Unusual Left Atrial Mass: Inverted Left Atrial Appendage Caused by Massive Pericardial Effusion

Left atrial appendage inversion: First computational study to shed light on the phenomenon

Inversion of the left atrial appendage is a rare phenomenon, which may occur during the de-airing maneuvers associated to routinely performed surgery procedures, such as cardiopulmonary bypass or left ventricular assist device implantation. In this case, the body of the inverted appendage can obstruct the mitral valve leading to severe complications. The mechanisms are still poorly known, and more specific studies are needed to better understand its causes and identify mitigating strategies. The current study attempts to gain a better comprehension of the conditions and the factors favourable to left atrial appendage inversion. Four patient specific appendage morphologies, obtained from computerised tomography and representative of the main typologies commonly used for the appendage classification (chicken wing, cactus, cauliflower, and windsock), were used for the study. The numerical models were subjected to the same loading pattern, made of subsequent different pressure curves. Results show that the morphologies invert and recover their original anatomical configuration at different pressure loads, indicating that their tendency to invert is associated to their specific morphological features. Moreover, the analysis highlights that, although restoring the physiological left atrium pressure is not sufficient to induce appendage recovery, pressures well below the ventricular ones can induce the return to the natural configuration. All models recovered the anatomical configuration at pressures well below the ventricular pressure (about 100 mmHg), suggesting that basic trans-catheter maneuvers, e.g. producing temporary mitral regurgitation, could be attempted to correct the appendage configuration, prior to opt for more invasive surgical approaches.

Intraoperative Inversion of the Left Atrial Appendage Following Ligation

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Intraoperative TEE improves the diagnosis of LAA inversion.

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Excess negative pressure causes inversion at predictable points in cardiac surgery.

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Structural characteristics of the LAA may influence inversion susceptibility.

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Ligation has been used to manage LAA inversion but may actually cause inversion.

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This may occur from altering the structural characteristics and shortening the LAA.

Left atrial mass in children following cardiac surgery: unravelling the diagnosis

The differential diagnosis of a left atrial mass on echocardiogram includes thrombus, vegetation, tumour, and other rare causes like septal aneurysm, pulmonary vein remnant, and septal haematoma. We present interesting echocardiographic images of a rare condition which can masquerade as a left atrial mass following cardiac surgery.

New-onset cardiac mass due to left atrial appendage inversion during cardiac surgery

Cardiac mass assessment is challenging in the intraoperative scenario. We present the case of a 22-year-old woman with a new-onset left atrial mass during cardiopulmonary bypass following closure of a ventricular septal defect. We discuss the role of intraoperative echocardiographic examination, the differential diagnosis, and raise awareness of the left atrial appendage as a rare etiology of an acute left atrial mass.

Transient Left Atrial Appendage Inversion During Transcatheter Closure Device Placement

A 72-year-old female patient underwent left atrial appendage closure. During recapture of the occlusion device, transient inversion of the appendageal wall occurred. We describe the mechanism with real-time imaging and share our experience of handling this situation. To the best of our knowledge, this is the first case report of this unique recapture complication.

Inverted left atrial appendage during minimally invasive mitral valve repair

Inverted left atrial appendage (LAA) is a rare complication in cardiac surgery. The echocardiographic appearance often leads to misdiagnosis of thrombus or some other cardiac mass. Patients misdiagnosed in this way often undergo unnecessary anticoagulation or surgical treatment. Recently, minimally invasive mitral valve surgery (MIMVS) has become more widespread. However, as the incision for MIMVS through the right thoracotomy is very small, the inverted LAA is not within the surgical field of the cardiac surgeon. We present a case of inverted LAA during MIMVS and provide images from transesophageal echocardiography.

Morbidity and mortality in infant mountain gorillas (Gorilla beringei beringei): A 46-year retrospective review

Long-term studies of morbidity and mortality in free-ranging primates are scarce, but may have important implications for the conservation of extant populations. Infants comprise a particularly important age group, as variation in survival rates may have a strong influence on population dynamics. Since 1968, the Mountain Gorilla Veterinary Project (MGVP, Inc.) and government partners have conducted a comprehensive health monitoring and disease investigation program on mountain gorillas (Gorilla beringei beringei) in Rwanda, Uganda, and the Democratic Republic of the Congo. In an effort to better understand diseases in this species, we reviewed reliable field reports (n = 37), gross post-mortem (n = 66), and histopathology (n = 53) reports for 103 infants (less than 3.5 years) mountain gorillas in the Virunga Massif. Our aim was to conduct the first comprehensive analysis of causes of infant mortality and to correlate histological evidence with antemortem morbidity in infant mountain gorillas. Causes of morbidity and mortality were described, and compared by age, sex, and over time. Trauma was the most common cause of death in infants (56%), followed by respiratory infections and aspiration (13%). Gastrointestinal parasitism (33%), atypical lymphoid hyperplasia (suggestive of infectious disease) (31%), and hepatic capillariasis (25%) were the most significant causes of antemortem morbidity identified post-mortem. Identifying the causes of mortality and morbidity in infants of this critically endangered species will help to inform policy aimed at their protection and guide ante- and post-mortem health monitoring and clinical decision-making in the future.

Postoperative pulmonary hypertensive crisis caused by inverted left atrial appendage after cardiopulmonary bypass surgery for congenital heart disease in a neonate

Postoperative pulmonary hypertensive crisis (PHC) caused by an inverted left atrial appendage (ILAA) is a rare complication following cardiac surgery. We present a case of 23 day-old male infant who developed postoperative PHC attacks after undergoing cardiopulmonary bypass (CPB) surgery for repair of the coactation of aorta. A hyperechogenic left atrial mass was detected via bedside transthoracic echocardiography (TTE), which was identified as an ILAA and corrected following repeat surgery. In this case, both the negative pressure in vent catheter and the long left atrial appendage (LAA) with a narrow base led to an irreversible ILAA. As in this neonate, ILAA had significant influence on the left atrial volume and caused PHC since the ILAA was located on the mitral valve orifice and interfered with the blood flow through the valve. Therefore, we recommend that the vent catheter should be turned off before removing to avoid this potential complication. Additionally, LAA should be carefully inspected after CPB surgery, and intra-operative and post-operative transoesophageal echocardiography (TEE) should be performed to detect ILAA intraoperatively so as to avoid the reoperation. When an ILAA is diagnosed postoperatively, whether conservative treatment or surgery will depend on the balance of benefit and risk for a particular patient.