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

Abstract

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.