Towards an understanding of the role of rescue angioplasty for failed fibrinolysis: comparison of the MERLIN, RESCUE and REACT trials.

Unlabelled: The large randomized trials on rescue angioplasty (rPCI) have been interpreted by some as showing differing results. We compared the protocols, demographics and 6-month clinical outcomes of the MERLIN trial with the RESCUE I and REACT trials to assess their differences.

Results: The RESCUE I trial did not involve the use of stenting or glycoprotein IIb/IIIa inhibitors, and patients with previous MI were excluded. The recruitment rate in MERLIN was 30.7 patients per center per year vs. 3.3 in REACT and 2.4 in the RESCUE I trial. The patients in the MERLIN trial were older. Streptokinase was used more commonly in the MERLIN trial: 96% vs. 60% in REACT. In the rPCI arm, pain onset to lysis time was longer, 180 vs. 140 minutes in MERLIN, but lysis to angiography (146 vs. 274 minutes) and pain onset to angiography (327 vs. 414 minute) times were shorter compared with the REACT trial. In the rPCI arms, mortality at 6 months was lower in the REACT trial than in the MERLIN trial although the difference was not statistically significant. This numeric difference in mortality is unlikely to be explained by the differences in the use of glycoprotein IIb/IIIa inhibitors or stenting. In the rPCI arms, reinfarction rates were higher in the MERLIN trial (7.8% vs. 2.1%), possibly due to lower rates of stenting (50.3% vs. 68.5%) and less use of glycoprotein IIb/IIIa inhibitors (3.3% vs. 43.4%). The three trials used different definitions of heart failure, with a trend towards a reduction in heart failure in all three studies.

Conclusion: These trials differ in various aspects. The RESCUE I trial enrolled lower-risk patients than the MERLIN trial and was done without the use of stents and glycoprotein IIb/IIIa inhibitors. The MERLIN trial is widely applicable to patients receiving streptokinase and had no age limit. REACT patients were younger and were enrolled more selectively. Although some outcomes were similar, differences in patient recruitment and protocols may have accounted for the numerical difference in mortality rates at 6 months in the MERLIN and REACT trials. Meta-analysis suggests an overall clinical benefit from rescue PCI (lower mortality, less reinfarction and less heart failure) at the expense of an increased risk of stroke and bleeding.