Beneficial effects from beta-adrenergic blockade in elderly patients undergoing noncardiac surgery

Background: Perioperative beta-blockade has been shown to improve long-term cardiac outcome in noncardiac surgical patients. A possible mechanism for the reduced risk of perioperative myocardial infarction is the attenuation of the excitotoxic effects of catecholamine surges by beta-blockade. It was hypothesized that beta-blocker-induced alteration of the stress response w as responsible for the reported improvements in cardiovascular outcome, Sev eral variables associated with the perioperative use of beta-blockade were also evaluated. Methods: Sixty-three patients were randomly assigned to one of three groups : group I, no atenolol; group II, pre- and postoperative atenolol; group II I, intraoperative atenolol, Hormonal markers of the stress response (neurop eptide Y, epinephrine, norepinephrine, cortisol, and adrenocorticotropic ho rmone) were evaluated preoperatively and for 72 h after surgery. Results: Perioperative beta-blockade did not significantly alter the hormon al stress response. However, the beta-blocked patients showed improved hemo dynamic stability during emergence and postoperatively. They also received less fentanyl intraoperatively (27.7%, P < 0.0001), experienced faster earl y recovery, had lower pain scores, and required less analgesia in the posta nesthesia care unit. Cardiac troponin I release was detected in 8 of 19, 4 of 20, and 5 of 10 patients in groups I, II, and hi, respectively (not sign ificant). Three patients in group I had cardiac troponin I levels consisten t with myocardial infarction, Conclusion: beta-blockade does not reduce the neuroendocrine stress respons e, suggesting that this mechanism is not responsible for the previously rep orted improved cardiovascular outcome. However, it confers several advantag es, including decreased analgesic requirements, faster recovery from anesth esia, and improved hemodynamic stability. The release of cardiac troponin I suggests the occurrence of perioperative myocardial damage in this elderly population, which appears to be independent of the neuroendocrine stress r esponse.