Feasibility of cardiovascular magnetic resonance to assess the orifice area of aortic bioprostheses

Abstract

Background-Prosthetic orifice area, usually calculated by transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE), provides important information regarding the hemodynamic performance of aortic bioprostheses. However, both TTE and TEE have limitations; therefore accurate and reproducible determination of the orifice area often remains a challenge. The present study aimed to investigate the feasibility ofcardiovascular magnetic resonance (CMR) to assess the orifice areas of aortic bioprostheses. Methods and Results-CMR planimetry of the orifice area was performed in 65 patients (43/22 stented/stentless prostheses; mean time since implantation, .1±2.8 years; mean orifice area [TTE], 1.70 ± 0.43 cm2; 62 normally functioning prostheses, 2 severe stenoses, and 1 severe regurgitation) in an imaging plane perpendicular to the transprosthetic flow using steady-state free-precession cine imaging under breath-hold conditions on a 1.5-T MR system. CMR results were compared with TTE (continuity equation, n=65) and TEE (planimetry, n=31). CMR planimetry was readily feasible in 80.0%; feasible with limitation in 15.4% because of stent, flow, and sternal wire artifacts; and impossible in 4.6% because of flow artifacts. Correlations of the orifice areas by CMR with TTE(r=0.82) and CMR with TEE (r=0.92) were significant. The average difference between the methods was ±0.02±0.24 cm2 (TTE) and 0.05±0.15 cm2 (TEE). Agreement was present for stented and stentless devices and independent of orifice size. Intraobserver and interobserver variabilities of CMR planimetry were 6.7±5.4% and 11.5±7.8%. Conclusions-The assessment of aortic bioprostheses with normal orifice areas by CMR is technically feasible and provides orifice areas with a close correlation to echocardiography and low observer dependency. (Circ Cardiovasc Imaging. 2009;2:397-404.) Copyright © 2009 American Heart Association, Inc.