Permanent right-to-left shunt is the key factor in managing patent foramen ovale

Trigger factors in patients with a patent foramen ovale-associated stroke: A case-crossover study

BACKGROUND

Patent foramen ovale (PFO) is a congenital anatomical variant which is associated with strokes in young adults. Contrary to vascular risk factors and atherosclerosis, a PFO is present from birth. However, it is completely unknown how an anatomical structure that is already present at birth in a large proportion of the population can convert into a PFO that causes stroke in a few. Recent studies reported a significant association between certain trigger factors and ischemic stroke in young adults. This study aims to investigate these triggers in PFO-associated stroke.

METHODS

The ODYSSEY study, a multicenter prospective cohort study between 2013 and 2021, included patients aged 18-49 years experiencing their first-ever ischemic event. Participants completed a questionnaire about exposure to potential trigger factors. A case-crossover design was used to assess the relative risks (RR) with 95% confidence intervals (95% CI). The primary outcome was the RR of potential trigger factors for PFO-associated stroke.

RESULTS

Overall, 1043 patients completed the questionnaire and had an ischemic stroke, of which 124 patients had a PFO-associated stroke (median age 42.1 years, 45.2% men). For patients with PFO-associated stroke, the RR was 26.0 (95% CI 8.0-128.2) for fever, 24.2 (95% CI 8.5-68.7) for flu-like disease, and 3.31 (95% CI 2.2-5.1) for vigorous exercise.

CONCLUSION

In conclusion, flu-like disease, fever, and vigorous exercise may convert an asymptomatic PFO into a stroke-causing PFO in young adults.

DATA ACCESS STATEMENT

The raw and anonymized data used in this study can be made available to other researchers on request. Written proposals can be addressed to the corresponding author and will be assessed by the ODYSSEY investigators for appropriateness of use, and a data sharing agreement in accordance with Dutch regulations will be put in place before data are shared.

Differences and similarities in interatrial shunts management

Atrial septal defects (ASD) and Patent foramen ovale (PFO) represent the most common congenital heart diseases (CHD) adulthood. These two clinical entities, having different embryological origin, as well as clinical manifestations, clinical course and treatment must be carefully distinguished. Right heart failure and pulmonary hypertension are considered the major determinants of morbidity and mortality in ASD. Conversely, new pathophysiology concepts have been raised in the management of PFO as left atrium cardiopathy. New diagnostic tools, including cardiac magnetic resonance and intracardiac echocardiography have joint transthoracic and transesophageal echocardiography in the diagnostic definition of both ASD and PFO as well as in guiding their percutaneous closure. Moreover, several innovations have been developed in the field of percutaneous ASD and PFO closure devices including new evidence supporting the safety and efficacy of device-based closure. Aim of the present review is to present review we provided and update overview on ASD and PFO, focusing on the novel concepts regarding their pathophysiological and therapeutic aspects.

Atrial septal aneurysm contribution to the risk of cryptogenic stroke in patients with patent foramen ovale: A brief updated systematic review and meta-analysis

Atrial septal aneurysms (ASA) play an important role in cryptogenic stroke (CS) in patients with patent foramen ovale (PFO) but its contribution remains still not fully clarified in current literature. We sought to evaluate the contribution of ASA to the risk of CS in PFO patients based on studies published so far by means of a systematic review and metanalysis. A literature search, based on PubMed, Google Scholar and EMBASE databases, was performed to locate articles, published English language between 2000 and 2021, analysing the relationship between ASA and CS. The final research was conducted in September 2021. A total of 577 articles were retrieved after excluding duplicates. The initial screening excluded 215 articles because they did not meet inclusion criteria, leaving 362 articles to assess for eligibility. Subsequently, after evaluation of the full-text articles, 354 were excluded and 8 investigations met the inclusion criteria. Overall, 822 patients (mean age 48.3 years) were enrolled in the reviewed manuscripts with a prevalence of males of 48.7% and a normal distribution of the classical cardiovascular risk factors. ASA was present in 25.3% (208 subjects) of the patients enrolled, while the association of PFO+ASA was observed in 24.3% (200 subjects) of patients enrolled. PFO Patients with ASA were at higher risk of CS compared to those without (odd ratio: 3.38, 95% CI: 2.72-5.51, p<0.001, I2=4.3%,). The relative funnel plot did not show any evident asymmetry, confirming absence of publication bias. Our updated metanalysis enhances the importance of ASA contribution to stroke in patients with patent foramen ovale, being present in a third of patients with symptomatic PFO to whom it confers an additional odd ratio of 3.38.

Comparison of the short-term efficacy of different Amplatzer models and similar occluders in the treatment of patent foramen ovale

Objective

To compare the recent efficacy and safety of different Amplatzer models and similar occluder in the treatment of patent foramen ovale (PFO).

Methods

Patients with PFO complicated with cryptogenic stroke or migraine who underwent transcatheter closure of PFO in the First Affiliated Hospital of Nanjing Medical University from September 2019 to March 2021 were selected. Patients were grouped according to the type of occluder device. The basic data of the patients were collected and followed up within 1 year after occlusion. Effectiveness was defined as no recurrence of stroke/remission of migraine symptoms and a negative postoperative foaming test, and safety events were counted as the combined results of serious adverse events.

