Prognosis value of central venous oxygen saturation in acute decompensated heart failure

Central venous oxygen saturation (ScvO2) provides an estimation of body oxygen consumption/delivery ratio. Its use has been suggested for monitoring treatment of patients admitted for acute decompensated heart failure (ADHF) but the optimal target value has never been clearly reported.

We aimed to address the prognostic value of ScvO2 in ADHF requiring inotrope support.

ScvO2 was prospectively assessed in 60 patients with ADHF requiring inotrope support (mean age 62±16 years; 45 men; left ventricular ejection fraction 25±7%) and was compared with major adverse cardiac events (MACE), defined as heart transplantation, cardiac assistance and death.

MACE occurred in 22 (35%) patients (14 deaths; eight referred for heart transplantation or cardiac assistance). Admission ScvO2 (mean 57±13%) did not differ between patients with and without MACE. At 24 hours ScvO2 (mean 62±7%) increased only in patients without MACE (65±6% vs. 58±7%; p<0.0001) and was associated with urine output, vena cava diameter and oxygen consumption reduction. No correlation was observed between ScvO2 and cardiac output or catecholamine rate. Multivariable analysis showed that ScvO2 at 24 hours remained an independent predictor of MACE. Using the optimal cut-off of 60% derived from receiver operating characteristic curves, MACE were observed in 81% of patients (17/21) with ScvO2≤60% at 24 hours vs. 13% (5/39) with ScvO2>60% at 24 hours.

In patients admitted for ADHF requiring inotrope support, ScvO2≤60% despite optimal treatment is a marker of poor outcome and might be an indicator for considering more aggressive therapy.