramen ovale (PFO) is highly prevalent among the adult population. It allows shunting of blood through the inter-atrial septum and has been associated with cryptogenic stroke, transient ischemic attack, platypnea-orthodeoxia syndrome, decompression sickness (e.g. deep-water divers), and migraines.Areas Covered: In this manuscript, we will review the anatomy of PFO with particular emphasis on the factors associated with increased risk of paradoxical embolization, as well as the different modalities for the diagnosis of PFO. We will discuss medical, surgical, and transcatheter therapy for secondary prevention in patients with PFO and cryptogenic stroke, and summarize the data from observational studies, randomized controlled trials (RCTs), and meta-analysis of RCTs that have established the beneficial effect of transcatheter PFO closure in this patient population. Finally, we will provide a brief overview of the role of transcatheter PFO closure in patients with migraine.Expert Opinion: Transcatheter closure is the preferred treatment option in young (<60 years) patients with PFO and cryptogenic stroke. A multi-disciplinary approach with input from clinical cardiologist, neurologist, hematologist, cardiac surgeon, and interventional cardiologist provides the best therapeutic plan for each patient taking into account the available data, but also medical, social, and occupational considerations.

EACVI survey on the management of patients with patent foramen ovale and cryptogenic stroke

AIMS

The European Association of Cardiovascular Imaging (EACVI) Scientific Initiatives Committee performed a global survey to evaluate the current practice for the assessment and management of patients with suspected patent foramen ovale (PFO) and cryptogenic stroke.

METHODS AND RESULTS

In total, 79 imaging centres from 34 countries across the world responded to the survey, which comprised 17 questions. Most non-invasive investigations for PFO were widely available in the responding centres, with the exception of transcranial colour Doppler which was only available in 70% of sites, and most commonly performed by neurologists. Standard transthoracic echocardiography, with or without bubbles, was considered the first-level test for suspected PFO in the majority of the centres, whereas transoesophageal echocardiography was an excellent second-level modality. Most centres would rule out atrial fibrillation (AF) as a source of embolism in all patients with cryptogenic stroke (63%), with the remainder reserving investigation for patients with multiple AF risk factors (33%). Cardiac magnetic resonance was the preferred tool for identifying other unusual aetiologies, like cardiac masses or thrombi. After PFO closure, there was variation in the use of antiplatelet therapy: a quarter recommended treatment for life, while only 12% recommended 5 years as stipulated in the guidelines (12%). Antibiotic prophylaxis prior to dental or endoscopic procedures was not recommended in 41% of centres, contrary to what the guidelines recommended.

CONCLUSION

Our survey revealed a variable adherence to the current recommendations for the diagnosis and management of patients with cryptogenic stroke and PFO. Efforts should focus on optimizing and standardizing diagnostic tests and treatment of this condition.