Transesophageal echocardiographic demonstration of distinct mechanisms for right to left shunting across a patent foramen ovale in the absence of pulmonary hypertension

Case report: Unusual cause of refractory hypoxemia after pacemaker lead extraction

A 59-year-old woman with a history of a pacemaker implanted for III-degree atrioventricular block was admitted due to pocket infection. The atrial and ventricular leads were removed via the right femoral vein using a needle's eye snare. Hypoxemia was observed immediately after the removal of the lead. It was refractory to oxygen therapy. The pulse oxygen saturation (SpO2) showed 89% in the supine position and 77% in the upright position. However, the CTPA and pulmonary perfusion SPECT/CT imaging did not reveal any signs of pulmonary embolism. Pulmonary function tests and chest CT showed normal results. Transthoracic contrast echocardiography revealed a patent foramen ovale (PFO) and a right-to-left intracardiac shunt, no significant tricuspid regurgitation, without any signs of elevated right heart pressure or pulmonary hypertension. Hypoxemia was considered to be associated with the right-to-left shunt through PFO. The condition was relieved by percutaneous closure of the PFO. Refractory hypoxemia resulting from an intracardiac right-to-left shunt following pacemaker lead extraction is a rare but serious complication. Transthoracic contrast echocardiography helps in diagnosis. If the right-to-left intracardiac shunt through PFO persists irreversibly and the associated hypoxemic symptoms are significant, closure of the PFO is necessary. Transesophageal echocardiography also revealed the presence of a left-to-right shunt through PFO during cardiac systole. The closure of the PFO is also necessary to avoid long-term complications, such as chronic pulmonary hypertension and right heart failure.

Orientation of the atrial septum to the inferior vena cava may contribute to the persistent patency of the foramen ovale

Purpose: There is growing evidence that paradoxical embolism through patent foramen ovale (PFO) is a cause for cryptogenic stroke. However, it is still unclear why the foramen ovale fails to close after birth. We studied whether the 3D relations between the atrial septum and the inferior vena cava (IVC) are associated with PFO. Methods: We recruited 30 patients (18-49 years) with a first-ever cryptogenic stroke and 30 age- and sex-matched stroke-free controls. Using cardiac magnetic resonance (CMR), an approach to evaluate the 3D relations between the atrial septum and the IVC was developed. The presence of interatrial right-to-left shunt was evaluated with transesophageal echocardiography (TEE) in patients and transcranial Doppler in controls. Results: Of 30 patients, 29 underwent successful TEE, of which 12 (41%) had a shunt. Patients with a shunt had a greater mean 3D angle (γ) between the atrial septal plane and the vector from the orifice of the IVC to the middle of the atrial septum compared with patients without a shunt (45±9° vs. 36±8°, p=0.017). Of 30 controls, 12 (40%) had a shunt and a greater mean γ compared with controls without a shunt (47±8° vs. 37±10°, p=0.007). In a pooled analysis, 24 (41%) of 59 subjects with a shunt had a mean γ of 46±9° compared with subjects without a shunt of 37±9° (p<0.001). Conclusions: More perpendicular orientation of the atrial septal plane to the orifice of the IVC is associated with PFO, possibly by directing the IVC flow to PFO.

Arterial embolism in a patient with pulmonary embolism and patent foramen ovale

Paradoxical embolization is an uncommon but devastating complication of pulmonary embolism and continues to be frequently missed. Although the prevalence of patent foramen ovale is 25% to 30%, the risk of paradoxical embolism is <2% of all arterial ischemia. Paradoxical embolism is infrequent but can involve almost any artery of the body. Here, we present a case of a 65-year-old woman with paradoxical systemic arterial embolism secondary to deep venous thrombosis and pulmonary embolism in the presence of patent foramen ovale. High suspicion for paradoxical embolism is needed in the event of unexplained arterial occlusion. Awareness of this complication with prompt recognition and treatment could serve to preclude significant disability and death.

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.

Nitric oxide therapy for post-laparoscopic surgery associated patent foramen ovale: incidence, mechanisms, diagnosis and therapy

OBJECTIVE

Postoperative hypoxemia is a common clinical challenge. The diagnosis of an underlying cause of hypoxemia may not immediately be apparent. Clinically silent and non-functional intracardiac shunt may become apparent and pose significant management problems in the postoperative period.

