Lupus Anticoagulant and Cardiopulmonary Bypass

Pleiotropic Effects of Heparin and its Monitoring in the Clinical Practice

“…The median ACT and heparin anti-Xa level at the end of CPB prior to protamine sulfate administration were 630 seconds (540-910) and 4.5 IU/mL (range: 4.0-6.2), respectively. 87 None of the patients had significant bleeding requiring transfusion, or thrombosis within 30 days. 87 Although monitoring the inhibition of FXa by heparin is considered the gold standard for measuring the anticoagulant effect of UFH, many hospital laboratories are not able to provide the heparin activity, as measured by the anti-Xa level, in a timely manner for patients undergoing CPB, making it challenging to use in routine clinical practice.…”

“…86 These effects are even more prominent in patients with LA in whom baseline ACT is affected by the presence of LA. 87 We previously assessed the correlation between ACT and heparin anti-Xa level in a single-center cohort study of 19 patients with LA with or without APS undergoing CPB. It was found that the correlation between heparin anti-Xa level and the ACT was poor (r ¼ 0.16, p ¼ 0.46).…”

“…87 Although monitoring the inhibition of FXa by heparin is considered the gold standard for measuring the anticoagulant effect of UFH, many hospital laboratories are not able to provide the heparin activity, as measured by the anti-Xa level, in a timely manner for patients undergoing CPB, making it challenging to use in routine clinical practice. 87 A heparin anti-Xa level >4.0 IU/mL is required during CPB. 85 However, the standard heparin anti-Xa assays become nonlinear at levels above 1.5 to 2.0 IU/mL, and some manufacturer(s) instructions prohibit diluting the specimen.…”

“…Nevertheless, serial dilutions of the sample in pooled normal plasma are required to obtain accurate levels above 2 IU/mL. 87 A point-of-care device is available to estimate the free plasma heparin level in whole blood (The Hepcon Hemostasis Management System [Hepcon HMS; Medtronic, Minneapolis, MN]), 88,89 which is shown to correlate well with heparin anti-Xa during CPB in some studies. [90][91][92] However, the role of this device in patients with LA has not been evaluated.…”

“…Maintaining an ACT level that is twice the normal range, adjusting ACT range for CPB based on baseline ACT, or creating a patient-specific ACT titration curve is also used in clinical practice. 87…”