Usefulness of preprocedural dedicated computed tomography for complex case in percutaneous left atrial appendage closure

Excerpt

An 86-year-old male with persistent atrial fibrillation (CHA₂DS₂-VASc score five points and HAS-BLED score three points) was referred for treatment of repeated gastrointestinal bleeding. He had a history of coronary artery bypass grafting and was taking an antiplatelet drug. A neurologist, interventional cardiologists, imaging cardiologist, and anesthesiologist of the local multidisciplinary brain–heart team decided to perform percutaneous left atrial appendage closure (LAAC) [1]. Transesophageal echocardiography (TEE) revealed no thrombus in the LAA and suitability for LAAC based on anatomical features. The maximum orifice diameter and depth of the LAA were 25.0 mm and 25.7 mm, respectively, at 135° by pre-procedural TEE. ECG-gated computed tomography angiography (CTA) was performed with the patient leaning 45° in a prone position on the left side using 320-row multi-detector CT before LAAC. The scan parameters were as follows: a collimation of 320 rows × 0.5 mm, a rotation time of 350–400 ms, and a tube voltage of 120 kV. The tube current (270–400 mA) was selected according to the standard deviation of the noise level measured on the CT projection radiograph. WATCHMAN access system® (WAS: Boston Scientific, Massachusetts, USA) also used the same protocol and was fused with CTA of each patient. In this patient, CTA demonstrated no thrombus and showed chicken-wing morphology. Normal pre-procedural CT was reconstructed as a dedicated volume-rendering (VR) image (Fig. 1a–b). Using this, we were able to specify the location of the fossa ovalis and accurate LAA morphology. Based on this information, the superior-posterior position in fossa ovalis was considered optimal septal puncture site despite an unusual position. Furthermore, a single-curve WAS was selected to deliver the device to the LAA (Fig. 1c–f). When we use a WATCHMAN® device (Boston Scientific, Massachusetts, USA), enough LAA depth is essential for a successful procedure. Our patient had a lobe of sufficient size only in the posterior. To deliver WAS to the posterior lobe in depth and to obtain the co-axiality of WAS and the posterior lobe, it was necessary to use the single-curve WAS and to go through the superior-posterior position of fossa. Otherwise, we would not deploy the device at an optimal position. Therefore, the superior-posterior position of fossa was the optimal position in this patient despite the unusual position. Furthermore, we implanted a WATCHMAN® 33-mm device using a standard technique, based on TEE findings [1]. Transseptal puncture was performed without complications at superior-posterior position of the fossa (Fig. 2). The single-curve WAS was smoothly delivered to the tip of the LAA along a 5-Fr pigtail catheter. Sequentially, the WATCHMAN® 33-mm device was deployed at the optimal position, meeting the PASS criteria. We released the device and closed the femoral access site. The procedure time was 21 min and 23 ml of contrast medium was used. The patient was discharged 2 days after the intervention without complications. TEE after 45 days revealed no device-related thrombus or leakage. A dedicated VR image reconstructed by normal CT may be useful for simplifying anatomically complex cases of LAAC.

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