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Editor,—I welcome Thorne’s editorial1 reiterating the pitfalls of overzealous venesection in adults with cyanotic congenital heart disease. As she states there is now a body of opinion highlighting the detrimental effects of inappropriate venesection. The evidence these conclusions are based on, however, is sparse and retrospective. This will unfortunately be a feature of a relatively new field such as adult congenital disease practice until multicentred collaboration and prospective studies are planned. Despite these limitations the work we have at present points towards the principles expounded by Thorne. A recent paper by Ammash and Warnes,2 not mentioned in Thorne’s editorial, provides further evidence regarding the lack of association between stroke and a high haematocrit. This study of cyanotic patients followed for 3135 patient-years did not identify an association between red cell mass and stroke. Of particular interest was the finding that iron deficiency and recurrent venesection were independent risk factors for cerebrovascular events. This study not only refutes the belief that we must treat haematocrits that are “too high” but positively demonstrates the dangers of venesection. These findings endorse the previous statement from Perloffet al that venesection should only be performed for “temporary relief of significant, intrusive hyperviscosity symptoms”.3
Unfortunately, in the UK this message is not getting through, even to cardiac specialists let alone general physicians or haematologists who may only occasionally come into contact with this patient group. In our recent survey of consultant cardiologists in Scotland,4 there was a great variation in practise regarding the perceived indications for and techniques of venesection. Only a minority of consultants caring for these patients appeared to be aware of the dangers of inappropriate venesection or the appropriate management of iron deficiency. Many patients were still being submitted to regular venesection for dubious indications with no fluid replacement and no monitoring for the onset of iron deficiency. In this specialist area, presenting simple guidelines such as those drafted by Thorne to a wider audience will hopefully redress this issue and improve patient care. It would be interesting to repeat a similar national survey of consultant practise in a year or so to determine whether this message is getting through.
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