Method to measure the 3D angular orientation of the aortic valve plane from a single image of a valvuloplasty balloon: findings of a large animal proof of concept experiment.

During transcatheter aortic valve replacement procedures, alignment of the interventional x-ray beam with the aortic valve plane is required to guide valve placement. The purpose of this work was to develop methods to measure x-ray beam angles which are aligned with the aortic valve plane from a single x-ray image of a valvuloplasty balloon inflated across the left ventricular outflow tract (LVOT). A custom valvuloplasty balloon and image analytics were developed. In-vivo pig experiments demonstrated that the angular orientation of the LVOT can be measured with precision less than 3°, including the influence of cardiac motion during rapid pacing. Using these methods, the angular orientation of the LVOT of a large mammal can be measured precisely and the continuous range of x-ray projection angles which are aligned with the aortic valve plane can be calculated.