The group at the San Francisco VA has continued, based on their past randomized trials, and more recent large retrospective studies, to find evidence of protective effects of periop beta blockade. They find that acute administration may be more dangerous than when Rx is started in advance. They’ve also found that atenolol may be better than metoprolol in protecting the heart. Their most recent retrospective study of 136k patients, with propensity-matching. They found that beta blockade was protective (NNT 18-241, depending on baseline risk (revised cardiac risk index). Beta blockade was most protective in patients with 4 risk factors or more. Interestingly, they found that beta blockade was not protective is vascular surgery! This is where we’ve often thought they’d be most protective, based on patients’ high baseline risks. One possible reason: vascular surgery patients bleed more, and beta blockade is the presence of hemorrhage appears to be detrimental.
The group at Michigan reviewed 57k anesthetics at their institution and concluded that :
Routine use of preoperative metoprolol, but not atenolol, is associated with stroke after noncardiac surgery, even after adjusting for comorbidities. Intraoperative metoprolol, but not esmolol or labetalol, is associated with increased risk of perioperative stroke. Drugs other than metoprolol, should be considered during theperioperative period if β blockade is required.
Here’s a PDF with the main findings from the most recent San Francisco study:
Association of Perioperative β-Blockade With Mortality and Cardiovascular Morbidity Following Major Noncardiac Surgery