Diagnosis of an anatomically and physiologically significant patent foramen ovale

Identification of candidates for PFO closure in the echocardiography laboratory

A patent foramen ovale (PFO) is implicated in several pathologic processes, including that of cryptogenic stroke (cCVA). Recent trials identify "high-risk" PFOs in patients with cCVA as likely to benefit from percutaneous closure. The younger the patient (<60 years old) the more likely a PFO may be attributable to the cCVA. The RoPE Score index helps determine the likelihood that an existing PFO is related to a cCVA. This may help guide the clinician and patient when contemplating percutaneous PFO closure. When evaluating a patient for possible percutaneous closure, one should identify the CVA as a typical ischemic type stroke. In order to "rule-out" other causes of CVA, imaging of the intracranial arteries, cervical, and aortic arch vessels should be performed. Small vessel disease or a lacunar-type infarct should be excluded. To rule out atrial fibrillation, prolonged monitoring should be performed. An index has been developed to determine the probability that a PFO is the causative etiology and calculates the risk of recurrence. This may help guide the clinician and patient in the decision for PFO closure. In addition, one should consider a work-up for a hypercoagulable state. We will obtain an ultrasound of the lower extremities or consider deep pelvic vein thrombosis (prolonged sitting or malignancy). If the closure is to be performed, the Food and Drug Administration (FDA) has approved the Amplatzer PFO Occluder and the GORE Cardioform Septal Occluder for percutaneous closure. These devices are both approved in patients predominately between ages 18 and 60 years with a cCVA due to presumed paradoxical embolism as verified by a neurologist and cardiologist and when other causes of ischemic CVA have been excluded. "High-risk" PFOs appear to achieve the most potential benefit from percutaneous closure.

Transcranial Doppler ultrasonography should it be the first choice for persistent foramen ovale screening?

Background

Persistent foramen ovale (PFO) is considered a cause of cryptogenic stroke and a risk factor for neurological events in young patients. The reference standard for identifying a PFO is contrast-enhanced transesophageal echocardiography (TEE).

The goal of this study was to evaluate the feasibility of transcranial color Doppler (TCD) and its diagnostic sensitivity compared with TEE.

Methods

We investigated 420 patients admitted to our department with cryptogenic stroke, transient ischemic attacks or other neurological symptoms. All patients underwent TCD and TEE evaluation. TCD and TEE examinations were performed according to a standardized procedure: air-mixed saline was injected into the right antecubital vein three times, while the Doppler signal was recorded during the Valsalva maneuver. During TCD the passage of contrast into the right-middle cerebral artery was recorded 25 seconds following the Valsalva maneuver.

Results

We detected a right-to-left shunt in 220 patients (52.3%) and no-shunts in 159 patients (37.9%) with both TCD and TEE. In 20 (4.8%) patients TEE did not reveal contrast passage which was then detected by TCD. In 21 (5.0%) patients only TEE revealed a PFO. The feasibility of both methods was 100%. TCD had a sensitivity of 95% and a specificity of 92% in the diagnosis of PFO.

Conclusions

TCD has a relatively good sensitivity and specificity. TCD and TEE are complementary diagnostic tests for PFO, but TCD should be recommended as the first choice for screening because of its simplicity, non-invasive character, low cost and high feasibility.

How to Understand Patent Foramen Ovale Clinical Significance: Part I

Patent foramen ovale (PFO) is a remnant of fetal circulation commonly found in healthy population. However, a large number of clinical conditions have been linked to PFO, the most important being ischemic strokes of undetermined cause (cryptogenic strokes) and migraine, especially migraine with aura. Coexistent atrial septal aneurysm, size of PFO, degree of the shunt, shunt at rest, pelvic deep vein thrombosis, and prothrombotic states (G20210A prothrombin gene mutation, Factor V Leiden mutation, MTHFR: C677T, basal homocystine, recent surgery, trauma, or use of contraceptives) could enhance stroke risk in subjects with PFO. Owing to the complexity of this issue, for any individual presenting with a PFO, particularly in the setting of cryptogenic stroke, it is not clear whether the PFO is pathogenically related to the neurological event or an incidental finding. Thus, a heart-brain team, which individually plans the best strategy, in accordance with neuroimaging findings and anatomical characteristics of PFO, is strongly recommended. In the first part of this review, we discuss the embryologic and anatomic features of PFO, the diagnostic techniques for its identification and evaluation, and the relationship between PFO and neurological syndromes. A special attention is made to provide some key points, useful in a daily clinical practice, which summarize how better we understand PFO clinical significance

