Comparative evaluation of the 2024 BSE and 2025 ASE guidelines for left ventricular diastolic dysfunction assessment: implications of age-specific thresholds

Background Left ventricular diastolic dysfunction (LVDD) is associated with significant morbidity and mortality. The 2024 British Society of Echocardiography (BSE) and 2025 American Society of Echocardiography (ASE) guidelines propose distinct algorithms incorporating left atrial reservoir strain (LARS), yet no study has directly compared their classification and prognostic performance in a community cohort with outcome data. Purpose To compare LVDD prevalence and grade distribution, evaluate reclassification patterns with emphasis on age-specific thresholds, and assess prognostic value for major adverse cardiovascular events (MACE) between BSE 2024 and ASE 2025 guidelines. Methods We applied BSE 2024 and ASE 2025 algorithms (fixed and age-specific e' thresholds) to 1,899 participants with preserved ejection fraction from the Project Baseline Health Study (median age 50.2 years; 43.6% male). Concordance was assessed via cross-tabulation. Echocardiographic profiling identified drivers of discordance. Stress echocardiography validated reclassification clinical relevance. Multivariable Cox models with cross-validated C-indices evaluated prognostic performance for MACE (92 events; median follow-up 4.3 years). Results LVDD prevalence varied across algorithms: 14.7% (ASE 2025 fixed), 10.3% (ASE 2025 age-specific), and 7.7% (BSE 2024). Age-specific thresholds shifted grade distribution toward higher severity, with Grade 2 accounting for 43.1% of ASE 2025 age-specific LVDD cases versus 28.0% with fixed thresholds. Overall concordance between BSE 2024 and ASE 2025 age-specific was 91.1%. Among 1,752 BSE-normal participants, 6.2% were reclassified to LVDD by ASE 2025: 2.3% to Grade 1 and 2.2% to Grade 2. Stress echocardiography revealed higher rates of stress E/e' >14 among reclassified participants versus those with no LVDD (20.0% vs 2.1%), suggesting subclinical filling pressure elevation. In multivariable Cox analysis, LVDD independently predicted MACE across all algorithms (HR 3.29, 2.98, and 2.57 for BSE 2024, ASE 2025 fixed, and age-specific, respectively), with comparable C-indices (0.79-0.80). Conclusions BSE 2024 and ASE 2025 yield meaningfully different LVDD prevalence (7.7% vs 14.7%) and grade distributions, yet equivalent prognostic discrimination. Reclassified participants demonstrate subclinical filling pressure elevation on stress testing, supporting clinical relevance of additional cases captured by ASE 2025. Clinicians should specify which guideline is applied when reporting LVDD.