Transmitral Doppler: a new transthoracic contrast method for patent foramen ovale detection and quantification

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Current management aspects in adult congenital heart disease: non-surgical closure of patent foramen ovale

A patent foramen ovale (PFO) is a remnant interatrial communication, best diagnosed with transoesophageal echocardiography (TOE) and bubble study. Although quite common and often asymptomatic, PFO is associated with cryptogenic stroke and migraine. Approximately one-half of patients with a cryptogenic stroke have a PFO, and the dilemma regarding whether or not to proceed with percutaneous device closure, to reduce the risk of future recurrent events due to paradoxical embolism, has been subject to debate for nearly two decades. Despite promising observational data, initial randomised clinical trials failed to demonstrate superiority of closure over medical therapy. However, long-term follow-up data from one of these early trials, combined with two new randomised trials, have provided more evidence for the benefits of closure in selected patients. This new evidence suggests that younger patients with high-risk features such as an atrial septal aneurysm (ASA) or large interatrial shunt are more likely to benefit from PFO closure, after fastidious exclusion of an alternative cause for the index stroke. However, issues which require further clarification include whether anticoagulant therapy is preferable to antiplatelet therapy for medical management, and which particular type of closure device is optimal. Finally, despite promising retrospective observational data suggesting improvement in migraine attacks after PFO closure, high quality evidence is lacking in this regard.

Ischaemic stroke with patent foramen ovale

BACKGROUND

There is no sound scientific documentation of current guidelines for the treatment of cerebral infarction assumed to be due to patent foramen ovale. In this article, we present a young patient with this condition. In addition, we provide a general overview of the prevalence, recommended assessment and indications for treatment of patent foramen ovale in ischaemic stroke patients.

METHOD

The article is based on a non-systematic search in PubMed. We emphasise three recently published randomised trials on the subject.

RESULTS

Transoesophageal echocardiography with saline contrast is the gold standard for detecting patent foramen ovale. Just who will benefit from the diagnosis and treatment of this condition remains unclear, however. None of the three randomised studies of antithrombotic treatment versus transcatheter closure in patients who have suffered ischaemic stroke show a difference in outcomes, but subgroup analyses indicate that closure in young patients (age <50 years) with a large foramen ovale reduces the number of recurrent ischaemic events. Two other randomised studies of antithrombotic treatment alone versus closure are presently ongoing.

INTERPRETATION

For stroke patients with patent foramen ovale, the choice between lifelong antithrombotic therapy alone and transcatheter closure is a difficult one. Treatment with antiplatelet agents remains the first choice in most cases. Well-designed studies are needed to identify which patients will benefit most from closure.

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

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

Paradoxical embolization: a potential cause of cerebral damage in Alzheimer's disease?

BACKGROUND

There are considerable overlaps between vascular dementia and Alzheimer's disease (AD), with a suggestion that cerebrovascular disease (CVD) contributes to the neurodegenerative pathology of AD. Paradoxical embolization of venous emboli into the systemic circulation through a venous to arterial circulation shunt (v-aCS), the most commonly a patent foramen ovale (PFO), is known to cause cryptogenic stroke in younger people. We reviewed the potential role of paradoxical embolization in AD.

METHODS

A review of the literature on paradoxical embolization in neurological disorders and techniques to detect v-aCS and PFO, supplemented by data from our own studies.

RESULTS

Before our research, the role of paradoxical embolism in dementia had not been studied. The potential role of embolization in cerebral damage was highlighted by studies in patients undergoing coronary artery bypass or carotid surgery. Paradoxical embolization was found to occur in patients with cryptogenic stroke, migraine, decompression sickles and during hip surgery. The methods for detecting v-aCS or PFO had not been standardized. We found 'significant' v-aCS (equivalent to PFO) in 32% of AD patients compared with 22% of controls, but the study was not sufficiently powered to test the statistic significance of this difference. In AD, there was evidence of an association between 'significant' v-aCS and the severity of white matter hyperintensities on magnetic resonance imaging (MRI).

CONCLUSION

Paradoxical embolization through a v-aCS may be a potentially preventable or treatable cause of CVD in AD.

