Coagulation disorders caused by hydroxyethyl starch

Area of Science:

• Biochemistry
• Pharmacology
• Clinical Medicine

Background:

• Hydroxyethyl starch (HES) characterization traditionally focused on in vitro molecular weight (MW), neglecting in vivo degradation.
• In vivo HES metabolism is influenced by the degree of substitution and substitution patterns (C2/C6 ratio).

Purpose of the Study:

• To investigate the relationship between HES characteristics, in vivo degradation, and clinical effects, particularly on coagulation factors.
• To highlight the importance of in vivo MW for predicting HES efficacy and safety.

Main Methods:

• Analysis of HES degradation based on degree of substitution and C2/C6 hydroxyethylation ratio.
• Observation of factor VIII/von Willebrand factor levels during HES infusion therapy.
• Comparison of different HES formulations (HES 200, HES 70, HES 480) and their metabolic profiles.

Main Results:

• Higher degree of substitution and higher C2/C6 ratio lead to slower HES degradation and higher in vivo MW.
• A 10-day infusion of a difficult-to-metabolize HES 200 resulted in an 80% drop in factor VIII/von Willebrand factor.
• Easily degraded HES 200 and low-MW HES 70 did not cause significant declines in factor VIII/von Willebrand factor.

Conclusions:

• In vivo MW, influenced by substitution patterns, is a critical determinant of HES's duration of action and impact on coagulation.
• High in vivo MW HES can lead to acquired von Willebrand syndrome and hemorrhagic complications.
• Future characterization of HES should prioritize in vivo MW over in vitro MW for accurate clinical assessment.