Prevention of deep leg vein thrombosis

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Editor, – I refer to the article 'Prevention of deep leg vein thrombosis'(Aust Prescr1998;21:37-9). The article puts the problems of deep vein thrombosis and pulmonary embolism into reasonable perspective, but one important aspect of this potentially lethal complication has been left out.

Many years ago, when taking part in a symposium on this subject at St. George Hospital, I surveyed the admissions to St. George Hospital with deep vein thrombosis/pulmonary embolism. The exact figures escape me now, but one surprising finding was that a number of patients admitted with this complication merely had mild flu, common colds, etc., and had been put to bed by their local general practitioner. It seems that prevention should be thought of when patients become ill in their own home but do not require admission to hospital. It would depend on the illness and the risk factors, but precautions could range from advice not to lie or sit around all day doing nothing, to low-dose aspirin (although this has not been found to be of significant help, certainly in postoperative situations),to graded pressure stockings and even once-daily low molecular weight heparin in the high-risk patient.

K.B. Orr
Kogarah, N.S.W.

Dr A. Gallus, the author of the article, comments:
The important question of deep vein thrombosis and its prevention in medical patients has received far too little attention.

In hospital-based surveys of pulmonary embolism, most pulmonary emboli arise in medical patients, not surgical patients. The attention paid to surgical prevention can be explained by the fact that surgery is a recognisable trigger and that prophylactic protocols can be built around this.

Deep vein thrombosis and pulmonary embolism in medical patients, in hospital or at home, are far more difficult issues. Incidence, risk factors and the effectiveness and cost-effectiveness of preventive measures have been so little studied that there are no good answers to the questions asked by Dr Orr. Nevertheless, his point is valid. At least as much attention should be given to deep vein thrombosis prevention in medical patients as in surgical practice, and medical admissions need great care with risk factor assessment. What studies are available suggest that the methods known to work in surgery (standard heparin, low molecular weight heparin, venous flow acceleration) are also effective in medical patients.