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.     

Radionuclide angiocardiography in evaluation of patients after repair of transposition of the great arteries

The ability of first pass radionuclide angiocardiography to detect and quantitate residual intracardiac shunts and systemic venous obstruction after repair of transposition of the great arteries was evaluated in 29 children. Information from radionuclide scans was compared with data obtained during cardiac catheterization. Three children had a residual right to left shunt detected with both methods. There was good agreement between radionuclide and catheterization quantitation of left to right shunt in the nine patients with a residual defect, five of whom had significant shunting. Nineteen patients with signs suggesting superior vena caval obstruction were evaluated with both radionuclide and catheterization methods. In eight, complete obstruction was detected with both techniques; in one additional patient, partial obstruction was found on catheterization only. One of six patients evaluated for possible inferior vena caval obstruction was identified with both techniques. In the group as a whole, information obtained with radionuclide angiography correlated well with cardiac catheterization data in evaluation of residual shunts and obstruction to systemic venous return.     

Platypnea-Orthodeoxia Syndrome: To Shunt or Not to Shunt,That is the Question

Platypnea-orthodeoxia syndrome is a rare disease defined by dyspnea and deoxygenation, induced by an upright position, and relieved by recumbency. Causes include shunting through a patent foramen ovale and pulmonary arteriovenous malformations.A 79-year-old woman experienced 2 syncopal episodes at rest and presented at another hospital. In the emergency department, she was hypoxic, needing 6 L/min of oxygen. Her chest radiograph showed nothing unusual. Transthoracic echocardiograms with saline microcavitation evaluation were mildly positive early after agitated-saline administration, suggesting intracardiac shunting. She was then transferred to our center.Right-sided heart catheterization revealed no oximetric evidence of intracardiac shunting while the patient was supine and had a low right atrial pressure. However, her oxygen saturation dropped to 78% when she sat up. Repeat transthoracic echocardiography while sitting revealed a dramatically positive early saline microcavitation-uptake into the left side of the heart. Transesophageal echocardiograms showed a patent foramen ovale, with right-to-left shunting highly dependent upon body position. The patient underwent successful percutaneous patent foramen ovale closure, and her oxygen supplementation was suspended.In patients with unexplained or transient hypoxemia in which a cardiac cause is suspected, it is important to evaluate shunting in both the recumbent and upright positions. In this syndrome, elevated right atrial pressure is not necessary for significant right-to-left shunting. Percutaneous closure, if feasible, is first-line therapy in these patients.     

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.     

Successful treatment of right ventricular failure with atrial septostomy

In the case reported, a patient with severe right ventricular failure following coronary revascularization was successfully weaned from cardiopulmonary bypass following creation of an atrial septal defect. This technique facilitated rapid decompression of the failing right ventricle by shunting blood to the more compliant left ventricle, thus augmenting left ventricular preload and enhancing cardiac output. Recovery of right ventricular function was demonstrated by progressive hemodynamic improvement, as well as reduction of right-to-left intracardiac shunting and resolution of arterial hypoxemia.     

Platypnea-Orthodeoxia Syndrome: Rare or Under-Diagnosed Syndrome? 3 Case Reports and a Literature Review

Platypnea-Orthodeoxia Syndrome (POS) is dyspnea and hypoxemia in the upright position that improves in the supine position. Cardiac POS is predominantly caused by congenital interatrial communications (CIC) paired with changes in the thoracic anatomy, allowing orthostatic right to left cardiac shunting. High suspicion, especially with hypoxemia without significant pulmonary disease, that does not easily correct with supplemental oxygen, should lead the clinician to obtain echocardiographic imaging, documenting right to left shunting, typically through a patent foramen ovale (PFO). Transcatheter closure of the CIC is highly successful in relieving symptoms of dyspnea and resolving hypoxemia in the majority of patients.     

Cyanosis in patients with atrial septal defect due to systemic venous drainage into the left atrium

Cyanosis and clubbing of the digits in patients with atrial septal defect usually are indicative of reversal of the interatrial shunt consequent to reduced right ventricular compliance and severe pulmonary hypertension. The condition may be considered inoperable. The cases reported herein emphasize the occurrence of cyanosis in patients with interatrial communication and continued significant left to right shunting, as a consequence of systemic venoarterial shunting into the left atrium. Carefully planned cardiac catherization is indicated to detect the less well recognized mechanisms of cyanosis so that such patients are not denied the benefits of surgical closure of the septal defect.     

Atrial septal aneurysm with right-to-left interatrial shunting

Interatrial shunting in the presence of an atrial septal aneurysm is an uncommon but well recognized abnormality. Previous case reports have demonstrated that elevated right atrial pressure secondary to pulmonary embolism or right ventricular infarction may cause right-to-left interatrial shunting in the presence of an atrial septal aneurysm. We describe a unique situation in which an atrial septal aneurysm was associated with a right-to-left shunt secondary to severe systemic hypotension and normal right atrial pressure. In this patient, we used midodrine, an oral alpha-1 agonist, to increase systemic arterial pressure, decrease the severity of the shunt, and treat the severe hypoxemia. This case establishes that right-to-left interatrial shunting can result from a decrease in left ventricular afterload with normal right atrial pressure. Oral alpha-1 agonist therapy can be used successfully to treat patients such as ours and possibly others with similar functional abnormalities.     

