Saline Contrast Echocardiography in the Era of Multimodality Imaging--Importance of "Bubbling It Right"

Contrast efficacy of novel phase convertible nanodroplets for safe CEUS imaging

Microbubble contrast agents in ultrasound/echocardiography are used to increase the echogenicity of the target tissues, thereby raising the contrast resolution of the resultant image. Recently, the trend has shifted toward the development of phase-convertible nanodroplets as ultrasound contrast agents due to their promising theragnostic potential by switching capability at the active site. Herein, we fabricated pre-PGS- perfluoropentane phase convertible nanodroplets and checked their in vitro and in vivo enhancement and safety profile. For this, we performed experiments on 20 male Wistar rats and 2 dogs. Biochemical assays of both rats and dogs included complete blood profiles, liver function tests, and renal function tests. For rat vitals, monitoring and histopathological analysis were also performed. Converted nanodroplets showed excellent contrast enhancement, better than Sonovue upon in vitro testing, with an enhancement time of up to 14 min. In vivo, experiments showed comparable opacification of the ventricles of both rats and dogs. All biochemical assays remained within the normal range during the study period. The histopathological analysis did not show any signs of drug-induced toxicity, showing the safety of these nanodroplets. Pre-PGS-PFP nanodroplets hold great potential for use in echocardiography and abdominal imaging in both human and veterinary applications after clinical trials.

Positive Bubble Study But No Evidence of Interatrial Defect in a Patient with Recurrent Cryptogenic Stroke

Pulmonary arteriovenous malformations (PAVMs) can be asymptomatic or result in a range of complications such as brain abscesses or cryptogenic emboli, which can contribute to morbidity and mortality if not diagnosed and treated in a timely manner. To date, there have been several reports of delayed diagnosis of PAVMs, which have been largely attributed to the misconception that PAVMs are too rare to be of clinical significance. Furthermore, because intracardiac shunting secondary to a patent foramen ovale (PFO) or atrial septal defect (ASD) also results in a positive saline contrast study with echocardiography, PAVM can be easily misdiagnosed as an intracardiac right-toleft shunt. However, there are unique echocardiographic features that differentiate between intracardiac shunting due to a PFO or ASD and extracardiac shunting such as in PAVM. This case details the course of a patient with recurrent cryptogenic strokes that was initially misattributed to a PFO and was only correctly diagnosed with multiple PAVMs after two failed attempts at PFO closure. This case serves as a reminder of an alternative etiology of right-to-left shunt and its presentation on imaging, which echocardiographers must be familiar with.

Unusual Left Superior Vena Cava, Connected to the Left Atrium via the Left Superior Pulmonary Vein

Persistent left superior vena cava (LSVC) that drains into the left atrium (LA) via the left superior pulmonary vein (LSPV) is a rare systemic venous drainage anomaly. It can cause cyanosis and unexplained recurrent strokes. Undiagnosed, it can seriously disrupt the conduct of the cardiopulmonary bypass (CPB), causing sudden air lock and/or flooding of the operative field with venous blood. Its connection with the LSPV outside the pericardium makes its intraoperative diagnosis difficult. We report here the case of a 48-year-old man operated for mitral and aortic valve endocarditis, complicating a Laubry-Pezzi syndrome. The opening of the LA was followed immediately by the entrance of high volume of air bubbles into the superior vena cava cannula which resulted in sudden air lock of the venous outflow line. After multiple lowerings and cessations of pump flow, partial clamping of this cannula resulted in flooding of the LA with venous blood coming from the LSPV. The heart luxation did not allow us to find the LSVC in its usual intrapericardial location, between the LSPV and the left appendage. We had to widely open the left pleura to expose its completely extrapericardial path and its communication with the LSPV. The LSVC was temporally clamped during the remainder of the surgical procedure, then ligated at both ends. The patient underwent mitral valve repair, closure of the infundibular septal defect, aortic valve replacement and tricuspid annuloplasty. He was discharged 10 days later.

Persistent Left Superior Vena Cava, Connected to the Left Atrium via the Left Superior Pulmonary Vein. An Unusual Cause of Air Lock

The intraoperative diagnosis of a persistent left superior vena cava (LSVC) that drains into the left atrium (LA) via the left superior pulmonary vein may be difficult because of its extrapericardial pathway. We report here the case of a 48-year-old man, operated for a mitro-aortic endocarditis complicating a Laubry-Pezzi syndrome. The opening of the LA was followed immediately by a sudden air lock. It was only after opening of the left pleura that we were able to find and then ligate the LSVC. The patient underwent mitral valve repair, closure of the infundibular septal defect and aortic valve replacement.