Results

A total of 92 patients were selected, including 45 cases in the symmetrical group and 47 cases in the asymmetric group. There were no serious adverse events in the 2 groups during follow-up. 3 days and 1 month after occlusion, the number of shunt patients in the asymmetric group was significantly less than that in the symmetric group (χ² = 5.484, P = 0.019; χ² = 5.146, P = 0.023). The negative rate of blocked residual shunts in the asymmetric group was higher than that in the symmetric group at 1, 3, 6 and 12 months after occlusion (χ² = 6.473, P = 0.011; χ² = 4.305, P = 0.038; χ² = 4.842, P = 0.027; χ² = 4.034, P = 0.045). Headache in migraine patients in the asymmetric group was significantly better than headache in patients in the symmetric group (P = 0.038; P = 0.049).

Conclusion

Asymmetric Amplatzer and similar occluders provide greater efficacy in short-term occlusion than symmetric ones.

Pitfalls of Using Imaging Technique in the Presence of Eustachian Valve or Chiari Network: Effects on Right-to-Left Shunt and Related Influencing Factors

When patent foramen ovale (PFO) combines with the prominent Eustachian valve or Chiari network (EV/CN), contrast transthoracic echocardiography (cTTE) may miss the diagnosis of PFO. We sought to determine the characteristics of right-to-left shunt (RLS) in PFO patients with prominent EV/CN on cTTE and identify the causal factors of missed diagnosis. We consecutively enrolled 98 patients who suffered from PFO-related stroke and with prominent EV/CN. All patients were divided into the delayed and non-delayed groups according to the characteristics of RLS on cTTE. The characteristics of RLS were compared with those of 42 intrapulmonary shunt patients. The anatomical characteristics of PFO and EV/CN were analyzed in the 98 PFO patients. Upon cTTE, significantly delayed occurrence and longer duration of the RLS in the delayed group were found both at rest and during the Valsalva maneuver, similar to the intrapulmonary shunt. Multivariate logistic analysis revealed that the length of EV/CN (>19 mm) and the diameter of PFO at the left atrium aspect (<1.2 mm) were high-risk factors for missed diagnosis. In conclusion, RLS showed delayed emergence and disappearance in some of the PFO patients with prominent EV/CN. The length of EV/CN and the diameter of PFO may have been related to the missed diagnosis of PFO.

Increased Blood Residence Time as Markers of High-Risk Patent Foramen Ovale

Previous investigations have suggested that patients with patent foramen ovale (PFO) often have an atrial dysfunction, like to that observed in patients with atrial fibrillation (AF) which may concur to an increased risk of cryptogenic stroke. The aim of the study is to compare the atrial resident time (Rt) of PFO patients to those with sinus rhythm (SR) and AF using patient-specific 3D computational fluid dynamics (CFD) analysis. Models of left atrium (LA) hemodynamics were obtained from time-resolved CT scans and transthoracic echocardiography (TTE). Enrolled patients were divided into three groups: 30 healthy subjects with SR, 30 with PFO, and 30 with AF without PFO. Blood stasis was evaluated by determining the blood residence time (Rt) distribution in the LA and left atrial appendage (LAA). Overall, 90 patients (mean age 47.4 ± 7.5 years, 51 males) were included into the analysis. PFO patients exhibit higher mean Rt values compared to healthy subjects (2.65 ± 0.2 vs 1.5 ± 0.2 s). Conversely, AF patients presented higher Rt when compared to PFO patients (2.9 ± 0.3 vs 2.3 ± 0.2 s). Moreover, PFO patients presenting cerebral lesions at magnetic resonance imaging have a higher Rt compared to those without (2.9 ± 0.3 vs 2.3 ± 0.2 s, respectively, p < 0.001). PFO patients have a higher degree of atrial Rt compared to healthy subjects similar to that observed in AF patients. The higher mean LA Rt values offer an insight into the pathophysiological mechanism linking PFO with cryptogenic stroke and might be a marker of high-risk PFOs.

Importance of direct right-to-left shunt as high-risk patent foramen ovale associated with cryptogenic stroke

BACKGROUND

Because transcatheter closure of patent foramen ovale (PFO) has become effective for preventing cryptogenic stroke (CS), it is necessary to determine high-risk PFO associated with CS. This study aimed to clarify the importance of direct right-to-left (RL) shunt through the PFO for identifying high-risk PFO.

METHODS

We analyzed 137 patients with and without CS who were confirmed to have PFO. The timing of RL shunt through the PFO was evaluated by cardiac cycles after right atrium (RA) opacification on saline contrast transesophageal echocardiography. Direct RL shunt was defined as microbubbles crossing the PFO before and at the same time of RA opacification.

RESULTS

Cardiac cycles of microbubbles crossing the PFO were shorter in patients with CS than in those without CS (2.0 ± 2.2 vs .5 ± 1.1, p < 0.01). Direct RL shunt was more frequently observed in patients with CS than in those without CS (77% vs 29%, p < 0.01), with a sensitivity of 79% and a specificity of 71% for the association with CS. Multivariate analysis revealed that direct RL shunt was related to atrial septal aneurysm and low-angle PFO. Regarding functional features of PFO, the detection rate of CS was 50% for large RL shunt alone, and was increased to 83% when direct RL shunt was added.

CONCLUSION

Direct RL shunt was associated with CS and had the incremental value in detecting PFO associated with CS for large RL shunt. The timing of RL shunt can be valuable for identifying high-risk PFO.

