Current ACC/AHA aortic stenosis définitions do not provide consistent prognostic impact after aortic valve replacement surgery.

Piérard, Sophie F. [UCL] de Meester de Ravenstein, Christophe [UCL] Seldrum, Stéphanie [UCL] Vancraeynest, David [UCL] Pasquet, Agnes [UCL] Gerber, Bernhard [UCL] Vanoverschelde, Jean-Louis [UCL]

Background: The 2008 ACC/AHA Guidelines categorize patients (pts) with severe aortic stenosis (AS, aortic valve area < 1cm2), in 2 groups: high gradient high velocity (HGHV, mean transvalvular gradient (MG) >40 mmHg and velocity >4 m/s), and low flow low gradient AS (LFLG, MG <30 mmHg and low cardiac output). This potentially leaves a significant number of SAS pts unclassified (UAS). To overcome this limitation, the category of paradoxical low flow AS (PLF, ejection fraction ≥ 50% and indexed stroke volume ≤35 ml/m2) was introduced. The aim of this study was to evaluate the amount of overlap between this new AS category and the ACC/AHA AS categories and to investigate how the various definitions of AS impact on prognosis after aortic valve replacement (AVR). Methods: From a prospective registry, all 863 pts (age 75±7 years) with AS who underwent AVR between 2000-2010 were followed. Pts were categorised in 3 groups based on the 2008 ACC/AHA guidelines and the amount of overlap with PLF was calculated. Hospital and long term Kaplan Meier survival curves were constructed for each group. Multivariate Cox analysis were computed to evaluate predictors of survival. Results: Mean follow up is 38 months. Based on the 2008 ACC/AHA Guidelines, 22% of pts with AS were unclassified (n=189), i.e. were neither HGHV (n=610, 71%) nor LFLG (n=64, 7%). Pts with PLF AS (n=285) overlapped with these 3 categories and amounted for 66% of HGHV, 10% of LFLG and 24% of UAS. Survival analysis indicated that HGHV, PLF AS and UAS have similarly good post operative hospital survival (94% and 95%, p=0.41), while LFLG AS had worse survival (87%, p=0.019). Multivariate Cox Analysis identified LFLG AS as predictor of hospital mortality (p=0.008). Long Term survival analysis indicated that HGHV and UAS have a different outcome (at 60 months: 86% and 73% respectively; p=0.035). PLF classification was not discriminant for the survival (p=0.14). Conslusion: The current classification of AS is confusing, and with the exception of LFLG AS, does not provide valuable prognostic information after AVR. PLF does not help to define high risk patients. Further studies should aim at designing AS classifications that are based on post operative clinical outcome.