A randomized trial of transfer for primary angioplasty versus on-site thrombolysis in patients with high-risk myocardial infarction: the Air Primary Angioplasty in Myocardial Infarction study

Abstract

Objectives: The Air Primary Angioplasty in Myocardial Infarction (PAMI) study was designed to determine the best reperfusion strategy for patients with high-risk acute myocardial infarction (AMI) at hospitals without percutaneous transluminal coronary angioplasty (PTCA) capability.

Background: Previous studies have suggested that high-risk patients have better outcomes with primary PTCA than with thrombolytic therapy. It is unknown whether this advantage would be lost if the patient had to be transferred for PTCA, and reperfusion was delayed.

Methods: Patients with high-risk AMI (age >70 years, anterior MI, Killip class II/III, heart rate >100 beats/min or systolic BP <100 mm Hg) who were eligible for thrombolytic therapy were randomized to either transfer for primary PTCA or on-site thrombolysis.

Results: One hundred thirty-eight patients were randomized before the study ended (71 to transfer for PTCA and 67 to thrombolysis). The time from arrival to treatment was delayed in the transfer group (155 vs. 51 min, p < 0.0001), largely due to the initiation of transfer (43 min) and transport time (26 min). Patients randomized to transfer had a reduced hospital stay (6.1 +/- 4.3 vs. 7.5 +/- 4.3 days, p = 0.015) and less ischemia (12.7% vs. 31.8%, p = 0.007). At 30 days, a 38% reduction in major adverse cardiac events was observed for the transfer group; however, because of the inability to recruit the necessary sample size, this did not achieve statistical significance (8.4% vs. 13.6%, p = 0.331).

Conclusions: Patients with high-risk AMI at hospitals without a catheterization laboratory may have an improved outcome when transferred for primary PTCA versus on-site thrombolysis; however, this will require further study. The marked delay in the transfer process suggests a role for triaging patients directly to specialized heart-attack centers.