Atrial septal defects type II: noninvasive evaluation of patients before implantation of an Amplatzer Septal Occluder and on follow-up by magnetic resonance imaging compared with TEE and invasive measurement

The purpose of this study was to evaluate morphological and functional MRI of atrial septal defects (ASD) before and after interventional occlusion by the Amplatzer Septal Occluder (AOC) in comparison to trans-oesophageal echocardiography (TEE), invasive balloon measurement (IVBM) and cardiac catheterisation (QCC). Sixty patients with an ASD type II were enrolled. They underwent TEE, IVBM, QCC and MRI at 1.5T. Cine gradient echo, steady-state free precession sequences and a gradient echo phase contrast sequence were used. In MRI, pulmonary-to-systemic flow ratio (Qp/Qs) was calculated and compared with the QCC Qp/Qs ratio. Qp/Qs ratio in baseline MRI examination was 1.56 +/- 0.29 (range: 1.05-2.2) and in QCC 1.71 +/- 0.30 (range: 1.2-2.4) with a significant correlation (R = 0.65, P < 0.01). Defect size on MRI was 15.3 +/- 7.4 mm (range: 3-30 mm), in TEE 14.3 +/- 4.9 mm (range: 4-24 mm), and the balloon stretched diameter in IVBM was 23.4 +/- 4.2 mm (range: 14-32 mm). Correlation between defect size in MRI vs. TEE was R = 0.67 (P < 0.01) and MRI vs. IVBM was R = 0.77 (P < 0.01). Right ventricular volumes decreased after intervention. MRI is an accurate noninvasive test for diagnosis, planning and follow-up after interventional ASD occlusion using an AOC.

Atrial Septal Rupture, Flail Tricuspid Valve, and Complete Heart Block Due to Nonpenetrating Chest Trauma

This is a report of a patient with an atrial septal defect with right-to-left shunting, flail tricuspid valve, and complete heart block secondary to blunt chest trauma after a motor vehicle accident. The patient surgically repaired with pericardial recreation of atrial septum, bioprosthetic tricuspid valve replacement, and pacemaker insertion. The patient had minimal problems during the hospital course and subsequently made a full postsurgical recovery.

Alternative explanations to the differences of femoral and brachial saline contrast injections for echocardiographic detection of patent foramen ovale

Patent foramen ovale (PFO) of the interatrial septum is a cardiac foetal remnant, which frequent persistence in adulthood has important implications in a variety of clinical conditions. Echographic diagnosis of PFO is based on detection of interatrial shunt by means of contrast microbubbles identification after venous injection of a first-generation echographic contrast agent. Current recommendations propose venous femoral injection of contrast for enhanced echographic detection of PFO instead of venous brachial administration, as femoral injection has been shown to have higher sensitivity for PFO detection. Inferior vena cava inflow directed toward interatrial septum has been considered the explanation for increased sensitivity of femoral delivery of contrast. In the present paper, it is hypothesised that the main determinants of these differences between injection sites are technical factors related to right atrial contrast opacification and proper transient right atrial pressure rise, rather than intraatrial flow streaming. Effects of inferior vena cava inflow stream, although significant during foetal life, would be negligible after birth. Rationale and evidence, basis for further research, and practical implications leading to a simpler and safer routine technique for echographic detection of PFO are presented and discussed.

Comparison of transthoracic echocardiography with harmonic imaging with transoesophageal echocardiography for the diagnosis of patent foramen ovale

The optimal diagnostic method for patent foramen ovale is currently unclear. This study compared bubble contrast second harmonic transthoracic (TTE) and transoesophageal echocardiography (TOE) on 87 consecutive patients referred for TOE for all indications. A right left shunt was diagnosed in 34 cases (39%), with TTE positive in 26 cases (sensitivity 76.5%), TOE positive in 27 cases (sensitivity 79.4%). Pitfalls of TTE included quality of echo and left sided valve lesions, and for TOE the ability to perform an adequate Valsalva manoeuvre. In conclusion, both tests have similar sensitivity and should be viewed as complementary modalities.

Transesophageal echocardiography in patients with cryptogenic stroke: does it alter their management? A 3-year retrospective study in a single non-referral centre

BACKGROUND

Cardiac embolism is estimated to be the aetiology of ischemic cerebral-vascular insults (CVI) in 25% of cases. Transesophageal echocardiography (TEE) is a reliable and widely used examination in the diagnosticwork-up of stroke. TEE is superior to transthoracic echocardiography (TTE) in the search of minor sources of cardiac embolism but it is time consuming and has its inherent risks.

