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

BACKGROUND: Echocardiographic 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 RESULTS: We 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 33 cm/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 <25 mmHg. CONCLUSION: Provided that Val is set to a constant of 33 cm/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.