Rapid Responses to:
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blockers for elective surgery in elderly patients: population based, retrospective cohort study
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No Nitrates does not mean absence of coronary disease
- Atef Michael (28 October 2005)
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Where are the large clinical trials in anaesthesia
- Richard J Innes (28 October 2005)
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Beta Blockers for elective Surgery in the Elderly
- Samer-ul Haque (16 November 2005)
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A response to ‘Beta-blockers for elective surgery in elderly patients: population based, retrospective cohort study’.
- Bruce M Biccard, Julian W. Giles, John W. Sear and Pierre Foëx (22 November 2005)
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Atef Michael, Specialist Registrar City Hospital, Birmingham,UK
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Dear Professor Redelmeier et al, You excluded patients with symptomatic coronary disease as evidenced by chronic use of nitrates. However, in real life some patients with symptomatic coronary disease are given another class of drugs for example a calcium blocker or a potassium channel opener, and some patients do not tolerate nitrates so they are discontinued. So more patients with symptomatic coronary disease might have been included in the study and not considered as such. This may have implications on the discontinuation of the beta blockers and increase confounding of concomittant illness. Competing interests: None declared |
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Richard J Innes, Consultant Anaesthetist Musgrove park Hospital Taunton Ta3 7a
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For the last two decades cardiology have been conducting large randomized studies evaluating the role of medication for the treatment of myocardial ischaemia. The results of these large trials has been clear evidence based medicine which significantly reduces mortality for this common condition. For patients having surgery one of the most likely reasons for dying postoperatively is a myocardial infarct. Despite this fact for many years we have had suggestions of potential treatments in the form of perioperative beta blockade, postoperative noctural oxygen, stains etc but as yet no large randomized trails to support them. Just tantilizing, small often retrospective studies. The POISE study currently underway in Canada will hopefully point the way with regard to beta blockers but why when the evidence has been around for so long has this study taken so long to organise and where are all the other studies? One can only assume that if there isn't a drug company sponsoring a trial ( and most of the drugs we are interested in are off patent) then the trial wont happen. Perioperative medicine and anaesthesia should maybe look at other specialties for inspiration and then just maybe these urgently needed studies will happen! Competing interests: None declared |
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Samer-ul Haque, SHO Surgical Rotation James Paget Hospital, NR31 6LA
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I was interested to read the article by Redelmeier et al comparing whether atenolol and metoprolol are associated with equivalent reduction in risk for elderly elective surgical patients.1 The authors mention that the limitation of the study is that they do not know whether the beta-blockers were withheld at the time of surgery and this decision is unlikely to differ between two groups. This in reality may not be the case. The older patients are more likely to miss the drug on the day of operation or the immediate post operative period due to confusion or perceived haemodynamic instability attributable to the drug etc. A long acting drug ensures compliance and at least minimal therapeutic response even if one or two doses are missed out. Hence it is likely that more patients in the metoprolol group would have missed their medication. However the assumption that metoprolol is short acting is not always true as in slow acetylator patients the therapeutic half life may equal that of atenolol.2 In future if well conducted randomised controlled trials prove that beta-blockers are indeed useful for elective surgery in elderly patients the only way to guarantee intake of such medications will be more involvement of physicians or more medical input in the post operative period. We should also consider the option of ensuring compliance by drug administration by nasogastric tube or intravenously if clinically appropriate. Samer-ul Haque SHO Surgical Rotation Samer@doctors.org.uk 1. Donald A. Redlmeier et al. Beta-blockers for elective surgery in elderly patients: population based, retrospective cohort study. BMJ 2005; 331:932-4. 2. Mantindale The Complete Drug Reference 32nd Edition. 1999. Edited by Kathleen Parfitt Competing interests: None declared |
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Bruce M Biccard, Clinical Research Fellow Nuffield Department of Anaesthetics, University of Oxford, Oxford, OX3 9DU, United Kingdom, Julian W. Giles, John W. Sear and Pierre Foëx
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EDITOR- Redelmeier and colleagues have presented important evidence on the need to consider the duration of action of beta-blockers in the peri-operative period.1 However, they have failed to recognise two important issues, which may result in the reader of their paper misinterpreting the data they present.
