Failure of low-dose heparin to prevent significant thromboembolic complications in high-risk surgical patients: interim report of prospective trial. Groote Schuur Hospital Thromboembolus Study Group.Br Med J 1979; 1 doi: http://dx.doi.org/10.1136/bmj.1.6176.1447 (Published 02 June 1979) Cite this as: Br Med J 1979;1:1447
The efficacy of low-dose subcutaneous heparin (5000 IU eight-hourly) is being studied in a single-centre, prospective randomised trial of patients aged over 40 submitted to major elective intra-abdominal surgery. The trial end-points are the objectively defined incidence and extent of deep vein thrombosis (as seen on uptake of 125I-labelled fibrinogen, Doppler ultrasonography, and bilateral ascending phlebography) and non-fatal pulmonary embolus (as measured by preoperative spirometry and preoperative and postoperative chest radiography and perfusion lung scanning performed on a routine, unselected basis). An interim analysis of the first 200 patients indicates that low-dose heparin significantly reduces the incidence of calf-vein thrombosis but does not reduce the incidence of proximal segment thrombosis or non-fatal pulmonary embolism. Thus the routine use of low-dose heparin prophylaxis in all major surgical procedures in patients aged over 40 may not be advisable.