Importance of Persistent Right-to-Left Shunt After Patent Foramen Ovale Closure in Cryptogenic Stroke Patients

Percutaneous closure of patent foramen ovale (PFO) is widely performed to prevent recurrent stroke or transient ischemic attack in patients with cryptogenic stroke. However, the influence of different degrees of right-to-left shunting (RLS) has rarely been reported. We retrospectively evaluated the cases of 268 patients with cryptogenic stroke who underwent PFO closure at our hospital from April 2012 through April 2015. In accordance with RLS severity, we divided the patients into 2 groups: persistent RLS during normal breathing and the Valsalva maneuver (n=112) and RLS only during the Valsalva maneuver (n=156). Baseline characteristics, morphologic features, and procedural and follow-up data were reviewed. The primary endpoint was stroke or transient ischemic attack. More patients in the persistent group had multiple or bilateral ischemic lesions, as well as a larger median PFO diameter (2.5 mm [range, 1.8-3.9 mm]) than did patients in the Valsalva maneuver group (1.3 mm [range, 0.9-1.9 mm]) (P <0.001). Atrial septal aneurysm was more frequent in the persistent group: 25 patients (22.3%) compared with 18 (11.5%) (P=0.018). Three patients in the persistent group had residual shunting. The annual risk of recurrent ischemic stroke was similar between groups: 0.298% (persistent) and 0.214% (Valsalva maneuver). Our findings suggest that patients with persistent RLS have more numerous severe ischemic lesions, larger PFOs, and a higher incidence of atrial septal aneurysm than do those without. Although our persistent group had a greater risk of residual shunting after PFO closure, recurrence of ischemic events did not differ significantly from that in the Valsalva maneuver group.

Reverse takotsubo cardiomyopathy caused by patent foramen ovale-related cryptogenic stroke: a case report

Background

Reverse takotsubo cardiomyopathy (rTTC) is recognized as an atypical type of TTC. It has been suggested that neurological events are typical trigger of rTTC, especially in young individuals.

Case summary

In this case report, we describe a 16-year-girl who presented with neurological deficits due to embolic stroke and acute heart failure. Transthoracic echocardiography on admission revealed a severely reduced left ventricular (LV) function with akinesis of basal to mid LV, but normal contraction in apex. Coronary computed tomography angiography confirmed unobstructed coronary arteries. Two weeks later, her LV wall motion and ejection fraction were completely normalized. Transthoracic echocardiography and transoesophageal echocardiography demonstrated no evidence of intracardiac thrombus but showed a patent foramen ovale (PFO) with large shunt. After thorough work-up and brain–heart team discussion, we concluded that the patient developed rTTC due to cryptogenic stroke related with her PFO. She underwent percutaneous PFO closure for secondary prevention with good clinical course.

Discussion

Reverse TTC is a rare condition. It should be considered in stroke patients with acute heart failure. Quick diagnosis and management with brain–heart team is crucial for better prognosis.

A new dimension in patent foramen ovale size estimation

BACKGROUND

Detailed multidimensional assessment of patent foramen ovale (PFO) size with transesophageal echocardiography (TOE) may help to determine PFO pathogenicity in cryptogenic stroke patients. We explored the potential additive value of Live xPlane and three-dimensional (3D) TOE anatomical PFO sizing techniques.

METHODS

Imaging data of 45 patients who underwent a 3D TOE-assisted percutaneous PFO closure were studied. The two-dimensional (2D) PFO separation distance and right-to-left (RL) contrast shunt magnitude were assessed on preprocedural TOE recordings. Peri-procedural measurements of the triangular anatomical PFO opening (base, height, and area) were performed after positioning of a stiff guidewire (SW) through the PFO, using Live xPlane imaging and 3D Zoom mode.

RESULTS

The PFO SW base appeared on average 5 times larger than the preprocedural 2D PFO separation (median difference [IQR] = 13[5] mm; P < .001). For a same PFO separation, the width of the PFO base may vary significantly. The PFO SW base was significantly larger in patients with a large versus a small-to-moderate PFO RL contrast shunt (18 vs 15 mm; P = .007) and in those with a spontaneous versus a provoked shunt (18 vs 14 mm; P = .003).

CONCLUSION

Live xPlane and 3D Zoom TOE allow peri-procedural measurement of the largest dimension of a PFO, which is the PFO base. Patients with a large or spontaneous RL contrast shunt appear to have a larger PFO base. The anatomical PFO base dimension may be taken into account for optimization of device and patient selection strategies.

Cough maneuver is superior to Valsalva maneuver for detecting mild-extent right-to-left shunt

Objective: The purpose of this study was to explore the different provocative maneuvers in detecting right-to-left shunt during contrast transthoracic echocardiography (cTTE). Methods: We evaluated 378 patients for right-to-left shunt detection by cTTE at the quiet respiration, during Valsalva maneuver (blowing into a face mask connected to a sphygmomanometer at 40 mmHg for 10 s), and during cough maneuver, performed in random order, and the degree of right-to-left shunt as the number of microbubbles in the left atrium per frame after each provocative maneuver was recorded. Results: The detection rates of right-to-left shunt for quiet respiration, Valsalva maneuver, and cough maneuver were 16%, 33%, and 38%, respectively (p < .001). The detection rate for cough maneuver was significantly higher than that for Valsalva maneuver (p < .001). There was no significant difference between Valsalva maneuver and cough maneuver in terms of detecting moderate- or severe-extent right-to-left shunt (p > .05), but cough maneuver was significantly better than Valsalva maneuver at detecting mild-extent right-to-left shunt (p = .001). Conclusions: Cough maneuver is an effective alternative to Valsalva maneuver, with a higher detection rate for mild-extent right-to-left shunt during cTTE, maybe due to its own mechanical characteristics.

Identification of High-Risk Patent Foramen Ovale Associated With Cryptogenic Stroke: Development of a Scoring System

BACKGROUND

Transcatheter closure of patent foramen ovale (PFO) has become an effective therapeutic strategy for cryptogenic stroke (CS). The identification of high-risk PFO is essential, but the data are limited. This study aimed to clarify the factors related to CS and to develop a score for high-risk PFO.

