Bubble Contrast Echocardiography Research Articles

Objective Quantification of Bilateral Bubble Contrast Echocardiography Correlates with Systemic Oxygenation in Patients with Single Ventricle Circulation.

Bubble contrast echocardiography is commonly used to diagnose pulmonary arteriovenous malformations (PAVMs) in single ventricle congenital heart disease (CHD), yet previous studies inconsistently report a correlation between bubble echoes and oxygenation. In this study, we sought to re-evaluate the correlation between bubble echoes and oxygenation by assessing total bilateral shunting and unilateral shunting. We conducted a single-center, retrospective study of patients with single ventricle CHD and previous Glenn palliation who underwent a cardiac catheterization and bubble echocardiogram during the same procedure from 2011 to 2020. Spearman's rank correlation was performed to examine the relationship between total bilateral shunting and measures of systemic oxygenation, as well as unilateral shunting and ipsilateral pulmonary vein oxygenation. For all patients (n = 72), total bilateral shunting moderately correlated with peripheral oxygen saturation (SpO2) (rs = -0.44, p < 0.0001). For patients with Glenn/Kawashima circulation (n = 49), total bilateral shunting was moderately correlated (SpO2: rs = -0.38, p < 0.01). In contrast, unilateral shunting did not correlate with ipsilateral pulmonary vein oxygenation for any vein measured (p = 0.16-p > 0.99). In conclusion, the total burden of bilateral bubble shunting correlated with systemic oxygenation and may better reflect the total PAVM burden from all lung segments. Unilateral correlation may be adversely influenced by non-standardized approaches to pulmonary vein sampling.

A large type I right pulmonary artery to left atrium fistula: underwent successful percutaneous device closure with duct occluder—a rare case report

BackgroundPulmonary artery to left atrium fistula is an unusual structural cause of silent cyanosis. Only less than 100 cases have been reported so far. A high index of clinical suspicion and proper evaluation with bubble contrast echocardiography and cardiac computed tomography (CT) will help to detect this treatable anomaly. The advent of safer percutaneous closure methods has replaced the need for more invasive surgical closure.Case presentationWe report an adolescent boy, who presented with long-standing cyanosis and progressive dyspnea with normal clinical cardiovascular examination. On evaluation, echocardiography and bubble contrast study revealed a large right pulmonary artery (RPA) to left atrium (LA) fistula. Cardiac CT confirmed the same with normal pulmonary venous drainage s/o a large 20 mm Type I RPA LA Fistula. He underwent successful percutaneous closure of the fistula tract with a 22 × 24 mm Cera™ duct occluder via transseptal approach uneventfully.ConclusionOur case enlightens the methodological approach to diagnosing this rare anomaly as well as the feasibility of percutaneous intervention in such cases as it is one of the largest fistula tracts closed percutaneously to date.

A retrospective review of divers treated for inner ear decompression sickness at Fiona Stanley Hospital hyperbaric medicine unit 2014-2020.

Inner ear decompression sickness (IEDCS) is increasingly recognised in recreational diving, with the inner ear particularly vulnerable to decompression sickness in divers with a right-to-left shunt, such as is possible through a persistent (patent) foramen ovale (PFO). A review of patients treated for IEDCS at Fiona Stanley Hospital Hyperbaric Medicine Unit (FSH HMU) in Western Australia was performed to examine the epidemiology, risk factors for developing this condition, the treatment administered and the outcomes of this patient population. A retrospective review of all divers treated for IEDCS from the opening of the FSH HMU on 17 November 2014 to 31 December 2020 was performed. Patients were included if presenting with vestibular or cochlear dysfunction within 24 hours of surfacing from a dive, and excluded if demonstrating features of inner ear barotrauma. There were a total of 23 IEDCS patients and 24 cases of IEDCS included for analysis, with 88% experiencing vestibular manifestations and 38% cochlear. Median dive time was 40 minutes and median maximum depth was 24.5 metres. The median time from surfacing to hyperbaric oxygen treatment (HBOT) was 22 hours. Vestibulocochlear symptoms fully resolved in 67% and complete symptom recovery was achieved in 58%. A PFO was found in 6 of 10 patients who subsequently underwent investigation with bubble contrast echocardiography upon follow-up. IEDCS occurred predominantly after non-technical repetitive air dives and ongoing symptoms and signs were often observed after HBOT. Appropriate follow-up is required given the high prevalence of PFO in these patients.

