Sequential assessment of mitral valve area during diastole using colour M-mode flow convergence analysis: new insights into mitral stenosis physiology

Aims In mitral stenosis (MS) transvalvular flow and velocity continually change throughout diastole but for mitral valve area (MVA), flow-dependent variations (valve reserve) are unknown. These physiologic changes can be studied by the proximal isovetocity surface area (PISA) method, using the high temporal resolution of cotour M-mode, essential for simultaneous measurements of flow and velocity. Hence, we aimed to validate the cotour M-mode PISA method for measurement of MVA in MS and to define using this method the physiologic flow-dependent changes of MVA during diastole. Methods and results In 50 patients with native MS, MVA was measured by planimetry (MVA-2D), Doppler pressure half-time (MVA-PHT), and two-dimensional PISA (2D-PISA). MVA measurement by colour M-mode PISA in early diastole (M-PISA) (1.27+/-0.46 cm(2)) with rigorously timed flow and velocity measurements by continuous wave Doppler did not differ and correlated well with MVA-2D (1.29+/-0.44 cm(2), p=0.59; r=0.85, p<0.001) and MVA-PHT (1.30+/-0.41 cm(2), p=0.52; r=0.80, p<0.001). In contrast a trend towards underestimation of MVA by 2D-PISA was observed (1.23+/-0.42 cm(2); p=0.10 and p=0.07). Timed analysis of transvalvular haemodynamics at early, mid, mid-late, and late diastole showed marked changes in flow and velocities (both p<0.0001) but not in MVA (respectively 1.27+/-0.46, 1.29+/-0.47, 1.28+/-0.51 and 1.27+/-0.49 cm(2); ns). Conclusions In MS, the high temporal resolution of cotour M-mode PISA allows accurate MVA measurements. It also allows for the first time, Sequential MVA assessment during diastole. Notwithstanding marked flow and velocities changes, MVA remained unchanged throughout diastole underscoring the tack of flow-related valvular reserve in MS. (C) 2003 Published by Elsevier Ltd on behalf of The European Society of Cardiology.