Prognostic value of left atrial strain index (LASI) in patients with heart failure with preserved ejection fraction
Authors: Chua A P A , Achten A , Weerts J , Nabeta T , Sarrazyn C , Lopez- Santi M P , Mourmans S G J , Su J , Bax J J , Knackstedt C , Van Empel V P M , Ajmone Marsan N 
Published: January 2025

Abstract

Background
Left atrial (LA) strain has been proposed as an additional echocardiographic parameter to conventional diastolic dysfunction assessment for the estimation of elevated left ventricular end-diastolic pressure (LVEDP). Recently, left atrial strain index (LASI) has been introduced, which integrates by a machine-learned algorithm the entire strain curve (not limited to either the reservoir or contractile function) into a single parameter, and which was able to distinguish elevated versus normal LVEDP upon validation with invasive measurements. However, the prognostic value of LASI has not been widely established in the clinical setting.

Purpose
To investigate the prognostic value of LASI in patients with heart failure with preserved ejection fraction (HFpEF).

Methods
A total of 211 diagnosed HFpEF patients from a dedicated outpatient program were retrospectively analysed. Patients with cardiac devices or low image quality for LA analyses were excluded. Extensive echocardiographic analysis was performed, and LASI was assessed: positive values indicating elevated LVEDP and negative values identifying normal LVEDP (Figure 1). Study outcome was a composite of heart failure hospitalisation and all-cause mortality.

Results
From the total population, 117 (55%) patients had elevated LVEDP based on LASI and 94 (45%) normal LVEDP. Patients with elevated LVEDP were slightly older (77±6 vs. 74±8 years, p=0.003), had more often atrial fibrillation (61% vs. 10%, p&lt;0.001), higher HFA-PEFF score (HFA-PEFF≥5 69% vs. 53%, p=0.017) and NT-proBNP (135 [62-194] vs. 44 [25-81] pmol/L, p&lt;0.001), and more impaired diastology parameters [LA indexed volume 57±20 vs. 44±12 ml/m2, p&lt;0.001; average E/e’ 13±5 vs. 11±3, p=0.005; tricuspid jet velocity 2.8±0.4 vs 2.6±0.4 cm/s, p=0.036). During a median follow-up of 61 months, a total of 95 events were recorded. The elevated LVEDP group had worse outcome compared to the normal LVEDP group classified based on LASI (p&lt;0.001, Figure 1). When stratifying first according to HFA-PEFF score (cut-off ≥5) and then into LVEDP groups, patients with the elevated LVEDP still had worse outcomes, regardless of HFA-PEFF score (Figure 2). Uni- and multivariable survival analysis demonstrated that the LASI classification was independently associated with outcome, after correcting for age, sex, NYHA class, comorbidities, kidney function and HFA-PEFF score (HR 2.716 [1.610-4.583], p&lt;0.001). Likelihood analysis showed an incremental value upon addition of LASI to the clinical factors (ꭓ2 44 to 56, p&lt;0.001). Subgroup analysis on patients in sinus rhythm also demonstrated similar association of LASI to outcomes, adding significant value to other parameters.

Conclusion
LASI is significantly associated with outcome in HFpEF patients, and can be an adjunct to current methods of diastolic dysfunction assessment to improve risk stratification of these patients.