MDCT evaluation of aortic root and aortic valve prior to TAVI. What is the optimal imaging time point in the cardiac cycle?

Abstract

ObjectivesTo determine the optimal imaging time point for transcatheter aortic valve implantation (TAVI) therapy planning by comprehensive evaluation of the aortic root.MethodsMultidetector-row CT (MDCT) examination with retrospective ECG gating was retrospectively performed in 64 consecutive patients referred for pre-TAVI assessment. Eighteen different parameters of the aortic root were evaluated at 11 different time points in the cardiac cycle. Time points at which maximal (or minimal) sizes were determined, and dimension differences to other time points were evaluated. Theoretical prosthesis sizing based on different measurements was compared.ResultsLargest dimensions were found between 10 and 20 % of the cardiac cycle for annular short diameter (10 %); mean diameter (10 %); effective diameter and circumference-derived diameter (20 %); distance from the annulus to right coronary artery ostium (10 %); aortic root at the left coronary artery level (20 %); aortic root at the widest portion of coronary sinuses (20 %); and right leaflet length (20 %). Prosthesis size selection differed depending on the chosen measurements in 25–75 % of cases.ConclusionSignificant changes in anatomical structures of the aortic root during the cardiac cycle are crucial for TAVI planning. Imaging in systole is mandatory to obtain maximal dimensions.Key Points• Most aortic root structures undergo significant dimensional changes throughout the cardiac cycle.• The largest dimensions of aortic parameters should be determined to optimize TAVI.• Circumference-derived diameter showed maximum dimension at 20 % of the cardiac cycle.

CT imaging prior to transcatheter aortic valve implantation in the UK

“…Some of this variation may be attributed to the perceived need to analyse the aortic annulus in both ventricular systole and diastole. While there is no consensus on the optimal acquisition technique, international guidelines advocate a preference for systolic scan coverage, as this is when the aortic annulus is most circular and has the largest orifice area for accurate valve sizing 5 15 16. However, reverse dynamism of the interventricular septum which is frequently seen in patients with sigmoid hypertrophy may favour dimensions measured in ventricular diastole, thus necessitating retrospective ECG-gated reconstructions throughout the entire cardiac cycle 5.…”

Patient‐specific simulation of guidewire deformation during transcatheter aortic valve implantation

“…Respiratory and cardiac movements may distort the complete structure . However, the proposed approach was to neglect the dynamic effects of this motion on the guidewire.…”

Comparison of the geometry of the left ventricle outflow tract, the aortic root and the ascending aorta in patients with severe tricuspid aortic stenosis versus healthy controls

“…The aortic annulus was assessed in the oblique transversal plane which crossed the level of the most basal attachments of the aortic cusps. The dimensions of the aortic root at the level of the STJ and the widest portion of the sinus of Valsalva were measured in the oblique transversal plane perpendicular to the course of the aorta [6].…”

“…The following measurements of the aortic root and the aortic valve were performed using MPRs: the long axis (maximum) of annulus, the short axis (minimum) of the annulus, the area of annulus (defined as an oval or a circle formed by linking the most basal portions of the leaflet attachments) [6], the perimeter of the annulus, the widest and the highest portion of the sinus of Valsalva diameter, the area and the perimeter of the sinus of Valsalva ( Fig. 1a-d).…”