Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible for inclusion.
Specific interventions included in the review
The intervention of interest was beta-blockers, given peri-operatively. No explicit inclusion criteria were stated with regards to the comparator. The beta-blockers used in the included studies were labetalol, atenolol, oxyprenolol, esmolol and bisoprolol; these were compared with placebo. The drugs were initiated up to 1 week pre-operatively to immediately prior to surgery. One study started treatment within 1 hour after surgery. Full details of the dosing regimens were given.
Participants included in the review
Studies on people undergoing noncardiac surgery were eligible for inclusion. The types of surgery undertaken in the included studies were abdominal, peripheral, orthopaedic, neurosurgery, aortic aneurysm repair, infrainguinal arterial bypass, carotid endartrectomy, knee arthroplasty and hip replacement. The participants had mild to moderate hypertension, known coronary artery disease (CAD) or risk factors for CAD, pre-operative ischaemia on Holter monitor, positive results on dobutamine echo, or were aged 65 years or older. The mean ages of the participants ranged from 63 to 76 years.
Outcomes assessed in the review
Studies evaluating mortality, myocardial infarction or myocardial ischaemia were eligible for inclusion. Results were given for peri-operative overall and cardiac mortality, long-term cardiac and all-cause mortality, myocardial infarction and myocardial ischaemia. Peri-operative mortality was defined as death during the initial hospitalisation and long-term mortality was assessed at 1 month to 2 years after the operation. Adverse events were also reported.
How were decisions on the relevance of primary studies made?
Two reviewers independently selected the papers.