Impact of intravenous Beta-Blockade before primary angioplasty on survival in patients undergoing mechanical reperfusion therapy for acute myocardial infarction

Abstract

Objectives

We sought to examine the effect of intravenous beta-blockers administered before primary percutaneous coronary intervention (PCI) on survival and myocardial recovery after acute myocardial infarction (AMI).

Background

Studies of primary PCI but not thrombolysis have suggested that beta-blocker administration before reperfusion may enhance survival. Whether oral beta-blocker use before admission modulates this effect is unknown.

Methods

The Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) trial randomized 2,082 AMI patients to either stenting or balloon angioplasty, each ± abciximab. In accordance with the protocol, intravenous beta-blockers were administered before PCI in the absence of contraindications.

Results

A total of 1,136 patients (54.5%, BB+ group) received beta-blockers before PCI, whereas 946 (45.5%, BB− group) did not. The 30-day mortality was significantly lower in the BB+ group than in the BB− group (1.5% vs. 2.8%, p = 0.03), an effect entirely limited to patients who had not been receiving beta-blockers before admission (1.2% vs. 2.9%, p = 0.007). In contrast, no survival benefit with pre-procedural beta-blockers was observed in patients receiving beta-blockers at home (3.3% vs. 1.9%, respectively, p = 0.47). By multivariate analysis, pre-procedural beta-blocker use was an independent predictor of lower 30-day mortality among patients without previous beta-blocker therapy (relative risk = 0.38 [95% confidence interval 0.17 to 0.87], p = 0.02). The improvement in left ventricular ejection fraction from baseline to seven months was also greater after intravenous beta-blockers (3.8% vs. 1.3%, p = 0.01), an effect limited to patients not receiving oral beta-blockers before admission.

Conclusions

In patients with AMI undergoing primary PCI, myocardial recovery is enhanced and 30-day mortality is reduced with pre-procedural intravenous beta-blockade, effects confined to patients untreated with oral beta-blocker medication before admission.