Noninvasive Hemodynamic Assessment of Shock Severity and Mortality Risk Prediction in the Cardiac Intensive Care Unit

Objectives: This study sought to define the 2-dimensional and Doppler echocardiographic hemodynamics associated with each Society for Cardiovascular Angiography and Interventions (SCAI) stage, and to determine their association with mortality.

Background: The SCAI shock stages classification stratifies mortality risk in cardiac intensive care unit (CICU) patients, but the echocardiographic and hemodynamic parameters that define these SCAI shock stages are unknown.

Methods: Unique CICU patients admitted from 2007 to 2015 who had a transthoracic echocardiogram within 1 day of CICU admission were included. Echocardiographic variables were evaluated as a function of SCAI shock stage. Multivariable logistic regression determined the association between echocardiographic parameters with adjusted hospital mortality.

Results: We included 5,453 patients with a median age of 69.3 years (interquartile range: 58.2 to 79.0 years) (37% women), and a median left ventricular ejection fraction (LVEF) of 50% (interquartile range: 35% to 61%). Higher SCAI shock stages were associated with lower LVEF and worse systemic hemodynamics. Hospital mortality was higher in patients with LVEF <40%, cardiac index <1.8 l/min/m², stroke volume index <35 ml/m², cardiac power output <0.6 W, or medial early mitral valve inflow velocity to early diastolic annular velocity (E/e') ratio >15 (particularly in SCAI shock Stages A to C). After multivariable adjustment, only stroke volume index <35 ml/m² (adjusted odds ratio: 2.0; 95% confidence interval: 1.4 to 3.0; p < 0.001) and E/e' ratio >15 (adjusted odds ratio: 1.52; 95% confidence interval: 1.04 to 2.23; p = 0.03) remained associated with higher hospital mortality.

Conclusions: Noninvasive 2-dimensional and Doppler echocardiographic parameters correlate with the SCAI shock stages and improve risk stratification for hospital mortality in CICU patients. Low stroke volume index and high E/e' ratio demonstrated the strongest association with hospital mortality.