DATA SOURCE

We describe a case where clinically significant hypoxemia resulted from a patent foramen ovale (PFO) after laparoscopic surgery due to changes in the intra-abdominal and intrathoracic pressures.

CONCLUSION

This condition was effectively diagnosed by bedside echocardiography, and was effectively treated with nitric oxide.

The brain's heart - therapeutic opportunities for patent foramen ovale (PFO) and neurovascular disease

Patent foramen ovale (PFO), a common congenital cardiac abnormality, is a connection between the right and left atria in the heart. As a "back door to the brain", PFO can serve as a conduit for paradoxical embolism, allowing venous thrombi to enter the arterial circulation, avoiding filtration by the lungs, and causing ischemic stroke. PFO-related strokes affect more than 150,000 people per year in the US, and PFO is present in up to 60% of migraine patients with aura, and in one out of four normal individuals. So, in such a highly prevalent condition, what are the best treatment and prevention strategies? Emerging studies show PFO-related neurovascular disease to be a multi-organ condition with varying individual risk factors that may require individualized therapeutic approaches - opening the field for new pharmacologic and therapeutic targets. The anatomy of PFO suggests that, in addition to thrombi, it can also allow harmful circulatory factors to travel directly from the venous to the arterial circulation, a concept important in finding novel therapeutic targets for PFO-related neurovascular injury. Here, we: 1) review emerging data on PFO-related injuries and clinical trials; 2) discuss potential mechanisms of PFO-related neurovascular disease in the context of multi-organ interaction and heart-brain signaling; and 3) discuss novel therapeutic targets and research frontiers. Clinical studies and molecular mapping of the circulatory landscape of this multi-organ disease will both be necessary in order to better individualize clinical treatment for a condition affecting more than a quarter of the world's population.

A unique presentation of four thrombotic events at a time

A 72-year-old man was referred to our hospital as a case of postcardiac arrest following a long distance air flight. Work-up in the emergency department revealed the presence of deep vein thrombosis (DVT), bilateral pulmonary embolism, inferior STEMI (ST elevation myocardial infarction) and ischaemic stroke. He received thrombolysis by recombinant tissue plasminogen activator (tPA) following which his haemodynamic status improved, but he developed haemorrhagic transformation of the stroke as a complication. The haemorrhagic lesion gradually resolved with conservative management, leaving behind a residual neurological deficit. His haemodynamic status was stable after the management. Although a diagnosis of right-to-left shunt lesion was highly suggestive in this condition, it could not be confirmed on the transthoracic echocardiogram. Our patient had a unique presentation of multiple thrombi in different organs that caused significant morbidity and haemodynamic instability. There are no well-established guidelines that discuss the acute management of such cases. This situation requires a careful assessment and management of the patient by a multidisciplinary team.

An autopsy case of acute cor pulmonale and paradoxical systemic embolism due to tumour cell microemboli in a patient with breast cancer

A 62-year-old woman was admitted to our hospital because of severe respiratory distress. Diagnostic imaging studies suggested the existence of inexplicable cor pulmonale. Although we immediately sought the aetiology of her severe condition, she died suddenly on the fourth day after admission. Postmortem autopsy revealed tumour cell microemboli in the small pulmonary arteries. In addition, tumour cell embolisation identical to that in primary breast cancer cells was also observed in microvessels in systemic multiple organs, such as the liver, brain, kidneys, spleen, uterus, bone marrow and adrenal glands-with simultaneous findings of peripheral infarction. Systemic tumour cell embolism mediated through the patent foramen ovale superimposed on pulmonary tumour cell emboli (PTCE) is considered to be the mechanism underlying inexplicable cor pulmonale. The rapid aggravation of her condition terminated in death.

Right-to-left atrial shunting associated with aortic root aneurysm: a case report of a rare cause of platypnea-orthodeoxia syndrome

Platypnea-orthodeoxia is a rare syndrome characterised by dyspnoea and hypoxaemia worsened on upright posture. We report the case of a 76 year-old man treated for lung adenocarcinoma who had developed severe hypoxaemia due to right-to-left shunt through a patent foramen ovale (PFO). Diagnosis was suspected by systemic uptake of isotope during lung scintigraphy performed to exclude pulmonary embolism. Arterial blood gas analysis in supine and upright positions demonstrated orthodeoxia. Contrast-enhanced transoesophageal echocardiography revealed a slightly redundant atrial septum and large right-to-left shunt through a PFO despite normal pulmonary pressure. Chest computed tomography and echocardiography showed a 59-mm aneurysm of the thoracic aorta. The opening of the PFO seemed to be the result of mechanical deformation of the atrial septum by aortic root dilatation. Transcatheter closure of the atrial defect has provided excellent results, including a rapid increase in systemic saturation and improvement of symptoms without any complications.

