AORTIC VALVE AREA IN TAVI PATIENTS MEASURED BY MDCT AND TEE: DOES THE GRADE OF AORTIC STENOSIS SEVERITY DIFFER?

Purpose: To compare aortic valve area (AVA) measurements acquired by multidetector CT (MDCT) planimetry to transeosophageal echocardiography (TEE) measurements in patients with severe and symptomatic aortic valve stenosis.

Materials and Methods: Thirty two patients referred to Transcatheter Aortic Valve Implantation (TAVI) were examined using both MDCT and TEE in order to determine severity of the aortic valve stenosis. AVA measured by MDCT planimetry at the cardiac cycle time point with the maximal valve opening was compared to AVA calculated from TEE measurements using continuity equation (T-test). Correlation and agreement of both methods in determination of aortic stenosis severity was investigated. Reproducibility of MDCT AVA measurements was also investigated using T-test.

Results: AVA determined by TEE was significantly lower than determined by MDCT (p<0.001). Mean±SD was 0.79±0.20 vs 0.98±0.23 cm2, range 0.4–1.2 vs 0.6–1.5 cm2. The correlation between MDCT and TEE AVA measurements was medium (r=0.406, p=0.02). MDCT measurements of AVA were well reproducible since no significant difference was noted between the first and second set of measurements (95% CI = [-0.1051, 0.0719]). The grading of aortic valve stenosis based on both methods was different in 10 patients out of 32, leading to downgrading of the stenosis severity if determined by MDCT. Eight subjects would have been shifted from severe aortic stenosis category (AVA<1.0 cm2) to moderate aortic stenosis category (AVA=1.0–1.5 cm2) and might not be therefore considered for TAVI.

Conclusion: MDCT and TEE AVA measurements differ significantly and correlation between measurements of both methods is medium. Aortic stenosis severity determined by MDCT and TEE is not identical and might influence clinical decision making in substantial number of patients.