Risks and benefits of β-blockade
=================================

* Stephen R. Workman

*   © 2005 Canadian Medical Association or its licensors

P.J. Devereaux and associates1 state that the current situation with respect to evidence for β-blocker therapy before surgery is similar to the situation that existed 12 years ago when estrogen replacement was widely recommended. I disagree. Estrogen has been implicated in the genesis of many fatal diseases, including breast cancer and thromboembolic diseases.2,3 The same material risks do not exist for β-blockers. Furthermore, the authors do not disclose or discuss the theoretical or empirical life-threatening risks of β-blockade. 

Devereaux and associates1 also argue that the benefits of preoperative β-blockade in small studies completed to date are “too good to be true.” They base this assessment upon the long-term benefits of β-blockade in coronary artery disease and congestive heart failure. However, for these conditions the drugs are administered over long periods, and in combination with many other drugs, to modify the long-term outcome of progressive and often fatal diseases. A more analagous situation is the relative risk of a myocardial infarction induced by another acute stressor, strenuous exercise. One study found that the relative risk of myocardial infarction during or immediately after vigorous exercise was increased 100-fold for habitually sedentary individuals.4 Most of the patients whom I am asked to see preoperatively are sedentary and thus very likely to benefit from preoperative β-blockade.

## References

1.  1. Devereaux PJ, Yusuf S, Yang H, Choi PTL, Guyatt GH. Are the recommendations to use perioperative β-blocker therapy in patients undergoing noncardiac surgery based on reliable evidence? [editorial]. CMAJ 2004;171(3):245-7. 
    
    [FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo5OiIxNzEvMy8yNDUiO3M6NDoiYXRvbSI7czoyMToiL2NtYWovMTcyLzEvMTQuMi5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

2.  2. Henderson BE, Bernstein L. The international variation in breast cancer rates: an epidemiological assessment. *Breast Cancer Res Treat* 1991; 18 (Suppl 1): S11-7.
    
    

3.  3. Goldhaber SZ. Epidemiology of pulmonary embolism. Semin Vasc Med 2001;1(2):139-46.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1055/s-2001-18481&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=15199496&link_type=MED&atom=%2Fcmaj%2F172%2F1%2F14.2.atom) 

4.  4. Mittleman MA, Maclure M, Tofler GH, Sherwood JB, Goldberg RJ, Muller JE. Triggering of acute myocardial infarction by heavy physical exertion: protection against triggering by regular exertion. N Engl J Med 1993;329:1677–83. 
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1056/NEJM199312023292301&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=8232456&link_type=MED&atom=%2Fcmaj%2F172%2F1%2F14.2.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1993MJ70700001&link_type=ISI)