Jf. Thompson et al., INTRAOPERATIVE HEPARINIZATION, BLOOD-LOSS AND MYOCARDIAL-INFARCTION DURING AORTIC-ANEURYSM SURGERY - A JOINT VASCULAR RESEARCH GROUP-STUDY, European journal of vascular and endovascular surgery, 12(1), 1996, pp. 86-90
Objectives: The primary aim of this prospective multi-centre study inv
olving patients undergoing elective abdominal aortic aneurysm (AAA) su
rgery was to investigate the relationship between intraoperative intra
venous heparinisation, blood loss during surgery and thrombotic compli
cations. Methods: Two hundred and eighty-four patients were randomised
to receive intravenous heparin (n = 145) or no heparin (n = 139). Gro
ups were evenly matched for age, sex, weight, aneurysm size, haemoglob
in concentration, platelet counts and distal occlusive disease measure
d by ankle/brachial systolic pressure. Results: There were no statisti
cally significant differences in blood loss (median 1400 ml vs. 1500 m
l; z = 0.02, p = 0.98, 95% C.I. = -200 to 200), blood transfused (4.0
units vs. 4.0 units; z = 1.09, p = 0.28, 95% C.I. = -1 to 0) or distal
thrombosis between the two groups. However, analysis of the clinical
outcome revealed that 5.7% of the non-heparin group but only 1.4% of t
he heparinised patients suffered a fatal perioperative myocardial infa
rction (MI); p < 0.05. All MI, including non fatal events, affected 8.
5% and 2% respectively (p = 0.02). Conclusions: Heparin does not incre
ase blood loss or the need for blood transfusion during surgery. Hepar
in is not necessary to prevent distal thrombosis when the aorta is cro
ss clamped. The results of the study are consistent with the known mec
hanisms leading to intraoperative MI and strategies for its prevention
. Intravenous heparin, given before aortic cross clamping, is an impor
tant prophylaxic against perioperative MI in relation to AAA surgery.