Feasibility of Aortic Annular Measurements Using Noncontrast-Enhanced Cardiac Computed Tomography in Preprocedural Evaluation of Transcatheter Aortic Valve Replacement: A Comparison With Contrast-Enhanced Computed Tomography

OBJECTIVE: Noncontrast-enhanced (NCE) cross-sectional images other than contrast-enhanced (CE)-computed tomography (CT) may be necessary for annular sizing before transcatheter aortic valve replacement (TAVR), because of the risk of contrast-induced nephropathy. We aimed to investigate the feasibility of aortic annular measurements using NCE-CT in TAVR candidates by comparing them with CE-CT measurements. METHODS: We retrospectively enrolled 46 patients who underwent CT for the purpose of pre-TAVR evaluation (17 men; mean age, 82.3 ± 5.0 years). On CE and NCE examination, measurements of the average diameter and perimeter of aortic annulus were performed by 2 observers, and coronary ostial heights were measured. Differences in annular parameters and coronary ostial heights between NCE and CE examinations were assessed using Bland-Altman analysis and intraclass correlation coefficients (ICCs). RESULTS: Aortic annulus measurement values were significantly larger in the NCE examinations compared with those in the CE examinations according to both readers (mean differences of 0.8 mm for the average diameter and 2.1 mm for the perimeter according to observer 1, and 1.1 mm for the average diameter and 3.4 mm for the perimeter according to observer 2; ICC, 0.771-0.923). The mean difference between coronary ostial height measurement on NCE and CE examination was 0.6 mm for left coronary ostium (ICC, 0.795) and 0.7 mm for right coronary ostium (ICC, 0.802). No case showed disagreement between NCE and CE examinations for hypothetical valve sizing. CONCLUSIONS: Noncontrast-enhanced cardiac CT examination may be feasible for aortic annular measurements before TAVR and provides comparable measurement values to CE examination.