Abnormal Agitated Saline Study Results after Tetralogy of Fallot Repair

Residual intracardiac or extracardiac shunting is frequently seen in patients with repaired congenital heart disease and can cause systemic hypoxemia. We present the case of an adult with tetralogy of Fallot who underwent two corrective surgical procedures as a child with subsequent pulmonary valve replacement due to residual pulmonary insufficiency. Further details of her operative history were otherwise unknown. After being lost to follow‐up for many years, she presented with unexplained cyanosis and a markedly abnormal agitated saline study on transthoracic echocardiography in which only the left heart filled after contrast administration. We review the differential diagnosis for such a presentation and discuss the utility of cardiac magnetic resonance imaging (MRI) to define the etiology. Cardiac MRI, a frequently used imaging modality to longitudinally assess adult patients with congenital heart disease, provides excellent image quality of cardiac structures and the ability to perform angiography in a variety of imaging planes. These advantages render cardiac MRI, a useful modality to determine the etiology of unexplained cyanosis in these patients as both intracardiac and extracardiac shunts can be detected.     

Left ventricular volumes by single-plane cineangiography: in vivo validation of the Kennedy regression equation

This study was performed to assess the accuracy and reliability of the regression equations of Kennedy et al and Wynne et al in the quantitation of single plane left ventricular (LV) volumes. In 15 patients with normal LV function and without intracardiac shunting or valvular insufficiency, gated equilibrium blood pool scintigraphy was performed simultaneously with the measurement of cardiac output (by thermodilution), after which left ventriculography was performed in the 30 degrees right anterior oblique (RAO) projection. From the scintigraphically determined LV ejection fraction (EF) and the thermodilution-measured stroke volume (SV), absolute LV volumes were calculated. The cineangiographic LV volumes obtained with the regression equation of Kennedy et al closely approximated those calculated by scintigraphy/thermodilution, whereas the volumes determined using the regression equation of Wynne et al were larger (p less than 0.05) than the calculated volumes. In 204 patients without intracardiac shunting or valvular insufficiency, SV was measured by the Fick or indicator dilution methods, after which single-plane left ventriculography was performed in the 30 degrees RAO projection. In the 83 patients without coronary artery disease with normal (n = 69) or depressed (n = 14) LVEF, cineangiographic SV (obtained using the regression equation of Kennedy et al) closely approximated forward SV. Similarly, this relation was excellent in the 142 patients whose LVEFs were greater than or equal to 0.50.(ABSTRACT TRUNCATED AT 250 WORDS)     

Enhancement of hypoxemia by atrial shunting in cystic fibrosis

Patients with CF may develop hypoxemia which seems disproportionate to the degree of pulmonary disease. In a series of patients with CF and advanced pulmonary disease undergoing transesophageal echocardiography for the evaluation of cor pulmonale, eight of 15 patients were found to have atrial shunts through a stretched foramen ovale. To our knowledge, this is the first observation of intracardiac shunting in CF. This phenomenon may account for unexplained levels of cyanosis and worsening of hypoxemia with exercise, vasodilators, or PEEP and poses the threat of paradoxic emboli when central venous lines are used in these patients.     

Platypnea-Orthodeoxia Syndrome: Diagnostic Challenge and the Importance of Heightened Clinical Suspicion

Platypnea-orthodeoxia syndrome is an uncommon condition of positional dyspnea and hypoxemia; symptoms occur when the patient is upright and resolve with recumbency. Causes can be broadly categorized into 4 groups: intracardiac shunting, pulmonary shunting, ventilation-perfusion mismatch, or a combination of these.Platypnea-orthodeoxia syndrome should be suspected when normal arterial oxygen saturations are recorded while an individual is supine, followed by abrupt declines in those saturations when upright. Further investigations with use of imaging and cardiac catheterization aid in the evaluation. When platypnea-orthodeoxia syndrome is due to intracardiac shunting without pulmonary hypertension, intracardiac shunt closure can be curative.In this article, we report a case of platypnea-orthodeoxia syndrome in an 83-year-old woman who was successfully treated by means of percutaneous transcatheter closure of an atrial septal defect.     

Endocardial cushion defect associated with cor triatriatum sinistrum or supravalve mitral ring

Clinical and angiographic or autopsy data, or both, on three children with a subdivided left atrium (cor triatriatum) and an associated endocardial cushion defect are reviewed. (One child had ostium primum defect, and two had complete atrioventricular [A-V] canal.) A fourth patient demonstrates the difficulties in differentiating subdivided left atrium from supravalve mitral stenosis in the presence of an endocardial cushion defect. The clinical findings are greatly influenced by the endocardial cushion defect. A pressure gradient between the pulmonary wedge and (left or right) ventricular end-diastolic pressures in patients with an endocardial cushion defect indicates pulmonary venous obstruction and should alert one to the possibility of these combined lesions. The exact diagnosis is made with injections of angiographic contrast medium into the proximal and distal left atrial chambers, to document the respective relations of the pulmonary veins, left atrial appendage and A-V valves to these atrial chambers. All three patients with an endocardial cushion defect and a subdivided left atrium had an associated patent ductus arteriosus. The common association of subdivided left atrium with intracardiac, pulmonary venous and aortic anomalies is again demonstrated.     

