For geometrical assessment, we implanted 2-mm sonomicrometry crystals (Sonometrics Corp., London, ON, Canada): 6 at the aortic annulus and 6 at the STJ (Fig. 1B). The crystals were placed with 1 crystal at each nadir and 1 crystal at each commissure, at the respective level (Fig. 2). The sonomicrometry method has been validated and described in detail in earlier porcine studies [14–17].