Low-flow low-gradient aortic stenosis: aortic valve area estimated by continuity equation versus projected aortic valve area

Abstract Introduction Accurately stratifying severity in low-flow, low-gradient (LFLG) aortic stenosis (AS) can be clinically challenging. The projected aortic valve area (AVAproj), which estimates the aortic valve area (AVA) at normal transvalvular flow rate, has been proposed as a more reliable marker of true stenosis. The TOPAS study previously demonstrated the prognostic relevance of AVAproj in identifying true severe aortic stenosis. Purpose To compare AS severity classification based on AVA estimated by continuity equation at peak dobutamine stress echocardiography (AVA-CE) versus AVAproj, and evaluate their prognostic value in predicting the composite outcome of aortic valve replacement (AVR) or all-cause mortality at 2 years. Methods Single-center retrospective study including individuals with AS who underwent dobutamine stress echocardiography (DSE). AVA at rest (AVA-rest), AVA-CE, and AVAproj were assessed. Reclassification rates were analyzed. Logistic regression models were constructed to assess the association of AS severity (as defined by AVA-CE or AVAproj) with the composite outcome. Results From a total of 57 individuals with AS submitted to DSE, we included 24 patients with transvalvular flow rate at peak stress inferior to 250 mL/s. The mean age was 69±10 years, 83% were male. Echocardiographic parameters are summarized in Table 1. When comparing absolute AVA values, AVA-rest and AVA-CE were both significantly different from the AVAproj (p