3D Printing Technology For Planning Left Atrial Appendage Occlusion

Atrial fibrillation is the most common cardiac arrhythmia, affecting 8.5% of the general population in Hong Kong. Systemic embolization, and particularly stroke, is the most frequent major complication of atrial fibrillation. Long-term oral anticoagulation is recommended for most atrial fibrillation patients for prevention of embolism. However, such therapy is associated with an increased risk of bleeding and not all individuals are candidates for this therapy. The left atrial appendage (LAA) is the usual source for clot that embolizes. Occlusion of the LAA ostium (LAAO) with percutaneous device in patients with nonvalvular atrial fibrillation has emerged as an alternative to anticoagulation for prevention of embolism. Procedural success requires careful planning and understanding of the anatomy of LAA, as well as the interaction between the appendage and the occlusion device. However, complexity and variability of LAA anatomy exists and these anatomical variations among individuals poses challenges to accurately sizing and positioning the device. Certain anatomic variations of the appendage, for instance the presence of a sharp bend in the proximal or middle portion of the dominant lobe, or prominent pectinate muscles, pose particular challenge to device implantation and demands pre-specified implantation technique. Assessment of LAA anatomy relies on imaging, usually combining peri-interventional 2D transesophageal echocardiography (TEE) with fluoroscopy guidance and, less frequently, with pre-interventional computed tomography (CT). Because lobes of the LAA exist in different planes, imaging must be done in multiple planes to visualize the entire LAA. Even with advanced imaging, complete understanding the 3D geometry of the appendage is challenging, and the mechanical interaction between the device and the anatomy is difficult to predict or quantify. The limitation of imaging in the assessment of LAA anatomy may lead to inaccurate device sizing. Over- or under