ABLE-SCORE, a simplified risk score for major adverse cardiovascular outcomes in left ventricular hypertrabeculation: a multicenter longitudinal cohort study.

Background: Left ventricular hypertrabeculation (LVHT) is a heterogeneous entity with life-threatening complications and variable prognosis. However, there are limited prediction models available to identify individuals at high risk of adverse outcomes, and the current risk score in LVHT is comparatively complex for clinical practice. This study aimed to develop and validate a simplified risk score to predict major adverse cardiovascular events (MACE) in LVHT.

Methods: This multicenter longitudinal cohort study consecutively enrolled morphologically diagnosed LVHT patients between January 2009 and December 2020 at Fuwai Hospital (derivation cohort, n = 300; internal validation cohort, n = 129), and between January 2014 and December 2022 at two national-level medical centers (external validation cohort, n = 95). The derivation/internal validation cohorts and the external validation cohort were followed annually until December 2022 and December 2023, respectively. MACE was defined as a composite of all-cause mortality, heart transplantation/left ventricular assist device implantation, cardiac resynchronization therapy, malignant ventricular arrhythmia, and thromboembolism. A simplified risk score, the ABLE-SCORE, was developed based on independent risk factors in the multivariable Cox regression predictive model for MACE, and underwent both internal and external validations to confirm its discrimination, calibration, and clinical applicability.

Results: A total of 524 LVHT patients (43.5 ± 16.6 years, 65.8% male) were included in the study. The ABLE-SCORE was established using four easily accessible clinical variables: age at diagnosis, N-terminal pro-brain natriuretic peptide levels, left atrium enlargement, and left ventricular ejection fraction ≤ 40% measured by echocardiography. The risk score showed excellent performance in discrimination, with Harrell's C-index of 0.821 [95% confidence interval (CI), 0.772-0.869], 0.786 (95%CI, 0.703-0.869), and 0.750 (95%CI, 0.644-0.856) in the derivation, internal validation, and external validation cohort, respectively. Calibration plots of the three datasets suggested accurate agreement between the predicted and observed 5-year risk of MACE in LVHT. According to decision curve analysis, the ABLE-SCORE displayed greater net benefits than the existing risk score for LVHT, indicating its strength in clinical applicability.

Conclusions: A simplified and efficient risk score for MACE was developed and validated using a large LVHT cohort, making it a reliable and convenient tool for the risk stratification and clinical management of patients with LVHT.