AIM

The aim of this study was to determine whether in patients younger than 65 years of age with CVI our TEE-findings would alter their management. Only patients in whom nor the medical record, nor TTE, nor Carotid Ultrasonography could establish an aetiology, were included.

METHODS

A 3-year retrospective study was done in patients admitted to the stroke unit of a regional medical centre covering 110,000 inhabitants. The TEE-database was reviewed and all TEE's performed in eligible patients were selected. Minor and major sources of cardiac embolism were listed. The impact of TEE-findings on the management of CVI was evaluated.

RESULTS

Fifty-four patients fulfilled the criteria for this study. The mean age was 52 years (range 18 - 65). A major source of cardiac embolism was seen in 6 cases (11.1%). Four patients (7.4%) had infective endocarditis (IE) with vegetations. A small apical thrombosis in a patient with isolated left ventricular non-compaction was noted and in 1 patient dysfunction of a mechanical prosthetic valve was documented. The most frequently encountered minor source of cardiac embolism was a patent foramen ovale (PFO) or small atrial septal defect (ASD) with documented right-to-left shunt during Valsalva manoeuvre (15 patients, 27.8%). Of these 15 patients, an atrial septum aneurysm(ASA) was seen in 7 patients (13%). Our TEE-findings altered the management of CVI substantially in 21 cases (38.9%). The 4 patients with IE and the patient with mechanical valve dysfunction had cardiac surgery. Twelve patients (22.2%) were referred for percutaneous closure of the PFO/ASD. Three patients with PFO/ASD and the patient with IVNC were treated with maintenance therapy of oral anticoagulation.

CONCLUSION

In 1 out of 3 patients, younger than 65 years, suffering from CVI in whom nor medical history, nor TTE, nor Carotid Ultrasound could reveal the cause of the CVI our TEE-findings altered their management.

Stroke in Childhood

BACKGROUND

Childhood stroke is increasingly recognized as an important cause of morbidity and mortality. Risk factors for stroke in childhood are different than those traditionally seen in adults.

REVIEW SUMMARY

This review summarizes, in brief, the epidemiology, risk factors, evaluation, treatment, outcome, and recurrence risk of children with arterial ischemic stroke (AIS). Areas of controversy and those that require further study are highlighted. Tables summarizing important points of the history, physical examination, and diagnostic evaluation of AIS are provided.

CONCLUSIONS

Children with stroke should be carefully evaluated for risk factors and possible etiology of stroke. At the present time, treatment is based upon extrapolation from the adult literature and expert opinion, as no evidence-based guidelines exist, except in sickle cell anemia. International, multicenter trials are beginning and should provide some answers over the next few years.

Patent foramen ovale: current pathology, pathophysiology, and clinical status

Patent foramen ovale (PFO) is experiencing increased clinical interest as a congenital cardiac lesion persisting into adulthood. It is implicated in several serious clinical syndromes, including stroke, myocardial infarction, and systemic embolism. The PFO is now amenable to percutaneous interventional therapies, and multiple novel technologies are either available or under development for lesion closure. The PFO should be better understood to take advantage of emerging percutaneous treatment options. This paper reviews PFO anatomy, pathology, pathophysiology, and clinical impact and discusses current therapeutic options.

The echocardiographer and the diagnosis of patent foramen ovale

PFO is diagnosed by echocardiography using the combination of transthoracic two-dimensional imaging of the interatrial septum, followed by color and spectral Doppler (and if necessary saline contrast) imaging. Transesophageal imaging is an important adjunct when transthoracic imaging is not conclusive or yields suboptimal images.Three-dimensional echocardiography is useful for defining fenestrations within a PFO.

Definitions and pathophysiology of the patent foramen ovale: broad overview

This article presents definitions and discusses pathophysiology pertaining to the patent foramen ovale.

Age as a determinant of adverse events in medically treated cryptogenic stroke patients with patent foramen ovale

BACKGROUND AND PURPOSE

Patent foramen ovale (PFO) is associated with cryptogenic stroke. There is no study that assessed the effect of age on adverse event rates in cryptogenic stroke patients with PFO. The purpose of this retrospective analysis from PFO in Cryptogenic Stroke Study (PICSS) database was to assess the effect of age on the risk of adverse events in medically treated cryptogenic stroke patients with PFO.

