PERI-OPERATIVE USE OF OESTROGEN CONTAINING MEDICATIONS AND DEEP-VEIN THROMBOSIS – A NATIONAL SURVEY

Abstract

Introduction: Large numbers of women are taking hormone replacement therapy (HRT) or an oestrogen containing contraceptive pill. They are being advised that these medications can increase their risk of developing deep vein thrombosis (DVT) and there has been considerable recent publicity.

Aim: To determine the practice of New Zealand orthopaedic surgeons when women taking such medications present for major surgery.

Method: A postal survey was sent to all New Zealand orthopaedic surgeons. The current practice was compared with recently revised national guidelines and manufacturers advice.

Results: The response rate was 80% (118/148). There was wide variation in the beliefs surrounding the peri-operative use of both of these medications. Of the surgeons who replied, 44% indicated that they would routinely advise discontinuing the combined oral contraceptive pill peri-operatively for major surgery, 24% indicated that they would routinely advise discontinuing HRT peri-operatively. The mean duration that surgeons would discontinue the medication pre-operatively was 13 days for the contraceptive pill and nine days for HRT. The mean time for re-starting medication post-operatively was 18 days for the contraceptive pill and 13 days for HRT.

Recently released New Zealand guidelines recommend that HRT should be stopped for at least 30 days prior to elective surgery and withheld for 90 days following surgery. Less than 3% of surgeons appeared to be routinely following this recommendation. Most manufacturers of combined oral contraceptive pills recommend stopping the medication for at least four weeks prior to elective surgery. Only 25% of surgeons routinely practice in accordance with these recommendations.

Discussion: This survey demonstrated substantial differences between actual clinical practice, recently revised national guidelines and manufacturers’ advice. These differences need to be brought to the attention of surgeons and guideline producers alike. A review of international literature and recommendations revealed that these guidelines are very conservative and that strong evidence for them is lacking. Issues to be considered include the practicalities of implementing such recommendations; the associated risks of discontinuing medication; the presence of other risk factors; the type of surgery; the use of thromboprophylaxis and not least the wishes of the patient. The possible medico-legal implications are uncertain and caution in this area is advised.