The 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging diastolic function guideline often classified patients as “indeterminate” and provided inconsistent risk stratification. The 2025 update introduced a stepwise algorithm designed to minimize indeterminate cases. We examined whether the new guideline reduced indeterminate classifications and improved prognostic stratification compared with the 2016 standard.

We retrospectively evaluated 156 patients hospitalized with heart failure (HF) who underwent predischarge echocardiography. Diastolic function was graded according to the 2016 and 2025 algorithms. The primary end point was HF hospitalization or all-cause mortality. To explore applicability in earlier HF stages, we also analyzed 300 consecutive outpatients who underwent echocardiography during routine care.

The 2025 algorithm eliminated indeterminate cases (23 reduced to 0) and redistributed classifications (normal increased from 24 to 46, grade I decreased from 45 to 24, grade II increased from 43 to 64, and grade III increased from 21 to 22). Brain natriuretic peptide levels and clinical outcomes demonstrated a clearer stepwise increase across risk categories with the 2025 criteria, whereas the 2016 definition showed less consistent separation between groups. During a median 3.7-year follow-up, 41 patients were readmitted for HF and 27 died. Elevated left atrial pressure defined by the 2025 algorithm was independently associated with adverse outcomes in multivariable models (hazard ratio, 3.56; 95% CI, 1.64-7.73; P = .001). Adding elevated left atrial pressure to the HOSPITAL score improved discrimination ( c statistic changed from 0.63 to 0.73; P = .003). An exploratory outpatient cohort showed similar physiological stratification of brain natriuretic peptide across grades, although without longitudinal outcomes.

Stepwise application of the 2025 diastolic algorithm at discharge eliminated indeterminate classifications, enhanced prognostic stratification, and improved discrimination beyond a clinical risk score in hospitalized HF. Exploratory outpatient findings suggest potential applicability in earlier HF stages, although prospective validation across the full HF spectrum is needed.

Comparison of 2016 vs 2025 Diastolic Function Algorithms. The 2016 ASE/EACVI algorithm often resulted in an indeterminate category, limiting risk stratification. The 2025 update introduced a stepwise approach that eliminated indeterminate classifications (23 reduced to 0) and reassigned patients into definitive grades (normal, grades I-III). This reclassification was associated with clearer separation (HR = 3.56; 95% CI, 1.64-7.73; P = .001).