METHODS

250 cryptogenic stroke patients from PICSS were followed-up for 24 months, with death and recurrent ischemic stroke as primary endpoints. Hazard ratios were calculated for determination of relative risk in cryptogenic stroke patients with and without PFO in 3 age groups (younger than 55, 55 to 64, and 65 years or older).

RESULTS

Among the 2 younger age groups, the presence of PFO did not significantly affect the risk of adverse events (P=0.15; hazard ratio=0.21; 95% CI, 0.02 to 1.78; 2-year event rates, 2.0% versus 9.3%; and P=0.70; hazard ratio=0.72; 95% CI, 0.14 to 3.73; 2-year event rates, 10.0% versus 13.9%). However, in those aged 65 years or older, the risk of adverse events was significantly higher in the patients with PFO (P=0.01; hazard ratio=3.21; 95% CI, 1.33 to 7.75; 2-year event rates 37.9% versus 14.5%).

CONCLUSIONS

In this exploratory analysis, the presence of PFO in the younger cryptogenic stroke patients did not increase the risk of adverse events. However, in the older patients, PFO significantly increased the risk of adverse events.

Atrial anatomy in non-cardioembolic stroke patients: effect of medical therapy

OBJECTIVES

The purpose of the study was to assess the mechanism responsible for increased stroke risk in patients with atrial septal aneurysm (SA) and patent foramen ovale (PFO), and to determine the efficacy of medical therapy for preventing stroke recurrence or death.

BACKGROUND

Atrial septal aneurysm and PFO are associated with stroke. However, the mechanism for this association is undefined, and the efficacy of medical therapy has not been investigated in a randomized fashion.

METHODS

The Patent foramen ovale In Cryptogenic Stroke Study (PICSS) evaluated transesophageal echocardiography findings in patients enrolled in the Warfarin-Aspirin Recurrent Stroke Study, a randomized double-blind trial to evaluate the efficacy of warfarin compared with aspirin.

RESULTS

Large PFO and prominent eustachian valve (EV) or right atrial (RA) filamentous strands were found more frequently in patients with SA compared with those without SA (37.7% vs. 10.9%, p < 0.001 and 59.4% vs. 43.1%, p = 0.02). Patients with SA and PFO had no significant difference in time to recurrent stroke or death compared with those having neither (hazard ratio [HR] 1.08, 95% confidence interval [CI] 0.49 to 2.38, p = 0.84; two-year event rates 15.9% vs. 14.5%). Patients with SA, PFO, and RA anatomy predisposing to paradoxical embolization also had no difference compared with those without these findings (HR 1.22, 95% CI 0.43 to 3.47, p = 0.71; two-year event rates 18.2% vs. 14.2%). There was no significant difference in time to recurrent stroke or death between the patients treated with warfarin or aspirin (HR 1.00, 95% CI 0.22 to 4.47, p = 1.0; two-year event rates 16.0% vs. 15.8%).

CONCLUSIONS

Atrial septal aneurysm is associated with the presence of large PFO and prominent EV or RA filamentous strands. On medical therapy, patients with SA and PFO did not experience increased risk of adverse events, and there was no difference between treatment results for warfarin and for aspirin.

Effect of medical treatment in stroke patients with patent foramen ovale: patent foramen ovale in Cryptogenic Stroke Study

BACKGROUND

Patent foramen ovale (PFO) is associated with stroke, but there are no randomized studies to evaluate the efficacy of antithrombotic therapies.

