External validation of a new staging system for severe aortic stenosis in a Portuguese cohort
Authors: Silva C , Maltes S , Freitas P , Ferreira A.M , Teles R.C , Andrade M.J , Nolasco T , Guerreiro S , Abecasis J.M , Horta E , Oliveira A.F , Ribeiras R , Brito J , Almeida M , Mendes M 
Published: November 2020

Abstract

Background
Recently, a new staging system for severe aortic stenosis (AS) based upon the extent of extra-aortic-valve cardiac damage has been developed (Genereux et al. Eur Heart J 2017). The present study aimed to: 1) determine the prevalence of the different stages of extra-aortic valvular cardiac damage and its impact on prognosis in a real-world Portuguese cohort and; 2) evaluate the distribution of aortic valve calcium score (AV-CaSc) and its prognostic value.

Methods
Consecutive patients evaluated at a single-centre TAVI-programme between Nov/2015 and Nov/2018 were retrospective selected. The extent of extra-aortic valve cardiac damage was defined by echocardiography as stage 0 (no cardiac damage), stage 1 (left ventricular damage), stage 2 (mitral valve or left atrial damage), stage 3 (tricuspid valve or pulmonary artery vasculature damage) or stage 4 (right ventricular damage). AV-CaSc was estimated routinely at CT-angiography as per TAVI-programme protocol. The primary endpoint was 1-year all-cause mortality after CT-angiography. Survival analysis (Cox-regression hazards model and Kaplan-Meier) was performed. To account for the effect of aortic valve replacement (AVR), this variable entered the Cox-regression model as a time-dependent covariate.

Results
A total of 443 patients (mean age 82±7 years, 44% men, median euroSCORE II 4% [IQR 2.4–5.8]) were identified. After Heart Team discussion, 79% (n=349) underwent AVR (TAVI=307; surgical valve repair=42); 9% (n=42) await intervention; 6% (n=25) remain under medical treatment; 4% (n=19) died during the period of evaluation; and 2% (n=8) underwent palliative aortic balloon valvuloplasty.
According to the proposed classification, the distribution of patients from stages 0 through 4 was: 0.2% (n=1), 7.5% (n=34), 67.8% (n=306), 14% (n=63), and 10.4% (n=47). Additionally, for each increasing stage of cardiac damage, the burden of AV-CaSc was higher (from stage 1 through 4: 1776 [IQR 1217–2448]; 2448 [1796–3442]; 2448 [1832–3622]; 2960 [1936–4878] units; p for trend = 0.002).
All-cause mortality at 1-year was 14% (n=63). Mortality increased alongside with increasing extent of cardiac damage (from stage 0 through 4: 0% [n=0], 6% [n=2], 12% [n=36], 20% [n=12], and 30% [n=13]) – Fig. Multivariable analysis revealed chronic renal disease (HR 1.37 per stage [1.15–1.64], p&lt;0.001), AV-CaSc (HR 1.02 per 100 units [1.01–1.03], p=0.007), AVR (HR 0.46 [0.26–0.81], p=0.007) and stage of cardiac damage (HR 1.54 per stage [1.15–2.05], p=0.004) as independent predictors of 1-year mortality.

Conclusion
In a real-world Portuguese cohort of severe AS patients, the extent of cardiac damage was associated with 1-year mortality. AV- CaSc grants additional prognostic information to this classification. Incorporation of this staging system into patient evaluation may be useful in the risk assessment of severe AS.
Survival analysis

Funding Acknowledgement
Type of funding source: None