Association of left ventricular end-systolic volume with peri-echocardiographic acute kidney injury proxy beyond ejection fraction: a retrospective linked echocardiographic cohort study.

BACKGROUND

Left ventricular ejection fraction (LVEF) remains the default echocardiographic summary of systolic performance, yet its ratio structure makes it sensitive to geometry and loading conditions. Left ventricular end-systolic volume (LVESV) may capture adverse remodeling more directly. The relation of LVESV to peri-echocardiographic renal dysfunction in hospitalized patients remains uncertain.

METHODS

This retrospective linked echocardiographic cohort study analyzed 1,022 complete biplane studies from 784 patients in the credentialed PhysioNet MIMIC-IV-ECHO-Ext-LVVOLUMES-A4C-ROI resource linked to MIMIC-IV v3.1 clinical tables. The primary endpoint was an acute kidney injury (AKI) proxy defined as maximum serum creatinine ≥ 2.0 mg/dL within a ± 24-hour peri-echocardiographic window. Hierarchical logistic regression with patient-level cluster-robust standard errors included age, sex, first-day SOFA score, and vasopressor exposure; 5 chained-equation imputations addressed missing SOFA. Temporal analysis compared echocardiography time with the first creatinine value meeting the endpoint threshold.

RESULTS

AKI proxy was present in 80 of 1,022 studies (7.8%). Among these 80 studies, 73 (91.3%) reached the creatinine threshold before echocardiography and 7 (8.8%) after echocardiography. For AKI proxy, LVESV showed modestly higher discrimination than LVEF (AUC 0.572 vs. 0.548; ΔAUC 0.024; p = 0.253). In the fully adjusted hierarchical model, LVESV remained associated with AKI proxy (OR 1.40 per SD increase, 95% CI 1.10-1.78; p = 0.006), whereas LVEF did not (OR 0.83 per SD decrease, 95% CI 0.62-1.10; p = 0.188). Model 3 yielded the highest C-statistic (0.727) and the lowest AIC (517.0), but BIC was not improved and reclassification gains were modest.

CONCLUSIONS

LVESV was associated with peri-echocardiographic AKI proxy after severity adjustment, but the temporal analysis indicates that the signal predominantly reflected concurrent renal illness rather than prospective prediction. Any incremental value beyond LVEF was modest and should be interpreted within the limits of a non-KDIGO creatinine-based proxy endpoint.