A pediatric case of portosystemic shunt presenting hypoxemia with brain abscess in an emergency department

Portosystemic shunt is a rare congenital vascular anomaly. The shunt is hard to clinically suspect because its symptoms develop insidiously and affect various systems at different time points. We report a case of an 11-year-old girl who presented with brain abscess and hypoxemia without respiratory distress. No abnormality related to the hypoxemia, such as intracardiac shunt, was found on the initial chest radiograph and echocardiogram. However, computed tomography showed a portosystemic shunt. An intrapulmonary shunt was demonstrated by bubble contrast echocardiography, indicating a grade 2 hepatopulmonary syndrome, a complication of portosystemic shunt. This case describes the diagnostic process of an unusual case presenting neurological abnormalities and hypoxemia without respiratory distress. Portosystemic shunt with hepatopulmonary syndrome should be considered in the differential diagnosis of unexplained hypoxemia.

Reverse Platypnea–Orthodeoxia with Atrial Septal Defect and Diffuse Pulmonary Arteriovenous Fistulae in Hepatopulmonary Syndrome

A 69-year-old male with a long-standing diagnosis of interstitial lung disease and on domiciliary oxygen therapy was evaluated by echocardiography. His supine oxygen saturation ranged between 77% and 86% and upright oxygen saturation was 93%–94%. Two-dimensional transthoracic echocardiography showed a secundum atrial septal defect of 15 mm diameter with left-to-right shunting but without dilatation of right-sided chambers. Air bubble contrast echocardiography showed no air bubbles crossing the atrial septum but bubbles appeared in left-sided chambers through pulmonary veins after five cardiac cycles indicating intra-pulmonary shunting. Computed tomography of the chest demonstrated a mosaic pattern of the lung parenchyma, characterized by the presence of alternating geographic areas of low attenuation with regions of relatively increased attenuation typical of diffuse pulmonary arteriovenous fistulae. This is a rare case of reverse platypnea-orthodexia with possible contribution of two different pathophysiologic mechanisms but precise mechanism remains elusive.

Association Between Patent Foramen Ovale and Overt Ischemic Stroke in Children With Sickle Cell Disease

Ischemic stroke is one of the most devastating complications of sickle cell anemia (SCA). Previous studies have shown that intracardiac shunting including patent foramen ovale (PFO) can be a potential risk factor for stroke in children with SCA. This study investigates the association between PFO and overt ischemic stroke in the DISPLACE (Dissemination and Implementation of Stroke Prevention Looking at the Care Environment) study cohort of 5,247 children with SCA of whom 1,414 had at least one clinical non-contrast transthoracic echocardiogram. Presence of PFO was taken from the clinical report. Further, we assessed the association between PFO and other clinical and hemolytic factors in children with SCA such as history of abnormal sickle stroke screen [elevated Transcranial Doppler ultrasound (TCD) velocity] and patient's baseline hemoglobin. In 642 children for whom all data were available, the adjusted odds ratio (OR) for overt stroke was higher in those with PFO but this was not statistically significant (OR: 1.49, 95% CI: 0.20–11.03, p = 0.6994). With an OR of 0.85, the study suggested less PFOs in those with abnormal TCD, but this was not statistically significant (95% CI: 0.17–4.25, p = 0.8463). Overall, the prevalence of PFO in this large sub study of non-contrast echocardiography amongst children with SCA is much lower than previous smaller studies using bubble contrast echocardiography. Overt stroke was non-statistically more common in children with SCA and PFO, but there was no evidence that PFO was more common in those with abnormal TCD, the most important pediatric sickle stroke screen.

