Abstract 2637: Perioperative Stroke in Non-Cardiac Surgery; The Impact of Prophylactic Beta-Blocker Therapy
Beta-blockers are widely used to improve postoperative cardiac outcome in patients with coronary artery disease scheduled for non-cardiac surgery. The recently published POISE (PeriOperative ISchemic Evaluation) trial using metoprolol controlled release (CR) therapy confirmed their beneficial effects for myocardial infarction and cardiovascular death. However, metoprolol CR was associated with an increased overall mortality rate. This was particularly due to ischemic strokes 41/4174; 1.0% vs 19/4177; 0.5% (odds ratio (OR) 2.2, 95% CI 1.3–3.7) that might be related to over treatment of beta blockers, resulting in perioperative hypotension. In the POISE trial metoprolol CR, up to 400 mg, was administered in four doses starting 2 to 4 hours prior to surgery. This dose is 100% of the maximal recommended therapeutic daily dose (MRTD). In contrast, in the DECREASE (Dutch Echo Cardiographic Risk Evaluation Applying Stress Echo) trials the average dose of bisoprolol was 2.5 mg once daily; 12.5% of the MRTD and started at least 30 days prior to surgery. To assess the incidence and risk factors associated with perioperative stroke in the DECREASE trials. All 3889 patients of the DECREASE trials were evaluated for bisoprolol dose as percentage of MRTD. The MRTD of bisoprolol at the start of the trial and during surgery was 12.5% and 16.5% respectively. All cardiac risk factors and medication use were noted. The incidence of stroke, diagnosed on clinical symptoms and CT scan, within 30 days after surgery is reported.
Results: The incidence of perioperative stroke in the DECREASE trials was 18/3889 (0.46%) compared to 41/4174 (0.98%) in the POISE trial, p= .006. Among beta-blocker users, the incidence was 0.5% in the DECREASE trials and 1.0% in the POISE study. In the DECREASE trials all strokes had an ischemic origin. A history of stroke was associated with perioperative stroke: OR 5.4, 95% CI 1.9 –15.2. Importantly, no association with bisoprolol therapy was assessed, OR 1.5, 95% CI 0.5– 4.3. In the DECREASE trials using low dose bisoprolol regimen starting at least 30 days prior to surgery, no association was observed between beta-blocker use and perioperative stroke, in contrast to high-dose metoprolol CR therapy in the POISE study.