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.

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.

Percutaneous balloon catheter closure of a patent foramen ovale in a patient with pulmonary disease, profound hypoxemia, and normal right heart pressures

Right-to-left intracardiac shunting across a patent foramen ovale (PFO) has been reported in patients with pulmonary embolism, right ventricular (RV) infarction, positive pressure ventilation with positive end-expiratory pressure, heart failure with left ventricular assist devices, cardiac tamponade, and unilateral diaphragmatic paralysis. The primary driving force for these shunts is a reduction in the compliance of the pulmonary bed or right ventricle; right atrial pressure is usually elevated and pulmonary hypertension is frequently present. Significant shunting and hypoxemia are unusual in the absence of these diseases. We encountered a patient with normal pulmonary pressures, severe hypoxemia, pulmonary disease, and intracardiac shunting across a PFO in whom it was difficult to determine how great a role intracardiac shunting was playing in his hypoxemia. To assess this, we performed percutaneous balloon catheter occlusion of the PFO, using transthoracic echocardiography with contrast to confirm closure of the PFO. Therapeutic balloon occlusion has been reported in severe hypoxemia due to shunting across a PFO in a patient with RV infarction. Our case is unique, however, in two respects. First, this patient had normal right-sided cardiac pressures and normal RV function and, thus, no obvious driving force for a significant right-to-left shunt. Second, transthoracic echocardiography with contrast was used before and after balloon inflation to confirm closure of the PFO. This technique helped to answer the important clinical question of whether surgical closure of the PFO in this patient with both lung disease and intracardiac shunting would significantly improve his oxygenation.

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.

The Incidental Finding of a Patent Foramen Ovale During Cardiac Surgery: Should It Always Be Repaired? A Core Review

With the increased use of intraoperative transesophageal echocardiography, patent foramen ovale (PFO) has become a common finding during heart surgery. This finding presents a difficult dilemma for cardiac surgeons, since the impact of intraoperatively diagnosed PFOs on postoperative outcome is unknown. Changes in the surgical plan required for closure of a PFO subject the patient to the possibility of additional risk. On the other hand, a decision to not close a PFO exposes the patient to unclear immediate and long-term consequences. Deciding whether or not to close a PFO currently depends on the clinicians' personal preferences, the probability of intraoperative and postoperative hypoxemia, and any anticipated deviation from the initial surgical plan. Most clinicians agree that an intraoperatively diagnosed PFO must be closed when surgery leads to a high risk of hypoxemia (e.g., left ventricular assist devices placement, heart transplantation); should be closed in most cases when minimal deviation from the initial surgical plan is needed for PFO closure (e.g., mitral valve or tricuspid valve surgeries); and probably, should be closed during heart surgeries performed without atriotomy and bicaval cannulation when the risk of perioperative or remote PFO-related complications is increased. The recent development of percutaneous methods of PFO closure provides a valuable backup for those cases when PFO is not closed and postoperative hypoxemia or other complications may be attributable to the uncorrected PFO.

Correlation or causation: Untangling the relationship between patent foramen ovale and migraine

Observational evidence from the literature has shown an association between migraine headaches and patent foramen ovale (PFO). This observation has led to hypotheses that could explain the etiology of migraines in those with a PFO, including right-to-left shunting of venous agents such as serotonin that are normally broken down in the pulmonary circulation. Further evidence suggests that closure of a PFO may improve migraine symptoms and serve as an effective treatment modality for migraines. Several randomized controlled double-blinded studies are underway that will more definitively establish the role of specific devices in PFO closure in those suffering from migraines.

Hypoxemia after Implantation of a Permanent Pacemaker

We describe a case in which the patient developed profound, intermittent hypoxemia after implantation of a permanent pacemaker and subsequently after revision of its leads. Cardiac catheterization demonstrated right-to-left shunting at the level of the atria in the presence of a patent foramen ovale that required closure, resulting in the resolution of symptoms. Our report highlights the fact that the presence of a patent foramen ovale with intermittent right-to-left shunting should be considered in a differential diagnosis of hypoxemia after implantation of heart rhythm devices.