Modeling Outcomes in Children With Biliary Atresia With Native Liver After 2 Years of Age.

Approximately 50% of infants with biliary atresia (BA) undergoing Kasai portoenterostomy show survival with native liver (SNL) at age 2 years. Predictors of disease progression after age 2 years are unknown, despite estimates of 20%‐30% undergoing liver transplant (LT) between age 2 and 18 years. We sought to address this knowledge gap by developing prognostic models in participants of the multicenter prospective National Institutes of Health‐supported Childhood Liver Disease Research Network. We extracted 14 clinical and biochemical variables at age 2 years to develop two models for future outcomes: 1) LT or death (LTD) and 2) first sentinel event (SE), either new onset ascites, hepatopulmonary syndrome (HPS), or gastrointestinal (GI) bleed. A total of 240 participants, enrolled between 2004 and 2017, were followed until a median age of 5.1 years (range, 2.0‐13.3 years). Of these participants, 38 underwent LT (n = 37) or death (n = 1); cumulative incidence, 23.7% (95% confidence interval [CI], 16.2%‐32.0%). Twenty‐seven experienced either new‐onset ascites (n = 13), HPS (n = 1), or GI bleed (n = 14). One participant had ascites and GI bleed concurrently; cumulative incidence, 21.5% (95% CI, 14.2%‐29.8%) by age 10 years. The Cox proportional hazard model predicted risk of LTD, using total bilirubin, albumin, platelet count, and history of either ascites or cholangitis (BA LTD model), with a C‐index of 0.88 (range, 0.86‐0.89). A cause‐specific hazard competing risk model predicted SE using platelet count and gamma glutamyltransferase levels (BA SE model) with a C‐index of 0.81 (range, 0.80‐0.84). Internal model validity was assessed using Harrell’s C‐index with cross‐validation. Conclusion: Stratification using these models identified risk of poor outcomes in patients with BA SNL after age 2 years. The models may identify those who would benefit from enhanced clinical surveillance and prioritization in clinical trials.

Cerebral arterial gas embolism proven by computed tomography following transthoracic echocardiography using bubble contrast

A 75 year-old male developed features of an acute stroke following bubble contrast echocardiography, which was shown on emergent computed tomography scanning to be a result of cerebral arterial gas embolism (CAGE) to the left middle cerebral artery. Ischaemic stroke symptoms have previously been reported as a rare complication of bubble contrast echocardiography. Radiologically proven CAGE from bubble contrast echocardiography had not been reported at the time this case occurred. Immediate provision of 100% oxygen and administration of hyperbaric oxygen are recommended treatments for CAGE and were associated with a substantial recovery for this patient.

Efficacy of bubble contrast echocardiography in detecting pulmonary arteriovenous fistulas in children with univentricular heart after total cavopulmonary connection.

Development of pulmonary arteriovenous fistulas in patients with cavopulmonary anastomosis may result in a significant morbidity. Although the use of bubble contrast echocardiography with selective injection into both the branch pulmonary arteries in identifying pulmonary arteriovenous fistulas has been increasing, the actual efficacy of this diagnostic modality has not been properly evaluated. Thus, this study aimed to assess the efficacy of bubble contrast echocardiography in detecting pulmonary arteriovenous fistulas in children with total cavopulmonary connection. A total of 140 patients were included. All patients underwent cardiac catheterisation. Bubble contrast echocardiographic studies were performed by injecting agitated saline solution into the branch pulmonary arteries. Transthoracic echocardiograms that use an apical view were conducted to assess the appearance of bubble contrast in the systemic ventricles. Then, the contrast echocardiogram results and other cardiac parameters were compared. No correlation was found between contrast echocardiogram grade and other cardiac parameters, such as pulmonary capillary wedge saturation and pulmonary artery resistance. Moreover, only 13 patients had negative results on both the right and left contrast echocardiograms, and 127 of the 140 patients had positive results on contrast echocardiograms even though they had normal pulmonary capillary wedge saturation. Results showed that bubble contrast echocardiography was a highly sensitive method and was likely to obtain false-positive results. Bubble contrast echocardiography might be highly false positive in detecting pulmonary arteriovenous fistulas in patients with cavopulmonary anastomosis. We have to consider how we make use of this method. Further standardisation of techniques is required.

