Echocardiographic discrepancies in severity grading of aortic valve stenosis with left ventricular outflow tract (LVOT) cut-off values in an Asian population.

Abstract

Inconsistencies in grading of aortic stenosis (AS) severity have been reported. However, it remains to be studied in an Asian population. We investigated consistency of grading AS severity at various left ventricular outflow tract diameter (LVOTd) categories, and postulated alternative cut-offs for more consistent grading of AS severity. Consecutive Asian patients (n = 350) with index echocardiographic diagnosis of severe AS were divided them into three groups based on LVOTd: 'small' (< 20mm), 'average' (20-22mm) and 'large' (> 22mm). In each group, the consistency of flow-dependent (transaortic mean pressure gradient (MG)) and flow-independent parameters (AVA) were used for classification of AS severity. Of 350 patients, 51.7% had small LVOTd, while 30.8% and 17.5% had average and large LVOTd respectively. Consistent grading by LVOTd based on AVA and MG, was seen in 33.7% of patients with small, 47.6% with average, 57.7% with large LVOTd. When an AVA cut-off of 0.9 cm2 was used, consistent grading improved to 38.0% in small, 56.5% in average and 70.0% in large LVOTd. At an AVA cut-off of 0.8 cm2, there was further incremental improvement in the small LVOTd group to 54.1% (p < 0.05). In conclusion, current severe AS guidelines are most inconsistent with those in the small LVOTd group. With majority of the study's Asian population having small LVOTd, this raises concerns that current AS guidelines may overestimate the severity of AS in the Asian cohort. Improved consistency in echocardiographic grading may be attained with a lower AVA cut-off in this Asian cohort.