Percutaneous left ventricular assist device complicated by a patent foramen ovale: Importance of identification and management

Recently, the TandemHeart percutaneous left ventricular assist device (pVAD) has become available as a means to both resuscitate and support patients in cardiogenic shock pending myocardial recovery or definitive surgical or percutaneous intervention. Hypoxia during pVAD support may arise from multiple pulmonary etiologies, including pulmonary edema and mechanisms resulting in right-to-left shunting. We report two cases of patients supported by pVADs in who patent foramen ovale (PFO) present as right-to-left shunts following initiation of TandemHeart support. A review of the mechanisms and hemodynamics resulting in PFO patency during pVAD support as well as suggestions for management are presented.

A mystery featuring right-to-left shunting despite normal intracardiac pressure

The cause of right-to-left atrial shunting despite normal intracardiac pressures and normal or near-normal pulmonary function through a patent foramen ovale has still not been completely clarified. It is probably responsible for several linked diseases, such as paradoxical embolism, platypnea-orthodeoxia syndrome, migraine with aura, transient global amnesia, and decompression sickness in sport divers. Despite modern diagnostic methods, the underlying anatomophysiologic and pathogenic mechanisms of right-to-left atrial shunting without abnormal intracardiac pressures remain a matter of debate and controversy. Holistically speaking, a return to a direct study of embryology, gross anatomy, and physiology may help us elucidate the real mechanism of this paradoxical shunting.

Analysis of the interatrial septum by transesophageal echocardiography in adult cardiac surgical patients: Anatomic variants and correlation with patent foramen ovale

OBJECTIVES

The purpose of this study was to document the perioperative prevalence of anatomic variants of the interatrial septum (IAS), to classify atrial septal aneurysm based on mobility pattern, and to correlate anatomic variants of IAS with patent foramen ovale (PFO).

DESIGN

A prospective observational study.

SETTING

University hospital (single institution).

PARTICIPANTS

Patients presenting for cardiac surgery requiring transesophageal echocardiography.

INTERVENTIONS

Multiplane TEE in 2 atrial views with color-flow Doppler and contrast echocardiography with a provocative respiratory maneuver.

MEASUREMENTS AND MAIN RESULTS

The cohort size was 206. PFO prevalence was 30.1%. The prevalence of IAS lipomatous hypertrophy was 43.2%, atrial septal flap (ASF) 43.2%, and atrial septal aneurysm (ASA) 28.6%. ASF and ASA were significantly ( p < 0.05) associated with PFO. Selected ASA subtypes are significantly associated with PFO ( p < 0.05).

CONCLUSIONS

IAS anatomic variants are common in adult cardiac surgical patients undergoing multiplane TEE. The presence of ASF and ASA predicts enhanced PFO detection. ASA mobility patterns significantly correlate ( p < 0.05) with the presence of PFO.

Patent foramen ovale and the platypnea-orthodeoxia syndrome

The platypnea-orthodeoxia syndrome is a rare but important condition caused by a variety of clinical entities. Several mechanisms have been postulated to cause platypnea and orthodeoxia. These mechanisms mainly involve intracardiac shunting, pulmonary vascular shunting, and ventilation-perfusion mismatching. Patent foramen ovale is an important type of intracardiac shunt that can produce platypnea-orthodeoxia in select patients. Concomitant pulmonary hypertension must be ruled out, but symptoms can occur without pulmonary hypertension in cases with altered intrathoracic anatomy and physiology. Diagnosis usually entails transthoracic or trans-esophageal echocardiogram, ideally with postural provocation by the tilt-table test. Treatment with surgical or percutaneous closure may result in symptomatic relief. The decision to intervene is based mainly on the severity of symptoms and potential morbidities associated with the defect.

Cardiac lipoma: A rare cause of right-to-left interatrial shunt with normal pulmonary artery pressure

Cardiac lipomas are rare tumors. They usually remain asymptomatic for a long time and cause angina, arrhythmia, dysfunction of the ventricles or valves, and peripheral embolization during the later stages of development. There is little or no information about right-to-left interatrial shunt with normal pulmonary artery pressure, produced as a consequence of the infiltration of the atrial septum, the right atrial wall, and the myocardium because of the presence of fat in patients with platypnea-orthodeoxia syndrome. We present a patient with this syndrome who was identified through transesophageal echocardiography. The study showed a massive right-to-left shunt without pulmonary hypertension, produced by an important cardiac infiltration of adipose tissue that created a narrow passage in the right atrium, and a redirection of the flow to a patent foramen ovale, explaining the pathophysiology of the syndrome.

