CORRESPONDENCE |
Chronic ß-adrenoreceptor blockade in surgical patients
* E-mail: kresimir.oremus{at}zg.t-com.hr
Editor—The role of ß-adrenoreceptor blocking agents in reducing perioperative cardiac morbidity in high-risk non-cardiac surgical patients continues to raise a great deal of interest among anaesthetists and remains a question of considerable debate. Therefore, we took great interest in the recent thorough review by Priebe1 on the aetiology and prevention of perioperative myocardial infarction, in which he took an impartial and balanced approach towards the practice of introducing acute ß-blocker therapy in the perioperative period. However, the question of the effect of continuing chronic ß-blockade during the perioperative period is less well elaborated and a suggestion is made that chronic ß-blocker therapy continued perioperatively is as effective as acute ß-blocker therapy in reducing the adverse cardiac event rate. Although chronic preoperative ß-blockade has been found to reduce mortality in patients undergoing coronary surgery,2 3 chronic ß-blockade has not been shown to convey the protective effects of acute perioperative ß-blocking therapy in the non-cardiac surgical setting.4 5 One possible explanation for this discrepancy, as suggested by Biccard in a recent review6 and the correspondence following, is that patients undergoing non-cardiac surgery receive chronic ß-blocking therapy predominantly because of angina and hypertension, and are more likely to die of ischaemia-related causes in the perioperative period, as opposed to cardiac surgical patients who are predominantly suffering from, and more likely to die of, heart failure. The effect of ß-blocking agents to lower the ischaemic threshold leading to the development of myocardial ischaemia at a lower heart rate than in patients not on chronic ß-blockade might therefore be more detrimental in patients undergoing non-cardiac surgery. Perioperative withdrawal of chronically administered ß-blockers may also result in increased cardiac morbidity and mortality.7 In contrast to established guidelines for acute perioperative ß-blockade, there is no consensus regarding the surgical patient on chronic ß-blocker therapy. Some suggested approaches include providing additional perioperative ß-blockade to keep the heart rate below the ischaemic threshold, or the addition of other drugs that have been shown to lower perioperative cardiac morbidity, including agents like calcium channel blockers, statins and 
2-adrenoreceptor agonists. So far, studies evaluating the efficacy and safety of such interventions are lacking.
Zagreb, Croatia
E-mail: priebe{at}ana1.ukl.uni-freiburg.de
Editor—I would like to thank Drs Oremus and Oremus for their interest in my review. They interpret a section of my article as suggesting that chronic ß-blocker therapy continued perioperatively is as effective in reducing perioperative cardiac morbidity and mortality as acutely instituted perioperative ß-blocker therapy. In the review, I stated that the findings by Boersma and colleagues8 could be interpreted as suggestive evidence of that—the emphasis being on the words ‘could’ and ‘suggestive evidence’. I entirely agree that no prospective study has demonstrated a perioperative cardio-protective effect of chronic ß-blocker therapy.9 On the other hand, although not proven by a controlled trial, findings in the non-operative10 11 and operative setting7 strongly argue in favour of not discontinuing chronic ß-blocker therapy perioperatively.
Freiburg, Germany
References
1 Priebe HJ. Perioperative myocardial infarction—aetiology and prevention. Br J Anaesth 2005; 95: 3–19
2 ten Broecke PWC, de Hert SG, Mertens E, Adriaensen HF. Effect of preoperative ß-blockade on perioperative mortality in coronary surgery. Br J Anaesth 2003; 90: 27–31
3 Ferguson TB, Coombs LP, Peterson ED for the Society of Thoracic Surgeons National Adult Cardiac Surgery Database. Preoperative ß-blocker use and mortality and morbidity following CABG surgery in North America. JAMA 2002; 287: 2221–7
4 Sear JW, Foëx P, Howell SJ. Effect of chronic intercurrent medication with beta-adrenoreceptor blockade or calcium channel entry blockade on postoperative silent myocardial ischaemia. Br J Anaesth 2000; 84: 311–15
5 Sear JW, Howell SJ, Sear YM, Yeates D, Goldacre M, Foëx P. Intercurrent drug therapy and perioperative cardiovascular mortality in elective and urgent/emergency surgical patients. Br J Anaesth 2001; 86: 506–12
6 Biccard BM. Peri-operative ß-blockade and haemodynamic optimisation in patients with coronary artery disease and decreasing exercise capacity presenting for major noncardiac surgery. Anaesthesia 2004; 59: 60–8[Medline]
7 Shammash JB, Trost JC, Gold JM, Berlin JE, Golden MA, Kimmel SE. Perioperative beta-blocker withdrawal and mortality in vascular surgical patients. Am Heart J 2001; 141: 148–53[CrossRef][Web of Science][Medline]
8 Boersma E, Poldermans D, Bax JJ, et al. for the DECREASE Study Group. Predictors of cardiac events after major vascular surgery: role of clinical characteristics, dobutamine echocardiography, and beta-blocker therapy. JAMA 2001; 285: 1865–73
9 Giles JW, Sear JW, Foëx P. Effect of chronic ß-blockade on peri-operative outcome in patients undergoing non-cardiac surgery: an analysis of observational and case control studies. Anaesthesia 2004; 59: 574–83[CrossRef][Web of Science][Medline]
10 Frishman WH. Beta-adrenergic blocker withdrawal. Am J Cardiol 1987; 59: 26F–32F[CrossRef][Medline]
11 Psaty BM, Koepsell TD, Wagner EH, LoGerfo JP, Inui TS. The relative risk of incident coronary heart disease associated with recently stopping the use of beta-blockers. JAMA 1990: 1263: 1653–7
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