Left atrial mechanical efficiency as a novel parameter to reflect congestion burden and predict outcome in heart failure with reduced and mildly reduced ejection fraction
D I Vasile, S Mihaila Baldea, D M Dodita, H Septar, B Spataru, A Andreescu, A Paduraru, D Mihalcea, L Balan, C Simionica, A Velcea, D VinereanuAbstract
Background
Congestion represents a central pathophysiological component in patients hospitalized for decompensated heart failure with reduced or mildly reduced ejection fraction (HFrEF / HFmrEF). While clinical, echocardiographic, and biological parameters are commonly used to assess congestion, the role of integrated atrial function indices remains insufficiently explored. Left atrial reservoir strain (LASr) and LA volumes reflect atrial remodeling; however, composite parameters combining functional and structural LA properties may provide a more comprehensive assessment of hemodynamic congestion and prognosis.
Purpose
To assess relationship between a proposed composite HF congestion score and LA mechanical efficiency (LAeff), and to investigate prognostic role of LAeff in patients with HFrEF / HFmrEF.
Methods
We prospectively included 152 patients hospitalized for HFrEF / HFmrEF and followed them for 22±14 months. All patients were analyzed by comprehensive echo, including systolic pulmonary artery pressure (sPAP), E/e’, LASr by 2D echo, and LA maximal volume (LAvol) by 3D echo. An HF congestion score, ranging from 1 to 5 points, was designed by assigning 1 point for each of the following parameters at admission: NT-proBNP >5700 pg/ml, NYHA class ≥3, pleural effusion on chest X-ray or CT, sPAP >30 mmHg, and E/e′ >12. Standardized (Z-score) values were used to reflect the overall burden of congestion, integrating clinical, biological, and hemodynamic markers. LA mechanical efficiency was calculated as: LAeff = LASr / LAvol. Primary outcome was a composite end-point (CE) of all-cause death and heart failure hospitalization.
Results
Mean LAeff, LASr, and LAvol were: 0.21±0.17, 8.3±5.5%, and 48±15 ml/m2, respectively. Compared with conventional LA indices (LAvol and LASr), LAeff showed the strongest correlation with HF congestion score (r=0.35 and r=-0.4 vs. r=-0.53, respectively, Z=5.61, all p < 0.001). By binary logistic regression, HF congestion score was an independent predictor of decreased LAeff (χ =18, p < 0.001). Thus, each one-unit increase in congestion score increased the odds of impaired LAeff nearly fourfold (Exp(B) = 4.3). By Cox regression, decreased LAeff independently predicted CE (χ² = 4.4, p = 0.04, HR 0.70), with a 27% increase in risk for each one-unit decrease in LAeff. Kaplan Meier survival curves showed that event-free survival was significantly worse in patients with LAeff <0.13 than in patients with LAeff >0.13 (χ² = 4.5; p = 0.03) (Figure); an LAeff <0.13 was associated with a 2.4-fold higher hazard of CE (95%CI 1.03–5.4; p = 0.04).
Conclusion
Our proposed HF congestion score is strongly associated with impaired LA mechanical efficiency in patients with decompensated HFrEF / HFmrEF. Moreover, reduced LA efficiency independently predicts clinical outcomes, suggesting that this parameter may represent a novel marker for risk stratification and congestion-guided management in HFrEF.Event free survival curves for LA efficiency