A Comparative Study of Invasive Modalities for Evaluation of Pulmonary Arteriovenous Fistula after Bidirectional Glenn Shunt

Development of pulmonary AV fistula (PAVF) after bidirectional glenn shunt (BDG) results in significant cyanosis, impaired exercise performance, and increased morbidity and mortality. We attempted to detect and quantify PAVF in post-BDG patients by saline contrast transesophageal echocardiography (TEE) and compare with pulmonary angiography and pulmonary vein oximetry. This was a prospective study done between 2017 and 2018. Twenty-five children who underwent BDG and planned for cardiac catheterization prior to Fontan completion were included in the study. All patients underwent pulmonary angiography, oximetry, and saline contrast TEE at the time of cardiac catheterization. Twenty-two patients had undergone unilateral BDG surgery and three were palliated by bilateral BDG. The mean oxygen saturation was 80 ± 5.2%. Thirteen patients (52%) had preserved antegrade pulmonary blood flow. Eighteen patients (72%) had PAVF by angiography and oximetry, while 19 (76%) had PAVF identified by contrast echocardiography. There was moderate correlation between the degree of pulmonary venous desaturation and grading of PAVF by contrast echocardiography. PAVF was predominantly located in the lower zones of the lungs. Higher grades of PAVF were not seen in patients with preserved antegrade flow after BDG. Angiographically detected PAVF showed a steady increase with increasing delay to cardiac catheterization from BDG. Significant reduction in systemic saturation was limited to advanced grades of PAVF in patients after BDG. Saline contrast TEE, pulmonary venous oximetry, and pulmonary angiography equally identified PAVF in patients after BDG. Prognostic utility of the same needs to be assessed by long-term follow-up of these subjects.

Point-of-care ultrasound in a pandemic: Practical guidance in COVID-19 units

The coronavirus disease 2019 (COVID-19) pandemic has stretched our healthcare system to the brink, highlighting the importance of efficient resource utilization without compromising healthcare provider safety. While advanced imaging is a great resource for diagnostic purposes, the risk of contamination and infection transmission is high and requires extensive logistical planning for intrahospital patient transport, healthcare provider safety, and post-imaging decontamination. This dilemma has necessitated the transition to more bedside imaging. More so than ever, during the current pandemic, the clinical utility and importance of point-of-care ultrasound (POCUS) cannot be overstressed. It allows for safe and efficient beside procedural guidance and provides front line providers with valuable diagnostic information that can be acted upon in real-time for immediate clinical decision-making. The authors have been routinely using POCUS for the management of COVID-19 patients both in the emergency department and in intensive care units turned into “COVID-units.” In this article, we review the nuances of using POCUS in a pandemic situation and maximizing diagnostic output from this bedside technology. Additionally, we review various methods and diagnostic uses of POCUS which can replace conventional imaging and bridge current literature and common clinical practices in critically ill patients. We discuss practical guidance and pertinent review of the literature for the most relevant procedural and diagnostic guidance of respiratory illness, hemodynamic decompensation, renal failure, and gastrointestinal disorders experienced by many patients admitted to COVID-units.

Pulmonary arteriovenous malformation with unexplained cyanosis as the first presentation of hereditary haemorrhagic telangiectasia, case report, and literature review

Background

Pulmonary arteriovenous malformations (PAVMs) are rare pulmonary vascular anomalies. They can result in right-to-left shunt and, if significant, low systemic saturation, cyanosis, polycythaemia, and paradoxical systemic embolization.

Case summary

Eighteen months old female child was referred to our centre due to unexplained central and peripheral cyanosis. Based on the agitated saline contrast echocardiography study, computed tomography scan confirmed the presence of abnormal vasculature at the left lower lobe. Percutaneous closure of the PAVM was performed using Amplatzer Duct Occluder type 1 device. The genetic study revealed a pathogenic mutation in the endoglin gene, which is a known cause of hereditary haemorrhagic telangiectasia (HHT) inhered in an autosomal dominance pattern.

Discussion

PAVM could be the first manifestation of HHT. Closing the malformation percutaneously is feasible, which can eliminate the right to left shunt and improves the saturation. Genetic study is warranted in these cases, as well as long-term follow-up.

Agitated saline contrast to delineate central venous catheter position in neonates

OBJECTIVE

Central venous catheter (CVC) insertion is required for the management of sick neonates. Ultrasonography/targeted neonatal echocardiography (TNE) with/without normal saline (NS) flush is used to identify CVC position. The present study compared the visibility and safety of agitated saline (AS) with normal saline (NS) flush.

STUDY DESIGN

This prospective interventional study included 110 CVC insertions, both umbilical venous catheterization (UVC) and peripherally inserted central catheterization (PICC). Catheter position was monitored by real-time TNE.

RESULTS

Overall visibility of catheter tip (combined UVC and PICC) was significantly better in AS (n = 55) compared with NS group (n = 55) [48/55 (87.2%) vs. 28/55 (50.9%); p < 0.0001]. Time to detect catheter tip by AS push was significantly less than that of NS push. There was no difference in the amount of saline flush required with either method. No major adverse effect was observed.

