ASSESSMENT OF ACCURACY OF THE DOPPLER PRESSURE HALF-TIME METHOD IN THE ESTIMATION OF THE MITRAL-VALVE AREA IMMEDIATELY AFTER BALLOON MITRALVALVULOPLASTY

Aim The reliability of Doppler echocardiography in determining the mit ral valve area after balloon mitral valvuloplasty has been questioned, as discrepancies were noted between measurements obtained by the pres sure half-time method and those derived haemodynamically, immediately following completion of the procedure. Recent investigations, however, have indicated that these discrepancies may be attributable to the ov er-estimation of the mitral valve area by haemodynamic measurements, c aused by the presence of the iatrogenic atrial septal defect complicat ing transseptal catheterization. The aim of the present study was to f urther test this hypothesis. Methods and results Measurements of the m itral valve area by the Doppler pressure half-time method and the Gorl in formula were obtained and compared in 238 consecutive patients befo re and immediately after retrograde non-transseptal balloon mitral val vuloplasty, which does not involve puncture and/or dilatation of the i nter-atrial septum. No significant difference was found between Dopple r- and Gorlin-derived measurements, neither before (1.04 +/- 0.23 vs 1 .03 +/- 0.23 cm(2), P=ns) nor immediately after (2.14 +/- 0.47 vs 2.12 +/- 0.49 cm(2), P=ns) valvuloplasty. Linear regression analysis demon strated a high degree of correlation between Doppler and Gorlin measur ements before (r=0.778) and after (r=0.886) the procedure. Good agreem ent was confirmed by the Bland-Altman method. Conclusion Doppler echoc ardiography yields accurate measurements of the mitral valve area imme diately after retrograde non-transseptal balloon mitral valvuloplasty. This finding supports the hypothesis that the creation of an iatrogen ic atrial septal defect during transseptal catheterization may contrib ute to the poor agreement between Doppler and Gorlin data after balloo n mitral valvuloplasty.