OBJECTIVES: This study compares 2-dimensional, transthoracic echocardiography with cardiac magnetic resonance imaging in the preoperative identification of bicuspid aortic valve before aortic valve surgery.
METHODS: Of 1203 patients who underwent an aortic valve operation, 218 had both preoperative transthoracic echocardiography and cardiac magnetic resonance imaging. Patients in the study group were aged 56 years and had an ejection fraction of 56%, 76% were male, and 29% had associated coronary artery disease. The results of transthoracic echocardiography and cardiac magnetic resonance imaging were classified as bicuspid aortic valve, trileaflet aortic valve, or non-diagnosticÂ Of the 218 patients, 123 (56%) had bicuspid aortic valve as determined at the time of surgery and 116 (53%) had an ascending aortic aneurysm.
RESULTS: Of the 123 patients with bicuspid aortic valve confirmed at surgery, by transthoracic echocardiography 76 (62%) were identified preoperatively with bicuspid aortic valve, 12 (10%) were misidentified with trileaflet aortic valve, and 35 (28%) were non-diagnostic for valve morphology. In the same patients with bicuspid aortic valve, by cardiac magnetic resonance imaging 115 (93%) were identified with bicuspid aortic valve, 5 (4%) were misidentified with trileaflet aortic valve, and 3 (2%) were non-diagnosticÂ The difference between transthoracic echocardiography and cardiac magnetic resonance imaging to determine the presence of bicuspid aortic valve was statistically significant (P<.001). In the entire cohort of patients, transthoracic echocardiography was diagnostic for valve morphology in 155 patients (71%) compared with cardiac magnetic resonance imaging, which was diagnostic in 212 patients (97%) (P<.001).
CONCLUSIONS: Cardiac magnetic resonance imaging is more diagnostic than transthoracic echocardiography in determining the presence of bicuspid aortic valve. A significant factor is the rate of non-diagnostic transthoracic echocardiography for aortic valve morphology. Cardiac magnetic resonance imaging can be performed as a complementary test when transthoracic echocardiography is non-diagnostic for aortic valve morphology.