The echocardiographer and the diagnosis of patent foramen ovale

Evaluating the potential risks of bubble studies during echocardiography

Objective:

Cardiac shunts are often identified using bubble studies in echocardiography, with agitated saline. Previous studies have recommended various safe amounts of agitated saline. This poses a potential risk for air microembolism. The purpose of this study was to quantify the bubbles created by various quantities of agitated saline.

Methods:

A closed circuit was constructed with a HeartMate pneumatic ventricular assist pump and a cardiotomy reservoir to remove air during recirculation. One empty 10 mL syringe and one 10 mL syringe containing 1 mL of air and 9 mL of saline were attached to a three-way stopcock. The air/saline bolus was then agitated between the two syringes five times to create bubbles and injected into the tubing proximal to the HeartMate. An EDAC bubble detector sensor was attached prior to the saline injection site and distal to the HeartMate I to measure the size and volume of the bubbles. This technique was repeated using 0.5 mL of air and 9.5 mL of saline bolus and 2 mL of air and 8 mL of saline bolus. Each bolus was tested 20 times.

Results:

This study identifies the potential risks of air administration and proposes a safer air volume to agitate for the administration of a bubble study.

Conclusions:

Further studies should be conducted to create either a guideline or a standard for agitated saline administration by the Intersocietal Commission for the Accreditation of Echocardiography Laboratories (ICAEL) in order to minimize the risk of air microembolism

The new patent foramen ovale occluder FIGULLA in complex septal anatomy: a case series

BACKGROUND

The appropriate treatment strategy for secondary stroke prevention in patients with cryptogenic stroke and patent foramen ovale (PFO) remains challenging. The aim of this study was to describe a case series of patients with PFO and complex septal anatomy who underwent percutaneous correction using a FIGULLA (Occlutech) septal occluder (FSO).

PATIENTS

Ten consecutive patients (6 females, 4 males, mean age 41.6 ± 16.0 years, range 17-52 years; group 1) with cryptogenetic stroke and/or transient cerebral ischemia and complex septal anatomy, as defined by intraprocedural transesophageal echocardiogram (TEE) were compared with a group of 25 patients (10 females, 15 males, mean age 43.7 ± 12.3 years; group 2) with usual tunnel-like PFO anatomy in whom PFO was closed by an Amplatzer septal occluder (ASO; AGA).

RESULTS

No significant differences were noted between group 1 and group 2 for immediate success rate, residual intraprosthetic shunt at the end of the procedure, discharge, 1, 6 and 12 months follow up, number of attempts, procedure time, fluoroscopy time, or cardiac complication (atrial arrhythmias, device embolism). The only significant difference was shown for delivery sheath size (11 ± 2 versus 9 ± 1 F) and incidence of local hematoma (30% versus 12%) between group 1 and group 2, without any clinical consequence (need of transfusion) or increase in length of stay.

CONCLUSION

FSO shows high performance in patients with PFO and complex septal anatomy when compared with patients with PFO and uncomplicated atrial anatomy treated by ASO. Its favorable behavior is probably related to fabric features such as the total amount of metal and the presence of titanium.

Diagnosing a Patent Foramen Ovale in Children

Background and Purpose—

Transesophageal echocardiography (TEE) is the gold standard for the diagnosis of a patent foramen ovale in adults. In children, acoustic windows on transthoracic echocardiography (TTE) are better than in adults; thus, an invasive TEE may not be necessary. Our goal was to assess the validity of TTE with agitated saline injection for the diagnosis of a patent foramen ovale in children using TEE as the gold standard.

Methods—

Fifty consecutive pediatric patients >1 year of age referred for TEE were prospectively enrolled. Imaging included 2-dimensional, color Doppler, and agitated saline contrast injections with and without Valsalva by TTE followed by TEE. Interpreters of the TTE were blinded to TEE results. Studies were categorized as “inconclusive” if the TTE images were inadequate for definitive diagnosis by the blinded interpreter.

Results—

TTE results were considered conclusive in 43 of 50 (86%) patients. Among the 43 conclusive studies, the 2 modalities disagreed in 1 patient. TTE had a positive predictive value of 100%, negative predictive value 97%, sensitivity of 88%, and specificity of 100% for detecting a patent foramen ovale.

Conclusions—

TTE with agitated saline injection is diagnostic for the assessment of atrial septal integrity in the majority of children.