Determination of the optimum number of cardiac cycles to differentiate intra-pulmonary shunt and patent foramen ovale by saline contrast two- and three-dimensional echocardiography

INTRODUCTION

Patent foramen ovale (PFO) and intra-pulmonary shunt (IPS) are potential causes of stroke. The most optimum cardiac cycle cutoff for bubbles to appear in the left heart on saline contrast transthoracic echocardiography (TTE) as criteria to differentiate the 2 entities is unknown.

METHODS

Ninety-five adult patients had saline contrast transesophageal echocardiography (TEE), two-dimensional (2D) and 3DTTE. Sensitivity and specificity of each cardiac cycle as cutoff to differentiate a PFO and IPS were obtained.

RESULTS

Transesophageal echocardiography showed IPS in 28 and PFO in 15 patients. If bubbles appeared in the left heart within the first 4 cardiac cycles (the 4th cardiac cycle rule) as compared to alternate cutoffs, a PFO was most accurately diagnosed by both 2D and 3DTTE. Bubbles appearing at or after the 5th cardiac cycle most accurately determined an IPS. 3D versus 2DTTE had a trend for a higher sensitivity (61% vs. 36%, P = 0.06), but similar specificity (94% vs. 91%) for IPS. Accuracy of 3DTTE was 84% and 2DTTE was 75% (P = 0.08) for IPS. For PFO, 2DTTE sensitivity (87%) and specificity (98%) did not differ (P = NS) from that of 3DTTE sensitivity (73%) and specificity (100%).

CONCLUSIONS

This study demonstrates for the first time that the 4th cardiac cycle rule differentiates PFO and IPS most optimally by 2D and 3DTTE. 3DTTE appears to have higher sensitivity for diagnosing IPS. These data suggest that 3DTTE is preferable when IPS is to be diagnosed. Both methods are similar for diagnosing PFO.

Respiratory maneuvers in echocardiography: a review of clinical applications

During echocardiographic examination, respiration induces cyclic physiological changes of intracardiac haemodynamics, causing normal variations of the right and left ventricle Doppler inflows and outflows and physiological variation of extracardiac flows. The respiration related hemodynamic variation in intra and extracardiac flows may be utilized in the echocardiography laboratory to aid diagnosis in different pathological states. Nevertheless, physiologic respiratory phases can cause excessive translational motion of cardiac structures, lowering 2D image quality and interfering with optimal Doppler interrogation of flows or tissue motion.

This review focuses on the impact of normal respiratory cycle and provocative respiratory maneuvers in echocardiographic examination, both in physiological and pathological states, emphasizing their applications in specific clinical situations.

A case of simultaneous pulmonary embolism and acute myocardial infarction secondary to a previously undiagnosed patent foramen ovale

We describe a 79-year-old male with recurrent high-grade liposarcoma who developed postoperative chest pain, dyspnea, and hypoxia suspicious for acute pulmonary embolism (PE). However, electrocardiogram (ECG) was suggestive of an acute ST-elevation myocardial infarction (MI). Heparin was initiated and emergent coronary angiography was performed, which demonstrated a "cutoff sign" in the distal left anterior descending artery (LAD) consistent with coronary embolism. A patent foramen ovale (PFO) and bilateral pulmonary emboli were subsequently identified. It was concluded that the patient had suffered an acute PE, with a portion of clot traversing the PFO and entering the LAD, resulting in a simultaneous acute ST-elevation MI. While the case described is rare, the underlying anatomical variant is common and may have practical significance. We discuss the literature regarding PFO with acute PE and paradoxical emboli.

Paradoxical Symptomatic Air Embolism after Saline Contrast Transesophageal Echocardiography

We describe one case of paradoxical air embolism after contrast transesophageal echocardiography realized to detect a patent foramen ovale. At the end of this procedure, the patient presented a left lateral homonymous hemianopsia attributed to air embolism. Total recovery was obtained after one therapeutic recompression.