Routine Early PCI after Fibrinolysis for STEMI
Routine Early PCI after Fibrinolysis for STEMI
Abstract & Commentary
By Andrew J. Boyle, MBBS, PhD, Assistant Professor of Medicine, Interventional Cardiology, University of California, San Francisco. Dr. Boyle reports no financial relationships relevant to this field of study.
Source: Cantor WJ, et al. Routine early angioplasty after fibrinolysis for acute myocardial infarction. N Engl J Med. 2009;360:2705-2718.
Primary percutaneous coronary intervention (PCI) results in more complete reperfusion of the infarct artery and lower rates of re-occlusion than fibrinolysis in patients with ST elevation myocardial infarction (STEMI). However, primary PCI is not performed at all centers, and fibrinolysis is still in widespread use. Facilitated PCI (routinely taking patients to the cardiac catheterization laboratory immediately after fibrinolysis) appears not to be beneficial, and may increase adverse bleeding outcomes. Performing PCI for occluded infarct arteries several days after MI also does not achieve any demonstrable clinical benefit (OAT trial). Whether there is a timeframe between these two where routine transfer for early PCI after fibrinolysis can improve outcomes is not known. To address this issue, Cantor et al performed a multicenter, randomized, controlled trial of immediate transfer for PCI after fibrinolysis vs. standard treatment after fibrinolysis, the TRANSFER-AMI Trial.
At 52 sites in three Canadian provinces, 1,059 patients presenting with STEMI within 12 hours of symptom onset, who received fibrinolysis, were then randomly assigned to receive standard care (n = 522) or early transfer for PCI (n = 537). All patients received aspirin, tenecteplase, and either unfractionated heparin or enoxaparin. During the study, the protocol was amended to include the recommendation to administer clopidogrel as well. Patients assigned to the standard care group had a repeat electrocardiograph (ECG) at 60-90 minutes, and those with persistent ST elevation and chest pain or hemodynamic instability were transferred for rescue PCI. All other patients in the standard care group were not transferred, but coronary angiography was recommended in the first two weeks after hospitalization. Patients assigned to the early PCI group were transferred immediately after administration of tenecteplase, with a goal of receiving PCI within six hours. Coronary stents were used whenever possible, and glycoprotein IIb/IIIa inhibitor use at the time of intervention was at the discretion of the operator. The primary endpoint was the combined incidence of death, re-infarction, recurrent ischemia, new or worsening heart failure, or cardiogenic shock at 30 days. Secondary endpoints included death or re-infarction at six months and an incidence of bleeding complications.
The groups were well-matched in terms of baseline characteristics, with 80% male, average age 56 years, and 15% with diabetes. The only significant differences between the groups were a higher incidence of previous TIA or stroke in the early PCI group (3.0% vs. 1.0%; p = 0.02) and a higher incidence of previous heart failure in the standard care group (2.1% vs. 0.6%; p = 0.03). Anterior MI was present in 56.2% of the early PCI group and 51.9% of the standard care group (p = ns). Ninety-one percent were Killip class 1, 7% were Killip class 2, and the remainder were Killip class 3 or 4, with no difference between the groups. Cardiac catheterization was performed in 88.7% of the standard treatment group at a median time of 32.5 hours post-randomization and in 98.5% of patients in the early PCI group at a median of 2.8 hours post-randomization. PCI was performed in 67.4% of the standard-treatment group at a median of 21.9 hours, compared to 84.9% of patients in the early PCI group at a median of 3.2 hours post randomization. Rescue PCI was performed urgently within 12 hours in 34.9% of the standard care group. Follow-up at 30 days was achieved in 99.9% of patients. Importantly, none of the early PCI group died during transfer and only one patient in the standard care group, who was being transferred for rescue PCI, died in transit.
The primary endpoint occurred in 11% of patients in the early PCI group and 17.2% of the standard care group (relative risk with early PCI 0.64; p = 0.004). There was no difference in the rates of death or cardiogenic shock between the groups, but the early PCI group had a lower incidence of recurrent ischemia (0.2% vs. 2.1%; p = 0.003) and new or worsening heart failure (3.0% vs. 5.6%; p = 0.04). The secondary endpoint of death or re-infarction at six months was not significantly different between groups. There was a trend toward more bleeding in the early PCI group, but no difference in major bleeding, intracranial hemorrhage, or transfusion requirement. Mild bleeding was more common in the early PCI group (13.0% vs. 9.0%; p = 0.04). Cantor et al conclude that, in patients with STEMI who cannot undergo timely primary PCI, a strategy of prompt inter-hospital transfer for early PCI after fibrinolysis reduced the incidence of the composite endpoint of death, re-infarction, recurrent ischemia, congestive heart failure, or cardiogenic shock at 30 days.
Commentary
Cantor et al have demonstrated that better outcomes can be safely achieved by routine PCI after thrombolysis, aiming for PCI within six hours. As described in detail in the accompanying editorial, this is consistent with previous smaller studies that showed benefit with routine PCI within the first 16 hours post-fibrinolytic. This study allays any fears that transfer this early after fibrinolysis is not safe, with no deaths during transport in the early PCI group. Performing PCI too early before all the fibrinolytic activity has worn off makes bleeding more common, and performing PCI too late after MI adds little clinical benefit. This study, using contemporary anti-thrombotic and anti-platelet strategies, shows there is a window in between where a routine strategy of transfer for PCI is safe and efficacious.
It is important to note, however, that the improvement in the composite primary endpoint was not due to lower mortality in the early PCI group, but rather to less recurrent ischemia and less incident heart failure. The majority of stents used were bare metal in this study, and whether the beneficial outcomes hold true for patients receiving drug-eluting stents remains unknown. Furthermore, the cost-effectiveness of this approach is not presented herein.
Primary percutaneous coronary intervention (PCI) results in more complete reperfusion of the infarct artery and lower rates of re-occlusion than fibrinolysis in patients with ST elevation myocardial infarction (STEMI). However, primary PCI is not performed at all centers, and fibrinolysis is still in widespread use.Subscribe Now for Access
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