Comparing the Activated Clotting Times Obtained From 2 Point-of-Care Devices in Patients Receiving Unfractionated Heparin During Percutaneous Coronary Intervention

To introduce the Medtronic Plus ACT device (Medtronic, Minneapolis, Minn) into practice, we compared the activated clotting times (ACTs) obtained from the Medtronic Plus ACT device with those obtained from the Hemochron 401 ACT device (International Technidyne Corp, Edison, NJ) in patients undergoing percutaneous coronary intervention. Patients undergoing cardiac catheterization who received unfractionated heparin provided blood at one or more arbitrarily selected time points during their procedure. The ACTs were obtained from the Hemochron 401 using Celite 510 tubes and simultaneously from the Medtronic Plus using either a low-range cartridge (LRC) or high-range cartridge (HRC). Data were divided into 2 groups for analysis based on which cartridge was used in the Medtronic device (ie, LRC or HRC). Linear regression lines and Bland-Altman plots were constructed comparing ACTs from the Hemochron device with those obtained from each Medtronic LRC and HRC groups. The correlation coefficients for both the HRC and LRC regression lines were R2 = 0.576 and R2 = 0.806, respectively. The Bland-Altman plots demonstrated a smaller, but more variable, bias with the HRC compared with the LRC. The ACT obtained during percutaneous coronary intervention in patients receiving unfractionated heparin is dependent on what technology is used. When laboratories introduce new technology to measure ACTs and guide therapy, proper quality assurance should be performed to minimize the risks of anticoagulation.