Benefit From Reperfusion With Primary Percutaneous Coronary Intervention Beyond 12 Hours of Symptom Duration in...

Area of Science:

• Cardiology
• Interventional Cardiology
• Acute Myocardial Infarction Management

Background:

• Current guidelines recommend primary percutaneous coronary intervention (PCI) for ST-segment-elevation myocardial infarction (STEMI) patients presenting more than 12 hours after symptom onset if ongoing ischemia is present.
• Evidence supporting this recommendation for late-presenting STEMI is limited, necessitating further investigation into the benefits and outcomes of primary PCI in this patient group.

Purpose of the Study:

• To evaluate the effectiveness of primary PCI on reperfusion success and infarct size in STEMI patients presenting 12 to 72 hours after symptom onset with ongoing ischemia.
• To compare outcomes, including myocardial salvage and final infarct size, between late-presenting (12-72 hours) and early-presenting (<12 hours) STEMI patients treated with primary PCI.

Main Methods:

• Cardiac magnetic resonance (CMR) imaging was performed on 865 STEMI patients shortly after primary PCI and again at 3 months.
• Patients were stratified into two groups: late presenters (12-72 hours post-symptom onset, n=58) and early presenters (<12 hours, n=807).
• Key outcome measures included area at risk, final infarct size, myocardial salvage index, and left ventricular function, assessed via CMR.

Main Results:

• Late-presenting STEMI patients had significantly larger final infarct sizes (13% vs. 11%, P=0.037) and smaller myocardial salvage indices (0.58 vs. 0.65, P=0.021) compared to early presenters, despite similar areas at risk.
• However, 65% of late-presenting patients achieved substantial myocardial salvage (≥0.50), indicating a positive response to primary PCI.
• The duration from symptom onset to primary PCI showed a weak correlation with final infarct size, salvage index, and left ventricular function (R² <0.05).

Conclusions:

• Primary PCI in STEMI patients with ongoing ischemia presenting 12 to 72 hours after symptom onset resulted in less myocardial salvage and larger infarcts compared to those presenting earlier.
• Despite these findings, a substantial proportion of late-presenting patients benefited from primary PCI, achieving significant myocardial salvage.
• The study suggests that primary PCI remains a viable treatment option for selected late-presenting STEMI patients with signs of ongoing ischemia.