Second harmonic transthoracic echocardiography: the new reference screening method for the detection of patent foramen ovale.

AIM: Transesophageal echocardiography (TEE) is still considered as the reference method for the non-invasive detection of right-to-left shunts. Echocardiographic laboratories are spending most of their time performing TEE studies to exclude a thromboembolic cardiac disease. In a considerable proportion of these patients the question can be simplified to exclude a PFO. Replacing these TEE studies by TTE would result in a considerable gain in time and money. We evaluated the value of transthoracic echocardiography with second harmonic imaging (TTE) (SH) and peripheral intravenous agitated saline solutions in the detection of patent foramen ovale (PFO) in a large cohort of patients. METHODS: In 256 consecutive patients, TEE and TTE (SH) with the consecutive administration of three intravenous contrast injections of agitated saline injections before the release phase of the Valsalva manoeuvre were performed. Semi-quantification and timing of contrast passage were assessed during both imaging modalities. A shunt was present if at least one imaging modality showed microbubbles appearing in the left atrium. PFO was defined when these bubbles appeared early and arteriovenous pulmonary malformations were suspected if bubbles appeared late after the opacification of the right atrium. Shunts were considered important when >20 bubbles were present in one frame in the left atrium or left ventricle. RESULTS: From the 256 patients, 60 presented a passage of contrast from the right to the left atrium in at least one imaging modality. PFO was detected by TEE in 53 patients and by TTE in 55 patients (sensitivity: 90.5% and specificity: 96.5% if TEE is accepted as the golden standard) (p>0.05). Considering only the important shunts TEE detected 39 important shunts and TTE 46 important shunts (sensitivity: 89.7% and specificity: 94.6%) (p>0.05). AV pulmonary malformations were detected by TEE in 7 patients and by TTE in 10 patients (sensitivity: 85.7% and specificity: 98.3%) (p>0.05). CONCLUSIONS: In this large cohort of patients TTE (SH) is as accurate as TEE for the detection of PFO and late right-to-left shunts. If the only purpose of TEE is the detection of PFO such as in young cryptogenic stroke patients and in divers, TEE can be replaced by TTE (SH).     

Transcranial Doppler with contrast injection for the detection of patent foramen ovale in stroke patients

Right-to-left shunt through a patent foramen ovale was searched for in 80 patients with acute ischemic stroke by simultaneously performing transthoracic two-dimensional echocardiography and transcranial Doppler during agitated saline injection. A patent foramen ovale was detected by echocardiography in 14 patients (17.5%). Transcranial Doppler correctly identified all 14 patients, and 7 more patients in whom echocardiographic findings were indeterminate. Prevalence of patent foramen ovale by transcranial Doppler was therefore 26.3% (21 of 80 patients). Concordance between the two tests was 91.3% (73 of 80 patients). The delivery of contrast material to cerebral vessels is therefore demonstrable by transcranial Doppler in all patients diagnosed by contrast echocardiography, suggesting that paradoxical embolization through a patent foramen ovale may be more frequent than previously thought. Transcranial Doppler with contrast injection is a valid alternative in case of poor echocardiographic image quality.     

经颅多普勒诊断卵圆孔未闭

经颅多普勒(trmscranial Doppler,TCD)诊断卵圆孔未闭(patent foramen ovale, PFO)的方法至今已有20年历史.1999年威尼斯会议规定了此方法的标准化步骤,同时也提出了一些问题.近10年来,研究者对该方法进行了更加深入的研究,文章对相关研究进展做了综述.     

Protocol for optimal detection and exclusion of a patent foramen ovale using transthoracic echocardiography with agitated saline microbubbles

Agitated saline bubble studies in conjunction with echocardiography, in particular transesophageal echocardiography, are currently the principal means in the diagnosis of patent foramen ovale (PFO). We describe techniques and guidelines for the detection and exclusion of a PFO. The potential for misinterpretation of these bubble studies exists and therefore, several false positive and false negative scenarios are illustrated and discussed.     

