Clinical, respiratory, haemodynamic, and metabolic determinants of lactate in heart failure

Lactate is an end-product of anaerobic cell metabolism. Although it is believed to have prognostic significance in heart failure (HF), data on the pathomechanisms that lead to lactate accumulation are scarce.

We aimed to determine the clinical, respiratory, biochemical, and haemodynamic correlates of lactate in HF.

Patients diagnosed with HF hospitalised in a single cardiac centre, who underwent haemodynamic monitoring, were included in this retrospective analysis.

The population consisted of 93 patients (44 acute HF [AHF] and 49 chronic HF [CHF] cases). The mean age, left ventricular ejection fraction, and lactate level were 60 ± 13 years, 33% ± 17%, 1.4 ± 0.9 mmol/L, respectively. The mean cardiac index (CI), right atrial pressure (RAP) and pulmonary capillary wedge pressure (PCWP) were 2.2 ± 0.5 L/min/m², 8.7 ± 6 mmHg, and 18 ± 6 mmHg, respectively. AHF patients had significantly higher RAP, heart rate (HR), and levels of N-terminal pro-B-type natriuretic peptide and creatinine, compared to the CHF group. Both HR and natriuretic peptide level were correlated with lactate. Among haemodynamic indices, lactate correlated with CI (r = -0.25, p = 0.01). We found no correlation between lactate and RAP (p > 0.05) or PCWP (p > 0.05). There was no relationship between lactate and peripheral blood gases. Lactate was strongly correlated with mixed venous oxygen saturation (svO2) (r = -0.61, p < 0.05). HR, svO2, and systemic vascular resistance (SVR) were found to be independent determinants of lactate.

Lactate accumulation in HF is not a result of respiratory disturbances or hypoxaemia. Among haemodynamic indices, CI is correlated with lactate. The strongest determinants of lactate included svO2, SVR, and HR.