Bubble Contrast Echocardiography for Alcohol Septal Ablation

Bubble Contrast Echocardiography for Alcohol Septal Ablation

Inadvertent Diversion of Superior Vena Cava to the Left Atrium- A Diagnosis Made by Bubble Contrast Echocardiography

Inadvertent Diversion of Superior Vena Cava to the Left Atrium- A Diagnosis Made by Bubble Contrast Echocardiography

The prevalence of electrocardiogram abnormalities in professional divers.

The underwater environment presents physiological challenges for the cardiovascular, renal and pulmonary systems. Increases in external hydrostatic pressure reduce the capacity of the venous compartment and cause blood to move toward the lung. The aim of this study was to evaluate retrospectively electrocardiographic (ECG) changes in a cohort of professional divers. Between January 2009 and January 2012, 225 randomly selected professional divers, 204 male (91%) and 21 female (9%) attended our clinic for their biannual diving medical assessment. Their ECG records were evaluated retrospectively. The most common ECG abnormality observed was incomplete right bundle branch block (IRBBB) in 30 divers (13.3%). Eleven divers (4.9%) showed right QRS axis deviation (seven with IRBBB). Six divers had a sinus tachycardia; in four divers there was early repolarization; three divers had ventricular extrasystoles; one diver had ST elevation in lead V3; there was one with sinus arrhythmia and another with T-wave inversion in leads V2, V3 and aVF. These ECG changes were evaluated retrospectively by a cardiologist who made various recommendations for further review including bubble contrast echocardiography for IRBBB. No serious ECG abnormalities were identified, but IRBBB should be further investigated because of its association with persistent (patent) foramen ovale. Rapid cardiological review of ECGs could be achieved using modern communications technology, such as telecardiography, and further clinical investigations directed by specialist recommendation arranged promptly if indicated.

Isolated Tracheal Telangiectasia

Clinical Image: A 23-year-old non-smoker woman presented with a seven-year history of intermittent hemoptysis, which always subsided spontaneously. There were no other symptoms and sources of bleeding. Her past medical, drug and familial history were unremarkable. Physical examination revealed nothing abnormal. Results from Para-clinical tests (CBC, U/A, S/E, Pulseoximetry, ABG, CXR, Air Bubble Contrast Echocardiography and pulmonary arterial pressure) were normal except showing a normocytic anemia. Laryngoscopy showed a nodule (five mm in diameter) and bloody strains on vocal cord (Figure 1A). Fiber-optic bronchoscopy showed telangiectatic lesions in the subglottic area to two-third of the proximal trachea (Figure 1B). The lesions were flat, non-pulsatile, and without active bleeding, surrounded by normal mucosa. One-third of distal trachea and main and lobar bronchi were normal. We diagnosed as Isolated Tracheal Telangiectasia. We performed palliative therapy with the Argon plasma coagulation device in three sessions (at first, second and eighth weeks). At a Six-month follow-up, there was no hemoptysis anymore and no problem in speech; Bronchoscopy showed vocal cord and tracheal lesions were less severe (Figure 1C and D). The patient remains asymptomatic in a one-year follow-up.

Transthoracic contrast echocardiography for detection of pulmonary arteriovenous malformations in hereditary hemorrhagic telangiectasia: How can the process be improved for patient safety?