CONCLUSIONS

AS push can be used as a safe method to delineate CVC position in neonates.

Hypoxemia, high alveolar-arterial gradient, and bubbles in both sides of heart: A case of hepatopulmonary syndrome in the setting of COVID-19 pandemic

In presence of tachypnea, digital clubbing and cyanosis in a patient with the hallmarks of chronic liver disease, hepatopulmonary syndrome should be suspected and investigated.

Modified bi-caval view-An ideal view for diagnosing left superior vena cava with large left innominate vein on saline contrast echocardiography

Left superior vena cava (LSVC) is the most common congenital thoracic venous anomaly which commonly drains into the right atrium via the coronary sinus. Various clinical implications are associated with LSVC and is commonly diagnosed with saline contrast echocardiography. In this case we discuss the importance of a modified bi-caval view over the mid-oesophageal four-chamber view in diagnosing LSVC with the large left innominate vein.

When sitting suffocates: a rare cause of platypnoea-orthodeoxia syndrome

Platypnoea-orthodeoxia syndrome refers to shortness of breath and oxygen desaturation in an upright position. Ventilation/perfusion mismatch is a rare cause of the same. Herein, we report a case of bilateral lower lobe tuberculosis, causing platypnoea and orthodeoxia. https://bit.ly/3jhJEQ1.

Right-heart contrast echocardiography reveals missed patent ductus arteriosus in a postpartum woman with pulmonary embolism: A case report

BACKGROUND

As an established, simple, inexpensive, and surprisingly effective diagnostic tool, right-heart contrast echocardiography (RHCE) might help in solving a vexing diagnostic problem. If performed appropriately and interpreted logically, RHCE allows for differentiation of various usual and unusual right-to-left shunts based on the site of injection and the sequence of microbubble appearance in the heart.

CASE SUMMARY

A 31-year-old woman was readmitted to hospital with a 2-mo history of worsening palpitation and chest distress. Two years prior, she had been diagnosed with postpartum pulmonary embolism by conventional echocardiography and computed tomography angiography. While the latter showed no sign of pulmonary artery embolism, the former showed pulmonary artery hypertension, moderate insufficiency, and mild stenosis of the aortic valve. RHCE showed microbubbles appearing in the left ventricle, slightly delayed after right-heart filling with microbubbles; no microbubbles appeared in the left atrium and microbubbles’ appearance in the descending aorta occurred nearly simultaneous to right pulmonary artery filling with microbubbles. Conventional echocardiography was re-performed, and an arterial horizontal bidirectional shunt was found according to Doppler enhancement effects caused by microbubbles. The original computed tomography angiography findings were reviewed and found to show a patent ductus arteriosus.

CONCLUSION

RHCE shows a special imaging sequence for unexplained pulmonary artery hypertension with aortic valve insufficiency and simultaneous patent ductus arteriosus.

Agitated Saline Contrast Echocardiography in the Identification of Intra- and Extracardiac Shunts: Connecting the Dots

Agitated saline contrast studies are an essential component of contemporary echocardiography. Agitated saline contrast plays a critical role in the elucidation of intracardiac versus intrapulmonary shunting and can have major therapeutic implications, particularly in light of the evolution of percutaneous treatment options for atrial septal defects or a patent foramen ovale. Despite their perceived simplicity, however, there are numerous pitfalls of these investigations that can occur during their performance and interpretation. As such, the authors review the "bubble study" in identifying intracardiac and extracardiac shunts, including the history of its development, the physics and physiology of contrast enhancement, how to optimally perform and interpret an agitated saline contrast study, and its safety in unique populations.

Diagnosing pulmonary arteriovenous malformations in the presence of atrial septal defect and anomalous pulmonary venous drainage-An imaging challenge

Saline contrast echocardiography is a simple and effective method to diagnose the presence and type of right-to-left shunt in patients with unexplained cyanosis. It is considered a very sensitive test to diagnose pulmonary arteriovenous malformations. Our patient presented with unexplained cyanosis and transthoracic echocardiography showed an atrial septal defect and anomalous pulmonary venous drainage of the right and left upper pulmonary veins to the superior venacava. We describe how we used saline contrast echocardiography to demonstrate the presence of pulmonary arteriovenous malformations even in the presence of atrial septal defect and anomalous pulmonary venous drainage.

Imaging Modalities in Congenital Heart Disease

Cardiac imaging provides invaluable guidance at all stages of the management of congenital heart disease. Advances in the field of cardiac imaging have contributed immensely to improved outcomes of these patients. Echocardiography remains the first-line imaging modality. Non-invasive cross-sectional imaging using computed tomography and magnetic resonance imaging supplements morphologic and physiologic evaluation and are being increasingly used for diagnosis and follow-up of patients with a malformed heart. Cardiac catheterization, being invasive, is mostly reserved for accurate assessment of hemodynamic status and percutaneous interventions. Simultaneous improvement in visualization techniques has amplified the information obtained from various imaging modalities. This review provides an overview of cardiac imaging and visualization techniques commonly used in the diagnosis and management of patients with congenital heart disease.

