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Middlesbrough Early Revascularization to Limit Infarction - MERLIN
Description:
The goal of the study was to evaluate the use of rescue angiography compared with conservative therapy in patients with ST elevation myocardial infarction (STEMI) who failed fibrinolytic therapy.
Study Design
Study Design:
Patients Enrolled: 307
Mean Follow Up: Three years
Mean Patient Age: Mean age 63 years
Female: 28
Patient Populations:
STEMI with hospital presentation within 10 hours of major symptom onset; failure to respond to fibrinolytic therapy, defined as failure to have resolution of the ST-segment elevation in the worst lead on a 12-lead ECG obtained 60 minutes after the onset of fibrinolytic therapy
Exclusions:
Cardiogenic shock; confounding features on the prefibrinolytic ECG, preventing ST-segment reduction analysis; reinfarction in the same ECG territory within two months of an original infarction; absent femoral pulses; pregnancy; and the presence of significant coexisting pathology likely to affect the prognosis during the follow-up period
Primary Endpoints:
All-cause mortality at 30 days
Secondary Endpoints:
Composite of death, reinfarction, stroke, heart failure, and clinically driven subsequent revascularization within 30 days; and LV function at 30 days, as assessed by regional wall motion index
Drug/Procedures Used:
All patients were treated with fibrinolytic therapy at presentation. Following ECG confirmation of persistent ST-segment elevation on the 60-minute ECG, patients were randomized to emergency coronary angiography with or without rescue percutaneous coronary intervention (PCI) (n=153) or conservative therapy (n=154). Early crossover from the medical therapy arm to the rescue arm was not allowed unless the patient was in cardiogenic shock.
Concomitant Medications:
Aspirin (300 mg initially followed by 75 mg/day); other agents at the discretion of the physician
Principal Findings:
The majority of patients in both arms had received streptokinase (149 in the conservative arm and 147 in the rescue arm). Mean time from symptom onset to angiography in the rescue arm was 327 minutes. None of the patients randomized to the conservative arm underwent immediate coronary catheterization or PCI.
There was no difference in the primary endpoint of all-cause mortality at 30 days between the conservative arm (11.0%) and the rescue arm (9.8%, p=0.7). However, the secondary composite endpoint of death, reinfarction, stroke, heart failure, and clinically driven subsequent revascularization was significantly lower in the rescue arm (37.3% vs. 50%, p=0.02), driven primarily by subsequent revascularization (6.5% vs. 20.1%, p<0.01), with no significant differences in reinfarction (7.2% vs. 10.4%, p=0.3) or heart failure (24.2% vs. 29.9%, p=0.30).
Stroke was significantly higher in the rescue arm (4.6% vs. 0.6%, p=0.03). Transfusion occurred more frequently in the rescue arm (11.1% vs. 1.3%, p<0.001). There was no difference in the length of hospitalization (seven days in both the rescue arm and conservative arm, p=0.95). Regional wall motion score at 30 days was similar in both groups (1.52 in the rescue arm vs. 1.58 in the conservative arm, p=NS).
Interpretation:
Among patients with STEMI who failed fibrinolytic therapy (persistent ST-segment elevation), rescue angiography with or without PCI was not associated with a difference in the primary endpoint of all-cause mortality at 30 days, but was associated with a reduction in the composite clinical endpoint. However, the composite endpoint was driven primarily by the component of subsequent revascularization, which indicated an initial revascularization in the conservative arm and a repeat revascularization in the rescue arm. Of particular concern was the high rate of stroke and transfusion in the rescue arm.
The large majority of the patients in the trial were treated with streptokinase rather than a fibrin-specific lytic agent. Results of the present trial may not be applicable to patients treated with a fibrin-specific lytic agent, such as tPA or TNK.
References:
Sutton AG, Campbell PG, Graham R, et al. A randomized trial of rescue angioplasty versus a conservative approach for failed fibrinolysis in ST-segment elevation myocardial infarction: The Middlesbrough Early Revascularization to Limit INfarction (MERLIN) trial. J Am Coll Cardiol 2004;44:287-96.
Keywords: Shock, Cardiogenic, Thrombolytic Therapy, Stroke, Streptokinase, Coronary Angiography, Catheterization, Heart Failure, Coronary Disease, Electrocardiography, Fibrin, Tissue Plasminogen Activator, Percutaneous Coronary Intervention
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