What is an expected requirement for an LAAO device to pass deployment tests?

An expected requirement for an LAAO device to pass deployment tests is that the device lobe must engage the LAA neck adequately. This is essential for ensuring proper occlusion of the left atrial appendage, which is the primary function of the device. Adequate engagement helps to prevent the risk of thrombus formation by effectively sealing off the appendage from the left atrium, thereby reducing the risk of stroke in patients with atrial fibrillation. This engagement must be secure and stable to ensure the effectiveness of the device post-deployment.

In the context of the other options, while visible markings for alignment can aid in positioning the device, they do not directly reflect the occlusion capability. The necessity of being entirely self-fixing is not practical, as many devices may require some external aids for proper deployment. Lastly, although conformity to the size of the left atrium is important, the specific requirement for deployment tests focuses on the lobe's engagement with the LAA neck, as this directly affects the device's function after placement.