Discrepancy of Aortic Valve Area Measurements by Doppler vs. Biplane Stroke Volume Measurements and Utility of Combining the Different Areas in Aortic Valve Stenosis - The Asian Valve Registry

Abstract

Background: The aortic valve area index (AVAI) in aortic stenosis (AS) is measured by echocardiography with a continuity equation using the stroke volume index by Doppler (SVIDoppler) or biplane Simpson (SVIBiplane) method. AVAI(Doppler) and AVA(Biplane) often show discrepancy due to differences between SVIDoppler and SVIBiplane. The degree of discrepancy and utility of combined AVAIs have not been investigated in a large population of AS patients, and the characteristics of subjects with larger discrepancies are unknown. Methods and Results: We studied 820 patients with significant AS (AVA(Doppler) <1.5cm(2)) enrolled in the Asian Valve Registry, a prospective multicenter registry at 12 Asian centers. All-cause death and aortic valve replacement were defined as events. SVIDoppler was significantly larger than SVIBiplane (49 +/- 11 vs. 39 +/- 11mL/m(2), P<0.01) and AVAI(Doppler) was larger than AVAI(Biplane) (0.51 +/- 0.15 vs. 0.41 +/- 0.14cm(2)/m(2), P<0.01). An increase in (AVAI(Doppler)-AVAI(Biplane)) correlated with shorter height, lower weight, older age, smaller left ventricular (LV) diameter and increased velocity of ejection flow at the LV outflow tract. Severe AS by AVAI(Doppler) or AVAI(Biplane) enabled prediction of events, and combining these AVAIs improved the predictive value of each. Conclusions: Discrepancy in AVAI by Doppler vs. biplane method was significantly more pronounced with increased LV outflow tract flow velocity, shorter height, lower weight, older age and smaller LV cavity dimensions. Combining the AVAIs enabled mutual and incremental value in predicting events.