Echocardiographic evaluation of the mitral valve area before and after percutaneous mitral commissurotomy: the pressure half-time method revisited.

BACKGROUND: Doppler pressure half-time (PHT) is widely used for mitral valve area (MVA) assessment but its accuracy has not been fully evaluated before and after percutaneous mitral commissurotomy (PMC) in a large series of patients.

METHODS: In 120 patients with severe mitral stenosis, MVA(PHT) was prospectively evaluated before and 24 to 48 hours after PMC and compared with 2-dimensional planimetry (MVA(2D)) as a reference method.

RESULTS: After PMC, MVA(2D) significantly increased (1.81 +/- 0.30 vs 1.03 +/- 0.23 cm2, P < .0001), mean transmitral gradient decreased (5 +/- 3 vs 10 +/- 5 mm Hg, P < .0001), and a good valve opening (MVA(2D) > or = 1.5 cm2) was observed in 107 patients (89%). Before PMC, correlation between MVA(PHT) and MVA(2D) was only fair overall (r = 0.52, P < .0001) and weak in subgroups of older patients (> or = 60 years; r = 0.16, P = .37) and in patients in atrial fibrillation (r = 0.38, P < .05). After PMC, MVA(PHT) (1.62 +/- 0.39 cm2) was significantly lower than MVA(2D) (P < .0001) and correlation was poor overall (r = 0.30, P = .0004; mean difference 0.33 +/- 0.30 cm2) and in all subgroups (r < 0.35). However, for the prediction of a good valve opening, a PHT less than 130 milliseconds (observed in 43 patients, 36%) had an excellent specificity (100%) despite a poor sensitivity (44%).

CONCLUSION: For MVA assessment, the PHT method should be used cautiously even before PMC, especially in older patients or those in atrial fibrillation. After PMC, it does not provide an accurate MVA evaluation but can still be used as a semiquantitative method: a PHT less than 130 milliseconds is associated with a good valve opening, which can be useful in difficult cases.