Inter- and intra-observer variability in detection of patent foramen ovale with contrast echocardiography

Patent foramen ovale is detected in-vivo using the techniqueof contrast echocardiography. A positive test depends on theability of an observer to recognise micro-bubbles passing fromthe right to the left heart, and to differentiate them frombackground noise and/or chordae tendinae. To assess the inter- and intra-observer variability of thistechnique four observers reviewed independently, and on twoseparate occasions, 100 consecutive contrast studies storedon video tape. The proportions of agreement (95% CI) for each separate observeron the two occasions for the presence of patent foramen ovalewere 0.91 (0.76–0.98), 0.88 (0.73–0.92), 0.80 (0.63–0.92)and 0.78 (0.60–0.91), and for its absence were 0.96 (0.88–0.99),0.95 (0.87–0.99), 0.90 (0.81–0.96) and 0.91 (0.82–0.96),respectively. The proportions of agreement (95% CI) betweenall observers on the first viewing were 0.78 (0.72–0.84)for the presence and 0.91 (0.87–0.93) for the absenceof patent foramen ovale. For the second viewing these were 0.81(0.75–0.86) and 0.91 (0.88–0.94), respectively (P= NS, Chi-squared test). These results indicate that contrast echocardiography is subjectto clinically acceptable inter- and intra-observer variability.     

老年卵圆孔未闭患者经胸超声心动图特点及临床分析

目的对老年卵圆孔未闭(PFO)患者经胸超声心动图特点及临床分析。方法回顾性分析8例老年PFO患者的临床特点;并通过彩色多普勒超声诊断仪检测老年PFO患者的经胸超声心动图特点及心脏的变化。结果老年PFO患者多有不同程度的心功能不全表现,多伴有心房颤动、左右心房及左心室的扩大及肺动脉压增高、左心室射血分数减低。4例治疗后病情好转,PFO消失或显示不清。彩色多普勒血流频谱显示,8例PFO患者血液分流方向均为左向右分流,3例病情最重时出现双向分流。PFO大小均在3～4 mm。4例患者住院期间并发重度肺部感染死亡,4例仍健在,继续接受治疗。结论老年PFO患者有其独特的特征,多伴有心功能不全、心房颤动、心腔扩大、肺动脉高压等,PFO血液分流方向多为左向右分流,病情严重时出现双向分流,预后较差。     

Enhanced detection of patent foramen ovale by systematic transthoracic saline contrast echocardiography

Objective

We aimed to evaluate the effectiveness of transthoracic saline contrast echocardiography (TSCE) in detecting patent foramen ovale (PFO).

Background

Transesophageal echocardiography (TEE) is semi-invasive and not ideal for PFO screening.

Methods

112 patients (48 males, 46 ± 14 years) with suspected PFO received intravenous agitated-saline contrast at rest and stress (strain and release phases of Valsalva maneuver and coughing). The presence of interatrial shunting was defined as > 5 bubbles appearing in the left heart within 3 cardiac cycles. The stage of the maneuver at which interatrial shunting occurred was recorded. The TSCE findings were validated by TEE.

Results

TEE identified PFO in 45% of patients. The sensitivities of TSCE in detecting PFO at rest, during strain and release of Valsalva maneuver, and coughing were 12.0%, 38.0%, 80.0% and 94.0% respectively (each p < 0.05 when compared to previous stage). Specificities were similar and > 95% for all stages. Moreover, the release phase of the maneuver improved the diagnostic accuracy [defined as (number of true positives + true negatives) divided by total in sample] with incremental value over the preceding strain phase (89.2 vs. 70.5%, p < 0.001).

Conclusions

Patent foramen ovale can be identified confidently with proper conduct of the Valsalva maneuver during the transthoracic saline contrast echocardiography.     

