Validation of methods for effective orifice area measurement of prosthetic valves by two-dimensional and Doppler echocardiography following transcatheter self-expanding aortic valve implantation

Abstract Background: The aim was to compare two echocardiographic methods for prosthetic valve effective orifice area (EOA) measurement following transcatheter self-expanding aortic valve implantation. Methods: EOA was calculated according to the continuity equation. Two methods were constructed. In Method #1, the left ventricular outflow tract diameter (LVOTd 1 ) was measured at the entry of the prosthesis (from trailing to leading edge); in Method #2, the LVOTd 2 was measured proximal to the prosthetic valve leaflets (from trailing to leading edge). VTI LVOT was recorded by pulse doppler (PW) from apical windows. The region of the PW sampling should match that of the LVOTd measurement with precise localization. Results: A total of 113 consecutive patients were included in the study. All patients were followed up at one year. The mean transvalvular pressure gradient correlated better with the indexed EOA 1 (EOAI 1 ) (r=-0.701, p<0.0001) than EOAI 2 (r=-0.645, p<0.0001). Intra-observer reliability of EOA 1 and was EOA 2 was excellent (ICCs ranging from: EOA 1 : 0.923 to 0.984, and EOA 2 : 0.898 to 0.979, respectively). Interobserver reliability of EOA 1 and was EOA 2 was good (ICCs ranging from: EOA 1 : 0.742 to 0.948, and EOA 2 : 0.589 to 0.901, respectively). Conclusions: For transcatheter self-expanding valve EOA measurement, LVOTd should be measured in the entry of the prosthesis stent (from trailing to leading edge), and VTI LVOT should be measured when the PW sample is located in the entry of the prosthesis stent.