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Venous thromboembolism (VTE) is an occasional cause of death after transurethral prostatectomy but there are no established guidelines for its prevention in relation to this operation. We assessed practice in the UK by mailing a questionnaire to 460 consultant members of the British Association of Urological Surgeons.
362 (79%) completed questionnaires were received. 280 of 362 (77%) respondents routinely used VTE prophylaxis with transurethral prostatectomy; 82 (23%) did not. 230 of the 280 urologists who took precautions used mechanical methods; 50 used low dose heparin, either with stockings or alone.
This survey indicates that, despite a lack of clear evidence, most British urologists favour some form of precaution against VTE in patients undergoing transurethral prostatectomy.
The 1991-1992 report of the National Confidential Enquiry into Perioperative Deaths (NCEPOD)1 highlighted venous thromboembolism (VTE) as an important cause of mortality in postoperative patients. Pulmonary embolism accounted for 7% of all postoperative deaths and was the third most common cause of death (16%) in patients who had undergone a prostatectomy. Despite these data, VTE is often perceived as being uncommon after transurethral prostatectomy; the incidence of deep venous thrombosis was 0.2% and of pulmonary embolism only 0.1% in the National Prostatectomy Audit published in 19972.
With the advent of clinical governance some trusts may wish to introduce a standardized policy for VTE prophylaxis in surgical patients. However, there are no established guidelines for the prevention of VTE in men undergoing a transurethral prostatectomy, one of the commonest urological operations. We felt it timely to survey the practice of urologists in the UK.
A postal questionnaire was sent to consultant members of the British Association of Urological Surgeons in the UK, enquiring whether they routinely used prophylactic measures against VTE in patients undergoing a transurethral prostatectomy and, if so, what.
362 (79%) of 460 questionnaires were returned and suitable for analysis. 280 (77%) of the respondents routinely used some form of prophylactic measures against VTE in patients having a transurethral prostatectomy; 82 (23%) did not. Most (230; 63%) advised mechanical methods of prophylaxis. Figure 1 shows the options favoured. A small number of respondents (20; 5%) emphasized the importance of precautions in patients with a previous history of deep venous thrombosis or pulmonary embolism and in patients with known carcinoma of the prostate. One consultant judged spinal anaesthesia to offer sufficient protection.
Transurethral prostatectomy is associated with a perioperative hypercoagulable state3 and is classified as being of medium risk for VTE by the Thromboembolic Risk Factor Consensus Group4. Although some epidemiological data suggest that the incidence of VTE in men after this operation2 is comparable to that in the general population5, 6, the recorded figures may be misleadingly low: whereas most patients stay in hospital for 5 days2, the usual time for postoperative VTE is 7-10 days. Some thromboembolic events may thus go unrecognized or come to the attention of another specialty.
This survey has established that most British urologists rely on mechanical methods of VTE prophylaxis in patients having a transurethral prostatectomy. Graduated compression stockings and intermittent calf compression devices have both been shown to reduce the incidence of deep vein thrombosis in postoperative surgical patients, although a reduction in pulmonary embolism has not been clearly demonstrated4,7. To our knowledge, no researchers have looked specifically at the benefits of these methods in relation to transurethral prostatectomy. A major advantage of mechanical methods of VTE prophylaxis is that they do not worsen the risk of perioperative bleeding, although pneumatic intermittent calf compression has been shown to increase intraoperative haemorrhage in patients undergoing a radical prostatectomy or cystectomy8. Of perhaps equal importance is the fact that many leg supports used for patients undergoing endoscopic urological surgery are soft, and sometimes they are self-regulating, so as to avoid undue pressure on the calf veins.
Low-dose unfractionated or low-molecular-weight heparins are one of the commonest modes of VTE prophylaxis in surgical patients. There is ample evidence that these agents are effective in reducing the incidence of deep venous thrombosis in patients having anything other than minor surgery9, but they may add to the risk of haemorrhagic complications9,10. Reports on the effect of prophylactic heparin on blood loss following transurethral prostatectomy have been contradictory, with one claiming an increase11 and another no difference12.
A further factor that needs to be considered is the form of anaesthesia used in patients undergoing this operation. Many patients receive spinal anaesthesia and there is evidence that this reduces the incidence of VTE in the absence of other prophylactic measures13,14,15. The precise reasons for this are unclear but peripheral vasodilatation, the reduction in viscosity resulting from fluid loading and the fact that local anaesthetic agents themselves decrease platelet adhesion, aggregation and release may all be relevant13.
Deep venous thrombosis and pulmonary embolism are serious complications that are largely preventable. Deep venous thrombosis can lead to venous insufficiency, with long-term morbidity and substantial health care costs; and pulmonary embolism can be fatal. However, to establish the optimum method of prophylaxis in patients undergoing transurethral prostatectomy would require a large prospective randomized study, with end-points such as venography or venous doppler scans. Since fatal pulmonary embolism is rare after this operation, as many as 100 000 patients would need to be recruited for adequate statistical power9. The simple truth is that, for patients having a transurethral prostatectomy, we are never likely to know for certain that one form of VTE prophylaxis is better than another or indeed none at all. Although there is no evidence that surgeons who use no specific measures are mistaken, this survey shows that most British urologists favour precautions of some sort.