Echocardiographic diagnosis of a giant thrombus passing through a patent foramen ovale from right atrium to the left atrium

Pulmonary embolus sourced by right atrial thrombus trapped in a patent foramen ovale is an unusual, rare condition. Thus in suspicion of massive pulmonary thromboembolus, echocardiographic examination carries great importance evaluate right ventricular functions and diagnose right sided intracardiac thrombus. We report a 76-year-old female with massive pulmonary embolism caused by a gigantic thrombus trapped in a patent foramen ovale. The echocardiography was the diagnostic procedure to display the source of the thromboembolism and urgent cardiac surgery was successful and life-saving treatment in this case.     

Electrocardiographic findings in patients with cryptogenic ischemic stroke and patent foramen ovale

Background

A characteristic electrocardiogram (ECG) pattern called crochetage has been described in patients with atrial septal defects. Nevertheless, there are discrepancies regarding its frequency in patients with patent foramen ovale (PFO).

Objective

We analyzed the ECGs of patients who had cryptogenic stroke to study crochetage and other possible patterns in relation to PFO.

Methods

We prospectively included consecutive patients who have had a cryptogenic stroke and are undergoing a right-to-left shunt (RLS) study with transesophageal echocardiography and simultaneous transcranial Doppler. Two blinded and independent cardiologists analyzed the ECGs for crochetage, defined as a notch near the apex of the R wave in inferior limb leads, P wave abnormalities, and right bundle branch block (RBBB).

Results

We studied 104 patients whose mean age was 55.1 ± 12.7 years; 60.6% were men. PFO was detected in 40.4% of patients. Cardiologists recorded crochetage in 26.2% of patients with PFO and 14.5% of patients without PFO (P = .204) and RBBB in 19% and 8% of patients, respectively (P = .132). P wave abnormalities were also detected in 54.8% of patients with PFO and 35.5% of patients without PFO (P = .070). In patients with PFO, biphasic P waves were more frequent in small RLS (P = .006). Although higher frequencies of crochetage in small RLS and RBBB in moderate RLS were detected, these differences did not reach statistical significance (P = .067 and P = .05, respectively).

Conclusion

There is no characteristic ECG pattern to identify the patients with cryptogenic stroke.     

Role of real-time three-dimensional transoesophageal echocardiography for guiding transcatheter patent foramen ovale closure

Patent foramen ovale (PFO) is a relatively common congenitalcondition which has been implicated in cryptogenic stroke asa result of paradoxical thromboembolism by right-to-left shunting.Many studies have demonstrated that transcatheter PFO closuresignificantly reduced the incidence of recurrent strokes ina small group of high-risk patients with PFO and atrial septalaneurysm compared with antithrombotic drugs. Two-dimensionaltransoesophageal echocardiography (2D TEE) has become the electiontechnique for guiding patent foramen ovale closure. Real-timeThree-dimensional transoesophageal echocardiography (3D TEE)may be potentially superior to 2D TEE in the accurate assessmentof the morphology and efficacy of transcatheter closure devicesbecause of a better spacial orientation.     

Transthoracic echocardiography guidance during percutaneous closure of patent foramen ovale

Background: Percutaneous closure of patent foramen ovale (PFO) has been increasingly performed for several indications; mostly due to cryptogenic stroke. In this study we aimed to evaluate the safety and efficacy of transthoracic echocardiographic (TTE) guidance during percutaneous closure of PFO in using the Amplatzer and Occlutech Figulla PFO occluder devices. Methods: Between October 2005 and March 2011, 139 patients (74 male, mean age: 40.4 ± 10.3) underwent transcatheter PFO closure. In all patients transesophageal echocardiography performed subsequently to diagnose, assess the size and evaluate for suitability of the defect for percutaneous closure. During the procedure fluoroscopy and TTE were used for guidance. Results: Among 139 patients, Amplatzer PFO occluder was used in 74 patients and in 65 of them Occlutech Figulla device was selected for occlusion. The indications for PFO closure were ischemic stroke in 98 (70.5%), recurrent transient ischemic attacks (TIA) in 40 (28.7%), peripheral embolism in 1 (0.8%) of the patients. In all patients, percutaneous intervention was performed successfully under TTE guidance. There have been no neurologic (recurrent strokes or TIAs) and cardiovascular complications during the immediate and long‐term follow‐up period (2–67 months, median 29). There was significant difference between the mean fluoroscopic time from the beginning which is 8.6 ± 3.4 min in the former versus 3.4 ± 1.9 min in the latter (P < 0.05). Conclusion: Our study confirms the efficacy and safety of TTE guidance during percutaneous closure of PFO, which shortens the procedural time and obviates the need for general anesthesia or endotracheal intubation. (Echocardiography 2011;28:1074‐1080)     

