title: Protamine reduces whole blood platelet aggregation after cardiopulmonary bypass.
abstract: OBJECTIVE
  Platelet dysfunction is an important cause of postoperative bleeding after cardiac surgery. Protamine is routinely used for reversal of heparin after cardiopulmonary bypass (CBP), but may affect platelet aggregation. We assessed changes in platelet function in relation to protamine administration.
  
  
  METHODS
  Platelet aggregation was analyzed by impedance aggregometry before and after protamine administration in 25 adult cardiac surgery patients. Aggregation was also studied after in vitro addition of heparin and protamine. The activators adenosine diphosphate (ADP), thrombin receptor activating peptide-6 (TRAP), arachidonic acid (AA) and collagen (COL) were used.
  
  
  RESULTS
  Platelet aggregation was reduced by approximately 50% after in vivo protamine administration; ADP 640 ± 230 (AU*min, mean ± SD) to 250 ± 160, TRAP 939 ± 293 to 472 ± 260, AA 307 ± 238 to 159 ± 143 and COL 1022 ± 350 to 506 ± 238 (all p < 0.001). Aggregation was also reduced after in vitro addition of protamine alone with activators ADP from 518 ± 173 to 384 ± 157 AU*min p < 0.001, and AA 449 ± 311 to 340 ± 285 (p < 0.01) and protamine combined with heparin (1:1 ratio) with activators ADP to 349 ± 160 and AA to 308 ± 260 (both p < 0.001); and COL from 586 ± 180 to 455 ± 172 (p < 0.05).
  
  
  CONCLUSIONS
  Protamine given after CPB markedly reduces platelet aggregation. Protamine added in vitro also reduces platelet aggregation, by itself or in combination with heparin.
authors.affiliation: a Department of Health Science , Blekinge Institute of Technology , Karlskrona , Sweden.|b Department of Cardiothoracic Anesthesiology and Intensive Care.
authors.forename: Anki
authors.initials: A
authors.lastname: Olsson
authors.affiliation: c Department of Cardiology.
authors.forename: Joakim
authors.initials: J
authors.lastname: Alfredsson
authors.affiliation: b Department of Cardiothoracic Anesthesiology and Intensive Care.
authors.forename: Erik
authors.initials: E
authors.lastname: Håkansson
authors.affiliation: d Department Cardiothoracic Surgery.|e Department of Medicine and Health Sciences , Linköping University, County Council of Östergötland , Linköping , Sweden.
authors.forename: Rolf
authors.initials: R
authors.lastname: Svedjeholm
authors.affiliation: a Department of Health Science , Blekinge Institute of Technology , Karlskrona , Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Berglund
authors.affiliation: b Department of Cardiothoracic Anesthesiology and Intensive Care.
authors.forename: Sören
authors.initials: S
authors.lastname: Berg
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D015536:Down-Regulation; D005260:Female; D006493:Heparin / Q000009:adverse effects; D006494:Heparin Antagonists / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D010974:Platelet Aggregation / Q000187:drug effects*; D010979:Platelet Function Tests; D019106:Postoperative Hemorrhage / Q000097:blood / Q000139:chemically induced; D011479:Protamines / Q000008:administration & dosage / Q000009:adverse effects*; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants; D006494:Heparin Antagonists; D011479:Protamines; D006493:Heparin
keywords: Cardiopulmonary bypass; platelet aggregation; platelet function tests; protamine