Long-term survival after TAVR in patients with low flow-low gradient vs high gradient aortic valve stenosis
Authors: Cardaioli F , Nai Fovino L , Rodino' G , Fabris T , Napodano M , Massussi M , Scotti A , Fraccaro C , Masiero G , Lorenzoni G , Continisio S , Montonati C , Iliceto S , Tarantini G 
Published: October 2022

Abstract

Introduction
Transcatheter aortic valve replacement (TAVR) has become the treatment of choice in elderly patients affected by severe aortic stenosis (AS). In patients with low-flow low-gradient (LFLG) AS, a clear benefit of TAVR over conservative treatment has been demonstrated. Notwithstanding, patients with classical LFLG (cLFLG) AS have shown worse early post-procedural outcomes compared to those with high-gradient (HG) AS.

Purpose
Given the absence of data, we aimed to evaluate long-term survival (up to 10 years) after TAVR in patients with cLFLG and paradoxical LFLG (pLFLG) AS as compared to those with HG-AS.

Methods
Consecutive patients undergoing TAVR at our center with a minimum 5-year follow up (i.e. treated between June 2007 and December 2016) were considered for this analysis. According to baseline echocardiography, patients were divided in three groups: 1) HG-AS (MG &gt;40 mmHg); 2) cLFLG-AS (MG &lt;40 mmHg, EF &lt;50%); and 3) pLFLG-AS (MG &lt;40 mmHg, EF &gt;50%). The study endpoint was post-procedural all-cause mortality. To test differences in long-term outcomes among groups, survival curves using the Kaplan Meier estimator were plotted and compared with the log-rank test. To adjust for possible baseline confounders, a propensity score weighted survival analysis was then performed (standard mean deviation &lt;0.1 for all the considered covariates).

Results
A total of 574 subjects were included in the analysis (419 [73%] HG-AS; 91 [15%] pLFLG-AS; and 64 [11%] cLFLG-AS). Median survival time was 4.8 years [IQR 2.3–6.2], with a maximum of 12.3 years. Patients with cLFLG-AS presented higher baseline cardiovascular risk compared to those with both HG-AS and pLFLG-AS. At unadjusted survival analysis, patients with cLFLG-AS showed the worst long-term prognosis after TAVR (overall log-rank test p=0.023). However, after propensity weighted adjustment, the long-term survival of patients with cLFLG-AS was similar to those with HG-AS (p=0.77). Patients with pLFLG and HG-AS presented similar survival rate. Unadjusted (Panels A and C) and adjusted (Panels B and D) survival curves are reported in Figure 1. Out of 64 patients with cLFLG-AS, 43 (67%) presented an improvement in LV-EF (&gt;15% from the baseline value) within the first year after TAVR. LV-EF improvement, but not baseline LV-EF, was apparently related to longer post-TAVR survival (Figure 2).

Conclusion
In the current study, patients with cLFLG-AS had worse long-term survival after TARV as compared to either HG or pLFLG-AS subjects. This difference was not present after adjusting for possible baseline confounders. Thus, the low-flow state condition per se might have a lower impact on long term prognosis of TAVR patients than previously hypothesized. Post-TAVR LV-EF recovery was common among patients with cLFLG-AS and was associated with improved long-term survival.

Funding Acknowledgement
Type of funding sources: None.