Abstract 16300: Preoperative Computed Tomography Angiography Reveals Leaflet-specific Contribution to Aortic Stenosis Influenced by Local Coronary Factors

Abstract

Background: Current computed tomography (CT)-based diagnosis of severe aortic stenosis (AS) using aortic valve calcification (AVC) load does not take into account interleaflet differences in calcification and leaflet dysfunction. Objectives: We sought to assess the functional impact of these differences and identify factors that can influence calcification load in a leaflet-specific manner. Methods: We retrospectively reviewed the CT angiograms (CTA) of 170 AS patients being considered for valvular intervention and 20 control normal-valve patients. We quantified AVC load, aortic valve leaflet calcification (AVLC) load, and systolic leaflet excursion (LE sys ), and used regression analysis to investigate their interrelationships. We further performed computer simulation to examine how interleaflet differences in LE sys affect aortic valve area (AVA). Lastly, we used regression analysis to identify contributors of leaflet-specific calcification. Results: We observed significant interleaflet differences in AVLC load in AS patients, with noncoronary cusp (NCC) carrying the most load (342.0 [220.3-603.1] AU), compared to the right coronary cusp (RCC) (278.5 [168.2-492.1] AU; P < 0.001) and the left coronary cusp (LCC) (240.6 [143.1-450.3] AU; P < 0.001). However, LCC, but not NCC, was associated with the least LE sys (43.0 [38.4-49.2] °), compared to both NCC (45.2 [41.2-49.9] °; P = 0.009) and RCC (47.8 [42.1-53.0] °; P < 0.001). Computer simulation of normal valve dynamics revealed that NCC and RCC contributed 10.4 [-1.6-15.7] % more ( P = 0.004) and 10.7 [4.9-20.4] % more ( P < 0.001) to AVA than LCC. In multiple regression analysis, only NCC and RCC AVLC loads predicted LE sys (b = -0.015, P < 0.001; b = -0.020, P < 0.001), but not LCC AVLC load (b = -0.008; P = 0.065). Both ostial/proximal occlusion and ostial height of right coronary artery predicted RCC AVLC load (b = 71.508, P = 0.007; b = 10.252, P = 0.008). Conclusions: NCC and RCC should be given more weight than LCC in the evaluation of AS because of their greater AVC loads, more predictable LE sys -AVLC relationships, and greater contributions to AVA. Ostial/proximal occlusion and large ostial height of RCA should signify risk for disease progression in RCC.