Patency of the infarct-related artery and time-dependant infarct transmurality on cardiovascular magnetic resonance in patients with ST-segment elevation myocardial infarction treated by primary percutaneous intervention

BackgroundOutcome in ST-segment elevation myocardial infarction (STEMI) is affected by patency of the infarct-related artery (IRA) on the initial angiogram. Therefore we decided to assess the relation between patent IRA and time-dependent infarct transmurality.Materials and methodsThe study included 62 patients with first STEMI (age 61 ± 9 years, 76% male) undergoing primary percutaneous coronary intervention (PCI). All patients underwent cardiovascular magnetic resonance (CMR) in the sub-acute phase to assess infarct transmurality. Infarction was considered as transmural if mean infarct transmurality exceeded >75%. IRA patency was defined as TIMI flow 2 or 3 on the initial angiogram.ResultsPatent IRA at baseline was found in 23 patients (37%) and was related to lower infarct transmurality in comparison to IRA occlusion (46.9 ± 27.3% vs. 82.4 ± 21.3%, p < 0.0001). Patients were divided into three groups according to time-to-PCI (≤2 h, >2–6 h, >6–12 h). Infarct transmurality increased with increasing time-to-PCI in patients with occluded IRA on the initial angiogram (p = 0.0006), but not in patients with initially patent IRA (p = 0.07). Similarly, the frequency of transmural infarctions increased with longer time-to-PCI in patients with occluded IRA (p = 0.01), but not in patients with initially patent IRA (p = 0.12).ConclusionsCardiovascular magnetic resonance demonstrated the relation between initial IRA patency in STEMI and time-dependant infarct transmurality. After 6–12 h from the onset of symptoms transmural infarctions were found in all patients with initially occluded IRA and only in about a third of patients with initially patent IRA.