Diagnosis of patent foramen ovale with multiplane transesophageal echocardiography in adult cardiac surgical patients

OBJECTIVE

To evaluate multiplane transesophageal echocardiography (TEE) for detection of patent foramen ovale (PFO) and to compare multiplane TEE with visual inspection (VI) for PFO detection.

DESIGN

A prospective observational study.

SETTING

University hospital (single institution).

PARTICIPANTS

Patients presenting for cardiac surgery requiring TEE.

INTERVENTIONS

Multiplane TEE including 2 atrial views with color-flow Doppler (CFD) and contrast echocardiography (CE) with a provocative respiratory maneuver (PRM) and comparison of multiplane TEE and VI with respect to PFO detection.

MEASUREMENTS AND MAIN RESULTS

The cohort size was 187. PFO prevalence was 27.3%. CFD with serial decrease of the Nyquist limit detected 51% of all PFO: 41.2% in the bicaval view alone, 27.5% in the 4-chamber view alone, and 9.8% in both views. CE detected 78.4% of all PFO: 72.5% with PRM, 45.1% with no PRM, and 27.4% with/without PRM. PFO detection by multiplane TEE and visual inspection were correlated in 41 subjects. TEE diagnosed 11 PFO (26.8% prevalence, 3 missed by VI). VI diagnosed 12 PFO (29.3% prevalence, 4 missed by TEE).

CONCLUSIONS

Multiplane TEE is a gold standard for detection of PFO. Despite advances in TEE technology, 2-dimensional imaging does not detect all PFO. To maximize PFO detection, multiple TEE modalities are required in multiple views, despite a low Nyquist limit for CFD or a PRM for CE. Even though multiplane TEE is equivalent to VI for PFO detection, the discrepancy rate may be an important consideration in the individual case.

Detection of air microbubbles in the internal jugular vein after intravenous injection of contrast agent for the diagnosis of patent foramen ovale

The use of agitated air and saline, injected intravenously, combined with monitoring of the middle cerebral artery using transcranial Doppler sonography, is an effective method for detecting paradoxic cerebral embolism caused by right-to-left intracardiac shunting. This technique is particularly useful in patients with a patent foramen ovale. In patients without temporal acoustic windows, the method can be modified by using sonographic monitoring of the common carotid artery. Observation of saline-contrast microbubbles in the internal jugular vein during this procedure suggests incompetence of the ipsilateral internal jugular valve. This noninvasive method may thus be useful for studying the competence of the internal jugular valve.

Right hemidiaphragmatic elevation with a right-to-left interatrial shunt through a patent foramen ovale: a case report and literature review

A right-to-left shunt (RLS) is an uncommon complication of a patent foramen ovale (PFO) that may cause hypoxemia from venous admixture and ischemic complications from paradoxic embolization. This report presents the third described patient whose RLS through a PFO and profound hypoxemia developed in association with right hemidiaphragm dysfunction (but without a pressure gradient driving the right-to-left flow). In addition to extending the available experience with this unusual clinical event, we report on the successful closure of the PFO by a catheter-deployed double-umbrella device, after the positioning of which the patient's oxygenation normalized.

[Patent foramen oval as a cause of severe hypoxia during the immediate postoperative period following heart transplantation]

We report the case of a 44-year-old man with dilated cardiomyocardiopathy, pulmonary hypertension and high pulmonary resistance who underwent orthotopic heart transplant. Following transplantation severe hypoxia was observed after weaning of cardiopulmonary bypass secondary to a patent foramen oval in the donor heart. This situation does not usually lead to problems in the donor, however taking into account the special hemodynamic conditions of the transplanted patient, with high pressure in the right side, an opening occurred producing a significant right-left shunt causing severe receptor hypoxia. Successful closure of the patent foramen oval was performed.

