Among high-risk STEMI patients, who were treated with fibrinolysis, transfer for PCI within six hours after fibrinolysis was associated with significantly fewer ischemic complications than was standard treatment, according to the TRANSFER-AMI trial results published in the June 25 issue in the New England Journal of Medicine.
Warren J. Cantor, MD, from the Southlake Regional Health Centre in Newmarket, Ontario and the University of Toronto, and colleagues undertook TRANSFER-AMI (The Trial of Routine Angioplasty aNd Stenting after Fibrinolysis to Enhance Reperfusion in Acute MI) because the role and optimal timing of routine PCI after fibrinolysis had not been established.
The researchers randomly assigned 1,059 high-risk STEMI patients, who were receiving fibrinolytic therapy at 52 sites in three Canadian provinces that did not have the capability of performing PCI to either standard treatment (including to another hospital and PCI within six hours after fibrinolysis. All patients received aspirin, tenecteplase and heparin or enoxaparin; concomitant clopidogrel also was recommended.
The primary endpoint was the composite of death, reinfarction, recurrent ischemia, new or worsening congestive heart failure, or cardiogenic shock within 30 days, the authors wrote.
The investigators noted that cardiac catheterization was performed in 88.7 percent of the patients assigned to standard treatment -- a median of 32.5 hours after randomization and in 98.5 percent of the patients assigned to routine early PCI -- a median of 2.8 hours after randomization.
At 30 days, Cantor and colleagues reported that the primary endpoint occurred in 11 percent of the patients who were assigned to routine early PCI and in 17.2 percent of the patients assigned to standard treatment (relative risk with early PCI, 0.64; 95 percent confidence interval). They noted that there were no significant differences between the groups in the incidence of major bleeding.
The authors noted that trials performed after widespread use of stents became routine have shown "encouraging results for PCI performed early after fibrinolysis." They said that their results are consistent with those of smaller trials and meta-analyses in which contemporary PCI techniques and pharmacotherapy were used. Specifically, they pointed out that their findings were similar to those seen in CARESS-in-AMI, in which a half-dose of reteplase combined with abciximab was used as the initial reperfusion therapy.
"The results of that trial, together with those of our study, suggest that, in order to be effective, such strategies would probably require adequate antiplatelet therapy with either glycoprotein IIb/IIIa antagonists combined with reduced-dose fibrinolysis or clopidogrel combined with full-dose fibrinolysis and the liberal use of glycoprotein IIb/IIIa antagonists during PCI," Cantor and colleagues wrote.
Based on their data, the researchers concluded that the goal is to perform catheterization and PCI within six hours after fibrinolysis; the actual median interval from lysis to balloon inflation in their study was 3.9 hours.
In an accompanying editorial, Freek W.A. Verheugt, MD, from the department of cardiology at Onze Lieve Vrouwe Gasthuis in Amsterdam, noted that the time intervals between fibrinolysis ranged from two to 17 hours in TRANSFER-AMI. He wrote that the the "former interval should be considered to be the lowest acceptable one, since PCI immediately after fibrinolysis has proved to be ineffective. On the other hand, an interval of 17 hours seemed to be as good as PCI at two hours. Waiting longer than 24 hours can be disadvantageous given the increasing risk of reocclusion of the infarct-related artery."
Verheugt concluded that timely primary PCI remains the optimal therapy for STEMI. However, "owing to the logistic and temporal restraints of primary PCI, fibrinolysis is still the only possible initial reperfusion strategy in large parts of the world, including large parts of the Western world. Fibrinolysis, however, should be followed by an early invasive approach; in this setting, PCI has a central role," he wrote.