METHODS

We retrospectively analyzed 57 patients with prior CS and 50 without CS who were scheduled for transcatheter closure. PFO characteristics were evaluated by transesophageal echocardiography. Based on factors related to CS, we estimated the risk score.

RESULTS

Patients with CS had a greater frequency of large-size PFO (≥2 mm in height), long-tunnel PFO (≥10 mm in length), atrial septal aneurysm, hypermobile interatrial septum, prominent Eustachian valve or Chiari's network, the large right-to-left shunt at rest and during Valsalva maneuver, and low-angle PFO (≤10° of PFO angle from inferior vena cava), compared with patients without CS. Multivariate analysis showed that long-tunnel PFO, the presence of hypermobile interatrial septum, the presence of prominent Eustachian valve or Chiari's network, the large right-to-left shunt during Valsalva maneuver, and low-angle PFO were independently related to CS. When the score was estimated based on 1 point for each factor, the proportion of CS was markedly elevated with a score of ≥2 points. The probability of CS was markedly different between scores of ≤1 or ≥2 points.

CONCLUSIONS

PFO risk can be assessed with a score based on high-risk features. The presence of two or more high-risk PFO features is associated with CS.

Right-to-left shunt and subclinical ischemic brain lesions in Chinese migraineurs: a multicentre MRI study

Background

Migraine is considered as a risk factor for subclinical brain ischemic lesions, and right-to-left shunt (RLS) is more common among migraineurs. This cross-sectional study assessed the association of RLS with the increased prevalence of subclinical ischemic brain lesions in migraineurs.

Methods

We enrolled 334 migraineurs from a multicentre study from June 2015 to August 2016. Participants were all evaluated using contrast-enhanced transcranial Doppler, magnetic resonance imaging (MRI), and completed a questionnaire covering demographics, the main risk factors of vascular disease, and migraine status. RLS was classified into four grades (Grade 0 = Negative; Grade I = 1 ≤ microbubbles (MBs) ≤ 10; Grade II = MBs > 10 and no curtain; Grade III = curtain). Silent brain ischemic infarctions (SBI) and white matter hyperintensities (WMHs) were evaluated on MRI.

Results

We found no significant differences between migraineurs with RLS and migraineurs without RLS in subclinical ischemic brain lesions.SBI and WMHs did not increase with the size of the RLS(p for trend for SBI = 0.066, p for trend for WMHs = 0.543). Furthermore, curtain RLS in migraineurs was a risk factor for the presence of SBI (p = 0.032, OR = 3.47; 95%CI: 1.12−10.76). There was no association between RLS and the presence of WMHs.

Conclusion

Overall, RLS is not associated with increased SBI or WMHs in migraineurs. However, when RLS is present as a curtain pattern, it is likely to be a risk factor for SBIs in migraineurs.

Trial registration

No. NCT02425696; registered on April 21, 2015.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1022-7) contains supplementary material, which is available to authorized users.

Atrial dyssynchrony and left atrial stiffness are risk markers for cryptogenic stroke in patients with patent foramen ovale

OBJECTIVE

The clinical and echocardiographic parameters associated with the risk predictors of cryptogenic stroke (CS) in patients with patent foramen ovale (PFO) still diverse and with a great debate. We hypothesized that left atrial stiffness (LASt) and atrial dyssynchrony may increase the risk of CS in patients with PFO.

METHODS

A total of 129 consecutive patients presented without clinical reasoning of stroke were recruited. Transesophageal echocardiographic assessment was performed to investigate the presence of PFO. PFO was identified in 52% (group I) and absent in 48% (group II). Utilizing speckle-tracking imaging LASt and atrial dyssynchrony was evaluated among patients with PFO (group I) vs those without PFO (group II).

RESULTS

LASt was significantly increased in group I patients compared with group II (P < .001). Likewise patients with PFO had a significant LA dyssynchrony compared with those in group II (P < .001). Interatrial dyssynchrony and left atrial dyssynchrony were correlated with LASt (r = .47 and 0.51, respectively; P < .001). Cardiac arrhythmias were significantly encountered in group I patients (at presentation and with Holter monitoring) P < .001. Besides significantly increase in atrial dyssynchrony and in LASt in patients with arrhythmias compared with those without (P < .001). ROC analysis revealed that LASt index ≥ 0.61 and LA dyssynchrony ≥ 23.5 predicts cardiac arrhythmias in CS patients with PFO with (AUC: 0.85 and 0.87, respectively, P < .001).

CONCLUSION

In conclusion, we demonstrated that LASt and atrial dyssynchrony might be risk markers of cryptogenic stroke in patients with PFO.

Effect of patent foramen ovale closure for prevention on recurrent stroke or transient ischemic attack in selected patients with cryptogenic stroke

OBJECTIVES

This study was sought to evaluate the effectiveness of patent foramen ovale (PFO) closure in selected patients (PFO shunt grade more than moderate) with cryptogenic stroke (CS).

BACKGROUND

Whether closure of PFO is an effective treatment for prevention of CS is still unclear.

METHODS

Consecutive 158 patients (mean age: 49.9 years old, closure group: 67 patients, medication group: 91 patients) were enrolled. The primary end point was a composite of recurrent stroke and transient ischemic attack.

