Senior Primary Angioplasty in Myocardial Infarction Study - SENIOR PAMI

Description:

The goal of the trial was to evaluate primary percutaneous coronary intervention (PCI) versus intravenous thrombolytic therapy among elderly (age ≥70 years) patients with acute myocardial infarction (MI).

Study Design

Study Design:

Patients Enrolled: 483
Mean Follow Up: One year
Mean Patient Age: Mean age 78 years (range 70-101 years)
Female: 41

Patient Populations:

Age ≥70 years, ST-segment elevation of ≥1 mm in ≥2 leads, clinical symptoms for >30 minutes, and symptom onset within 12 hours

Exclusions:

Prior thrombolytic therapy, cardiogenic shock, prior cerebrovascular event, prolonged CPR, blood pressure >180/100 mm Hg, active bleeding, international normalized ratio >1.4, aspirin or heparin allergy, history of neutropenia, thrombocytopenia, hepatic dysfunction, renal insufficiency, or peripheral vascular disease

Primary Endpoints:

Death or disabling stroke at 30 days

Secondary Endpoints:

Death, disabling stroke, or reinfarction at 30 days

Drug/Procedures Used:

Patients with ST elevation MI and age ≥70 years were randomized to primary PCI (n=252) or thrombolytic therapy (n=229). Type of fibrinolytic was at the investigator's discretion. Randomization was stratified by those age 70-80 years and age >80 years.

Concomitant Medications:

Aspirin, beta-blockers, and low-dose heparin (60 U/kg bolus, maximum 4000 U)

Principal Findings:

The trial was discontinued early at the recommendation of the Data Safety Monitoring Board after 91% (483/530) of patients were enrolled due to slow recruitment. Patients had more co-morbid conditions than is often seen in ST elevation MI trials, with 66% having a history of hypertension, 9% peripheral vascular disease, and 21% Killip class ≥2. Median time from chest pain to treatment was longer in the PCI group (237 minutes vs. 210 minutes, p=0.014) and fewer patients in the PCI group had an inferior MI (49% vs. 60%, p=0.022). Final TIMI flow grade of 3 was achieved in 86.1% of patients in the PCI group. In the thrombolyic group, fibrin-specific lytics were used in 62% of patients and nonfibrin-specific lytics in 38%. During the index hospitalization, nonprotocol catheterization was performed in 51% of the thrombolytic group and PCI in 37%.

Intracranial bleeding occurred during the index hospitalization in 1.3% of the thrombolytic group and none of the PCI group (p=0.11). There was no difference in in-hospital major bleeding (5.6% for PCI vs. 6.2% for thrombolytic, p=0.79). The primary endpoint of death or disabling stroke at 30 days did not differ by treatment group (11.3% for PCI vs. 13% for thrombolytic, p=0.57). However, the secondary composite endpoint of death, disabling stroke, or reinfarction was lower in the PCI group (11.6% vs. 18%, p=0.05), driven by a reduction in reinfarction (1.6% vs. 5.4%, p=0.039).

There was no difference in the individual components of death (10% vs. 13%, p=0.48) or disabling stroke (0.8% vs. 2.2%, p=0.26). In the subgroup of patients age 70-80 years (n=352), the PCI group had a lower rate of death, disabling stroke, or reinfarction (7.7% vs. 17%, p=0.009) and a trend toward a lower rate of death or disabling stroke (7.7% vs. 12%, p=0.18). However, in the subgroup of patients age >80 years (n=130), there was no apparent difference between the PCI and the thrombolytic groups (22% each for death, disabling stroke, or reinfarction).

Interpretation:

Among elderly (age ≥70 years) patients with acute MI, primary PCI was not associated with a difference in the primary endpoint of death or disabling stroke at 30 days compared with thrombolytic therapy, but it was associated with reductions in reinfarction.

Optimal management of acute MI in the elderly patient is often not clear-cut, as many fibrinolytic trials excluded patients >75 years and results in PCI trials have shown conflicting results. In a subgroup analysis of prior PAMI studies, elderly patients were shown to have poorer angioplasty results and higher bleeding rates compared with younger angioplasty patients.

The present trial is the first large-scale randomized trial of primary PCI compared with thrombolytic therapy in the elderly. The event rate in the thrombolytic arm was lower than expected with very low rates of stroke and intracranial hemorrhage, suggesting the lower heparin dose may have offset some of the excess safety risk seen in earlier trials.

While the benefit of primary PCI in SENIOR-PAMI was evident in the subgroup of patients age 70-80 years, there was no apparent benefit in the very elderly subgroup of patients >80 years, although the sample size was small. This ultra-elderly population did poorly regardless of the reperfusion strategy, with mortality rates of 18% by 30 days.

References:

Presented by Dr. Cindy L. Grines at TCT 2005, Washington, DC.

Clinical Topics: Anticoagulation Management, Invasive Cardiovascular Angiography and Intervention, Prevention, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), Interventions and Vascular Medicine, Hypertension

Keywords: Thrombolytic Therapy, Stroke, Myocardial Infarction, Heparin, Fibrinolytic Agents, Angioplasty, Peripheral Vascular Diseases, Percutaneous Coronary Intervention, Stents, Intracranial Hemorrhages, Chest Pain, Catheterization, Hypertension


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