Off-pump coronary artery bypass grafting using continuous heparin infusion

Levels of anticoagulation during off-pump coronary artery bypass grafting (OPCAB) remain controversial. Prolonged activated clotting time (ACT) during OPCAB increases blood loss during surgery and can also cause paradoxical increase in postoperative myocardial infarction. Shorter ACT can increase thrombotic complication. Maintaining a steady ACT level is challenging. We have used continuous heparin infusion after initial bolus during OPCAB to maintain a steady low target ACT. The objective of the present study was to assess the effectiveness and safety of heparin infusion in maintaining a steady target ACT level.

This was a prospective study of consecutive OPCAB patients. ACT was measured after initial bolus dose of heparin. Once ACT of more than 200seconds was achieved, heparin infusion was started to maintain the required level of anticoagulation. CPK-MB was measured in operation room, 6 and 24hours postoperatively to rule out ischemic complication.

ACT could be maintained in target range with heparin infusion in 80.1% patients (161/201). Of the 40 patients with one or more ACT reading less than 200seconds, 38 patients were managed by increasing the dose of heparin infusion and only 2 patients required additional bolus dose of heparin.

Heparin infusion maintains a steady target ACT level and avoids peaks and troughs associated with bolus doses. Lower level of anticoagulation using continuous heparin infusion does not increase ischemic complications. This is the first ever study of use of heparin infusion during OPCAB. We may conclude that heparin infusion is a safe anticoagulation strategy for OPCAB.