AUTHOR=Tessari Fernanda Castiglioni , Lopes Maria Antonieta Albanez A. de M. , Campos Carlos M. , Rosa Vitor Emer Egypto , Sampaio Roney Orismar , Soares Frederico José Mendes Mendonça , Lopes Rener Romulo Souza , Nazzetta Daniella Cian , de Brito Jr Fábio Sândoli , Ribeiro Henrique Barbosa , Vieira Marcelo L. C. , Mathias Wilson , Fernandes Joao Ricardo Cordeiro , Lopes Mariana Pezzute , Rochitte Carlos E. , Pomerantzeff Pablo M. A. , Abizaid Alexandre , Tarasoutchi Flavio 

TITLE=Risk prediction in patients with classical low-flow, low-gradient aortic stenosis undergoing surgical intervention

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 10 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2023.1197408

DOI=10.3389/fcvm.2023.1197408

ISSN=2297-055X

ABSTRACT=Introduction: Classical low-flow, low-gradient aortic stenosis (LFLG-AS) is an advanced stage of aortic stenosis, which has not only a poor prognosis with medical treatment but also a high operative mortality after surgical aortic valve replacement (SAVR). There is currently a paucity of information regarding both the current prognosis of classical LFLG-AS patients undergoing SAVR, as well as the lack of a reliable risk assessment tool for this particular subset of AS patients. The present study aims to assess mortality predictors in a population of classical LFLG-AS patients undergoing SAVR.
Methods: Prospective study including 41 consecutive classical LFLG-AS patients (aortic valve area≤1.0cm², mean transaortic gradient<40mmHg, left ventricular ejection fraction <50%). All patients underwent dobutamine stress echocardiography (DSE), 3D echocardiography, and T1-mapping cardiac magnetic resonance (CMR). Patients with pseudo-severe aortic stenosis were excluded. Patients were divided in groups according to the median value of the mean transaortic gradient (≤25mmHg and >25mmHg). All-cause mortality, intraprocedural, 30-day and 1-year mortality were evaluated. 
Results: All of the patients had degenerative aortic stenosis, with a median age of 66 [60-73] years, most of them being male (83%). The median EuroSCORE II was 2.19 (1.5-4.78)% and the median STS was 2.19 (1.6-3.99)%. On DSE, 73.2% had flow reserve (FR), i.e. an increase in stroke volume≥20% during DSE, with no significant differences between groups. On CMR, late gadolinium enhancement mass was lower in the group with mean transaortic gradient>25 mmHg (2.0 [0.0-8.9] vs 8.5 [2.3-15.0]g; p=0.034), and myocardium extracellular volume fraction (ECV) and indexed ECV were similar between groups. The 30-day and 1-year mortality were 14.6% and 43.8%, respectively. Median follow-up was 4.1 [0.3-5.1] years. By multivariate analysis adjusted for FR, only mean transaortic gradient was an independent predictor of mortality (HR:0.923, 95% CI 0.864-0.986, p=0.019). A mean transaortic gradient≤25mmHg was associated to higher all-cause mortality rates (log-rank p=0.038), while there was no difference in mortality regarding FR status (log-rank p=0.114). 
Conclusions: In patients with classical LFLG-AS undergoing SAVR, mean transaortic gradient was the only independent mortality predictor in patients with LFLG-AS, specially if ≤25mmHg. The absence of left ventricular FR had no prognostic impact on long-term outcomes.