Abstract 705: Comparison Between Transthoracic Echocardiography and Cardiac Magnetic Resonance Imaging in Patients Status Post Mustard Procedure
Patients status post Mustard procedure for D-TGA require monitoring for complications and systemic RV dysfunction. TTE may be inadequate due to a limited field of view often seen with scarring. As cardiac magnetic resonance imaging (CMR) is considered a gold standard for assessment of ventricular function with a nearly unlimited field of view, many patients undergo CMR to better assess the surgical baffles and degree of RV dysfunction. The aim of this study was to compare image quality, cost, and data obtained by TTE vs. CMR in Mustard patients to determine the optimal imaging approach. Twelve patients (age 25+/−3 years, 58% female) with DTGV status post Mustard procedure with both TTE and CMR were included. A mean of 126 days (range 0 to 392) passed between studies. In an independent and blinded fashion, three experienced echocardiography and three experienced CMR physicians reviewed images and graded the quality on a scale: poor, fair, adequate, excellent. Estimated TTE and CMR volume-analyzed RV ejection fractions (RVEF) were compared. Correlations of image quality (Spearman’s) and RVEF (Pearson’s) between TTE and CMR were performed. Also, institutional charges were compared. TTE RVEF (36.1%+/−5.6%) underestimated CMR RVEF (47.8%+/−15%, p=0.002) with close correlation (r=0.91, p<0.0001). TTE image quality (2.64+/−0.6) rated lower than CMR (3.55+/−0.3, p=0.0002). The baffles were better seen in CMR. The SVC baffle was seen in 86+/-0.2% of TTE compared to 100% of CMR (p=0.017). The IVC baffle was seen in 33+/-0.3% of TTE compared to 97+/−0.1% of CMR (p=0.0001). The PV pathway was seen in 92+/−0.2% of TTE and in 100% of CMR (p=0.082). TTE costs $3,494 compared to $4,248 for CMR. The results suggest that CMR is a better modality to evaluate anatomy and function in Mustard patients. Using CMR as a gold standard for ventricular volume analysis, TTE may underestimate RVEF. CMR image quality was consistently rated higher and allowed for more structures to be seen. The cost differences are minimal. We propose that CMR, with better image quality and function assessment, be considered first-line for following these patients and also be considered for other adult patients with complex congenital heart disease when TTE cannot provide complete or reliable images.