Relationship between resting parameters of the mitral valve and exercise capacity in patients with mitral stenosis: can the diastolic filling period predict exercise capacity?

摘要

BACKGROUND AND AIMS OF THE STUDY: In order to provide patients with better exercise capacity, interventional therapy to the mitral valve is often carried out in mitral stenosis (MS). Hence, it is crucial to determine exercise capacity before deciding on the time of intervention. The study aim was to demonstrate whether resting parameters of the mitral valve, notably left ventricular diastolic filling period (LVDFP) and mitral valve resistance (MVR), relate to restricted exercise capacity. METHODS: Forty-six patients (30 females, 16 males; mean age 44+/-11 years; range: 33-55 years) with rheumatic MS were enrolled. Exercise capacities of patients were grouped according to NYHA classification and maximal exercise tolerance values obtained using exercise testing. Exercise capacity in male patients was quantified. Relationships between patient variables and exercise capacity were evaluated using simple linear regression analysis. In order to identify determinants of exercise capacity, a discriminate multivariate analysis was performed with variables, which were found to correlate significantly in the univariate analysis. RESULTS: There were no correlations between echo score, MVR, planimetric mitral valve area (MVA), MVA obtained by the pressure half-time method or calculated by the continuity equation, and transmitral mean gradient and exercise capacity classes as defined by both NYHA and exercise testing. The only predictor of exercise capacity class determined by discriminate multivariate analysis using the significant parameters in the linear regression analysis was LVDFP. The quantified exercise capacity in male patients correlated only with LVDFP (r = 0.64, p = 0.008). CONCLUSION: Exercise capacity cannot be predicted using routine resting parameters of the mitral valve (including MVR) in patients with MS. In this respect, the LVDFP may be of value.