Efficacy and Safety of a Pharmaco-Invasive Strategy With Half-Dose Alteplase Versus Primary Angioplasty in ST-Segment-Elevation Myocardial Infarction: EARLY-MYO Trial (Early Routine Catheterization After Alteplase Fibrinolysis Versus Primary PCI in Acute ST-Segment-Elevation Myocardial Infarction)

Abstract

Background: Timely primary percutaneous coronary intervention (PPCI) cannot be offered to all patients with ST-segment-elevation myocardial infarction (STEMI). Pharmaco-invasive (PhI) strategy has been proposed as a valuable alternative for eligible patients with STEMI. We conducted a randomized study to compare the efficacy and safety of a PhI strategy with half-dose fibrinolytic regimen versus PPCI in patients with STEMI.

Methods: The EARLY-MYO trial (Early Routine Catheterization After Alteplase Fibrinolysis Versus Primary PCI in Acute ST-Segment-Elevation Myocardial Infarction) was an investigator-initiated, prospective, multicenter, randomized, noninferiority trial comparing a PhI strategy with half-dose alteplase versus PPCI in patients with STEMI 18 to 75 years of age presenting ≤6 hours after symptom onset but with an expected PCI-related delay. The primary end point of the study was complete epicardial and myocardial reperfusion after PCI, defined as thrombolysis in myocardial infarction flow grade 3, thrombolysis in myocardial infarction myocardial perfusion grade 3, and ST-segment resolution ≥70%. We also measured infarct size and left ventricular ejection fraction with cardiac magnetic resonance and recorded 30-day clinical and safety outcomes.

Results: A total of 344 patients from 7 centers were randomized to PhI (n=171) or PPCI (n=173). PhI was noninferior (and even superior) to PPCI for the primary end point (34.2% versus 22.8%, P_{noninferiority}<0.05, P_superiority=0.022), with no significant differences in the frequency of the individual components of the combined end point: thrombolysis in myocardial infarction flow 3 (91.3% versus 89.2%, P=0.580), thrombolysis in myocardial infarction myocardial perfusion grade 3 (65.8% versus 62.9%, P=0.730), and ST-segment resolution ≥70% (50.9% versus 45.5%, P=0.377). Infarct size (23.3%±11.3% versus 25.8%±13.7%, P=0.101) and left ventricular ejection fraction (52.2%±11.0% versus 51.4%±12.0%, P=0.562) were similar in both groups. No significant differences occurred in 30-day rates of total death (0.6% versus 1.2%, P=1.0), reinfarction (0.6% versus 0.6%, P=1.0), heart failure (13.5% versus 16.2%, P=0.545), major bleeding events (0.6% versus 0%, P=0.497), or intracranial hemorrhage (0% versus 0%), but minor bleeding (26.9% versus 11.0%, P<0.001) was observed more often in the PhI group.

Conclusions: For patients with STEMI presenting ≤6 hours after symptom onset and with an expected PCI-related delay, a PhI strategy with half-dose alteplase and timely PCI offers more complete epicardial and myocardial reperfusion when compared with PPCI. Adequately powered trials with this reperfusion strategy to assess clinical and safety outcomes are warranted.

Clinical trial registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01930682.

Keywords: fibrinolysis; microcirculation; myocardial infarction; percutaneous coronary intervention.