Catheter closure of the persistent foramen ovale: mid-term results in 162 patients

Four different types of occluder systems were used to close a persistent foramen ovale (PFO) in 162 patients with paradoxical embolic events. Ninety-eight patients had ischemic stroke, 60 transient ischemic attacks (TIA) or prolonged reversible ischemic neurological deficit (PRIND), and 4 had peripheral arterial embolism. The age of the patients was 40.2 +/- 11.9 years and the ischemic event had happened 7 +/- 10 months before device closure. CardioSeal and Amplatzer occluders were the most commonly used devices (73 and 77 cases, respectively). Implantations were successful in all patients. Serious catheter-related complications included two device embolizations and two venous bleedings. Six patients had documented supraventricular arrhythmias within the first month after implantation, which disappeared spontaneously within some weeks without therapy in three patients; the other three patients with atrial fibrillation needed conversion to sinus rhythm. Residual leaks were found in 5 out of 116 patients who had been followed by transesophageal echocardiography (TEE) and one leak was closed by a second device. During a follow-up period of 19.4 +/- 16.2 months per patient, TIA and PRIND occurred in 3 of 116 patients. Interventional closure of PFO is a simple, effective and quick method that is superior to surgery and avoids the problems of life-long anticoagulation.

Morphological and functional characteristics of patent foramen ovale and their embolic implications

BACKGROUND AND PURPOSE

Transesophageal echocardiography (TEE) has detected a high prevalence of patent foramen ovale (PFO) in stroke patients, but the clinical implications of the distinctive characteristics of this patency are still a matter of debate.

METHODS

We studied 350 patients with acute ischemic stroke or transient ischemic attack (TIA) within 1 week of admission. Of these, 101 (29%) were identified by contrast TEE to have a PFO; 86 patients (25%) were cryptogenic stroke patients, and 163 were excluded because of the presence of a definite or possible arterial or clinical evidence of a source of emboli or small-vessel disease. Thirteen PFO subjects without a history of embolism were designated as the control group. All PFO and cryptogenic stroke patients were followed up by neurological visits.

RESULTS

Compared with controls, PFO patients with acute stroke or TIA more frequently presented with a right-to-left shunt at rest and a higher membrane mobility (P:<0. 05). Patients with these characteristics were considered to be at high risk. During a median follow-up period of 31 months (range, 4 to 58 months), 8 PFO and 18 cryptogenic stroke patients experienced recurrent cerebrovascular events. The cumulative estimate of risk of cerebrovascular event recurrence at 3 years was 4.3% (95% confidence interval [CI], 0% to 10.2%) for "low-risk" PFO patients, 12.5% (95% CI, 0% to 26.1%) for "high-risk" PFO patients, and 16.3% (95% CI, 7. 2% to 25.4%) for cryptogenic stroke patients (high-risk PFO versus low-risk PFO, P:=0.05).

CONCLUSIONS

The association of right-to-left shunting at rest and high membrane mobility, as detected by contrast TEE, seems to identify PFO patients with cerebrovascular ischemic events who are at higher risk for recurrent brain embolism.

Platypnea-orthodeoxia syndrome related to an aortic aneurysm combined with an aneurysm of the atrial septum

We report the case of a 71-year-old man bearing a severe right-to-left shunt through a patent foramen ovale in the absence of elevated right-sided heart or pulmonary artery pressures. He presented with platypnea-orthodeoxia syndrome, but he had no pulmonary or extracardiac diseases that are known to be associated with this syndrome. Chest radiography showed a bulky aneurysm of the thoracic aorta. A peripheral contrast transesophageal echocardiography demonstrated a large right-to-left shunt through a patent foramen ovale. In addition, the atrial septum was severely deformed by an aneurysm including this patent foramen ovale. We hypothesized that the opening of the foramen ovale was the result of a mechanical deformation of the atrial septum by two contributing factors: the aneurysm of the thoracic aorta and the aneurysm of the septum itself.

Methodological parameters influence the detection of right-to-left shunts by contrast transcranial Doppler ultrasonography

BACKGROUND AND PURPOSE

Contrast transcranial Doppler ultrasonography is a new method to detect intracardiac right-to-left shunts, such as the patent foramen ovale. However, the methodology of the procedure varies considerably among investigators. This study was undertaken to assess the influence of methodological parameters on the results of the contrast transcranial Doppler examination in the detection of right-to-left shunts.

METHODS

A total of 72 patients (mean age, 58.2+/-14.7 years) had a contrast transcranial Doppler ultrasonography examination. To study the influence of methodological factors, patients with evidence of a right-to-left shunt underwent repeated examinations with modified procedures. Parameters under investigation were the timing of the Valsalva maneuver, the dose of the contrast medium, and the patient's posture during the examination.