Introduction: Patients with hereditary hemorrhagic telangiectasia (HHT) are at risk for pulmonary arteriovenous malformations (PAVMs). Extracardiac right-to-left shunts due to PAVMs can lead to systemic emboli; clinical sequelae including strokes and brain abscesses. Regular screening is required, with appropriate medical/interventional management to alleviate morbidity and mortality from PAVMs. International HHT guidelines recommend standardized transthoracic contrast echocardiogram (TTCE) with agitated saline (in an HHT Foundation-accredited laboratory) as the initial screening test, and, when needed, non-contrast computerized tomography of the chest (CT Chest) to follow up on a positive TTCE. Case presentation: A 40-year-old woman was seen for evaluation of HHT and referred for TTCE as part of her PAVM screen. Following administration of agitated saline, she developed a headache, visual changes in her right eye, and right arm weakness, followed by posturing and stiffness in her right arm. Her symptoms resolved after five minutes, consistent with a transient ischemic attack (TIA). Clinical impact: Protocols at our institution were amended following this index case and echocardiography laboratory protocols were adjusted to use a maximum of 0.1 cc air to 9.9 cc saline for TTCE studies in the HHT population. Only the attending echocardiologist who is familiar with possible systemic air embolism during bubble contrast echocardiography in patients with HHT should perform agitation and infusion of contrast and should directly review the images for appropriate visualization during the exam for this test to be appropriately interpreted. Paradoxical emboli due to right-to-left shunt are important to recognize. Best practice for PAVM screening in HHT patients includes use of standardized protocols for the performance and reporting of TTCE in the evaluation of pulmonary shunts.

An unusual cause of central cyanosis in a nine-year-old boy

Pulmonary arteriovenous malformations are rare vascular anomalies which rarely present in childhood. We discuss a nine-year-old male child who presented with the classical triad of exertional dyspnea, cyanosis and clubbing since six years of age. Pulmonary arteriovenous malformation was suspected on chest radiography and was later confirmed on computed tomography scan. A bubble contrast echocardiography showed the presence of an extracardiac shunt. Pulmonary angiography was done to delineate the anatomy of the pulmonary vasculature and to plan embolization. The child has undergone two sittings of transcatheter coil embolization with improvement in oxygenation.

Mirror-image Gerbode defect?

A 43-year-old man with a repaired partial atrioventricular septal defect presented post-stroke. Transthoracic and bubble contrast echocardiography was positive, suggesting a right-to-left shunt. Transoesophageal echocardiography (TOE) was arranged to define the anatomy. TOE demonstrated an atrial septal and left atrioventricular valve repair with mild central regurgitation and a second small jet of presumed residual regurgitation through the valve. Bubble contrast injection showed bubbles in the left heart immediately after the …

Pulmonary arteriovenous malformations after a Fontan operation in the left isomerism and absent inferior vena cava☆

To evaluate the occurrence of pulmonary arteriovenous malformations after a Fontan operation in the left isomerism and absent inferior vena cava. We retrospectively reviewed 19 patients with the left isomerism and absent inferior vena cava who underwent Fontan operations at our institution. We divided the patients into two groups: bilateral superior vena cava (group A, n=9), and single superior vena cava (group B, n=10). Median age at Fontan operation was 6.2 years (1.0-24.1). Diagnosis of pulmonary arteriovenous malformations was made by pulmonary angiography and bubble contrast echocardiography. Median follow-up was 5.3 years (0.2-17.3) with one hospital death. Seven patients suffered from pulmonary arteriovenous malformations. In six out of the seven patients, the occurrence of pulmonary arteriovenous malformations was related to biased pulmonary perfusion of the hepatic venous flow. In group A, the distance between the dominant superior vena cava (which the venous flow from the lower half of the body drains into) and the hepatic venous channel over the distance between the smaller superior vena cava and the hepatic venous channel was larger in patients with pulmonary arteriovenous malformations than in patients without pulmonary arteriovenous malformations (3.83+/-1.28 vs 1.53+/-1.45, p=0.071). In group B, pulmonary arteriovenous malformations developed in two patients whose venous channels did not overlap. Pulmonary arteriovenous malformations developed in only one patient after we changed the hepatic venous channel design to approximate the hepatic venous channel to the dominant superior vena cava as closely as possible. We might prevent pulmonary arteriovenous malformations in patients with the left isomerism and absent inferior vena cava by designing the venous channels to achieve better mixing of the superior vena cava and the hepatic venous flow.

