Comparison of magnetic resonance imaging and cardiac catheterization in patients with suspected severe aortic stenosis.

Objective: Magnetic resonance imaging (MRI) is a novel technique used in the assessment of aortic stenosis. The aim of the study was to compare MRI and cardiac catheterization (CAT) that is still considered to be a "golden standard" in this indication.

Methods: Thirty-four patients referred to CAT for the evaluation of aortic stenosis were enrolled into the study. CAT was performed according to the standardized protocol. Cardiac output was measured by thermodilution and mean aortic gradient was determined using simultaneous blood pressure measurement in aorta and left ventricle. MRI was performed within the period of 3 weeks after CAT. True FISP sequence with retrospective ECG gating was used for the imaging of the aortic valve orifice. Planimetry of the aortic valve area (AVA) was performed at the time of maximal opening of the valve during systole.

Results: MRI enabled the measurement of AVA in all patients enrolled. Mean AVA defined by CAT and MRI were 0,97 (+/- 0,41) cm2 and 1,38 (+/- 0,55) cm2, respectively. The correlation between the evaluated methods was statistically significant (p=0,003), but not very strong (r=0,43). The comparison of both methods in the identification of the severe aortic stenosis was characterized by kappa value of 0,331.

Conclusion: Our study shows low agreement between cardiac catheterization and magnetic resonance imaging in the assessment of aortic stenosis. However, MRI might have a role in the diagnostic algorithm in patients with suspected severe aortic stenosis and moderate mean aortic gradient or concomitant valvular insufficiency.