Intussusception of the Left Atrial Appendage: A Systematic Review

Abstract

Background: Intussusception of the left atrial appendage (LAA) is an uncommon and often underrecognized finding; poor knowledge of this condition is still widespread in clinical practice. A systematic review was carried out to provide a comprehensive and updated overview on this condition.

Methods: A bibliographic search using major databases resulted in 25 case reports meeting the criteria. Included records reported data from patients aged > 18 years with a diagnosis of LAA intussusception, determined either intraoperatively or incidentally by imaging tools, and findings on baseline demographics, clinical findings, imaging diagnostic workup, and management.

Results: For the 25 patients included, the median age was 54 years, with a predominance of female sex (53%). Most of intussuscepted LAA cases were disclosed intraoperatively (60%) or incidentally by imaging tools (20%) in the absence of associated clinical findings. All reported cases underwent transoesophageal echocardiography, and in most, LAA intussusception was confirmed by intraoperative inspection (44%) or further imaging (23%). In most cases, LAA intussusception was resolved interventionally (60%). In fewer subjects, LAA eversion occurred spontaneously (32%), and in the remaining cases, a conservative approach was adopted (8%).

Conclusions: This study presents the largest systematic review to date of an adult patient population with a diagnosis of intussuscepted LAA. Regardless of the various etiologies and clinical manifestations associated with LAA intussusception, physicians should be aware of the possibility of this rare entity, to provide timely recognition and thereby avoid misleading diagnoses and enable appropriate decision-making.

Figure 1

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) diagram depicting the literature selection process and included records.

Figure 2

(A) Mid-esophageal bidimensional transoesophageal echocardiography 4-chamber view showing a large left atrial mass (arrow). (B) Mid-esophageal bidimensional transoesophageal echocardiography 2-chamber view revealing the mobile mass arising from the anterolateral wall of the left atrium, between the ostium of the left upper pulmonary vein and the mitral annulus (arrow; reproduced from Nunes et al. J Echocardiogr 2010;8:30-2, with permission of the publisher). LA, left atrium; LUPV, left upper pulmonary vein; LV, left ventricle; MA, mitral annulus; RA, right atrium; RV, right ventricle.

Figure 3

Cardiac magnetic resonance imaging showing (A, B, thin arrows) the intussusception of left atrial appendage mimicking a cystic mass in the left atrium (LA);and (C, D, thick arrows) left atrial appendage being pushed and invaginated into the LA by a massive pericardial effusion (PE) ; reproduced from Gecmen et al. Echocardiography 2011;28:E134-6, with permission of the publisher).

Figure 4

(A) Transoesophageal echocardiography showing a tongue-like mass (arrows) with a central high-echogenic portion protruding to the left atrium (LA). (B, C) Cardiac computed tomography (CT) showing a mass-like lesion with internal fat tissue (asterisks) and an air bubble (arrowhead) arising from the anterolateral wall of the LA between the left upper pulmonary vein (LUPV) and the mechanical mitral valve (curved arrow). (D) A 3-dimensional endoluminal of the CT image obtained during the diastolic phase revealing the intussuscepted left atrial appendage (arrows) at the posterior aspect of the mitral inflow tract, with no significant obstruction. (E) A follow-up CT scan obtained at 15 months showing the spontaneous eversion of the left atrial appendage (arrows; reproduced from Yoon et al. Circulation 2014;130:e66-7, with permission of the publisher). Ao, ascending aorta; LCx, left circumferential artery; LV, left ventricle; PA, pulmonary artery.