--LAA Occluder View for post-implantation Evaluation (LOVE)--standardized imaging proposal evaluating implanted left atrial appendage occlusion devices by cardiac computed tomography

Abstract

Background: A standardized imaging proposal evaluating implanted left atrial appendage (LAA) occlusion devices by cardiac computed tomography angiography (cCTA) has never been investigated.

Methods: cCTA datasets were acquired on a 3(rd) generation dual-source CT system and reconstructed with a slice thickness of 0.5 mm. An interdisciplinary evaluation was performed by two interventional cardiologists and one radiologist on a 3D multi-planar workstation. A standardized multi-planar reconstruction algorithm was developed in order to assess relevant clinical aspects of implanted LAA occlusion devices being outlined within a pictorial essay.

Results: The following clinical aspects of implanted LAA occlusion devices were evaluated within the most appropriate cCTA multi-planar reconstruction: (1) topography to neighboring structures, (2) peri-device leaks, (3) coverage of LAA lobes, (4) indirect signs of neo-endothelialization. These are illustrated within concise CT imaging examples emphasizing the potential value of the proposed cCTA imaging algorithm: Starting from anatomical cCTA planes and stepwise angulation planes perpendicular to the base of the LAA devices generates an optimal LAA Occluder View for post-implantation Evaluation (LOVE). Aligned true axial, sagittal and coronal LOVE planes offer a standardized and detailed evaluation of LAA occlusion devices after percutaneous implantation.

Conclusions: This pictorial essay presents a standardized imaging proposal by cCTA using multi-planar reconstructions that enables systematical follow-up and comparison of patients after LAA occlusion device implantation.

Keywords: Cardiac CTA; LAA occluder; LAA occlusion device; Lobe coverage; Neo-endothelialization; Peri-device leak; Thrombus.

Figures

Fig. 1

Illustration of a stepwise standard multimodal imaging to generating optimal LAA Occluder View for post-implantation Evaluation (LOVE) planes from anatomical cCTA planes. Figure shows 5 standardized steps (panels I-V) for the ACP® device

Fig. 2

Illustration of a stepwise standard multimodal imaging to generating optimal LAA Occluder View for post-implantation Evaluation (LOVE) planes from anatomical cCTA planes. Figure shows 5 standardized steps (panels I-V) for the WATCHMAN® device

Fig. 3

LOVE coronal (panel a) and sagittal (panel b) reformations demonstrating the anatomic relationship to relevant neighboring structures that should be reported. Panel a shows the close anatomic relationship to the left upper pulmonary vein (LUPV) and the left circumflex coronary artery (LCX) that is adjacent directly to the LAA occlusion device (* in panels a and b). The pulmonary artery (PA) is the third relatively close neighboring structure that should be inspected carefully on LOVE axial reformations

Fig. 4

The figure summarizes schematically the four main follow-up scenarios on cardiac CTA after LAA occlusion device implantation. Panel a demonstrates optimal positioning of the LAA occlusion device without any residual lobe, any peri-device leak and without any residual contrast filling (blue dots in LAA) indicating complete neo-endothelialization. Panel b demonstrates a peri-device leak with contrast filling of the LAA. Panel c shows sub-optimal positioning of the LAA occlusion device with in-complete lobe coverage leaving a residual left atrial appendage. Panel d shows optimal positioning of the LAA occlusion device with in-complete neo-endothelialization that is suggested indirectly by the contrast enhancement of the LAA (blue dots in LAA). Please note that all three scenarios can occur in combination. In case of an existing peri-device leak with contrast filling of the LAA assessment of endothelialization is not feasible with cardiac CT

Fig. 5

LOVE - axial (panel a), − sagittal (panel b), - coronal (panel c), and 3D (panel d) reformations of a 72 year-old male patient who underwent cardiac CTA 9 months after implantation of a ACP® LAA occlusion device. Panels a, b, and c show optimal positioning of the device with no peri-device leak, complete lobe coverage as well as complete neo-endothelialization of the device suggested by the absence of contrast enhancement < 50 Hounsfield units in the LAA (* in B and C). Volume rendered reconstructions

Fig. 6

LOVE - axial (panel a), − sagittal (panel b), and - coronal (panel c) reformations of a 80-year-old male patient who underwent cardiac CTA 8 months after implantation of a WATCHMAN® LAA occlusion device. Panels a and c show a small peri-device leak <3 mm at the cranial LAA entry causing complete contrast filling of the LAA (white arrow). Panel b demonstrates the correct positioning of the device with complete lobe coverage, as indicated by the correctly positioned sealing part (proximal cap of the WM device) parallel to the plane of the LAA ostium (red line). Due to the presence of the peri-device leak the assessment of endothelialization is not feasible with cardiac CTA

Fig. 7

LOVE - axial (panel a), − sagittal (panel b), and - coronal (panel c) reformations of a 83-year-old female patient who underwent cardiac CTA 9 months after implantation of the ACP® LAA occlusion device. Panels a, b and, c demonstrate no peri-device leak. Panel b shows incomplete lobe coverage with a small residual LAA lobe. The uncovered LAA lobe is seen between the angle of the sealing part of the ACP device (proximal disk) and the plane of the LAA ostium (angle in between red lines, marked by white arrow). The contrast filling of the LAA in combination with the clear absence of a peri-device leak reflects indirectly in-complete endothelialization of the ACP® LAA occlusion device

Fig. 8

LOVE - axial (panel a), − sagittal (panel b), and - coronal (panel c) reformations of a 75-year-old male patient who underwent cardiac CTA 4 months after implantation of a WATCHMAN® LAA occlusion device. Panel a shows a 20° offset of the device around the entry axis to the LAA (red line in A). The rotation led to an in-complete lobe coverage with a small residual left atrial appendage < 5 mm that is best seen on the LOVE coronal reformation (arrow in panel c). The residual slight contrast enhancement (* in panels a and b) of the LAA that is approximately 50 % lower when compared to the contrast enhancement in the left atrium suggests beginning, but still in-complete neo-endothelialization of the device