Radius of proximal isovelocity surface area in the assessment of rheumatic mitral stenosis: Connecting flow to anatomy and hemodynamics

Abstract

BackgroundEchocardiographic assessment of left atrial pressure (LAP) in mitral stenosis (MS) is controversial. We sought to examine the role of the radius of the proximal isovelocity surface area (PISA-r) in the assessment of the hemodynamic status of MS after fixing the aliasing velocity (Val). Methods and resultsWe studied 42 candidates of balloon mitral valvuloplasty (BMV), for whom pre-BMV echocardiography was done and LAP invasively measured before dilatation. PISA-r was calculated after fixing aliasing velocity to 33cm/s. In addition, the ratio IVRT/Te’–E was also measured, where IVRT was isovolumic relaxation time, and Te’–E was the time difference between the onset of mitral flow E-wave and mitral annular early diastolic velocity. IVRT/Te’–E and PISA-r showed a strong correlation with LAP (r=−0.715 and −0.637, all p<0.001) and with right-sided pressures. In addition, PISA-r correlated with mitral valve area by planimetry method (MVA) and with left ventricular outflow tract stroke volume (r=0.66 and 0.71, all p<0.001). Receiver operator characteristic curve (ROC-curve) showed that PISA-r was not inferior to IVRT/Te’–E in differentiating LAP ⩾25 from <25mmHg. ConclusionProvided that Val is set to a constant of 33cm/s, PISA-r can assess the hemodynamic status of MS, and seems a simple alternative to the tedious IVRT/Te’–E for estimation of LAP.