Planimetry of orifice area in aortic stenosis using multiplane transesophageal echocardiography

The purpose of this study was to investigate whether the orifice area in aortic stenosis can be determined accurately and reliably by multiplane transesophageal echocardiography.

Monoplane transesophageal echocardiography has been used for planimetry of aortic valve orifice areas; however, obtaining a precise short-axis view is sometimes impossible.

In 41 consecutive patients with known valvular calcific aortic stenosis (20 men, mean age 64 +/- 9 years), aortic valve orifice area was measured by planimetry using a multiplane transesophageal echocardiographic probe that allows full rotation of the cross-sectional plane. Results were compared with invasive measurements obtained by the Gorlin formula and areas determined noninvasively by transthoracic echocardiography using the continuity equation.

Multiplane transducer technology enabled the rotation of the cross-sectional plane from an exactly aligned long-axis view of the stenosed valve to a precise short-axis view without moving the tip of the echocardiographic probe, thus achieving an orifice cross section at a level predetermined in the long-axis view. Planimetry was feasible in 38 patients (93%). In three patients with pinhole stenosis (area determined by the Gorlin formula < 0.4 cm2), the valve area could not be exactly delineated. Correlation between areas derived by transesophageal echocardiographic planimetry (0.56 +/- 0.31 cm2) and by the Gorlin formula (0.58 +/- 0.31 cm2) was excellent (r = 0.95; standard deviation of regression [SDR] = 0.054; Y = 0.92X + 0.085, where Y = Gorlin area and X = planimetry area). Correlation between Gorlin- and continuity equation-derived areas (0.65 +/- 0.46 cm2) was r = 0.79; for continuity equation- and transesophageal planimetry-derived areas it was r = 0.83. Severe aortic stenosis (valve area < or = 0.75 cm2) was predicted with high sensitivity (96%) and specificity (88%).

Multiplane transesophageal echocardiography is a practical and accurate clinical tool for the assessment of the severity of aortic stenosis.