Echocardiographic assessment of left ventricular longitudinal function in critically ill patients

In the intensive care unit (ICU), conventional assessment of left ventricular systolic function relies on left ventricular ejection fraction (LVEF), but LVEF often has limited prognostic ability. Measures of longitudinal LV performance [global longitudinal strain (GLS), mitral annular plane systolic excursion (MAPSE), and tissue Doppler-derived systolic velocity (S')] are increasingly used in critical care echocardiography and may capture clinically relevant dysfunction better than LVEF. To date, the prognostic implications of GLS, MAPSE, and S' have been studied mainly in septic cohorts, while their feasibility and prognostic value in mixed ICU populations remain uncertain. We therefore aimed to evaluate the feasibility and prognostic value of these parameters in a mixed ICU cohort.

In this exploratory secondary analysis of a prospective observational ICU cohort, transthoracic echocardiography was performed within 24 hours of ICU admission. LVEF by Simpson biplane, GLS, MAPSE, and S' were analysed offline. Feasibility was quantified as the proportion of patients with analysable measurements. Associations between echocardiographic parameters were assessed using simple linear regression and are reported as coefficients of determination (R²). Associations with 90-day mortality were assessed using logistic regression, with adjustment for age, Simplified Acute Physiology Score 3, and cardiac index.

Of 411 enrolled patients, 377 had at least one parameter available and were included. Feasibility was 71% for LVEF, 65% for GLS, 90% for MAPSE, and 83% for S'. GLS correlated most strongly with LVEF (R²=0.516), whereas correlations were weaker for MAPSE (R²=0.268) and S' (R²=0.195). Ninety-day mortality was 27% (101/377). After adjustment, GLS (odds ratio [OR] 1.08 per 1% less negative strain, 95% confidence interval [CI] 1.00-1.16; p=0.048) and MAPSE (OR 1.17 per 1 mm decrease, 95% CI 1.06-1.30; p=0.002) remained associated with mortality, whereas LVEF and S' did not. MAPSE ≤10 mm was independently associated with mortality (adjusted OR 2.48, 95% CI 1.31-4.71; p=0.005).

In a mixed ICU cohort, impaired MAPSE and GLS were associated with increased mortality, in contrast to LVEF and S'. MAPSE was also the most feasible measurement. Incorporation of MAPSE into routine ICU echocardiography may improve detection and risk stratification of LV dysfunction in critical illness.

Secondary analysis of data from a single-centre prospective observational study focused on systolic dysfunction in ICU patients (Clinical Trials ID: NCT03787810).