Firstly, when they discuss the potential cardioprotective benefits of peri-operative beta-blockade they refer specifically to acute peri-operative beta-blocker administration.2 Their study design however identifies patients who had beta-blockers administered in the year prior to surgery, assuming that these beta-blockers would be continued into the peri-operative period.1 Their paper therefore describes patients undergoing surgery on chronic (as opposed to acute) beta-blockade. This distinction is vital, as although acute peri-operative beta-blockade may provide peri-operative cardioprotection,3 there is currently no evidence of cardioprotective efficacy of chronic beta-blockade in the peri-operative period.4
This brings us to the second point. Unfortunately, there was no control group consisting of patients who were not on chronic beta-blocker therapy in the peri-operative period. The concern therefore is that although there was a significant difference in outcome between the metoprolol and atenolol patient groups, we do not know how this compares to patients who did not receive peri-operative beta-blockers. Although atenolol was shown to be safer than metoprolol,1 this does not imply that chronic atenolol therapy is cardioprotective in the peri-operative period.4
In various studies, we have been unable to show a difference in a number of postoperative cardiac outcomes between patients who were chronically beta-blocked and patients who were not. There was no difference in postoperative silent myocardial ischaemia,5,6 postoperative troponin I or T release above the upper reference limit,7 30 day mortality,8,9 and 1 year mortality,6 as shown in the Table.
Table 1. Cardiac outcomes in chronically beta-blocked patients undergoing elective surgery
We must therefore disagree with Redelmeier et al1 in that chronic beta-blockade appears to afford no protection for peri-operative cardiac events. Our observations tally with those of Lee et al10 in the patient cohort in whom they defined the risk factors in their index.
1. Redelmeier D, Scales D, Kopp A. Beta blockers for elective surgery in elderly patients: population based, retrospective cohort study. BMJ 2005;331:932.
2. Auerbach AD, Goldman L. beta-Blockers and reduction of cardiac events in noncardiac surgery: scientific review. JAMA 2002;287:1435-44.
3. Devereaux PJ, Beattie WS, Choi PT, Badner NH, Guyatt GH, Villar JC, et al. How strong is the evidence for the use of perioperative beta blockers in non-cardiac surgery? Systematic review and meta-analysis of randomised controlled trials. BMJ 2005;331:313-21.
4. Giles JW, Sear JW, Foex P. Effect of chronic beta-blockade on peri-operative outcome in patients undergoing non-cardiac surgery: an analysis of observational and case control studies. Anaesthesia 2004;59:574-83.
5. Sear JW, Foex P, Howell SJ. Effect of chronic intercurrent medication with beta-adrenoceptor blockade or calcium channel entry blockade on postoperative silent myocardial ischaemia. Br J Anaesth 2000;84:311-5.
6. Giles JW, Sear JW, Higham H, Sear YM. Chronic beta-adrenoceptor blockade does not reduce incidence of early adverse cardiac outcomes in vascular surgery patients. Br J Anaesth 2003;90:419P.
7. Higham H, Sear JW, Sear YM, Kemp M, Hooper RJ, Foex P. Peri-operative troponin I concentration as a marker of long-term postoperative adverse cardiac outcomes--a study in high-risk surgical patients. Anaesthesia 2004;59:318-23.
8. Sear JW, Howell SJ, Sear YM, Yeates D, Goldacre M, Foex P. Intercurrent drug therapy and perioperative cardiovascular mortality in elective and urgent/emergency surgical patientst. Br J Anaesth 2001;86:506-12.
9. Sear JW, Howell SJ, Sear Y, M., Yeates D, Goldacre M, Foex P. A nested case-control study of risk factors for perioperative cardiovascular death. Br J Anaesth 2001;87:669P.
10. Lee TH, Marcantonio ER, Mangione CM, Thomas EJ, Polanczyk CA, Cook EF, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation 1999;100:1043-9. Competing interests: None declared | ||||||||||||||||||||||||||||||