RESULTS

Baseline characteristics were similar between the two groups, except age which was younger in the closure group (47.7 ± 10.8 vs 51.9 ± 9.9, P = 0.013), and the presence of shunt at rest was more common in the closure group (35.8% vs 10.4%, P = 0.000). Procedural success was 94.0%. Over a mean follow-up of 27.8 months, a total of six primary end point, all of which were strokes, occurred only in the medication group (6.6% vs 0%, P = 0.039). Stroke-free survival rate was significantly higher in the closure group (P = 0.026) CONCLUSIONS: Our study showed that PFO closure may be an effective treatment strategy to prevent recurrent stroke or TIA for patients with CS if it is conducted in selective patients who have PFO shunt more than moderate grade.

Endocardial Device Leads in Patients with Patent Foramen Ovale: Echocardiographic Correlates of Stroke/TIA and Mortality

BACKGROUND

Echocardiographically detected patent foramen ovale (PFO) has been associated with stroke/transient ischemic attack (TIA) in patients with cardiac implantable electronic devices (CIEDs). We sought to evaluate the relationship between echocardiographic characteristics and risk of stroke/TIA and mortality in CIED patients with PFO.

METHODS

In 6,086 device patients, PFO was detected in 319 patients. A baseline echocardiogram was present in 250 patients, with 186 having a follow-up echocardiogram.

RESULTS

Of 250 patients with a baseline echocardiogram, 9.6% (n = 24) had a stroke/TIA during mean follow-up of 5.3 ± 3.1 years; and 42% (n = 105) died over 7.1 ± 3.7 years. Atrial septal aneurysm, prominent Eustachian valve, visible shunting across PFO, baseline or change in estimated right ventricular systolic pressure (RVSP)/tricuspid regurgitation (TR), or maximum RVSP were not associated with postimplant stroke/TIA (P > 0.05). An exploratory multivariate analysis using time-dependent Cox models showed increased hazard of death in patients with increase in TR ≥2 grades (hazard ratio [HR] 1.780, 95% confidence interval [CI] 1.447-2.189, P < 0.0001), or increase in RVSP by >10 mm Hg (HR 2.018, 95% CI 1.593-2.556, P < 0.0001), or maximum RVSP in follow-up (HR 1.432, 95% CI 1.351-1.516, P < 0.0001). A significant increase (P < 0.001) in TR was also noted during follow-up.

CONCLUSIONS

In patients with CIED and PFO, structural and hemodynamic echocardiographic markers did not predict future stroke/TIA. However, a significantly higher TR or RVSP was associated with higher mortality.

Recurrent and Residual Shunts After Patent Foramen Ovale Closure: Results From a Long-Term Transcranial Doppler Study

OBJECTIVES

Assess the evolution of right-to-left shunt (RLS) after transcatheter patent foramen ovale (PFO) closure.

BACKGROUND

Despite the high number of interventional procedures performed worldwide, limited systematic data on the long-term abolition of RLS after percutaneous closure are available.

METHODS

All patients treated at our Institution between February 2001 and July 2009 were included in this single center, prospective study, and were asked to repeat late contrast transcranial Doppler (cTCD). Rate of complete closure, residual RLS (i.e., a shunt that persists after closure), and recurrent RLS (i.e., a shunt that reappears after a previous negative cTCD) was assessed.

RESULTS

Long-term follow-up was completed in 120 patients (56% male). RLS was still detectable 4.9 ± 2.3 years (range 1.3-10.3) after the procedure in 55 patients; 20 (17%) had residual RLS and 35 (29%) had recurrent RLS. Multivariate analysis revealed that significant predictors of residual RLS included post-procedural shunt at transesophageal echocardiography (OR 3.07, 95%CI 0.97-9.7), use of a bigger device (35 vs 25 mm, OR 3.85, 95%CI 1.22-12.2) and length of follow-up (OR 0.75, 95%CI 0.57-0.98), while only length of follow-up (OR 0.77, 95%CI 0.62-0.95) was associated with recurrent RLS. Neurological recurrences (1 stroke, 6 transient ischemic attacks) were equally distributed between the groups.

CONCLUSION

A significant number of recurrent and residual shunts may be observed by cTCD up to 5 years after PFO closure. Management of late RLSs includes periodic re-evaluation, exclusion of device-induced complications or secondary sources of RLS, and optimization of antithrombotic treatment with or without a second intervention.

Patent Foramen Ovale and Stroke

A patent foramen ovale (PFO) is common and found in nearly 25% of healthy individuals. The majority of patients with PFO remain asymptomatic and they are not at increased risk for developing a stroke. The presence of PFO, however, has been found to be higher in patients with cryptogenic stroke, suggesting there may be a subset of patients with PFO who are indeed at risk for stroke. Paradoxical embolization of venous thrombi through the PFO, which then enter the arterial circulation, is hypothesized to account for this relationship. Although aerated-saline transesophageal echocardiography is the gold standard for diagnosis, aerated-saline transthoracic echocardiography and transcranial Doppler are often used as the initial diagnostic tests for detecting PFO. Patients with cryptogenic stroke and PFO are generally treated with antiplatelet therapy in the absence of another condition for which anticoagulation is necessary. Based on the findings of 3 large randomized clinical trials, current consensus guidelines do not recommend percutaneous closure, though this is an area of controversy. The following review discusses the relationship of PFO and cryptogenic stroke, focusing on the epidemiology, pathophysiological mechanisms, diagnostic tools, associated clinical/anatomic factors and treatment. (Circ J 2016; 80: 1665-1673).

