New alternatives to the standard Doppler method in measuring transmitral pressure gradient

OBJECTIVES
Mitral valve pressure gradient measured by echocardiography is a very useful method for the evaluation of mitral valve disease. The standard method is based on the calculation of mean mitral valve pressure gradient with the use of the modified Bernoulli equation, which includes manual drawing of the border of Doppler signal. Recently, two new methods have been described by Devlin M et al. and Yang SS, respectively. This study aimed to compare the results of the standard method with those of the new methods.

STUDY DESIGN
We prospectively studied 78 patients (55 women, 23 men; mean age 43±14 years; range 17 to 78 years) with mitral valve gradient either due to mitral stenosis or mitral valve replacement. Atrial fibrillation was present in 31 patients. The mean mitral valve gradient was measured using the standard method. As for the new methods, measurements of the mean mitral valve gradient were made without manual drawing of the border of Doppler signal and using the formulas which included the peak and trough velocities. Transmitral gradient was also obtained by cardiac catheterization in 14 patients.

RESULTS
The mean transmitral pressure gradients were 9.2±5.7 mmHg, 9.4±6.2 mmHg, and 10.6±6.6 mmHg by the standard method, the first, and the second methods, respectively. The new methods were in good correlation with the standard method (for both methods, r=0.98, p<0.001). Subgroup analyses based on mitral valve area, rhythm, and the presence of associated valve lesions did not change the consistency of correlations. Transmitral gradients obtained by catheterization were also correlated with those obtained by the standard, first, and second methods (r=0.97, r=0.96, r=0.96, respectively).

CONCLUSION
Considering that the standard Doppler method and two different approaches yield similar results, the new approaches seem to facilitate the measurement of mitral valve gradient in daily clinical practice.