TY - JOUR
T1 - Transvalvular Flow Rate Determines Prognostic Value of Aortic Valve Area in Aortic Stenosis
AU - Namasivayam, Mayooran
AU - He, Wei
AU - Churchill, Timothy W.
AU - Capoulade, Romain
AU - Liu, Shiying
AU - Lee, Hang
AU - Danik, Jacqueline S.
AU - Picard, Michael H.
AU - Pibarot, Philippe
AU - Levine, Robert A.
AU - Hung, Judy
N1 - Publisher Copyright:
© 2020 American College of Cardiology Foundation
PY - 2020/4/21
Y1 - 2020/4/21
N2 - Background: Aortic valve area (AVA) ≤1.0 cm2 is a defining characteristic of severe aortic stenosis (AS). AVA can be underestimated at low transvalvular flow rate. Yet, the impact of flow rate on prognostic value of AVA ≤1.0 cm2 is unknown and is not incorporated into AS assessment. Objectives: This study aimed to evaluate the effect of flow rate on prognostic value of AVA in AS. Methods: In total, 1,131 patients with moderate or severe AS and complete clinical follow-up were included as part of a longitudinal database. The effect of flow rate (ratio of stroke volume to ejection time) on prognostic value of AVA ≤1.0 cm2 for time to death was evaluated, adjusting for confounders. Sensitivity analysis was performed to identify the optimal cutoff for prognostic threshold of AVA. The findings were validated in a separate external longitudinal cohort of 939 patients. Results: Flow rate had a significant effect on prognostic value of AVA. AVA ≤1.0 cm2 was not prognostic for mortality (p = 0.15) if AVA was measured at flow rates below median (≤242 ml/s). In contrast, AVA ≤1.0 cm2 was highly prognostic for mortality (p = 0.003) if AVA was measured at flow rates above median (>242 ml/s). Findings were irrespective of multivariable adjustment for age, sex, and surgical/transcatheter aortic valve replacement (as time-dependent covariates); comorbidities; medications; and echocardiographic features. AVA ≤1.0 cm2 was also not an independent predictor of mortality below median flow rate in the validation cohort. The optimal flow rate cutoff for prognostic threshold was 210 ml/s. Conclusions: Transvalvular flow rate determines prognostic value of AVA in AS. AVA measured at low flow rate is not a good prognostic marker and therefore not a good diagnostic marker for truly severe AS. Flow rate assessment should be incorporated into clinical diagnosis, classification, and prognosis of AS.
AB - Background: Aortic valve area (AVA) ≤1.0 cm2 is a defining characteristic of severe aortic stenosis (AS). AVA can be underestimated at low transvalvular flow rate. Yet, the impact of flow rate on prognostic value of AVA ≤1.0 cm2 is unknown and is not incorporated into AS assessment. Objectives: This study aimed to evaluate the effect of flow rate on prognostic value of AVA in AS. Methods: In total, 1,131 patients with moderate or severe AS and complete clinical follow-up were included as part of a longitudinal database. The effect of flow rate (ratio of stroke volume to ejection time) on prognostic value of AVA ≤1.0 cm2 for time to death was evaluated, adjusting for confounders. Sensitivity analysis was performed to identify the optimal cutoff for prognostic threshold of AVA. The findings were validated in a separate external longitudinal cohort of 939 patients. Results: Flow rate had a significant effect on prognostic value of AVA. AVA ≤1.0 cm2 was not prognostic for mortality (p = 0.15) if AVA was measured at flow rates below median (≤242 ml/s). In contrast, AVA ≤1.0 cm2 was highly prognostic for mortality (p = 0.003) if AVA was measured at flow rates above median (>242 ml/s). Findings were irrespective of multivariable adjustment for age, sex, and surgical/transcatheter aortic valve replacement (as time-dependent covariates); comorbidities; medications; and echocardiographic features. AVA ≤1.0 cm2 was also not an independent predictor of mortality below median flow rate in the validation cohort. The optimal flow rate cutoff for prognostic threshold was 210 ml/s. Conclusions: Transvalvular flow rate determines prognostic value of AVA in AS. AVA measured at low flow rate is not a good prognostic marker and therefore not a good diagnostic marker for truly severe AS. Flow rate assessment should be incorporated into clinical diagnosis, classification, and prognosis of AS.
KW - aortic stenosis
KW - flow rate
KW - low flow
KW - low gradient
KW - outcome
KW - prognosis
UR - http://www.scopus.com/inward/record.url?scp=85080039214&partnerID=8YFLogxK
U2 - 10.1016/j.jacc.2020.02.046
DO - 10.1016/j.jacc.2020.02.046
M3 - Article
C2 - 32299587
AN - SCOPUS:85080039214
SN - 0735-1097
VL - 75
SP - 1758
EP - 1769
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 15
ER -