Quantification of intracardiac shunts by gold-195m, a new radionuclide with a short half life

Gold-195m, a radionuclide with a short half life (30.5 s) was used to quantify left to right intracardiac shunts. The results of this method were compared with those obtained with technetium-99m, a method that was validated against oximetry. In five patients the pulmonary to systemic flow ratio (greater than 3:1) obtained by both radionuclides indicated that the level of shunting was too high to be measured accurately. In one patient fragmentation of the bolus meant that no satisfactory gamma fit could be obtained. In the remaining 16 patients there was no significant difference between two successive 195mAu studies. The agreement between 99mTc results and 195mAu results was excellent. Oxygen administration, straight leg raising exercise, and the use of oblique projections did not affect the values of the pulmonary to systemic flow ratio. The technique of quantification of intracardiac shunts by 195mAu gives reproducible and accurate results and the low radiation dose means that it is suitable for use in children with suspected left to right shunts.     

Quantification of intracardiac shunts by gold-195m, a new radionuclide with a short half life.

Gold-195m, a radionuclide with a short half life (30.5 s) was used to quantify left to right intracardiac shunts. The results of this method were compared with those obtained with technetium-99m, a method that was validated against oximetry. In five patients the pulmonary to systemic flow ratio (greater than 3:1) obtained by both radionuclides indicated that the level of shunting was too high to be measured accurately. In one patient fragmentation of the bolus meant that no satisfactory gamma fit could be obtained. In the remaining 16 patients there was no significant difference between two successive 195mAu studies. The agreement between 99mTc results and 195mAu results was excellent. Oxygen administration, straight leg raising exercise, and the use of oblique projections did not affect the values of the pulmonary to systemic flow ratio. The technique of quantification of intracardiac shunts by 195mAu gives reproducible and accurate results and the low radiation dose means that it is suitable for use in children with suspected left to right shunts.     

Increased systemic vascular resistance in neonates with pulmonary hypertension.

The time necessary for aortic diastolic pressure to decrease to 50 percent of an initially selected value after dissipation of the dicrotic notch (T 1/2) was determined in newborn infants with and without pulmonary hypertension. The mean T 1/2 was 671 +/- 167 msec in seven infants with clinical evidence of pulmonary hypertension and documented right to left ductus arteriosus shunting; 849 +/- 243 msec in nine infants with clinical evidence of pulmonary hypertension but no documented right to left ductus arteriosus shunting; and 457 +/- 66 msec in eight infants with hyaline membrane disease and no clinical evidence of pulmonary hypertension or a patent ductus arteriosus. The mean T 1/2 values in the former two groups were significantly different from that in the group with no pulmonary hypertension (P less than 0.01). An evaluation of factors affecting T 1/2 leads to the conclusion that the patients with pulmonary hypertension had increased systemic vascular resistance as well. This finding has important diagnostic, etiologic and therapeutic implications.     

A Change of Heart: Reopening of a Foramen Ovale

Platypnea-orthodeoxia is a rare syndrome characterized by dyspnea and hypoxemia that is exacerbated by assuming an upright position. The most common cause is intracardiac shunting through an atrial septal defect or patent foramen ovale (PFO). We present a 63-year-old man with dyspnea after right pneumonectomy for lung cancer, who was found to have a large PFO with right-to-left shunt in the presence of normal right-sided pressures. Percutaneous closure of the PFO led to resolution of symptoms.     

Right-to-left shunting through a patent foramen ovale without pulmonary hypertension. Transient improvement after balloon catheter closure

A patient had a history of right tuberculosis and severe hypoxemia secondary to right-to-left shunting through a patent foramen ovale without pulmonary hypertension. A balloon tip catheter was positioned in the left atrium and retracted against the atrial septum and the hypoxemia was temporarily resolved.     

Monitoring cardiac function with nuclear techniques

Noninvasive Imaging with radioactive tracers has become widely used since its introduction in the early 1970s. Improvements continue to be made in the techniques and the clinical applications. Much of the information provided by these techniques is new. The first transit studies are used mainly in the evaluation of pulmonary transit time, detection of intracardiac shunting, evaluation of right ventricular function, measurement of ejection fraction and detection of wall motion abnormalities at rest and after exercise. The gated blood pool study is found to be most useful in assessment of global left ventricular function, regional wall motion, valve regurgitation and right ventricular function.

The techniques of nuclear cardiac imaging are noninvasive, simple, successfully performed in almost 100 percent of cases. They are easy to interpret, able to be quantified and able to be almost totally automated. Their use is likely to become more widespread in the future.