Occlusion myocardial infarction in type I NSTEMI: prevalence, characteristics, management, and long-term outcome

The prevalence, characteristics, management, and long-term outcome of patients with non-ST-segment elevation myocardial infarction (NSTEMI) due to a completely occluded culprit coronary artery (NSTEMI-OMI) remain insufficiently characterised.

In this international multicentre study, consecutive patients with centrally adjudicated type I NSTEMI were classified as NSTEMI-OMI if they had a TIMI flow grade of 0 or 1 or grade 2 with severe coronary narrowing (> 70%) and a high-sensitivity cardiac troponin T (hs-cTnT) ≥ 500 ng/L. Prospectively recorded chest pain characteristics, 12-lead ECG, serial hs-cTnT concentrations, time to coronary angiography/revascularisation, and 5-year mortality were compared in patients with NSTEMI-OMI versus other type I NSTEMI (NSTEMI-NOMI).

Among 801 patients with type I NSTEMI (median age 68 years, 22.2% female), 251 patients (31.3%) had NSTEMI-OMI. Patients with NSTEMI-OMI presented more often with persistent chest pain (56.1% vs. 37.9%, p < 0.001), more often had ST-segment depression (34.3% vs. 23.0%, p < 0.001), and exhibited higher and faster rising hs-cTnT concentrations. Time from admission to coronary angiography (median 7.2 h [IQR 4.7, 21.8] vs. 19.6 h [IQR 6.2, 27.9], p < 0.001) and coronary revascularisation (median 8.2 h [IQR 4.9, 24.0] vs. 22.0 h [IQR 6.3, 46.1], p < 0.001) were both significantly shorter in patients with NSTEMI-OMI versus NSTEMI-NOMI. Five-year mortality was comparable in patients with NSTEMI-OMI versus NSTEMI-NOMI (adjHR 1.13 [95% CI 0.78-1.63], p = 0.51).

One in three patients with type I NSTEMI had NSTEMI-OMI. These patients more often present with very high-risk clinical, ECG, and biomarker features and receive earlier invasive management. Likely related to the latter, 5-year mortality was similar between NSTEMI-OMI and NSTEMI-NOMI.