Heparinization in aortic surgery

A prospective study was conducted on 35 patients (25 males and 10 females) undergoing elective reconstructive aortic surgery to examine the heparin activity after a bolus dose of sodium heparin (100 U/kg) given five minutes prior to aortic cross clamping. Recording of heparin activity were made 15 minutes later, on release of the aortic clamp, at abdominal wound closure and hourly thereafter until minimal activity was reached. In 10 patients, protamine was used to reverse anticoagulation. These results were related to clinical parameters of age, renal function, plasma cholesterol, blood pressure, position of the aortic clamp and blood loss. High peak levels of heparin activity were more likely in patients with impaired renal function or high plasma cholesterol concentrations. Heparin activity was prolonged at therapeutic levels in patients with renal impairment, and in this group of patients the use of protamine was significantly increased as was the requirement for blood replacement.