Left ventricular outflow tract velocity time integral correlates with low cardiac output syndrome in patients with acute decompensated heart failure

Purpose: Left ventricular outflow tract velocity time integral (LVOT VTI) is a simple method by Doppler echocardiography to calculate left ventricular stroke volume. In ESC guidelines, LVOT VTI<15cm is defined as an abnormality suggesting reduced left ventricular stroke volume, however it is unknown whether it correlates with low cardiac output syndrome (LOS) or not. The aim of this study is to elucidate the usefulness of LVOT VTI when diagnosing LOS and to decide the optimal cut-off value for inotrope administration in acute decompensated heart failure (ADHF). Methods: A total of 212 patients admitted for ADHF were divided into two groups according to LVOT VTI. Clinical characteristics were compared between High-VTI (VTI≥15cm, n=99) and Low-VTI (VTI<15cm, n=113). Results: Low-VTI showed younger age (p=0.0001), lower systolic blood pressure (p=0.005), faster HR (p=0.0004), higher plasma BNP levels (p=0.0134), lower %FS (16.1 vs. 23.6%, p<0.0001), compared with High-VTI. Low-VTI showed higher prevalence of inotrope administration (37.2 vs. 14.1%, p=0.0002) and LOS signs, such as pulsus alternans (17.7 vs. 8.1%, p=0.0006), cool extremities (26.6 vs. 9.1%, p=0.0012) and proportional pulse pressure<25% (17.7 vs. 8.1%, p=0.0436). There was no difference in in-hospital and 3-year mortality between two groups. In ROC curve analysis, the optimal cut-off value of LVOT VTI for prediction of LOS signs and inotrope administration were 13.9cm (sensitivity 0.68; specificity 0.69; AUC 0.72) and 12.3cm (sensitivity 0.68; specificity 0.81; AUC 0.76), respectively. Conclusions: Low-VTI was associated with the presence of LOS signs and requirement of inotrope administration in patients with ADHF, suggesting importance of LVOT VTI measurements to assess LOS in ADHF.