Echocardiographic Factors Associated with Prolonged Duration of Inotrope Therapy and ICU Length of Stay in a Retrospective Study of Cardiac Surgery Patients

Introduction: Post-operative heart failure following cardiac surgery carries risk and can impact patient outcomes. Preoperative echocardiography can be useful for stratifying risk. Although there has been a historical focus on left ventricular ejection fraction (LVEF), the importance of left ventricular (LV) size, as measured by left ventricle end-diastolic diameter (LVEDD), may be an underappreciated echocardiographic factor which can help predict risk in patients undergoing cardiac surgery. Aim of the study: To investigate the association between LVEF and LVEDD with inotrope use, inotrope duration, and intensive care unit (ICU) length of stay (LOS) in patients undergoing cardiac surgery. Materials and methods: Retrospective cohort study including 2,965 adult patients undergoing non-emergent cardiac surgery at a single academic institution between February 2017 and October 2021. Primary outcomes were the use of inotropes and duration of inotrope therapy. The secondary outcome was ICU LOS. Results: In adjusted analyses, a one standard deviation increase in LVEF was associated with decreased odds of inotrope initiation (OR 0.45, 95% CI: 0.41 to 0.50; P < 0.001), while a one standard deviation increase in LVEDD was associated with increased odds of receiving inotropes (OR 1.18, 95% CI: 1.07 to 1.31; P = 0.001). Among those receiving inotropes, a one standard deviation increase in LVEF was associated with a 25% decrease in inotrope hours in adjusted analyses (0.75, 95% CI: 0.68 to 0.82; P < 0.001). An interaction was observed such that LVEDD modified the association between LVEF and ICU LOS (0.98, 95% CI: 0.95 to 0.99; P = 0.03). Conclusions: Preoperative LVEDD, particularly when combined with LVEF, can predict risk after cardiac surgery.