Caught in the act: serial, real time images of a thrombus traversing from the right to left atrium across a patent foramen ovale.

AIMS: To illustrate the association between a patent foramen ovale (PFO) and paradoxical embolization. METHODS AND RESULTS: We report a unique case of a paradoxical embolization across a PFO noted during a transesophageal echocardiographic study. Serial images demonstrate the thrombus migrating from the superior vena cava to the left atrium across the PFO. CONCLUSIONS: This case establishes the association between the PFO and paradoxical embolism unequivocally.     

Eustachian valve interfering with transcatheter closure of patent foramen ovale

A prominent Eustachian valve (EV) is a common finding in patientswith a patent foramen ovale (PFO). Its presence might compromisetranscatheter closure of the PFO.     

Harmonic imaging improves sensitivity at the expense of specificity in the detection of patent foramen ovale

Contrast echocardiography using agitated saline is widely employed to detect right to left shunt in patients with suspected patent foramen ovale (PFO). The sensitivity of fundamental transthoracic echocardiography (FTTE) is often limited by poor far-field resolution. The purpose of this study was to evaluate the test characteristics of harmonic imaging during transthoracic echocardiography (HTTE) for the detection of PFO. METHODS: Sixty-four patients referred for transesophageal echo (TEE) for clinical indications underwent FTTE and HTTE during saline contrast injections. RESULTS: TEE identified nine PFOs. For FTTE, the sensitivity was 78% and the specificity was 100%. For HTTE, the sensitivity was 100% and the specificity was 82%. All ten false positives with HTTE occurred after five cardiac cycles, suggesting transpulmonary transit of the bubbles. CONCLUSION: In the detection of PFO, HTTE improves sensitivity at the expense of specificity, particularly if the timing of contrast appearance in the left heart is ignored.     

Traditional contrast echocardiography may fail to demonstrate a patent foramen ovale: negative contrast in the right atrium may be a clue.

We describe a patient who suffered a stroke of unknown origin and presented a patent foramen ovale (PFO) at contrast echocardiography. This PFO was clearly detectable after contrast delivery in the femoral vein, while repeated contrast delivery in an antecubital vein only showed a negative contrast effect, which suggests that the blood crossing the PFO originated from the vena cava inferior. However, enhanced detection of a PFO by femoral contrast delivery, compared to antecubital injection has been published many years ago, this mode is not widely implemented yet. With this case report we would like to illustrate that the negative contrast effect may be used as an indicator that a PFO cannot be excluded and a switch to femoral contrast injection is then mandatory.     

Patent foramen ovale in cerebral infarction

Recent studies support the hypothesis of a close aetiological and pathogenic association between the presence of patent foramen ovale (PFO) and cryptogenic stroke. The therapeutic options currently used in the treatment of these patients range from standard antiaggregation and standard-dose anticoagulation to the percutaneous occlusion of the PFO. The use or recommendation of treatment is based both on clinical risk factors associated with PFO, such as age, detection of states of hypercoagulability and previous history of stroke, and on the risks associated to right-to-left shunt (RLSh) and PFO, such as the size of PFO, magnitude of RLSh and the presence of atrial septal aneurysm (ASA). However, there is currently no consensus regarding the most suitable treatment and it is surprising to observe the widespread use of certain therapeutic approaches which are not supported by clinical evidence. In this revision, we analyse the relevance of PFO in cryptogenic stroke, consider the main evidence available for determining the best management of these patients and make diagnostic and therapeutic management recommendations.