METHODS AND RESULTS

The PFO in Cryptogenic Stroke Study was a 42-center study that evaluated transesophageal echocardiographic findings in patients randomly assigned to warfarin or aspirin in the Warfarin-Aspirin Recurrent Stroke Study. In this study, 630 stroke patients were enrolled, of whom 312 (49.5%) were randomized to warfarin and 318 (50.5%) to aspirin. Of these, 265 patients experienced cryptogenic stroke and 365 experienced known stroke subtypes. End points were recurrent ischemic stroke or death. PFO was present in 203 patients (33.8%). There was no significant difference in the time to primary end points between those with and those without PFO in the overall population (P=0.84; hazard ratio 0.96; 95% CI 0.62 to 1.48; 2-year event rates 14.8% versus 15.4%) or in the cryptogenic subset (P=0.65; hazard ratio 1.17; 95% CI 0.60 to 2.37; 2-year event rates 14.3% versus 12.7%). There was no significant difference among those with no, small, or large PFO (P=0.41 for small PFO and P=0.16 for large PFO; 2-year event rates for no, small, and large PFO, 15.4%, 18.5%, and 9.5%, respectively). There was no significant difference between patients with isolated PFO and those with PFO in association with atrial septal aneurysm (P=0.84; 2-year event rates 14.5% versus 15.9%). In patients with PFO, there was no significant difference in the time to primary end points between those treated with warfarin and those treated with aspirin (P=0.49; hazard ratio 1.29; 95% CI 0.63 to 2.64; 2-year event rates 16.5% versus 13.2%).

CONCLUSIONS

On medical therapy, the presence of PFO in stroke patients did not increase the chance of adverse events regardless of PFO size or the presence of atrial septal aneurysm.

Transesophageal echocardiography for quantifying size of patent foramen ovale in patients with cryptogenic cerebrovascular events

BACKGROUND AND PURPOSE

Patent foramen ovale (PFO) is a risk factor for paradoxical embolism, and severe shunting and wide opening of PFO are risk factors for severe and recurrent cerebrovascular events. Neither contrast echocardiography nor 2-dimensional (2D) measurement of PFO size have been validated or compared with invasive balloon sizing.

METHODS

We performed transesophageal echocardiography (TEE) in 100 patients with cryptogenic stroke and catheter closure of PFO. The amount of contrast shunting through the PFO during cubital and femoral contrast delivery and the PFO size measured by 2D TEE were compared with balloon sizing.

RESULTS

There was a significant correlation (r(2)=0.8; P<0.0001) between 2D TEE measurement and invasive balloon sizing. Mean balloon-sized PFO diameter was significantly larger than mean PFO diameter measured by 2D TEE (8.3+/-2.6 versus 5.2+/-1.7 mm). Semiquantitative contrast TEE correlated with PFO size (r(2)=0.7; P<0.0001) only if the contrast agent was administered through a femoral vein. Correlation was poor when the contrast agent was administered via a cubital vein.

CONCLUSIONS

We conclude that 2D TEE measurement of a PFO size is more accurate than the traditionally used contrast technique.

Patent foramen ovale: a review of associated conditions and the impact of physiological size

Patent foramen ovale (PFO) is implicated in platypnea-orthodeoxia, stroke and decompression sickness (DCS) in divers and astronauts. However, PFO size in relation to clinical illness is largely unknown since few studies evaluate PFO, either functionally or anatomically. The autopsy incidence of PFO is approximately 27% and 6% for a large defect (0.6 cm to 1.0 cm). A PFO is often associated with atrial septal aneurysm and Chiari network, although these anatomic variations are uncommon. Methodologies for diagnosis and anatomic and functional sizing of a PFO include transthoracic echocardiography (TTE), transesophageal echocardiography (TEE) and transcranial Doppler (TCD), with saline contrast. Saline injection via the right femoral vein appears to have a higher diagnostic yield for PFO than via the right antecubital vein. Saline contrast with TTE using native tissue harmonics or transmitral pulsed wave Doppler have quantitated PFO functional size, while TEE is presently the reference standard. The platypnea-orthodeoxia syndrome is associated with a large resting PFO shunt. Transthoracic echocardiography, TEE and TCD have been used in an attempt to quantitate PFO in patients with cryptogenic stroke. The larger PFOs (approximately > or =4 mm size) or those with significant resting shunts appear to be clinically significant. Approximately two-thirds of divers with unexplained DCS have a PFO that may be responsible and may be related to PFO size. Limited data are available on the incidence of PFO in high altitude aviators with DCS, but there appears to be a relationship. A large decompression stress is associated with extra vehicular activity (EVA) from spacecraft. After four cases of serious DCS in EVA simulations, a resting PFO was detected by contrast TTE in three cases. Patent foramen ovales vary in both anatomical and functional size, and the clinical impact of a particular PFO in various situations (platypnea-orthodeoxia, thromboembolism, DCS in underwater divers, DCS in high-altitude aviators and astronauts) may be different.