Evaluation of the severity of mitral stenosis with a new index: isovolumic myocardial acceleration

Objectives: Although right ventricular (RV) systolic dysfunction is an important indicator for the severity of mitral stenosis (MS), its diagnosis is difficult before systemic signs of venous congestion occur. We assessed the association between tissue Doppler (TDI)-derived isovolumic myocardial acceleration (IVA) and the severity of MS. Study design: The study included 112 MS patients (79 mild to moderate, 33 severe MS). Two-dimensional and Doppler echocardiographic parameters (mitral valve area, transmitral diastolic gradients, pulmonary artery pressure, RV fractional shortening, pulmonary flow acceleration time, tricuspid valve annular systolic excursion) were calculated. Additionally, TDIderived systolic velocities of the tricuspid annulus (IVA, peak myocardial velocity during isovolumic contraction -IVV, peak systolic velocity during ejection period-Sa) were recorded. The results were compared with those of 60 age-and sexmatched healthy controls. Results: All TDI-derived systolic velocities (IVV, Sa and IVA) were significantly decreased in patients with MS (p< 0.0001). However, IVA was the only parameter to distinguish the severity of MS (p< 0.0001). It also showed significant correlations with the following parameters with which IVV and Sa were not correlated: mitral valve area (r= 0.79, p< 0.0001), mean (r= -0.54, p< 0.0001) and maximum (r= 0.58, p< 0.0001) transmitral diastolic gradients, pulmonary artery pressure (r= -0.54, p< 0.0001), and left atrial diameter (r= -0.68, p< 0.0001). The ROC curve analysis showed that an IVA of < 2.9 m/ sec2 predicted MS patients with 86% sensitivity, 87% specificity, and an IVA of < 2 m/sec(2) predicted severe MS with 82% sensitivity and 77% specificity. Conclusion: Tissue Doppler-derived right ventricular IVA may be used as an adjunctive, alternative noninvasive parameter to determine the severity of MS in patients without signs of systemic venous congestion.