Evaluation of effect and distribution of heparin administered in vascular reconstructive surgery

The aim of this study was to find out whether intravenously administered heparin is distributed equally not only proximal but also distal to the arterial occlusion level in vascular reconstructive surgery.

Ten consecutive patients (7 men and 3 women) with an average age of 69.9 years (range, 51 to 76 years) who underwent graft replacement for aortic abdominal aneurysm from April to December 1994 were studied. Mean aortic clamp time was 76 minutes. Heparin sodium (100 U/kg) was administered intravenously to keep activated clotting time (ACT) over 250 secs and was neutralized by protamine sulfate (1 mg/kg) just after reperfusion. ACT, blood lactate and CPK-MM in the brachial and dorsal pedis artery were measured before heparin administration (control), just after arterial occlusion, just before reperfusion and 10 minutes after protamine administration.

ACT was significantly prolonged after arterial occlusion and recovered after protamine administration with no significant differences between proximal and distal values at each point. Lactate showed significant increase after arterial occlusion which was more remarkable distally. CPK-MM was all the way within the normal range.

In vascular reconstructive surgery which requires temporary arterial occlusion for as long as 80 minutes, the effect of heparin is excellent and equal throughout the body by collateral vessels, and the metabolic influence due to blockade of the blood flow is not so critical as to lead to cellular damage although anaerobic glycolysis is promoted distally due to hypoxia.