Relationship between the sublingual microcirculation and lactate levels in patients with heart failure

Introduction

Treatment of patients with severe heart failure aims at normalizing hemodynamic and metabolic parameters. We tested whether the sublingual functional capillary density (FCD), an indicator of tissue perfusion at the microvascular level, correlates with lactate levels in heart failure patients.

Methods

We investigated 12 heart failure patients, treated with inotropes, within 24 hours after hospital admission. Sidestream dark-field imaging was used to investigate the sublingual microcirculation. At least three video sequences of the microcirculation were recorded and analyzed. Microscan Analysis Software was used to measure the FCD, where the FCD was determined as the total length of perfused capillaries per field of view. Capillaries were defined as microvessels with a diameter <25 μm.

Results

The mean arterial pressure was 75 (68–78) mmHg, lactate levels were 1.2 (1.0–1.7) mmol/l and SvO₂ was 0.78 (0.65–0.84) mol/mol. The FCD was 11.7 (10.1–12.2) μm^-1. The correlation between lactate and FCD is shown in Figure 1 (regression line: β₁ = -0.88, P = 0.05).

Figure 1

Conclusion

In this study, FCD correlated with lactate levels. This finding is indicative for a relationship between global hemodynamics and the sublingual microcirculation in patients treated for heart failure. Based on the interim results, more patients will be included in this study for final analysis and conclusions.