Microbubble Formulations: Synthesis, Stability, Modeling and Biomedical Applications

Microbubbles are increasingly being used in biomedical applications such as ultrasonic imaging and targeted drug delivery. Microbubbles typically range from 0.1 to 10 µm in size and consist of a protective shell made of lipids or proteins. The shell encapsulates a gaseous core containing gases such as oxygen, sulfur hexafluoride or perfluorocarbons. This review is a consolidated account of information available in the literature on research related to microbubbles. Efforts have been made to present an overview of microbubble synthesis techniques; microbubble stability; microbubbles as contrast agents in ultrasonic imaging and drug delivery vehicles; and side effects related to microbubble administration in humans. Developments related to the modeling of microbubble dissolution and stability are also discussed.

Right superior caval vein to the left atrium in a child with vein of Galen malformation

Vein of Galen malformation (VGM) is a rare intracranial vascular malformation. High output heart failure is common in infancy and is characterized by dilatation of all the cardiac chambers. We report an unusual case of VGM in a 3-month-old infant without dilatation of the right-sided cardiac chambers. We then demonstrate importance of comprehensive evaluation in detecting rare coexistence of anomalous right superior caval vein connection to the left atrium.

Diagnostic approach to neuropsychiatric lupus erythematosus: what should we do?

Neuropsychiatric systemic lupus erythematosus is a diagnostic challenge due to the multifarious neurological and psychiatric manifestations that define it but, when suspected, diagnostic imaging can give a fundamental help. The advancements and variety of neuroimaging techniques allow us to perform more and more accurate evaluations of structure, perfusion, and metabolism of the brain and to detect cerebral and spinal lesions. Moreover, vascular districts of the neck and the brain, as well as the electrical brain and peripheral muscle activity may be accurately investigated, thus giving us a wide panoramic view. Although magnetic resonance is recognized as a fundamental neuroimaging technique to reach a correct diagnosis, the juxtaposition of other diagnostic techniques has improved the possibility to make diagnoses but has also increased the confusion about deciding which of them to use and when. Our aim was to combine the number of available techniques with the need to simplify the diagnostic path. Therefore, through the construction of an algorithm from an evidence based approach, we believe we are providing some added improvements to facilitate and expedite the diagnosis of NPSLE.

Persistent left superior vena cava in atrial septal defect sinus venosus type: diagnosis with saline contrast echocardiography-a case series

Persistent Left Superior Vena Cava (PLSVC) should be suspected if we find dilatation of coronary sinus. Sophisticated imaging is not always available in each health care provider. Transthoracic echocardiography (TTE) with agitated saline injections through the left and right antecubital veins provides a simple, and inexpensive, but effective study for a rapid bedside diagnosis of PSLVC.

Clarifying the anatomy and physiology of totally anomalous systemic venous connection

The description of totally anomalous systemic venous connection is limited to case reports. In this review, we seek to clarify anatomic, physiologic, and hemodynamic aspects of this extremely rare anomaly. We also present findings of two patients in whom connection of all the systemic veins was anomalous. In the first patient, with usual atrial arrangement, all systemic veins, including the coronary sinus, were connected anomalously to the morphologically left atrium. Limited left-to-right shunt across an atrial septal defect provided the only source of blood flow to the lungs. The diagnosis was established by saline contrast echocardiography and cardiac catheterization. Extreme hypoplasia of the right ventricle precluded corrective surgery, so we performed a bidirectional Glenn operation, along with atrial septectomy. The second patient had isomerism of the left atrial appendages, which creates problems in the definition in anatomic terms since the connection of the systemic veins can never be normal anatomically when both atriums possess a morphologically left appendage. Our patient, nonetheless, had all the systemic and pulmonary veins, connected to the left-sided atrial chamber which then connected to the left ventricle, thus producing hemodynamics of totally anomalous systemic venous connection. We propose an algorithm for evaluation of this hemodynamic combination and discuss management options. We also intend to clarify the potential differences between connection and drainage, with particular attention to the arrangement of atrial appendages. Even though the hemodynamics may be comparable, in anatomic terms, both systemic and pulmonary venoatrial connection will always be anomalous with isomeric atrial appendages.

Saline contrast echocardiography for the detection of anomalous origin of pulmonary artery from aorta

Saline contrast echocardiography is a well-established modality for the diagnosis of right-to-left shunt lesions. In this brief report, we demonstrate, for the first time, its usefulness in the diagnosis of anomalous origin of right pulmonary artery from aorta.