The prognostic value of non-invasively estimated left atrial pressure in patients undergoing cardiac resynchronization therapy
Authors: Beela A , Lyon A , Manetti C , Prinzen F , Delhaas T , Herbots L , Lumens J 
Published: June 2023

Abstract

Funding Acknowledgements
Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union’s Horizon 2020 research and innovative program under the Marie Sklodowska -Curie grant agreement No. 860745.

Background
The impact of non-invasively estimated left atrial pressure (LAP) on cardiac resynchronization therapy (CRT) outcome has been previously investigated, yet with inconsistent results.

Aim
We aim at investigating the association between baseline LAP and CRT outcome applying both the standard guideline approach (Nagueh et al 2016) and the integrated guideline + LA strain approach.

Methods
Datasets of 219 CRT patients were retrospectively analyzed. All patients had full echocardiographic diastolic function assessment before CRT and were classified based on the guidelines approach for estimation of LAP into normal LAP (nLAP = 40%), elevated LAP (eLAP = 49%) and undetermined LAP (uLAP = 11%, when classification was not possible due to missing data, Figure A, solid bars). All baseline characteristics, comorbidities, and ECG data in addition to LA strain components before CRT were collected and analyzed. The amount of CRT-induced LV reverse remodeling was assessed at 12±6 months after CRT and was defined as percentage decrease of LV end-systolic volume (LVESV) compared to baseline. Patients were followed up for a mean of 4.8 years (interquartile range (IQR): 2.7–6.0) for all-cause mortality.

Results
Compared to patients with eLAP, patients with nLAP were more of female sex (40% vs. 21%) and they had lower serum creatinine (1.1 ± 0.4 vs. 1.5 ± 0.6 mg/dl). ECG data showed that they had less prevalence of AF (9 vs. 15%). All LA strain indices were better in patients with nLAP (23 ± 9 vs. 12 ± 7% for reservoir strain, 10 ± 4 vs. 7 ± 5% for conduit strain and 11 ± 7 vs. 4 ± 4% for pump strain, P &lt; 0.01 for all comparisons). At follow-up, LVESV was reduced more in patients with nLAP than in patients with eLAP (47 ± 28 vs. 30 ± 30%, P &lt; 0.01, figure B solid bars). Survival rates of patients with nLAP was significantly higher than patients with eLAP (Hazard ratio (HR): 0.40; confidence interval (CI): 0.22–0.27; P &lt; 0.01, figure C solid lines). In the subgroup of uLAP an LA reservoir strain was used to further identify patients with nLAP (LA reservoir strain ≥ 18%). Accordingly, the integrated guideline+LA strain approach improved the feasibility for classification from 89% to 97%, where the percentage of the uLAP dropped from 11% to 3% (only patients with no baseline LA strain remained classified as uLAP, figure A). Patients with nLAP according to the integrated approach showed very similar CRT-induced LV reverse remodeling (figure B dashed bars) and long-term survival as compared to patients with nLAP according to the standard approach (figure C dashed lines).

Conclusion
Applying the standard guideline approach for LAP, patients with nLAP before CRT show more LV reverse remodeling and better long-term survival after CRT, as compared to patients with eLAP. The guideline + LA strain approach markedly improves the feasibility of LAP estimation, while not influencing the association between LAP and outcome after CRT.