Acute peri‐operative beta blockade in intermediate‐risk patients

We would like to comment on Biccard, Sear and Foex's [1] paper on the likely benefits of peri-operative beta blockade in intermediate risk patients. The authors should be commended on such an interesting analysis of a difficult subject. The initial data, which shows a reduction in episodes of myocardial ischaemia, is encouraging with a number-needed-to-treat (NNT) of only 10, and no significant complications. Despite good evidence that myocardial ischaemia increases the risk of major cardiovascular complications it is somewhat disappointing that, when these two elements are combined, the predicted overall risk reductions are likely to be small, with the NNT too large to justify the regular use of beta blockade therapy in those intermediate patients. It is surprising that with all the interest in reducing cardiac risk using beta blockers, there is no mention of the use of clonidine. Wallace et al. [2] have shown that clonidine administration reduces the incidence of both myocardial ischaemia peri-operatively and also the 2-year mortality in high cardiac risk patients undergoing non-cardiac surgery. The study was a well conducted, randomised controlled study of nearly 200 patients, which used a well-described regimen of only 4 days of treatment. This would be easy to reproduce as it uses a single agent and a single regimen, whereas there is still no consensus on the optimum timing, agent or dose of beta-blockers. The results in this high risk group show clonidine to have similar efficacy to beta blockade therapy in the reduction of significant cardiovascular complications. Further research in the intermediate cardiac risk group might therefore be better directed towards this drug.