PFO: Button me up, but wait … Comprehensive evaluation of the patient

Patent foramen ovale (PFO) is a slit or tunnel-like communication in the atrial septum occurring in approximately 25% of the population. A wide number of pathological conditions have been linked to its presence, most notably, cryptogenic stroke (CS) and migraine. However, in the setting of a neurological event, it is not often clear whether the PFO is pathogenically related to the index event or an incidental finding. Therefore, a detailed analysis of several clues is needed for understanding PFO's clinical significance, with a frequent case-by-case decision about destination therapy. Indeed, the controversy about PFO's pathogenicity prompted a paradigm shift of research interest from medical therapy with antiplatelets or anticoagulants to percutaneous transcatheter closure, in secondary prevention. Observational data and meta-analysis of observational studies had previously suggested that PFO closure with a device was a safe procedure with a low recurrence rate of stroke. To date, however, recent randomized controlled trials have not shown the superiority of PFO closure over medical therapy. Thus, the optimal strategy for secondary prevention of paradoxical embolism in patients with a PFO remains unclear. Moreover, the latest guidelines for the prevention on stroke restricted indications for PFO closure to patients with deep vein thrombosis and high-risk of its recurrence. Given these recent data, in the present review, we critically discuss current treatment options, pointing out the role of a comprehensive patient evaluation in overcoming PFO closure restrictions and planning the best management for each patient.

Patent foramen ovale

Patent foramen ovale (PFO) is the most common congenital heart abnormality of fetal origin and is present in approximately ∼25% of the worldwide adult population. PFO is the consequence of failed closure of the foramen ovale, a normal structure that exists in the fetus to direct blood flow directly from the right to the left atrium, bypassing the pulmonary circulation. PFO has historically been associated with an increased risk of stroke, the mechanism of which has been attributed to the paradoxical embolism of venous thrombi that shunt through the PFO directly to the left atrium. However, several studies have failed to show an increased risk of stroke in asymptomatic patients with a PFO, and the risk of stroke recurrence is low in patients who have had a stroke that may be attributed to a PFO. With the advent of transoesophageal and transthoracic echocardiography, as well as transcranial Doppler, a PFO can be routinely detected in clinical practice. Medical treatment with either antiplatelet or anticoagulation therapy is recommended. At the current time, closure of the PFO by percutaneous interventional techniques does not appear to reduce the risk of stroke compared to conventional medical treatment, as shown by three large clinical trials. Considerable controversy remains regarding the optimal treatment strategy for patients with both cryptogenic stroke and PFO. This Primer discusses the epidemiology, mechanisms, pathophysiology, diagnosis, screening, management and effects on quality of life of PFO.

The RoPE Score and Right-to-Left Shunt Severity by Transcranial Doppler in the CODICIA Study

BACKGROUND

For patients with cryptogenic stroke (CS) and patent foramen ovale (PFO), it is unknown whether the magnitude of right-to-left shunt (RLSh) measured by contrast transcranial Doppler (c-TCD) is correlated with the likelihood an identified PFO is related to CS as determined by the Risk of Paradoxical Embolism (RoPE) score. Additionally, for patients with CS, it is unknown whether PFO assessment by c-TCD is more sensitive for identifying RLSh compared with transesophageal echocardiography (TEE). Our aim was to determine the significance of RLSh grade by c-TCD in patients with PFO and CS.

METHODS

We evaluated patients with CS who had RLSh quantified by c-TCD in the Multicenter Study into RLSh in Cryptogenic Stroke (CODICIA) to determine whether there is an association between c-TCD shunt grade and the RoPE Score. For patients who underwent c-TCD and TEE, we determined whether there is agreement in identifying and grading RLSh between these two modalities.

RESULTS

The RoPE score predicted the presence versus the absence of RLSh documented by c-TCD (c-statistic = 0.66). For patients with documented RLSh by c-TCD, shunt severity was correlated with increasing RoPE score (rank correlation (r) = 0.15, p = 0.01). Among 293 patients who had both c-TCD and TEE performed, c-TCD was more sensitive (98.7%) for detecting RLSh. Of the 97 patients with no PFO identified on TEE, 28 (29%) had a large amount of RLSh seen on c-TCD.

CONCLUSIONS

For patients with CS, severity of RLSh by c-TCD is positively correlated with the RoPE score, indicating that this technique for shunt grading identifies patients more likely to have pathogenic rather than incidental PFOs. c-TCD is also more sensitive in detecting RLSh than TEE. These findings suggest an important role for c-TCD in the evaluation of PFO in the setting of CS.

Prevention of recurrent stroke in patients with patent foramen ovale

Patent foramen ovale (PFO) is common and only rarely related to stroke. The high PFO prevalence in healthy individuals makes for difficult decision making when a PFO is found in the setting of a cryptogenic stroke, because the PFO may be an incidental finding. Recent clinical trials of device-based PFO closure have had negative overall summary results; these trials have been limited by low recurrence rates. The optimal antithrombotic strategy for these patients is also unknown. Recent work has identified a risk score that estimates PFO-attributable fractions based on individual patient characteristics, although whether this score can help direct therapy is unclear.

