Non-contrast computed tomography versus cinefluoroscopy for the assessment of mechanical prosthetic valve leaflet motion

Abstract

Introduction: valve replacement remains the definitive treatment of most cases with severe valvular heart disease. Mechanical prosthetic valves remain the main option in younger patients. Objective: evaluation of mechanical prosthetic valve function by comparing the feasibility of leaflet motion assessment by cinefluoroscopy vs. CT. Materials and methods: Leaflet motion was assessed in 30 bileaflet mechanical prostheses (21 mitral and 9 aortic) by cinefluoroscopy and non-contrast CT. Assessment was considered feasible when the ‘in profile’ projection (with the radiographic beam parallel to both the valve ring plane and the tilting axis of discs) could be achieved. Results: Overall feasibility of fluoroscopic assessment was 74% (mitral, 66% vs. aortic, 93%; p=0.071), while feasibility of CT assessment was 100% (p=0.003). Among prostheses with unfeasible fluoroscopic assessment, CT suggested an extreme C-arm angulation to achieve the “in profile” projection (RAO: 76.0±5.8°, LAO: 122.7±32.5°, CRA: 51.4±16.0°, CAU: 57.0±18.2°). Among prostheses with feasible assessment by both techniques, fluoroscopy and CT yielded similar opening and closing angles (intraclass correlation coefficient, 0.959 - 0.998) with lower irradiation with CT as compared with fluoroscopy (26.2[21.1-29.3] vs. 289[179-358] mGy, p<0.001). While CT scan took 8.7±0.5 seconds, fluoroscopy required 2.64±1.56 minutes to achieve and record the “in profile” projection.