Early lung ultrasound for clinical risk stratification in acute coronary syndrome: a prospective cohort study

Early identification of pulmonary congestion in acute coronary syndrome (ACS) remains challenging and is associated with adverse outcomes. Lung ultrasound (LUS) is a rapid bedside tool that may improve early clinical risk stratification. We conducted a prospective observational cohort study including 189 patients with type-1 ACS. LUS was performed within 24 h of admission; LUS positivity was defined as ≥ 3 B-lines in ≥ 2 zones per hemithorax. The number of lung segments with ≥ 3 B-lines was analyzed as a continuous variable. NT-proBNP and CA125 were also measured within 24 h of admission. The primary in-hospital outcome was acute heart failure (AHF), defined as the need for intravenous diuretics or mechanical ventilatory support. The long-term outcome was a 1-year composite of all-cause death, stroke, reinfarction, or hospitalization for heart failure. LUS positivity was present in 15.9% of patients. AHF occurred in 90% of LUS-positive patients compared with 20.8% of LUS-negative patients (p < 0.001). After multivariable adjustment, LUS positivity remained strongly associated with AHF. Each additional LUS-positive lung segment independently increased the odds of AHF (OR 1.59 per segment, 95% CI 1.29–1.97, p < 0.001). Receiver operating characteristic analysis showed good discrimination for NT-proBNP (AUC 0.84) and LUS-positive segments (AUC 0.78) in identifying AHF, while CA125 showed moderate discrimination (AUC 0.71). During 1-year follow-up, 27 patients experienced the composite endpoint. LUS positivity independently predicted the outcome (adjusted HR 8.2, 95% CI 3.1–21.6, p < 0.001), and each additional LUS-positive segment increased event risk (adjusted HR 1.4 per segment, 95% CI 1.2–1.7, p < 0.001). LUS findings provided incremental prognostic value beyond clinical variables and NT-proBNP. Early lung ultrasound provides robust and independent prognostic information in ACS for both early heart failure deterioration and 1-year outcomes. LUS, together with NT-proBNP and CA125, may improve early clinical risk stratification using a simple bedside approach.