Clinical implications of pulmonary shunting on saline contrast echocardiography

Pulmonary right-to-left shunting can be encountered using transthoracic contrast echocardiography (TTCE) with agitated saline. Diseases associated with pulmonary shunting on saline TTCE include hereditary hemorrhagic telangiectasia (HHT), hepatopulmonary syndrome, and some congenital heart defects after partial or complete cavopulmonary anastomosis. Furthermore, small pulmonary shunts on saline TTCE are also documented in a proportion of healthy individuals. Pulmonary shunting carries the risk for severe neurologic complications due to paradoxical embolization. In HHT, additional chest computed tomography is recommended in case of any pulmonary shunt detected on saline TTCE, to evaluate the feasibility for transcatheter embolotherapy of pulmonary arteriovenous malformations. Furthermore, antibiotic prophylaxis is advised in case of any pulmonary shunt on saline TTCE to prevent brain abscesses after procedures with risk for bacteremia. The present review provides an overview of important aspects of pulmonary shunting and its detection using saline TTCE. Furthermore, advances in understanding the clinical implications of different pulmonary shunt grades on saline TTCE are described. It appears that small pulmonary shunts on saline TTCE (grade 1) lack any clinical implication, as these shunts cannot be used as a diagnostic criterion for HHT, are not associated with an increased risk for neurologic complications, and represent pulmonary arteriovenous malformations too small for subsequent endovascular treatment. This implies that additional chest computed tomography could be safely withheld in all persons with only small pulmonary shunts on saline TTCE and sets the stage for further discussion about the need for antibiotic prophylaxis in these subjects. Besides further optimization of the current screening algorithm for the detection of pulmonary arteriovenous malformations in HHT, these observations can be of additional clinical importance in other diseases associated with pulmonary shunting and in those healthy individuals with documented small pulmonary shunts on saline TTCE.

Pathophysiology of paradoxical embolism: evaluation of the role of interatrial septum anatomy based on the intracardiac echocardiography assessment of patients with right-to-left shunting

BACKGROUND

Detailed anatomic variants of the interatrial septum in patients with right-to-left shunt and contribution of specific anatomies to the risk of ischaemic recurrences has not yet been comprehensively classified.

OBJECTIVE

To report a classification of the anatomic variants of the interatrial septum as observed by intracardiac echocardiography and its correlation with clinical and functional characteristics.

METHODS

We retrospectively reviewed the medical and instrumental data of 520 consecutive patients (mean age 44±15. 5 years, 355 women) who had over a 10-year period undergone intracardiac echocardiography and right-to-left shunt catheter-based closure. The four main features used to analyse were: (a) diameter of the oval fossa, (b) presence and length of the channel, (c) presence and degree of atrial septal aneurysm, and (d) rim thickness. The presence of Eustachian valve was also tabulated.

RESULTS

The combinations of interatrial septum anatomical features were classified into six main anatomical subgroups. Recurrent embolism, multiple ischaemic foci on brain magnetic resonance imaging, high grade shunt, and permanent shunt before transcatheter closure procedure were associated with type 2, type 4, and type 6. Type 4 anatomical subtype (OR 4.1, 1.5-8 [95% CI], p<0.001) and type 2+presence of Eustachian valve (OR 4.3, 1.6-9 [95% CI], p<0.001) were the strongest predictors of recurrent ischaemic events before transcatheter closure.

CONCLUSION

Our study showed that interatrial septum anatomy greatly differs among patients with right-to-left shunt, as well as the risk of ischaemic recurrences in different anatomies.

Echocardiographic findings in simple and complex patent foramen ovale before and after transcatheter closure

AIMS

Percutaneous closure of patent foramen ovale (PFO) in cryptogenic cerebrovascular events is an alternative to medical therapy. The interpretation of residual shunts after implantation of different devices for PFO with different morphologies is controversial.

METHODS AND RESULTS

Transcatheter PFO closure was performed in 123 patients with a history of ≥1 paradoxical embolism using three different devices: Amplatzer (n = 46), Figulla Occlutech (n = 41), and Atriasept Cardia (n = 36). Fifty-six patients presented with simple PFO and 67 patients had complex morphologies. All patients were studied with contrast enhanced transesophageal echocardiography (TEE) before interventional procedure and thereafter at 1 and 6 months and every 6-12 months in case of incomplete closure. Definite closure was confirmed in at least two consecutive TEE studies. Various PFO morphologies were identified by TEE before device implantation. The device size to PFO diameter ratio was significantly increased in patients with complex PFO compared with those patients with a simple PFO morphology (P < 0.05). The difference between the closure rate of S-PFO and C-PFO concerning each device type was significant (Amplatzer P = 0.0027, Figulla P = 0.0043, and Atriasept P < 0.01). The mean follow-up period was 3.4 years (median 2.7 years) with a cerebrovascular re-event rate of 2.4% per year. In three patients, thrombi were detected in the 6-month TEE controls and resolved after medical therapy. In three other patients, the implantation of an adjunctive device was necessary for residual shunt.

CONCLUSION

In our series of patients, the closure rate was dependent on PFO morphology more than occluder size and type. An adjunctive device was implanted in selected cases.

Iron deficiency, ischaemic strokes, and right-to-left shunts: From pulmonary arteriovenous malformations to patent foramen ovale?

Has the recent identification of iron deficiency as a risk factor for ischaemic stroke in patients with pulmonary arteriovenous malformations (AVMs) unmasked a new paradigm for stroke/infarct pathogenesis? This commentary reviews evidence that spans associations between iron deficiency and ischaemic strokes, iron deficiency enhancement of platelet aggregation in response to serotonin/5HT, settings in which plasma 5HT is elevated, and clinical trial confirmation that 5HT receptor antagonists prevent ischaemic stroke. The critical leap which directs attention away from atherothrombotic events at the neurovascular wall is that ischaemic strokes due to pulmonary AVMs are attributable to compromised pulmonary capillary bed filtration of venous blood. Right-to-left shunting is continuous through pulmonary AVMs, but also occurs intermittently in approximately 30% of the general population with intracardiac shunts such as patent foramen ovale (PFO). The testable hypothesis presented is that paradoxical embolism of venous platelet-based aggregates may constitute part of the causal chain between iron deficiency and ischaemic stroke, not only in the rare disease state of pulmonary AVMs, but also in major subgroups of the general population.

