0582: Discordance between mitral valve area and mean transmitral pressure gradient in mitral stenosis: is mean gradient marker of the severity or parameter of tolerance in severe mitral stenosis?

Background Definition of objective criteria to conclude the severity of MS is still important. Aims (1) to evaluate correlation between the mean transmitral gradient (MTG) and severity of MS in patients with a severe or very severe MS (2) To analyze the different parameters which determine the mean transmitral gradient. Methods We conducted a prospective study including fifty patients admitted for severe or very severe MS, over a period of one year. We first studied the correlation between mitral valve area and MTG. Then we separately analyzed two groups of patients: those with a MTG  10mmHg (group2). We performed for each group an univariate correlation between MTG and dyspnea, heart rate, cardiac decompensation, regularity of rhythm, function of right ventricle and systolic pulmonary artery pressure (SPAP). Results 64% of our patients had a severe MS and 36% had a very severe MS. 52% had a MTG  10mmHg; suggesting lack of correlation between the severity of MS and MTG (Pearson coefficient R: –0.137). Regarding dyspnea, 80% of patients in group 1 had a dyspnea stage II of NYHA and 70% of patients in group 2 had a dyspnea stage III (41%) or IV (29%). The analytical study of heart rate (HR) and the presence of cardiac decompensation compared with MTG showed a significant correlation. Among the patients in group 1, 96% had a HR between 60 and 100 bpm and no patient was in cardiac decompensation. In group 2, 54% (13 patients) had a HR >100 bpm and 7 of them (53%) were in left heart failure. The study of SPAP in the two groups found a statistically significant correlation between the SPAP and MTG. Conclusion Mean transmitral gradient is a good indicator of the tolerance of mitral stenosis, but it reflects poorly severity because it depends on several hemodynamic parameters.