title: [Discordance between mitral valve area (MVA) and pressure gradient in patients with mitral valve stenosis: mean transmitral valve gradient is a severity index or a tolerance index of severity of mitralss valve stenosis?]
abstract: Rheumatic mitral valve stenosis (MVS) is a frequent valvulopathy in developing countries. However, industrialized countries have seen the emergence of new etiologies of MVS in recent years, in particular drug-induced and/or toxic valvular regurgitation and stenosis. For this reason, the echocardiographic assessment of MVS and especially the definition of objective diagnostic criteria for severe MVS remains relevant. The objectives are: to determine whether there is a direct causal link between mean transmitral gradient (MTG) and severity of MVS in patients with severe MVS or true severe MVS (primary criterion); to analyze different parameters determining mean transmitral gradient (MTG) (secondary criterion). We conducted a single-center cross-sectional study including all patients with severe or true severe MVS admitted to the Department of Cardiology, University Hospital Ibn Rushd, Casablanca over a period of one year (January 2014-December 2014). We analyzed data from two groups of patients separately: those with a mean transmitral gradient<10 mmHg (group 1) and those with a gradient>10mmHg (group 2). 50 patients with severe or true severe MVS have been included in the study. The average age of our patients was 41.7 years with a female predominance (sex ratio 0,25). 64% of patients had severe MVS and 36% of patients had true severe MVS. 52% (26 patients) had MTG < 10mmHg and 48% (24 patients) had mean gradient> 10mmHg, suggesting no direct correlation between the severity of MVS and MTG (Pearson's correlation coefficient R: -0,137). With regards to dyspnea, 80% of patients of group 1 had stage II NYHA dyspnea (classification system) and 70% of patients of group 2 had stage III NYHA dyspnea (41%) or IV NYHA dyspnea (29%), which means that there was a significant correlation between MTG and the severity of dyspnea (R: 0,586 and p: 0,001). The analytical study of heart rate and the presence of cardiac decompensation compared with mean gradient transmitral showed a significant correlation. Indeed, among patients in group 1, 96% had HR between 60 and 100 bpm and no patient had decompensated heart failure. In group 2, 54% (13 patients) had a HR> 100 bpm and 7 of them (53%) had left decompensated heart failure. The analysis of systolic pulmonary artery pressure conducted in both groups of the study revealed the existence of a statistically significant correlation (R: 0,518 and P: 0,001) between systolic pulmonary artery pressure (SPAP) and MTG. Ventricular rhythm regularity and right ventricular function were not correlated with MTG (R: 0,038 and R: - 0,002 respectively). Mean transmitral gradient is a good indicator of mitral stenosis tolerance but it imperfectly reflects mitral stenosis severity as this depends on several hemodynamic parameters. True severe mitral stenosis may have mean transmitral gradient < 10mmHg, that is why the value of MTG should never be interpreted as single value.
authors.affiliation: Service de Cardiologie, CHU Ibn Rochd, Casablanca, Maroc.
authors.forename: Hayat
authors.initials: H
authors.lastname: Najih
authors.affiliation: Service de Cardiologie, CHU Ibn Rochd, Casablanca, Maroc.
authors.forename: Salim
authors.initials: S
authors.lastname: Arous
authors.affiliation: Service de Cardiologie, CHU Ibn Rochd, Casablanca, Maroc.
authors.forename: Aziza
authors.initials: A
authors.lastname: Laarje
authors.affiliation: Service de Cardiologie, CHU Ibn Rochd, Casablanca, Maroc.
authors.forename: Dalila
authors.initials: D
authors.lastname: Baghdadi
authors.affiliation: Service de Cardiologie, CHU Ibn Rochd, Casablanca, Maroc.
authors.forename: Mohamed Ghali
authors.initials: MG
authors.lastname: Benouna
authors.affiliation: Service de Cardiologie, CHU Ibn Rochd, Casablanca, Maroc.
authors.forename: Leila
authors.initials: L
authors.lastname: Azzouzi
authors.affiliation: Service de Cardiologie, CHU Ibn Rochd, Casablanca, Maroc.
authors.forename: Rachida
authors.initials: R
authors.lastname: Habbal
mesh_terms: D000328:Adult; D000368:Aged; D062186:Arterial Pressure / Q000502:physiology; D003430:Cross-Sectional Studies; D004417:Dyspnea / Q000453:epidemiology / Q000209:etiology; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000453:epidemiology*; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000503:physiopathology*; D008946:Mitral Valve Stenosis / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D009018:Morocco; D012214:Rheumatic Heart Disease / Q000150:complications; D012720:Severity of Illness Index; D016278:Ventricular Function, Right / Q000502:physiology; D055815:Young Adult
keywords: Severe mitral stenosis; mean transmitral gradient; surface of the mitral valve