Cardiac right-to-left shunt subtypes in Chinese patients with cryptogenic strokes: a multicenter case-control study

BACKGROUND AND PURPOSE

Data on the possible association between cardiac right-to-left shunt (RLS) and cryptogenic stroke are lacking in Asians. RLS and its subtypes in Chinese cryptogenic stroke patients were investigated.

METHODS

Patients (n = 153, mean age 42 ± 10 years, 81 male) with cryptogenic stroke from four medical centers in China and 135 healthy volunteers (mean age 34 ± 8 years, 54 male) were recruited. Contrast transcranial Doppler was used to assess the prevalence of RLS. A three-level RLS categorization was applied as follows: none, 0 microbubbles (MBs); small, 1-25 MBs; and large, >25 MBs. RLS was considered latent if it occurred only after the Valsalva maneuver or permanent when it occurred also during normal respiration.

RESULTS

Overall, RLS (P = 0.02), large RLS (P < 0.001) and permanent RLS (P = 0.02) were more frequently detected in patients with cryptogenic stroke than in healthy volunteers. The prevalences of small RLS and latent RLS in the two groups were similar (22% vs. 21% and 11% vs. 10%, respectively). The proportion of large RLSs amongst the subjects with RLS was much higher in the patient group than in healthy volunteers (45% vs. 18%, P < 0.001), whilst the proportion of permanent RLS was similar (72% vs. 64%, P = 0.11). Most large RLSs in the patient group (22/27, 81%) were permanent RLSs.

CONCLUSIONS

Cardiac RLS is associated with cryptogenic stroke in Chinese. However, the higher prevalence of overall RLS in the patient group was mainly due to the increased proportion of large RLSs. The results only support large RLSs as a pathological condition.

Grade of pulmonary right-to-left shunt on contrast echocardiography and cerebral complications: a striking association

BACKGROUND

A pulmonary right-to-left shunt (RLS) carries the risk of cerebral paradoxical embolization and severe neurologic complications. Recognizing patients at risk is important to facilitate appropriate management strategies, but a direct relation between pulmonary shunt size and risk of complications remains controversial. This study evaluated the potential relation between pulmonary shunt grade on transthoracic contrast echocardiography (TTCE) and prevalence of cerebral manifestations in patients screened for hereditary hemorrhagic telangiectasia (HHT).

METHODS

We conducted a two-center, cross-sectional study of all consecutive patients screened for HHT between 2004 and 2011. Pulmonary shunt grading on TTCE (grade 0, no microbubbles; grade 1, &lt; 30 microbubbles; grade 2, 30-100 microbubbles; grade 3, &gt; 100 microbubbles) was performed according to contrast opacification of the left ventricle. Cerebral complications were defined as ischemic stroke, transient ischemic attack, or brain abscess diagnosed by a neurologist and confirmed by appropriate imaging techniques.

RESULTS

A pulmonary RLS was present in 530 out of 1,038 patients (51.1%; mean age, 44.3 ± 15.6 years; 58.6% women). The presence of a cerebral manifestation (n = 51) differed significantly among pulmonary shunt grades on TTCE: 1.4%, 0.4%, 6.5%, and 20.9% for grades 0, 1, 2 and 3, respectively. A pulmonary shunt grade 1 was not associated with an increased prevalence of cerebral manifestations (OR, 0.44; 95% CI, 0.05-4.13; P = .47), whereas pulmonary shunt grade 2 (OR, 4.78; 95% CI, 1.14-20.0; P = .03) and grade 3 (OR, 10.4; 95% CI, 2.4-45.3; P = .002) were both independent predictors for the prevalence of a cerebral ischemic event or brain abscess.

CONCLUSIONS

The pulmonary RLS grade on TTCE is strongly associated with the prevalence of cerebral complications in patients screened for HHT.

Transesophageal echocardiography in cryptogenic stroke and patent foramen ovale: analysis of putative high-risk features from the risk of paradoxical embolism database

BACKGROUND

Patent foramen ovale (PFO) is associated with cryptogenic stroke (CS), although the pathogenicity of a discovered PFO in the setting of CS is typically unclear. Transesophageal echocardiography features such as PFO size, associated hypermobile septum, and presence of a right-to-left shunt at rest have all been proposed as markers of risk. The association of these transesophageal echocardiography features with other markers of pathogenicity has not been examined.

METHODS AND RESULTS

We used a recently derived score based on clinical and neuroimaging features to stratify patients with PFO and CS by the probability that their stroke is PFO-attributable. We examined whether high-risk transesophageal echocardiography features are seen more frequently in patients more likely to have had a PFO-attributable stroke (n=637) compared with those less likely to have a PFO-attributable stroke (n=657). Large physiologic shunt size was not more frequently seen among those with probable PFO-attributable strokes (odds ratio [OR], 0.92; P=0.53). The presence of neither a hypermobile septum nor a right-to-left shunt at rest was detected more often in those with a probable PFO-attributable stroke (OR, 0.80; P=0.45; OR, 1.15; P=0.11, respectively).

CONCLUSIONS

We found no evidence that the proposed transesophageal echocardiography risk markers of large PFO size, hypermobile septum, and presence of right-to-left shunt at rest are associated with clinical features suggesting that a CS is PFO-attributable. Additional tools to describe PFOs may be useful in helping to determine whether an observed PFO is incidental or pathogenically related to CS.