RESULTS

The median contrast signal count was 58.5 and 48.0 (P<0.001) and the median latency of the first intracranially detected contrast signal was 12.5 and 8.5 seconds (P=0.05) when the Valsalva maneuver was performed 5 and 0 seconds after the start of the injection, respectively. Reducing the contrast medium dose from 10 to 5, 2.5, and 1.2 mL resulted in a decline of the median signal count from 54.5 to 28.5, 20.5, and 12.0 (P<0.01), respectively, while the latency of the first contrast signal increased from 13.3 to 14.0, 14.6, and 15.0 seconds (P<0.05). The sitting position also produced a lower signal count than the supine position (P<0.02).

CONCLUSIONS

This study demonstrates that several essential methodological parameters influence the results of the contrast transcranial Doppler ultrasonography examination. Therefore, it is necessary to standardize the procedure to permit comparable quantitative assessments of the shunt volume. The findings of the present study suggest that 10 mL of contrast medium be injected with the patient in the supine position and that the Valsalva maneuver be performed 5 seconds after the start of the injection.

Patent foramen ovale is an important predictor of adverse outcome in patients with major pulmonary embolism

BACKGROUND

Right-to-left shunt through a patent foramen ovale is frequently diagnosed by contrast echocardiography and can be particularly prominent in the presence of elevated pressures in the right side of the heart. Its prognostic significance in patients with pulmonary thromboembolism, however, is unknown.

METHODS AND RESULTS

The present prospective study included 139 consecutive patients with major pulmonary embolism diagnosed on the basis of clinical, echocardiographic, and cardiac catheterization criteria. All patients underwent contrast echocardiography at presentation. The end points of the study were overall mortality and complicated clinical course during the hospital stay defined as death, cerebral or peripheral arterial thromboembolism, major bleeding, or need for endotracheal intubation or cardiopulmonary resuscitation. Patent foramen ovale was diagnosed in 48 patients (35%). These patients had a death rate of 33% as opposed to 14% in patients with a negative echo-contrast examination (P=.015). Logistic regression analysis demonstrated that the only independent predictors of mortality in the study population were a patent foramen ovale (odds ratio [OR], 11.4; P<.001) and arterial hypotension at presentation (OR, 26.3; P<.001). Patients with a patent foramen ovale also had a significantly higher incidence of ischemic stroke (13% versus 2.2%; P=.02) and peripheral arterial embolism (15 versus 0%; P<.001). Overall, the risk of a complicated in-hospital course was 5.2 times higher in this patient group (P<.001).

CONCLUSIONS

In patients with major pulmonary embolism, echocardiographic detection of a patent foramen ovale signifies a particularly high risk of death and arterial thromboembolic complications.

Patent foramen ovale and transcranial Doppler. Comparison of different procedures

BACKGROUND AND PURPOSE

The capability of transcranial Doppler sonography (TCD) to detect a patent foramen ovale (PFO) has been established. However, which provocative maneuver and what timing of contrast injection are most effective to induce a right-to-left shunt has not yet been determined.

METHODS

We selected 38 cerebrovascular patients (21 men, 17 women) with positive contrast study for PFO on transesophageal echocardiography. Patients underwent a TCD with bilateral monitoring of the middle cerebral arteries (MCAs) and injection of a contrast solution. The injection was repeated (1) during normal breathing (basal conditions); (2) before Valsalva maneuver (VM); (3) during VM; (4) immediately after VM; and (5) during cough. The latency time and the total number of microbubbles for each side were recorded.

RESULTS

TCD found positive results for PFO in 30 patients. Twenty were positive even during basal conditions. The number of positive cases varied according to the timing of the VM in relation to the contrast injection: 28, 25, and 27 cases were positive when the injection was performed before, during, and after VM, respectively, while 26 were positive during cough. There were significant differences in the number of microbubbles in the MCAs between the procedures (P < .001, ANOVA): the highest number was detected in the injection before VM and the lowest number during basal conditions (P < .001, Wilcoxon's test with Bonferroni's correction). The latency time was significantly shorter when the injection followed VM.

CONCLUSIONS

The injection performed before VM appeared to be the most effective TCD procedure in determining the transit of microbubbles through a PFO and subsequently in the MCAs.