Impact of a cardiothoracic ultrasound protocol in patients with ST-elevation myocardial infarction: the Focused Assessment in STEMI (FASTEMI) protocol

Abstract Background/Introduction ST-elevation myocardial infarction (STEMI) remains a condition with high mortality rates. Current prognosis is based on epidemiological and clinical characteristics, offering suboptimal accuracy. Point-of-care ultrasound (POCUS) is solidifying its role as a part of standard clinical evaluation. We hypothesized that adding a routine POCUS evaluation into STEMI initial assessment can yield crucial information, contributing to differential diagnoses, early identification of mechanical complications and prognostic predictors. Purpose The aim of this study is to evaluate the feasibility and impact of implementing a POCUS protocol in the acute management of STEMI. Methods This is a single-center prospective cohort study conducted in a tertiary care hospital. Patients with STEMI admitted to the emergency room within 12 hours of symptoms onset were screened. All enrolled patients underwent systematic POCUS evaluation performed by trained cardiology fellows at admission, including lung ultrasound (LUS), screening for mechanical complications, assesment of left and right ventricular dysfunction, measurement of left ventricular outflow tract velocity-time integral (LVOT VTI) and evaluation of inferior vena cava. Results Between June 2023 and February 2024, a total of 153 patients were screened, 11 were excluded and 9 had an alternative diagnosis. 131 patients had confirmed STEMI (Figure 1). Mean age was 63 years and 61% were male. Cardiogenic shock was present in 12% upon admission. In-hospital mortality was 11.9%. Among STEMI patients, 47 (35%) had left ventricular dysfunction, 20 (15%) right ventricular dysfunction, 1 (0.76%) ventricular septal defect and 3 (2.2%) large pericardial effusion. The mean LVOT VTI was 16.3 cm, and the median lung-positive zone was 1 (IQR 0-3). The average time required for ultrasound assessment was 5 minutes and it did not delay the median door-to-balloon time when compared to our historical cohort [50 min (IQR 35-60) vs 60 min (IQR 35-80) respectively, p = 0.01]. Notably, considering the total of 153 patients, POCUS prompted a change in diagnosis and/or in medical management in 18 cases (12%) (Table 1). An association with mortality was observed in the presence of a LVOT VTI <16.3 cm [14 (23.3%) vs 2 (2.8%) p<0.01]; >2 lung positive zones [9 (23.7%) vs 7 (7.3%) p = 0.008]; and visual left ventricular dysfunction [12 (25.5%) vs 4 (4.8%) p<0.01]. The analysis of intraclass correlation coefficients (ICC) showed excellent agreement for two key variables: 0.95 (p<0.001) for positive lung zones and 0.89 (p<0.001) for LVOT VTI. Conclusions Systematic POCUS assessment is feasible and might change diagnosis and/or medical management in 12% of patients admitted with STEMI in the emergency room. Additionally, it can potentially identify novel ultrasound prognostic predictors in these patients.Figure 1.Table 1.