title: Monitoring activated clotting time for combined heparin and aprotinin application: an in vitro evaluation of a new aprotinin-insensitive test using SONOCLOT.
abstract: The kaolin-based activated clotting time (ACT) is commonly used for monitoring heparin-induced anticoagulation alone and combined with aprotinin during cardiopulmonary bypass. However, aprotinin prolongs ACT measurements. Recently, a new so-called 'aprotinin-insensitive' ACT test (SaiACT) has been developed for the SONOCLOT analyzer. In this study we evaluated and compared this new test for the SONOCLOT analyzer in vitro with an established kaolin-based ACT from HEMOCHRON (HkACT). Twenty-five patients undergoing elective valve surgery donated 80 mL of blood after induction of anesthesia. The blood was withdrawn in citrated tubes and processed to analyze effects of heparin (0, 1, 2, and 3 U x mL(-1)), aprotinin (0, 200 kIU x mL(-1)), and 25% hemodilution with calcium-free lactated Ringer's solution on ACT measurements. A total of 400 blood samples were analyzed and ACT was measured in a wide, clinically relevant range in duplicate with SaiACT and HkACT. Addition of aprotinin to heparinized blood samples induced no significant changes of SaiACT measurements. By contrast, HkACT readings increased significantly: aprotinin prolonged HkACT in heparinized blood samples by 20% +/- 37% (2 U x mL(-1)) and 24% +/- 18% (3 U x mL(-1)), respectively, and in vitro hemodilution increased this effect.
  
  
  CONCLUSIONS
  Current standard techniques to measure heparin-induced anticoagulation during cardiopulmonary bypass are affected by aprotinin, a drug widely used in this setting. The aim of this study was to investigate in vitro a new, so-called 'aprotinin-insensitive' test from SONOCLOT to measure heparin-induced anticoagulation more reliably in combination with aprotinin.
authors.affiliation: *Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA; †Institute of Anesthesiology and Intensive Care Medicine and ‡Division of Cardiac Surgery, Triemli City Hospital, Zurich, Switzerland; and §Department of Psychosocial Medicine, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Ganter
authors.forename: Seraina
authors.initials: S
authors.lastname: Dalbert
authors.forename: Kirk
authors.initials: K
authors.lastname: Graves
authors.forename: Richard
authors.initials: R
authors.lastname: Klaghofer
authors.forename: Andreas
authors.initials: A
authors.lastname: Zollinger
authors.forename: Christoph K
authors.initials: CK
authors.lastname: Hofer
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage* / Q000627:therapeutic use*; D007611:Aprotinin / Q000008:administration & dosage* / Q000627:therapeutic use*; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D005260:Female; D019918:Heart Valve Prosthesis Implantation; D006438:Hemodilution; D006490:Hemostatics / Q000008:administration & dosage* / Q000627:therapeutic use*; D006493:Heparin / Q000008:administration & dosage* / Q000627:therapeutic use*; D006801:Humans; D007616:Kaolin; D008297:Male; D008875:Middle Aged; D014465:Ultrasonics; D014914:Whole Blood Coagulation Time
chemical_list: D000925:Anticoagulants; D006490:Hemostatics; D007616:Kaolin; D006493:Heparin; D007611:Aprotinin