Cardiac Events Seen With β-Blockers, Surgical Anemia
β-blockers linked to adverse events after non-cardiac surgery if hemoglobin falls >35 percent
TUESDAY, Jan. 5 (HealthDay News) -- Patients undergoing non-cardiac surgery who develop acute surgical anemia are more likely to have major cardiac complications and mortality if they receive perioperative β-blockers, according to research published in the January issue of Anesthesiology.
W. Scott Beattie, M.D., of the University of Toronto, and colleagues analyzed data from 4,387 patients who underwent major non-cardiac surgeries. The primary outcome was major adverse cardiac events, comprising myocardial infarction, nonfatal cardiac arrest, and in-hospital mortality.
The researchers found that major adverse cardiac events were more likely to occur in β-blocked patients (relative risk, 2.38). However, β-blockers were only associated with higher risk when patients had a decrease in hemoglobin of greater than 35 percent.
"We have shown that acute surgical anemia, a reduction of 35 percent from baseline, increased the risk of cardiac outcomes. This relationship is much worse in β-blocked patients. These findings suggest that the transfusion triggers should be higher for elective surgical patients on β-blockers. Owing to the relatively low risk of our population, we are unable to extend these finding to higher risk β-blocked patients who have been shown in the past to have reduced cardiac outcomes," the authors conclude.