Background: Although functional anatomy of the aortic valve complex has been well studied on animal models using radio opaque markers or ultrasonomicrometric crystals, theses invasive techniques cannot be used in clinical practice. Intracardiac Echocardiography (ICE) might be an interesting tool to describe precisely the dynamics of the human aortic valve. We studied its relevance on normal aortic roots in an ovine model.

Methods: Six sheeps underwent ICE under general anaesthesia (AcuNav^®, Siemens). Images were obtained using a high resolution probe (5 to 10 MHz), introduced through the left internal jugular vein into the right atrium. Under stable hemodynamic conditions, coaptation height, systolic and diastolic diameters of the aortic root at the levels of the base of the aortic annulus, sinuses of valsalva, sino-tubular junction and ascending aorta were studied.

Results: All attempts were successful in the placement of the probe and comprehensive echographic examination was always possible. Aortic root diameters and expansion rate were analyzed (table).

Moreover, ICE allowed good visualization of valvular coaptation, with a mean coaptation height of 0.27 ± 0.07 cm.

Conclusions: ICE provided a precise analysis of aortic root dynamics and valvular coaptation in an ovine model. Further studies are needed to correlate these data to the normal human aortic valve. ICE could represent an interesting tool to investigate the aortic valve for conservative aortic valve surgery or percutaneous valve replacement.