Letter to the editor

Editor, – I refer to G. Weisz' recent letter 'Economy class syndrome' (Aust Prescr 2001;24:52). My understanding is that a recent meta-analysis demonstrated no value in the use of aspirin for venous thromboembolism as prophylaxis and treatment, and a reported 3% chance of some degree of gastrointestinal bleeding. It would seem that the use of this drug is best left to the management of arterial problems. Recommendation as a therapy for prevention of deep vein thrombosis is not supported by the Australian Medicines Handbook ('Aspirin is probably ineffective in the prevention of venous thromboembolism'), and in view of the incidence of adverse effects I would not advise its use for this purpose.

I would be interested to learn of any studies which support the view that there is a place for aspirin in this setting, or indeed in any situation with a recognised risk of venous thrombosis.

Ashley Collard
General Practitioner
Fairlight, NSW

The Editorial Executive Committee welcomes letters, which should be less than 250 words. Before a decision to publish is made, letters which refer to a published article may be sent to the author for a response. Any letter may be sent to an expert for comment. When letters are published, they are usually accompanied in the same issue by their responses or comments. The Committee screens out discourteous, inaccurate or libellous statements. The letters are sub-edited before publication. Authors are required to declare any conflicts of interest. The Committee's decision on publication is final.

Comments

Agnes Vitry, Senior Editor, Australian Medicines Handbook, comments:

A recent editorial in the Medical Journal of Australia concluded that the evidence on the risk of venous thromboembolism associated with air travel was, as yet, missing.1 Most of the evidence comes from case series and two conflicting prospective case-control studies.2,3 Given the current uncertainty about possible increased risk, it seems common sense and harmless to give the usual advice about regular foot exercises, generous fluid intake and avoiding excessive alcohol. A recent randomised trial showed that compression stockings may prevent symptomless deep venous thrombosis but may cause superficial thrombophlebitis in varicose veins.4

The second edition of the Australian Medicines Handbook did not recommend the use of aspirin for prevention of venous thromboembolism on the basis of a meta-analysis, which suggested aspirin provided relatively little protection for postoperative patients compared to heparins or oral anticoagulants.5 A recent large trial showed that aspirin (160 mg daily, started before surgery and continued for five weeks) slightly reduced the risk of pulmonary embolism and deep venous thrombosis, but not the overall mortality in patients with hip fracture.6 Results of this trial are difficult to interpret, as only some of the patients received additional prophylaxis with heparin or low molecular weight heparins, and also as aspirin has not been directly compared with these first-line treatments.

Low-dose aspirin may be used in addition to first-line treatments in patients with hip fracture at low risk of bleeding. At present, low-dose aspirin cannot be recommended for the prevention of venous thromboembolism in other situations.

References

  1. Gallus AS, Baker RI. Economy class syndrome. Med J Aust 2001;174:264-5.
  2. Ferrari E, Chevallier T, Chapelier A, Baudouy M. Travel as a risk factor for venous thromboembolic disease: a case-control study. Chest 1999;115:440-4.
  3. Kraaijenhagen RA, Haverkamp D, Koopman MM, Prandoni P, Piovella F, Buller HR. Travel and risk of venous thrombosis. Lancet 2000;356:1492-3.
  4. Scurr JH, Machin SJ, Bailey-King S, Mackie IJ, McDonald S, Smith PD. Frequency and prevention of symptomless deep-vein thrombosis in long-haul flights: a randomised trial. Lancet 2001;357:1485-9.
  5. Collaborative overview of randomised trials of antiplatelet therapy - III: Reduction in venous thrombosis and pulmonary embolism by antiplatelet prophylaxis among surgical and medical patients. Antiplatelet Trialists' Collaboration. Br Med J 1994;308:235-46.
  6. Prevention of pulmonary embolism and deep vein thrombosis with low dose aspirin: Pulmonary Embolism Prevention (PEP) trial. Lancet 2000;355:1295-302.