Assessment of left ventricular mass regression after aortic valve replacement--cardiovascular magnetic resonance versus M-mode echocardiography.

OBJECTIVE: In patients with aortic valve disease, the presence of left ventricular hypertrophy (LVH) carries a significant risk of adverse cardiovascular events. Regression of hypertrophy after aortic valve replacement (AVR) is associated with a reduction in risk. In general, M-mode echocardiography has been used for quantitative assessment of left ventricular mass (LVM) and regression, but this technique is believed to have limitations from which cardiovascular magnetic resonance (CMR) does not suffer. The objective of this study therefore was to determine whether quantitative assessment of LVM and regression after AVR using the two techniques was comparable.

METHODS: Thirty-nine patients with aortic valve disease were studied before and 1 year after AVR. Transthoracic M-mode echocardiography and four different formulae were used to calculate left ventricular mass index (LVMI), and then compared with CMR measurements.

RESULTS: Overall, correlation between the techniques for single measurement of LVMI was moderate (r-values from 0.64 to 0.69), with a tendency for overestimation by echocardiography; there was no agreement in degree of regression (r-values from 0.004 to 0.18). The Bland-Altman limits of agreement ranged from 85 to 131% for single measurement of LVMI, and 328-470% for regression. The change in LVMI with CMR was 43+/-28 g/m2, vs. 27 to 54+/-19 to 41 g/m2 using echocardiography.

CONCLUSIONS: M-mode echocardiography does not provide reliable quantification of regression of LVH in individuals, and for accurate measurement CMR is superior. The use of CMR in future studies may reduce costs since fewer subjects are needed to accurately detect significant changes in LVMI after AVR.