Cardiac computed tomography following Watchman FLX implantation: device-related thrombus or device healing?

Abstract

Aims Cardiac computed tomography (CT) is increasingly utilized during follow-up after left atrial appendage closure (LAAC). Hypoattenuated thickening (HAT) is a common finding and might represent either benign device healing or device-related thrombosis (DRT). The appearance and characteristics of HAT associated with the Watchman FLX have not been previously described. Therefore, we sought to investigate cardiac CT findings during follow-up after Watchman FLX implantation with a focus on HAT and DRT. Methods and results Retrospective single-centre, observational study including all patients with successful Watchman FLX implantation and follow-up cardiac CT between March 2019 and September 2021 (n = 244). Blinded analysis of CT images was performed describing the localization, extent, and morphology of HAT and correlated to imaging and histology findings in a canine model. Relevant clinical and preclinical ethical approvals were obtained. Overall, HAT was present in 156 cases (64%) and could be classified as either subfabric hypoattenuation (n = 59), flat sessile HAT (n = 78), protruding sessile HAT (n = 16), or pedunculated HAT (n = 3). All cases of pedunculated HAT and five cases of protruding sessile HAT were considered as high-grade HAT (n = 7). Subfabric hypoattenuation and flat sessile HAT correlated with device healing and endothelialization in histological analysis of explanted devices. Conclusion Subfabric hypoattenuation and flat sessile HAT are frequent CT findings for Watchman FLX, likely representing benign device healing and endothelialization. Pedunculated HAT and protruding HAT are infrequent CT findings that might represent DRT.

Left atrial appendage occlusion

“…TAVR and MitraClip [Abbott]), those with specific indications (e.g., very low or very high risk for bleeding or stroke or cerebral amyloid angiopathy), those that optimise procedural strategies (e.g., ICE or composite angio/ CT-fused imaging), and new technologies such as coated surfaces. (Reproduced with permission from 99 ).…”

“…Using TOE, DRT is defined as a homogeneous, echo-dense mass adherent to the atrial surface of the LAAO device visible in multiple projections 36 . Cardiac CT relies on the detection of subtle changes of HAT on the atrial surface which may not be readily detected by TOE 36,99 (Figure 21). Categorisation of HAT into low or high grade is based on imaging characteristics of the HAT localisation, extent and morphology which may help guide clinical management based on the assumption that subtle changes likely represent device healing and carry a low embolic risk 36 .…”

“…High-grade features: protruding sessile or (H) pedunculated HAT without LA wall continuity or inhomogeneous surface (highlighted with red). (Reproduced with permission from99 ).…”

Kairiojo Prieširdžio Ausytės Uždarymas Ir Susiję Iššūkiai

“…hypoattenuated thickening), jo dažnį bei fenotipus po KPrA uždarymo procedūros "Watchman FLX" uždarikliu, siekiant nustatyti KPrAU trombozę. Nors tyrimo metu nebuvo vertinta koreliacija tarp skirtingų KT radinių ir kli-nikinių įvykių, tačiau yra pagrindas tolesniems tyrimams, nes tai buvo pirmasis tyrimas, vertinantis normalų gijimo procesą ir įvairius fenotipus stebint kontrastinės medžiagos ryškumo sumažėjimą sustorėjimo zonose arba kitaip KPrAU trombozę [12].…”

Perioperative Treatment with Rivaroxaban and Dabigatran on Changes of Coagulation and Platelet Activation Biomarkers following Left Atrial Appendage Closure

“…Long-term follow-up studies have indicated that LAAC intervention can mitigate the thrombotic risk associated with LAA thrombus formation, concurrently minimizing the bleeding risks associated with anticoagulant use [ 4 , 5 ]. Notably, device-related thrombosis (DRT) after successful closure implantation on LAA poses a major challenge, with reported incidence ranging from 3% to 5%, associated with an increased risk of thrombus events [ 6 , 7 ].…”