Perioperative β-blockade: atenolol is associated with reduced mortality when compared to metoprolol.

BACKGROUND: The Atenolol study of 1996 provided evidence that perioperative β-blockade reduced postsurgical mortality. In 1998, the indications for perioperative β-blockade were codified as the Perioperative Cardiac Risk Reduction protocol and implemented at the San Francisco Veterans Affairs Medical Center. The current study tested the following hypothesis: Is there a difference in mortality rates between patients receiving perioperative atenolol and metoprolol?
METHODS: Epidemiologic analysis of the operations performed at the San Francisco Veterans Affairs Medical Center since 1996 was performed. High-risk inpatients with perioperative β-blockade were divided into two groups: patients who received perioperative atenolol only and those who received metoprolol only. Patients who switched between the two chronic oral β-blocker medications were excluded. IV administration of β-blockers was ignored. Propensity matching analysis was used to correct for population differences in risk factors.
RESULTS: There were 38,779 operations performed from 1996 to 2008, with 24,739 inpatient procedures. Based on analysis of inpatient medication use, 3,787 patients received atenolol only (1,011) or metoprolol only (2,776). Thirty-day mortality (atenolol 1% vs. metoprolol 3%, P < 0.0008) and 1-yr mortality (atenolol 7% vs. metoprolol 13%, P < 0.0001) differed between the two β-blockers. Analysis based on inpatient and outpatient β-blocker use showed a similar pattern. Propensity matching that corrected for multiple cardiac risk factors found an odds ratio (OR) of 2.1 [95% CI 1.5-2.9], P < 0.0001 for increased 1-yr mortality with metoprolol for inpatient use.
CONCLUSION: Perioperative β-blockade using atenolol is associated with reduced mortality compared with metoprolol.