Response to Dr Kula: Asymptomatic hypoxia in a young pregnant lady—Unusual presentation of atrial septal defect

We thank Dr Kula and colleagues for their comments [1] on our recent case report ‘Asymptomatic hypoxia in a young pregnant lady—an unusual presentation of atrial septal defect [2]’. The patient described was noted to have an ejection systolic murmur in the pulmonary area with fixed wide splitting of the first heart sound without a loud pulmonary component on clinical examination. A bubble contrast echocardiography which was done as a diagnostic procedure did demonstrated passage of a few bubbles (b5) from the right to left atrium even at rest before a Valsalva manoeuvre but bubbles were more pronounced with the Valsalva manoeuvre (N20) consistent with the diagnosis of an atrial septal defect (ASD) without any evidence of pulmonary hypertension. We agree that the passage of bubbles from right to left side at rest is very common in patients with pulmonary hypertension but still could be seen in patients with large atrial septal defects, as seen in our case. At 3 months after pregnancy, a transoesophageal echocardiography examination demonstrated a Qp/Qs ratio of 1.7:1 without any features suggestive of pulmonary hypertension. She did not undergo any right or left heart catheterisation due to the lack of pulmonary hypertension, well delineated os secundum ASD on echocardiography and a low risk for coronary artery disease. Following referral to a tertiary centre, she had an uncomplicated percutaneous closure of her ASD. We believe that the hypoxia noted during her pregnancy and just immediately post-partum might well be related to transient right to left sided shunting, but after the device closure of the ASD, a subsequent TOE did not demonstrated any residual shunting. There was no further hypoxia after procedure which was confirmed in her arterial blood gas analysis. We agree with Dr Kula colleagues that a differential diagnosis to consider in this kind of scenario is a pulmonary atrio-venous malformations or fistula, as a fifth of patients do remain asymptomatic. This diagnosis was considered in our patient but the subsequent investigations clearly revealed the presence of large os secundum ASD. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology [3].

Spontaneous left atrial thrombus during patent foramen ovale closure

A 52-year-old male smoker suffered a left-sided stroke. Bubble contrast echocardiography demonstrated an aneurysmal atrial septum and patent foramen ovale (PFO). The patient was referred for percutaneous closure of his PFO to reduce his risk of further stroke. Despite dual antiplatelet therapy and pre-procedural heparin, he developed a spontaneous thrombus during balloon sizing of the defect identified by transoesophageal echocardiography. The balloon was immediately withdrawn to the right side and removed. Periprocedural echocardiography using either transoesophageal or intracardiac echo is essential to monitor for this potential procedural complication of percutaneous PFO closure.

Lower patent foramen ovale detection with transthoracic echocardiography in atrial fibrillation

Patent foramina ovale (PFO) are small defects within the atrial septum that may play a role in paradoxical embolism, stroke and migraines. The relationship between PFO and atrial fibrillation (AF) has not been formally studied. We prospectively studied patients with a history of AF, versus those without (controls), in order to compare PFO prevalence among them. Sixty-one patients with AF and forty-one controls completed the study, all undergoing transthoracic echocardiography using agitated saline microbubbles and a Valsalva maneuver. In the control group, 12/41 participants (29.2%) had PFOs compared to 5/61 (8.2%) in the AF group (P < 0.01). PFO positive patients within the entire study population demonstrated greater leftward inter-atrial septal shifting (82% vs 49%, P < 0.05). There was also reduced leftward inter-atrial septal shift observed within the AF group compared to controls (32/61 (52%) vs 31/41 (76%), P < 0.05). This study is the first to demonstrate an apparent lower rate of PFO in patients with AF, using bubble contrast echocardiography.