Hyperviscosity of the blood and haemostasis in the newborn infant

Area of Science:

• Neonatal Medicine
• Hematology
• Pediatric Coagulation

Background:

• Neonatal polycythaemia can lead to hyperviscosity syndrome, increasing the risk of thromboembolic events.
• The coagulation and fibrinolytic status in infants with hyperviscosity syndrome requires further elucidation.

Purpose of the Study:

• To investigate the coagulation and fibrinolytic systems in newborn infants diagnosed with hyperviscosity syndrome.
• To identify potential hemostatic abnormalities contributing to thrombotic complications in this population.

Main Methods:

• Analysis of coagulation parameters and fibrinolytic activity in 15 newborn infants with central haematocrit ≥65% and elevated blood viscosity.
• Assessment included platelet counts, ethanol gelation tests for fibrin/fibrinogen degradation products (FDP), and plasma fibrinolytic activity assays.
• Evaluation of antithrombin III (heparin cofactor activity) levels.

Main Results:

• No significant defects were found in the coagulation system of the infants.
• Most patients exhibited no demonstrable abnormal proteolysis in circulation; FDP were detected in only two infants.
• Low antithrombin III levels were noted, potentially exacerbated by impaired microcirculation.

Conclusions:

• Newborns with hyperviscosity syndrome due to polycythaemia do not typically present with overt coagulation or fibrinolysis activation.
• Reduced antithrombin III levels, coupled with microcirculatory impairment, may elevate the risk of thrombotic complications.
• Haemodilution, preferably with plasma, is recommended for symptomatic infants to mitigate thrombotic risks.