Left ventricular-arterial coupling and mortality in the cardiac intensive care unit.

Abstract

Background: Left ventricular (LV) ventricular-arterial coupling (VAC) refers to the ratio of afterload (effective arterial elastance) to contractility (end-systolic elastance) as an integrated marker of cardiac performance. We sought to determine whether the echocardiographic VAC ratio, defined using the ratio of LV end-systolic volume (LVESV) to stroke volume (SV), predicted mortality in the cardiac intensive care unit (CICU).

Methods: Mayo Clinic CICU patients from 2007 and 2018 were included. VAC ratio was calculated as the Teichholz LVESV divided by the SV calculated from LV outflow tract Doppler. The primary outcome was in-hospital mortality and the secondary outcome was all-cause one-year mortality.

Results: A total of 4685 patients were included with a median age of 69 (58, 79) years (37.2% females), with acute coronary syndrome in 54.9% and heart failure in 49.0%. A higher VAC ratio was associated with greater severity of illness, worse echocardiographic findings, and more use of critical care therapies. A total of 329 (7%) patients died during hospitalization. Patients with a higher VAC ratio had higher in-hospital mortality overall and in each admission diagnosis subgroup. After multivariable adjustment, patients with a VAC ratio >2 were at higher risk of in-hospital mortality (adjusted OR 1.63, 95% CI 1.17-2.28, p=0.010). One-year mortality was higher for patients with a higher VAC ratio, especially VAC >2.

Conclusion: Ventricular-arterial uncoupling was associated with worse outcomes in an unselected CICU cohort. The echocardiographic VAC ratio is a simple non-invasive bedside measure that can be used for risk prediction in the CICU.