Intracardiac shunting and stroke in children: a systematic review

In adults, patent foramen ovale or other potential intracardiac shunts are established risk factors for stroke via paradoxical embolization. Stroke is less common in children and risk factors differ. The authors examined the literature on intracardiac shunting and stroke in children, identifying the methods employed, the prevalence of detectible intracardiac shunts, associated conditions, and treatments. PubMed searches with keywords related to intracardiac shunting and stroke in children identified articles of interest. Additional articles were identified via citations in these articles or in reviews. The authors found that studies of intracardiac shunting in children with stroke are limited. No controlled studies were identified. Detection methods vary and the prevalence of echocardiographically detectible intracardiac shunting appears lower than reported in adults and autopsy studies. Defining the role of intracardiac shunting in pediatric stroke will require controlled studies with unified detection methods in populations stratified by additional risk factors for paradoxical embolization. Optimal treatment is unclear.

Intracardiac shunt with hypoxemia caused by right ventricular dysfunction following pericardiocentesis

Significant hypoxemia can result from right-to-left intracardiac shunting through a patent foramen ovale, an atrial septal defect or a ventricular septal defect. Pulmonary embolus, congenital heart disease and pericardial tamponade are well-recognized causes of right-to-left shunting. However, right-to-left shunting can also follow pericardiocentesis. A case of profound hypoxemia caused by right ventricular hypokinesis precipitated by pericardial tap is reported. This under-recognized entity can be responsible for significant morbidity in the critical care setting. The clinical presentation, natural history, diagnosis and treatment of hypoxemia caused by intracardiac shunt following pericardiocentesis are discussed.

Percutaneous closure of patent foramen ovale: a case series and literature review

Patent foramen ovale (PFO) is an anatomical variant of the interatrial septum with an overall prevalence of 27% in autopsy studies. PFOs have a potential role in causation of stroke, platypneaorthodeoxia, decompression sickness, right to left shunt and migraine headaches. Data regarding percutaneous closure of PFO in low volume tertiary care centers is lacking. Retrospective review of 14 percutaneous PFO closures done in our facility from March 2005 to August 2006 was performed for efficacy of procedure and safety. All patients received clopidogrel for a period of 3 months, and aspirin and subacute bacterial endocarditis prophylaxis for 6 months. Mean age of the study population was 54 years. Fifty percent (7 of 14) of patients experienced an atrial septal aneurysm and 14% (2 patients) exhibited a hypercoagulable state. The indication for closure in 13 patients was transient ischemic attacks or strokes, while one patient had persistent hypoxia due to a severe right to left shunt at PFO. Patients received either a CardioSEAL or Amplatzer device. Deployment rate was 100%. All patients completed a minimum of 6 months of follow-up, with a mean follow-up time of 14.9 +/- 7.6 months. No immediate or late bleeding complication occurred in any patient. One patient developed paroxysmal atrial fibrillation and one patient developed thrombotic complications at 7 months post-procedure secondary to the progression of her anal carcinoma and subsequently died. Pending the results of the four large randomized trials that are enrolling patients, percutaneous closure of PFO for cryptogenic strokes is an attractive alternative to lifelong anticoagulation with relatively few complications, even in low volume centers. There are many challenges in the management of this subset of patients, the foremost being the selection of a target patient population. Role of PFO in migraines is less clear.

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.

Controversies in the medical clearance of recreational scuba divers: updates on asthma, diabetes mellitus, coronary artery disease, and patent foramen ovale

Primary care and sports medicine physicians are frequently consulted on medical clearance for prospective recreational divers. We discuss four common and controversial medical conditions--asthma, diabetes mellitus, coronary artery disease, and patent foramen ovale--as they relate to fitness to dive. For each condition we review the relevant anatomy and physiology, current recommendations, and the pertinent medical literature. Finally, we offer evidence-based recommendations regarding fitness to dive for potential divers with these conditions.

Radiological Reasoning: Pulmonary Embolism—Thinking Beyond the Clots

OBJECTIVE

We discuss the CT findings in a case of pulmonary embolism complicated by paradoxical embolism in a patient with a patent foramen ovale and atrial septal aneurysm.

CONCLUSION

When confronted with a case of pulmonary embolism on CT, besides evaluating the extent of pulmonary artery occlusion, the radiologist should examine the cardiovascular system to identify any unsuspected underlying or associated conditions.