OCT-based comparative evaluation of culprit lesion morphology in very young versus older adult patients with STEMI.

Background: The clinical and pathophysiological characteristics of coronary artery disease in very young adults are poorly described. Aims: Using optical coherence tomography (OCT), we compared culprit lesion morphology in very young adult patients (≤35 years) versus older adult patients (>60 years) with ST-segment elevation myocardial infarction (STEMI). Methods: Culprit lesion morphology was classified as plaque rupture, plaque erosion, or calcified nodule. Thrombus age was subclassified into acute (intraluminal thrombus with surface irregularity) or subacute (mostly mural thrombus with a smooth surface). Results: A total of 61 patients who underwent thrombolysis within 24 hours from symptom onset were included, with 38 (59.7%) subjects ≤35 years and 23 (40.3%) subjects >60 years of age. As an underlying mechanism of STEMI thrombosis, plaque erosion was more common in very young patients (52.6% vs 21.7%; p=0.02) while plaque rupture was more common in elderly patients (65.2% vs 36.8%; p=0.03). Acute or subacute thrombus was identified in 68.9% (42/61) of patients, with red thrombus being more frequent in very young patients. In the entire patient cohort, acute thrombus was more frequent in plaque rupture compared with plaque erosion (62.0% vs 28.0%; p=0.01), whereas subacute thrombus was more common in plaque erosion versus plaque rupture (52.0% vs 10.3%; p=0.0008). Conclusions: OCT showed that plaque erosion and plaque rupture were the most common underlying STEMI mechanisms in very young patients and older patients, respectively, and that subjects with plaque erosion had greater evidence of subacute thrombus.