Microcirculatory effects of heparin: Evidence for endothelial glycocalyx degradation in children and young adults.

AIMS: Heparin, a widely used anticoagulant in acute care, is known to interact with and modulate the endothelial glycocalyx (EG). This interference becomes particularly relevant in conditions such as sepsis, where microvascular dysfunction and endothelial degradation contribute substantially to organ failure. However, the immediate effects of heparin on microcirculatory parameters in humans remains insufficiently characterized. This study investigates the acute effects of heparin on microcirculation and EG integrity in-vivo using darkfield microscopic imaging.

METHOD: This pre-postinterventional study includes 34 patients (mean age 11.8 ± 10.2 years; 53% female) who underwent cardiac catheterisation receiving a standardized heparin bolus. Before and 15 min after administration of heparin we measured sublingual microcirculation and EG using the GlycoCheck® (Version 5.2) system with Sidestream Dark Field (SDF) imaging. Red blood cell flow (RBC Flow), perfused microvessel density (PVD), capillary blood volume (CBV), and perfused boundary region (PBR), a surrogate for glycocalyx integrity, were assessed.

RESULTS

Heparin administration was associated with a significant increase in PBR, indicating EG degradation and a concomitant reduction in PVD, while RBC Flow and CBV remained unchanged. These effects persisted after adjustment for systemic hemodynamic and respiratory changes and were independent of baseline hemoglobin, hematocrit and blood glucose levels.

CONCLUSION

These findings provide insights into the short-term effects of heparin on EG integrity and microcirculation and highlight potential for unintended microvascular effects of heparin. Further studies are warranted to investigate drug-induced microvascular alterations and their long-term clinical consequences.

CLINICAL TRIAL REGISTRATION: German Clinical Trials Register, DRKS00035631 https://www.drks.de/drks_web/.