Non-valvular atrial fibrillation (NVAF) is the most common sustained arrhythmia observed in critically ill patients, linked to a higher risk of embolic and haemorrhagic events. Conventional tools, such as CHADS2, CHA2DS2-VASc, and HAS-BLED scores, are ineffective for risk stratification and do not offer guidance for anticoagulation strategies in this population. Recently, we engineered new machine-learning (ML) models retrospective cohorts, with promising results; in this work, we aim to validate our ML models in a larger cohort. We performed a retrospective analysis of all consecutive critically ill patients admitted to our step-down unit over a 10-year period who had a history of NVAF. We calculated classical risk scores and trained our ML models on pre-specified outcomes: the main outcome (MO) which was a composite of in-hospital death or intensive care unit (ICU) transfer, stroke/TIA, and major bleeding (MB) during the admission. After eliminating trauma and non-critical patients, we obtained 2105 subjects, with 314 MO, 134 cardioembolic stroke/TIA and 227 MB. Classical risk scores (APACHE-II for MO, CHADS2 and CHA2DS2-VASc for stroke/TIA, HAS-BLED for MB) performed poorly, while ML confirmed its accuracy in predicting outcomes also in this extended cohort (AUC APACHE-II:0.6397; 95%CI:0.6064-0.6729; AUC MO-ML:0.96; 95%CI:94.6-97.2; p<0.0001; AUC CHADS2:0.5775; 95%CI:0.5332-0.6218; p<0.0001; AUC CHA2DS2-VASc:0.5793; 95%CI:0.5357-0.6228; AUC stroke/TIA-ML:0.95; 95%CI:94.3- 96.6; p<0.0001; AUC HAS-BLED:0.5089 95%CI:0.4786-0.5392; AUC MB-ML:0.973 95%CI 95.5–98.1; p<0.0001). ML models can be considered as potential candidates in this setting to guide anticoagulant therapy. Multicenter, prospective cohorts will be necessary to establish their applicability in clinical practice.

The Atrial Fibrillation In Critically Ill patients (AFICILL) studies: validation and implemetation of topological data analysis and machine learning techniques in the prediction of atrial-fibrillation related outcomes in patients admitted to medical sub-intensive care units / Guerrieri, Emanuele. - (2026 Mar 24).

The Atrial Fibrillation In Critically Ill patients (AFICILL) studies: validation and implemetation of topological data analysis and machine learning techniques in the prediction of atrial-fibrillation related outcomes in patients admitted to medical sub-intensive care units

GUERRIERI, EMANUELE
2026-03-24

Abstract

Non-valvular atrial fibrillation (NVAF) is the most common sustained arrhythmia observed in critically ill patients, linked to a higher risk of embolic and haemorrhagic events. Conventional tools, such as CHADS2, CHA2DS2-VASc, and HAS-BLED scores, are ineffective for risk stratification and do not offer guidance for anticoagulation strategies in this population. Recently, we engineered new machine-learning (ML) models retrospective cohorts, with promising results; in this work, we aim to validate our ML models in a larger cohort. We performed a retrospective analysis of all consecutive critically ill patients admitted to our step-down unit over a 10-year period who had a history of NVAF. We calculated classical risk scores and trained our ML models on pre-specified outcomes: the main outcome (MO) which was a composite of in-hospital death or intensive care unit (ICU) transfer, stroke/TIA, and major bleeding (MB) during the admission. After eliminating trauma and non-critical patients, we obtained 2105 subjects, with 314 MO, 134 cardioembolic stroke/TIA and 227 MB. Classical risk scores (APACHE-II for MO, CHADS2 and CHA2DS2-VASc for stroke/TIA, HAS-BLED for MB) performed poorly, while ML confirmed its accuracy in predicting outcomes also in this extended cohort (AUC APACHE-II:0.6397; 95%CI:0.6064-0.6729; AUC MO-ML:0.96; 95%CI:94.6-97.2; p<0.0001; AUC CHADS2:0.5775; 95%CI:0.5332-0.6218; p<0.0001; AUC CHA2DS2-VASc:0.5793; 95%CI:0.5357-0.6228; AUC stroke/TIA-ML:0.95; 95%CI:94.3- 96.6; p<0.0001; AUC HAS-BLED:0.5089 95%CI:0.4786-0.5392; AUC MB-ML:0.973 95%CI 95.5–98.1; p<0.0001). ML models can be considered as potential candidates in this setting to guide anticoagulant therapy. Multicenter, prospective cohorts will be necessary to establish their applicability in clinical practice.
24-mar-2026
La fibrillazione atriale non valvolare (NVAF) rappresenta l’aritmia sostenuta più comune nei pazienti critici. I classici score CHADS2, CHA2DS2-VASc e HAS-BLED, risultano inefficaci per la stratificazione del rischio tromboembolico ed emorragico e non forniscono indicazioni utili per le strategie di anticoagulazione in questi pazienti. Recentemente abbiamo sviluppato modelli di machine learning (ML) su coorti retrospettive con risultati promettenti; nel presente lavoro ci proponiamo di validare i modelli ML in una coorte di dimensioni maggiori. Abbiamo analizzato tutti i pazienti critici consecutivi con NVAF ricoverati nella nostra Medicina d’Urgenza in 10 anni. Sono stati calcolati gli score ed i modelli ML sono stati addestrati su outcome pre-specificati: l’outcome principale (main outcome, MO), definito come composito di morte intraospedaliera o trasferimento in unità di terapia intensiva (intensive care unit, ICU), stroke/TIA e sanguinamenti maggiori (major bleeding, MB) durante il ricovero. Escludendo i pazienti traumatizzati e non critici, sono stati arruolati 2105 soggetti, con 314 MO, 134 stroke/TIA cardioembolici e 227 MB. I classici score di rischio (APACHE-II per MO, CHADS2 e CHA2DS2-VASc per stroke/TIA, HAS-BLED per MB) hanno mostrato performance insoddisfacenti, mentre i modelli ML hanno confermato un’elevata accuratezza nella predizione degli outcome anche in questa coorte ampliata (AUC APACHE-II:0.6397; 95%CI:0.6064-0.6729; AUC MO-ML:0.96; 95%CI:94.6-97.2; p&lt;0.0001; AUC CHADS2:0.5775; 95%CI:0.5332-0.6218; p&lt;0.0001; AUC CHA2DS2-VASc:0.5793; 95%CI:0.5357-0.6228; AUC stroke/TIA-ML:0.95; 95%CI:94.3- 96.6; p&lt;0.0001; AUC HAS-BLED:0.5089 95%CI:0.4786-0.5392; AUC MB-ML:0.973 95%CI 95.5–98.1; p&lt;0.0001). I modelli ML possono essere considerati potenziali strumenti in questo contesto per guidare la terapia anticoagulante. Saranno necessari studi multicentrici e prospettici per definirne l’applicabilità nella pratica clinica.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11566/353073
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