Abstract
Heparin is widely used in clinical practice; its effect on secondary hemostasis is well known, but its effects on primary hemostasis are controversial. The Innovance (R) Platelet Function Analyzer-200 (TM) (PFA-200) performs a group of tests that evaluate the primary hemostasis of whole blood.
It is frequently used in critically ill patients, but the effect of heparin on its results expressed as closure time is controversial. The purpose of this study was to describe whether different types and doses of heparin may influence closure time results on PFA-200 devices.
For this study, 30 patients were recruited and divided into three groups based on the type and dose of heparin being administered. The first group included ten patients who were treated with a high dose of unfractionated heparin (concentration from 3 to 4 mg/kg) before commencement of cardiopulmonary bypass during cardiac surgery.
The second group consisted of ten patients from both vascular and thoracic surgery who were administered a low dose of unfractionated heparin (concentration 1 mg/kg). The remaining ten patients from intensive care units received a prophylactic dose of low-molecular-weight heparin monitored by anti-Xa.
We compared closure times on PFA-200 devices with collagen/ADP and collagen/epinephrine cartridges before and after anticoagulant administration. The results showed that only a high dose of unfractionated heparin prolonged the collagen/ADP closure time.
The other groups failed to show any difference. We consider this finding to be important for clinicians using extracorporeal systems to differentiate primary hemostasis pathology caused by heparin or by extracorporeal devices themselves.